TOP245R [POWERINT]
Family Extended Power, Design Flexible,Integrated Off-line Switcher; 家庭扩展的电源，设计灵活，集成离线式开关
| 型号： | TOP245R |
| 厂家： | 
Power Integrations |
| 描述： | Family Extended Power, Design Flexible,Integrated Off-line Switcher |
| 文件： | 总48页 (文件大小：768K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
®
TOP242-249
®
TOPSwitch -GX Family
Extended Power, Design Flexible,
EcoSmart®, IntegratedOff-line Switcher
Product Highlights
+
Lower System Cost, High Design Flexibility
AC
IN
DC
OUT
• Extended power range to 250 W
-
• Features eliminate or reduce cost of external components
• Fully integrated soft-start for minimum stress/overshoot
• Externally programmable accurate current limit
D
S
L
• Wider duty cycle for more power, smaller input capacitor
CONTROL
C
• Separate line sense and current limit pins on Y/R packages
• Line under-voltage (UV) detection: no turn off glitches
• Line overvoltage (OV) shutdown extends line surge limit
TOPSwitch-GX
X
F
• Line feed forward with maximum duty cycle (DCMAX
reduction rejects line ripple and limits DCMAX at high line
• Frequency jittering reduces EMI and EMI filtering costs
• Regulates to zero load without dummy loading
)
PI-2632-060200
Figure 1. Typical Flyback Application.
• 132 kHz frequency reduces transformer/power supply size
• HalffrequencyoptioninY/Rpackagesforvideoapplications
• Hysteretic thermal shutdown for automatic fault recovery
• Large thermal hysteresis prevents PC board overheating
OUTPUT POWER TABLE
230 VAC 15%4
85-265 VAC
PRODUCT3
Open
Open
Adapter1
Adapter1
Frame2
Frame2
EcoSmart - Energy Efficient
TOP242 P or G
TOP242 R
9 W
10 W
10 W
15 W
22 W
22 W
6.5 W
7 W
7 W
10 W
14 W
14 W
• Extremely low consumption in remote off mode
(80 mW @ 110 VAC, 160 mW @ 230 VAC)
• Frequency lowered with load for high standby efficiency
• Allows shutdown/wake-up via LAN/input port
TOP242 Y
TOP243 P or G
TOP243 R
13 W
20 W
13 W
25 W
43 W
45 W
9 W
15 W
15 W
15 W
23 W
30 W
TOP243 Y
Description
TOP244 P or G
TOP244 R
16 W
28 W
30 W
30 W
52 W
65 W
11 W
18 W
20 W
20 W
28 W
45 W
TOPSwitch-GX uses the same proven topology as TOPSwitch,
cost effectively integrating the high voltage power MOSFET,
PWM control, fault protection and other control circuitry onto
a single CMOS chip. Many new functions are integrated to
reduce system cost and improve design flexibility, performance
and energy efficiency.
TOP244 Y
TOP245 R
TOP245 Y
33 W
40 W
58 W
85 W
20 W
26 W
32 W
60 W
TOP246 R
TOP246 Y
37 W
60 W
65 W
125 W
24 W
40 W
36 W
90 W
Depending on package type, the TOPSwitch-GX family has
either1or3additionalpinsoverthestandardDRAIN,SOURCE
and CONTROL terminals. allowing the following functions:
line sensing (OV/UV, line feedforward/DC max reduction),
accurate externally set current limit, remote on/off, and
synchronization to an external lower frequency and frequency
selection (132 kHz/66 kHz).
TOP247 R
TOP247 Y
41 W
85 W
73 W
165 W
26 W
55 W
43 W
125 W
TOP248 R
TOP248 Y
43 W
78 W
28 W
70 W
48 W
155 W
105 W 205 W
45 W 82 W
120 W 250 W
TOP249 R
TOP249 Y
30 W
80 W
52 W
180 W
All package types provide the following transparent features:
Soft-start, 132kHzswitchingfrequency(automaticallyreduced
Table 1. Notes: 1. Typical continuous power in a non-ventilated
enclosed adapter measured at 50 °C ambient. Assumes 1 sq. in. of
2 oz. copper heat sink area for R package. 2. Maximum practical
continuous power in an open frame design at 50 °C ambient. See
Key Applications for detailed conditions. Assumes 3 sq. in. of 2 oz.
copper heat sink area for R package. 3. See Part Ordering Information.
4. 230 VAC or 100/115 VAC with doubler.
at light load), frequency jittering for lower EMI, wider DCMAX
,
hysteretic thermal shutdown and larger creepage packages. In
addition, all critical parameters (i.e. current limit, frequency,
PWM gain) have tighter temperature and absolute tolerance, to
simplify design and optimize system cost.
July 2001
TOP242-249
Section List
Functional Block Diagram ......................................................................................................................................... 3
Pin Functional Description........................................................................................................................................ 4
TOPSwitch-GX Family Functional Description ........................................................................................................ 5
CONTROL (C) Pin Operation ................................................................................................................................. 6
Oscillator and Switching Frequency ....................................................................................................................... 6
Pulse Width Modulator and Maximum Duty Cycle ................................................................................................. 7
Light Load Frequency Reduction............................................................................................................................ 7
Error Amplifier ......................................................................................................................................................... 7
On-chip Current Limit with External Programmability ............................................................................................. 7
Line Under-Voltage Detection (UV) ........................................................................................................................ 8
Line Overvoltage Shutdown (OV) ........................................................................................................................... 8
Line Feed Forward with DCMAX Reduction .............................................................................................................. 8
Remote ON/OFF and Synchronization ................................................................................................................... 9
Soft-Start ................................................................................................................................................................ 9
Shutdown/Auto-Restart .......................................................................................................................................... 9
Hysteretic Over-Temperature Protection ................................................................................................................ 9
Bandgap Reference................................................................................................................................................ 9
High-Voltage Bias Current Source........................................................................................................................ 10
Using Feature Pins.................................................................................................................................................... 11
FREQUENCY (F) Pin Operation........................................................................................................................... 11
LINE-SENSE (L) Pin Operation ............................................................................................................................ 11
EXTERNAL CURRENT LIMIT (X) Pin Operation ................................................................................................. 11
MULTI-FUNCTION (M) Pin Operation .................................................................................................................. 12
Typical Uses of FREQUENCY (F) Pin ...................................................................................................................... 15
Typical Uses of LINE-SENSE (L) and EXTERNAL CURRENT LIMIT (X) Pins....................................................... 16
Typical Uses of MULTI-FUNCTION (M) Pin ............................................................................................................. 19
Application Examples ............................................................................................................................................... 21
A High Efficiency, 30 W, Universal Input Power Supply........................................................................................ 21
A High Efficiency, Enclosed, 70 W, Universal Adapter Supply.............................................................................. 22
A High Efficiency, 250 W, 250 - 380 VDC Input Power Supply ............................................................................. 23
Multiple Output, 60 W, 185 - 265 VAC Input Power Supply.................................................................................. 24
Processor Controlled Supply Turn On/Off ............................................................................................................ 25
Key Application Considerations .............................................................................................................................. 27
TOPSwitch-II vs. TOPSwitch-GX.......................................................................................................................... 27
TOPSwitch-FX vs. TOPSwitch-GX ....................................................................................................................... 28
TOPSwitch-GX Design Considerations ................................................................................................................ 29
TOPSwitch-GX Layout Considerations................................................................................................................. 31
Quick Design Checklist......................................................................................................................................... 31
Design Tools ......................................................................................................................................................... 33
Product Specifications and Test Conditions .......................................................................................................... 34
Typical Performance Characteristics ...................................................................................................................... 41
Part Ordering Information ........................................................................................................................................ 45
Package Outlines ...................................................................................................................................................... 45
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TOP242-249
V
C
0
1
DRAIN (D)
CONTROL (C)
Z
C
INTERNAL
SUPPLY
SHUNT REGULATOR/
ERROR AMPLIFIER
+
-
SOFT START
5.8 V
4.8 V
-
5.8 V
+
INTERNAL UV
COMPARATOR
I
FB
V
I (LIMIT)
CURRENT
LIMIT
ADJUST
SOFT
START
-
÷ 8
ON/OFF
+
V
+ V
T
BG
SHUTDOWN/
AUTO-RESTART
CURRENT LIMIT
COMPARATOR
EXTERNAL
CURRENT LIMIT (X)
HYSTERETIC
THERMAL
STOP LOGIC
SHUTDOWN
1 V
LINE-SENSE (L)
CONTROLLED
TURN-ON
V
BG
GATE DRIVER
STOP SOFT-
OV/UV
START
D
LINE
SENSE
MAX
DC
MAX
DC
MAX
CLOCK
SAW
S
R
Q
HALF
FREQ.
-
LEADING
EDGE
BLANKING
FREQUENCY (F)
+
OSCILLATOR WITH JITTER
PWM
COMPARATOR
LIGHT LOAD
FREQUENCY
REDUCTION
R
E
SOURCE (S)
PI-2639-060600
Figure 2a. Functional Block Diagram (Y or R Package).
V
C
0
1
CONTROL (C)
DRAIN (D)
Z
C
INTERNAL
SUPPLY
SHUNT REGULATOR/
ERROR AMPLIFIER
+
-
SOFT START
5.8 V
4.8 V
-
5.8 V
+
INTERNAL UV
COMPARATOR
I
FB
V
I (LIMIT)
CURRENT
LIMIT
ADJUST
SOFT
START
-
÷ 8
ON/OFF
+
SHUTDOWN/
AUTO-RESTART
CURRENT LIMIT
COMPARATOR
V
+ V
T
BG
V
STOP LOGIC
HYSTERETIC
THERMAL
SHUTDOWN
MULTI-
FUNCTION (M)
CONTROLLED
TURN-ON
GATE DRIVER
BG
STOP SOFT-
OV/UV
DC
START
D
LINE
SENSE
MAX
DC
MAX
MAX
CLOCK
SAW
S
R
Q
-
LEADING
EDGE
BLANKING
+
OSCILLATOR WITH JITTER
PWM
COMPARATOR
LIGHT LOAD
FREQUENCY
REDUCTION
R
E
SOURCE (S)
PI-2641-061200
Figure 2b. Functional Block Diagram (P or G Package).
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TOP242-249
connected to SOURCE pin and 66 kHz if connected to
CONTROL pin. The switching frequency is internally set for
fixed 132 kHz operation in P and G packages.
Pin Functional Description
DRAIN (D) Pin:
High voltage power MOSFET drain output. The internal start-
up bias current is drawn from this pin through a switched high-
voltage current source. Internal current limit sense point for
drain current.
SOURCE (S) Pin:
Output MOSFET source connection for high voltage power
return. Primary side control circuit common and reference point.
CONTROL (C) Pin:
VUV = IUV x RLS
VOV = IOV x RLS
+
Error amplifier and feedback current input pin for duty cycle
control. Internal shunt regulator connection to provide internal
bias current during normal operation. It is also used as the
connection point for the supply bypass and auto-restart/
compensation capacitor.
For RLS = 2 MΩ
2 MΩ
RLS
VUV = 100 VDC
OV = 450 VDC
V
DC
Input
Voltage
DCMAX@100 VDC = 78%
DCMAX@375 VDC = 38%
D
S
L
CONTROL
LINE-SENSE (L) Pin: (Y or R package only)
C
Input pin for OV, UV, line feed forward with DCMAX reduction,
remoteON/OFFandsynchronization. AconnectiontoSOURCE
pin disables all functions on this pin.
For RIL = 12 kΩ
LIMIT = 69%
I
X
See fig. 55 for other
resistor values (RIL)
to select different ILIMIT
RIL
12 kΩ
-
EXTERNAL CURRENT LIMIT (X) Pin: (Y or R package only)
Input pin for external current limit adjustment, remote
ON/OFF, and synchronization. A connection to SOURCE pin
disables all functions on this pin.
values
PI-2629-040501
Figure 4. Y/R Package Line Sense and Externally Set Current
Limit.
MULTI-FUNCTION (M) Pin: (P or G package only)
This pin combines the functions of the LINE-SENSE (L) and
EXTERNAL CURRENT LIMIT (X) pins of the Y package into
one pin. Input pin for OV, UV, line feed forward with DCMAX
reduction, external current limit adjustment, remote ON/OFF
and synchronization. A connection to SOURCE pin disables all
functions on this pin and makes TOPSwitch-GX operate in
simple three terminal mode (like TOPSwitch-II).
+
VUV = IUV x RLS
VOV = IOV x RLS
For RLS = 2 MΩ
RLS
2 MΩ
V
V
UV = 100 VDC
OV = 450 VDC
DC
Input
Voltage
DCMAX@100 VDC = 78%
DCMAX@375 VDC = 38%
D
S
M
CONTROL
C
FREQUENCY (F) Pin: (Y or R package only)
Input pin for selecting switching frequency: 132 kHz if
-
Y Package (TO-220-7C)
PI-2509-040501
Tab Internally
Connected to
SOURCE Pin
7
D
Figure 5. P/G Package Line Sense.
5
4
3
2
1
F
S
X
L
C
+
For RIL = 12 kΩ
ILIMIT = 69%
R Package
(TO-263-7C)
For RIL = 25 kΩ
P Package (DIP-8B)
G Package (SMD-8B)
ILIMIT = 43%
DC
Input
Voltage
See fig. 55 for other
resistor values (RIL)
to select different
M
S
S
S
1
2
8
7
D
S
M
I
LIMIT values
CONTROL
C
RIL
S
C
3
4
5
-
D
1 2 3 4 5
C L X S F
7
D
PI-2517-040501
PI-2724-033001
Figure 3. Pin Configuration (top view).
Figure 6. P/G Package Externally Set Current Limit.
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TOP242-249
TOPSwitch-GX Family Functional Description
Like TOPSwitch, TOPSwitch-GX is an integrated switched
Auto-restart
ICD1
mode power supply chip that converts a current at the control
input to a duty cycle at the open drain output of a high voltage
powerMOSFET. Duringnormaloperationthedutycycleofthe
powerMOSFETdecreaseslinearlywithincreasingCONTROL
pin current as shown in Figure 7.
IB
I
= 125 µA
L
132
I
< I
L(DC)
L
I
= 190 µA
L
InadditiontothethreeterminalTOPSwitchfeatures,suchasthe
high voltage start-up, the cycle-by-cycle current limiting, loop
compensation circuitry, auto-restart, thermal shutdown, the
TOPSwitch-GX incorporates many additional functions that
reduce system cost, increase power supply performance and
design flexibility. A patented high voltage CMOS technology
allows both the high voltage power MOSFET and all the low
voltage control circuitry to be cost effectively integrated onto a
single monolithic chip.
30
IC (mA)
Auto-restart
ICD1
IB
Three terminals, FREQUENCY, LINE-SENSE, and
EXTERNAL CURRENT LIMIT (available in Y or R package)
or one terminal MULTI-FUNCTION (available in P or G
Package) have been added to implement some of the new
functions. These terminals can be connected to the SOURCE
pin to operate the TOPSwitch-GX in a TOPSwitch-like three
terminal mode. However, even in this three terminal mode, the
TOPSwitch-GX offers many new transparent features that do
not require any external components:
78
Slope = PWM Gain
I
= 125 µA
L
38
10
I
< I
L(DC)
L
I
= 190 µA
L
TOP242/5 1.6 2.0
TOP246/9 2.2 2.6
5.2 6.0
5.8 6.6
1. A fully integrated 10 ms soft-start limits peak currents and
voltages during start-up and dramatically reduces or
eliminates output overshoot in most applications.
2. DCMAX of 78% allows smaller input storage capacitor, lower
input voltage requirement and/or higher power capability.
3. Frequency reduction at light loads lowers the switching
losses and maintains good cross regulation in multiple
output supplies.
4. Higher switching frequency of 132 kHz reduces the
transformer size with no noticeable impact on EMI.
5. Frequency jittering reduces EMI.
6. Hysteretic over-temperature shutdown ensures automatic
recoveryfromthermalfault.Largehysteresispreventscircuit
board overheating.
IC (mA)
Note: For P and G packages IL is replaced with IM.
PI-2633-060500
Figure 7. Relationship of Duty Cycle and Frequency to CONTROL
Pin Current.
The pin can also be used as a remote ON/OFF and a
synchronization input.
The EXTERNAL CURRENT LIMIT (X) pin is usually used to
reducethecurrentlimitexternallytoavalueclosetotheoperating
peak current, by connecting the pin to SOURCE through a
resistor. This pin can also be used as a remote ON/OFF and a
synchronization input in both modes. See Table 2 and Figure 11.
7. Packages with omitted pins and lead forming provide large
drain creepage distance.
For the P or G packages the LINE-SENSE and EXTERNAL
CURRENTLIMITpinfunctionsarecombinedononeMULTI-
FUNCTION (M) pin. However, some of the functions become
mutually exclusive as shown in Table 3.
8. Tighter absolute tolerances and smaller temperature vari-
ations on switching frequency, current limit and PWM gain.
The LINE-SENSE (L) pin is usually used for line sensing by
connecting a resistor from this pin to the rectified DC high
voltage bus to implement line overvoltage (OV), under-voltage
(UV) and line feed forward with DCMAX reduction. In this
mode,thevalueoftheresistordeterminestheOV/UVthresholds
and the DCMAX is reduced linearly starting from a line voltage
above the under-voltage threshold. See Table 2 and Figure 11.
The FREQUENCY (F) pin in the Y or R package sets the
switching frequency to the default value of 132 kHz when
connected to SOURCE pin. A half frequency option of 66 kHz
can be chosen by connecting this pin to CONTROL pin instead.
Leaving this pin open is not recommended.
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TOP242-249
CONTROL (C) Pin Operation
in excess of the consumption of the chip is shunted to SOURCE
through resistor RE as shown in Figure 2. This current flowing
through RE controls the duty cycle of the power MOSFET to
provide closed loop regulation. The shunt regulator has a finite
low output impedance ZC that sets the gain of the error amplifier
when used in a primary feedback configuration. The dynamic
impedance ZC of the CONTROL pin together with the external
CONTROL pin capacitance sets the dominant pole for the
control loop.
The CONTROL pin is a low impedance node that is capable of
receiving a combined supply and feedback current. During
normal operation, a shunt regulator is used to separate the
feedback signal from the supply current. CONTROL pin
voltage VC is the supply voltage for the control circuitry
includingtheMOSFETgatedriver. Anexternalbypasscapacitor
closely connected between the CONTROL and SOURCE pins
is required to supply the instantaneous gate drive current. The
total amount of capacitance connected to this pin also sets the
auto-restart timing as well as control loop compensation.
When a fault condition such as an open loop or shorted output
preventstheflowofanexternalcurrentintotheCONTROLpin,
the capacitor on the CONTROL pin discharges towards 4.8 V.
At 4.8 V, auto-restart is activated which turns the output
MOSFET off and puts the control circuitry in a low current
standby mode. The high-voltage current source turns on and
charges the external capacitance again. A hysteretic internal
supply under-voltage comparator keeps VC within a window of
typically4.8to5.8Vbyturningthehigh-voltagecurrentsource
on and off as shown in Figure 8. The auto-restart circuit has a
divide-by-8 counter which prevents the output MOSFET from
turningonagainuntileightdischarge/chargecycleshaveelapsed.
This is accomplished by enabling the output MOSFET only
when the divide-by-8 counter reaches full count (S7). The
counter effectively limits TOPSwitch-GX power dissipation by
reducing the auto-restart duty cycle to typically 4%. Auto-
restart mode continues until output voltage regulation is again
achieved through closure of the feedback loop.
When rectified DC high voltage is applied to the DRAIN pin
duringstart-up,theMOSFETisinitiallyoff,andtheCONTROL
pincapacitorischargedthroughaswitchedhighvoltagecurrent
sourceconnectedinternallybetweentheDRAINandCONTROL
pins. When the CONTROL pin voltage VC reaches
approximately 5.8 V, the control circuitry is activated and the
soft-start begins. The soft-start circuit gradually increases the
duty cycle of the MOSFET from zero to the maximum value
over approximately 10 ms. If no external feedback/supply
currentisfedintotheCONTROLpinbytheendofthesoft-start,
thehighvoltagecurrentsourceisturnedoffandtheCONTROL
pin will start discharging in response to the supply current
drawn by the control circuitry. If the power supply is designed
properly, and no fault condition such as open loop or shorted
output exists, the feedback loop will close, providing external
CONTROL pin current, before the CONTROL pin voltage has
had a chance to discharge to the lower threshold voltage of
approximately 4.8 V (internal supply under-voltage lockout
threshold). When the externally fed current charges the
CONTROL pin to the shunt regulator voltage of 5.8 V, current
Oscillator and Switching Frequency
Theinternaloscillatorlinearlychargesanddischargesaninternal
capacitance between two voltage levels to create a sawtooth
VUV
VLINE
0 V
S0
S0
S7
S1
S2
S6
S7 S0
S1
S2
S6
S7
S1 S2
S6
S7
S7
5.8 V
4.8 V
VC
0 V
VDRAIN
0 V
VOUT
0 V
1
2
3
2
4
Note: S0 through S7 are the output states of the auto-restart counter
PI-2545-082299
Figure 8. Typical Waveforms for (1) Power Up (2) Normal Operation (3) Auto-restart (4) Power Down.
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TOP242-249
waveform for the pulse width modulator. This oscillator sets
the pulse width modulator/current limit latch at the beginning
of each cycle.
136 kHz
Switching
Frequency
128 kHz
The nominal switching frequency of 132 kHz was chosen to
minimize transformer size while keeping the fundamental EMI
frequency below 150 kHz. The FREQUENCY pin (available
only in Y or R package), when shorted to the CONTROL pin,
lowers the switching frequency to 66 kHz (half frequency)
which may be preferable in some cases such as noise sensitive
videoapplicationsorahighefficiencystandbymode. Otherwise,
theFREQUENCYpinshouldbeconnectedtotheSOURCEpin
for the default 132 kHz.
4 ms
VDRAIN
Time
Figure 9. Switching Frequency Jitter. (Idealized VDRAIN waveform)
To further reduce the EMI level, the switching frequency is
jittered (frequency modulated) by approximately 4 kHz at
250 Hz (typical) rate as shown in Figure 9. Figure 46 shows the
typical improvement of EMI measurements with frequency
jitter.
cycle of 0% (refer to Figure 7). The minimum frequency is
typically30kHzand15kHzfor132kHzand66kHzoperation,
respectively.
Thisfeatureallowsapowersupplytooperateatlowerfrequency
at light loads thus lowering the switching losses while
maintaining good cross regulation performance and low output
ripple.
Pulse Width Modulator and Maximum Duty Cycle
The pulse width modulator implements voltage mode control
by driving the output MOSFET with a duty cycle inversely
proportional to the current into the CONTROL pin that is in
excess of the internal supply current of the chip (see Figure 7).
The excess current is the feedback error signal that appears
across RE (see Figure 2). This signal is filtered by an RC
network with a typical corner frequency of 7 kHz to reduce the
effectofswitchingnoiseinthechipsupplycurrentgeneratedby
the MOSFET gate driver. The filtered error signal is compared
with the internal oscillator sawtooth waveform to generate the
dutycyclewaveform. Asthecontrolcurrentincreases, theduty
cycle decreases. A clock signal from the oscillator sets a latch
whichturnsontheoutputMOSFET. Thepulsewidthmodulator
resets the latch, turning off the output MOSFET. Note that a
minimum current must be driven into the CONTROL pin
before the duty cycle begins to change.
Error Amplifier
The shunt regulator can also perform the function of an error
amplifier in primary side feedback applications. The shunt
regulator voltage is accurately derived from a temperature-
compensatedbandgapreference. Thegainoftheerroramplifier
is set by the CONTROL pin dynamic impedance. The
CONTROL pin clamps external circuit signals to the VC
voltage level. The CONTROL pin current in excess of the
supply current is separated by the shunt regulator and flows
through RE as a voltage error signal.
On-chip Current Limit with External Programmability
The cycle-by-cycle peak drain current limit circuit uses the
output MOSFET ON-resistance as a sense resistor. A current
limit comparator compares the output MOSFET on-state drain
to source voltage, VDS(ON) with a threshold voltage. High drain
current causes VDS(ON) to exceed the threshold voltage and turns
the output MOSFET off until the start of the next clock cycle.
The current limit comparator threshold voltage is temperature
compensated to minimize the variation of the current limit due
totemperaturerelatedchangesin RDS(ON)oftheoutputMOSFET.
The default current limit of TOPSwitch-GX is preset internally.
However, with a resistor connected between EXTERNAL
CURRENT LIMIT (X) pin (Y or R package) or MULTI-
FUNCTION (M) pin (P or G package) and SOURCE pin,
current limit can be programmed externally to a lower level
between 30% and 100% of the default current limit. Please
refer to the graphs in the typical performance characteristics
section for the selection of the resistor value. By setting current
limit low, a larger TOPSwitch-GXthan necessary for the power
required can be used to take advantage of the lower RDS(ON) for
higher efficiency/smaller heat sinking requirements. With a
The maximum duty cycle, DCMAX,is set at a default maximum
value of 78% (typical). However, by connecting the LINE-
SENSEorMULTI-FUNCTIONpin(dependingonthepackage)
to the rectified DC high voltage bus through a resistor with
appropriate value, the maximum duty cycle can be made to
decreasefrom78%to38%(typical)asshowninFigure11when
input line voltage increases (see line feed forward with DCMAX
reduction).
Light Load Frequency Reduction
The pulse width modulator duty cycle reduces as the load at the
power supply output decreases. This reduction in duty cycle is
proportional to the current flowing into the CONTROL pin. As
the CONTROL pin current increases, the duty cycle decreases
linearly towards a duty cycle of 10%. Below 10% duty cycle, to
maintain high efficiency at light loads, the frequency is also
reducedlinearlyuntilaminimumfrequencyisreachedataduty
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7
TOP242-249
secondresistorconnectedbetweentheEXTERNAL CURRENT
LIMIT (X) pin (Y or R package) or MULTI-FUNCTION (M)
pin (P or G package) and the rectified DC high voltage bus, the
current limit is reduced with increasing line voltage, allowing
a true power limiting operation against line variation to be
implemented. When using an RCD clamp, this power limiting
technique reduces maximum clamp voltage at high line. This
allows for higher reflected voltage designs as well as reducing
clamp dissipation.
40% of the initial UV threshold to allow extended input voltage
operating range (UV low threshold). If the UV low threshold
is reached during operation without the power supply losing
regulation the device will turn off and stay off until UV (high
threshold) has been reached again. If the power supply loses
regulation before reaching the UV low threshold, the device
will enter auto-restart. At the end ofeach auto-restart cycle (S7),
the UV comparator is enabled. If the UV high threshold is not
exceededtheMOSFETwillbedisabledduringthenextcycle(see
figure 8). The UV feature can be disabled independent of OV
feature as shown in Figure 19 and 23.
The leading edge blanking circuit inhibits the current limit
comparator for a short time after the output MOSFET is turned
on. The leading edge blanking time has been set so that, if a
power supply is designed properly, current spikes caused by
primary-side capacitances and secondary-side rectifier reverse
recovery time should not cause premature termination of the
switching pulse.
Line Overvoltage Shutdown (OV)
ThesameresistorusedforUValsosetsanovervoltagethreshold
which, once exceeded, will force TOPSwitch-GX output into
off-state. The ratio of OV and UV thresholds is preset at 4.5 as
canbeseeninFigure11. WhentheMOSFETisoff,therectified
DC high voltage surge capability is increased to the voltage
rating of the MOSFET (700 V), due to the absence of the
reflected voltage and leakage spikes on the drain. A small
amountofhysteresisisprovidedontheOVthresholdtoprevent
noise triggering. The OV feature can be disabled independent
of the UV feature as shown in Figure 18 and 32.
The current limit is lower for a short period after the leading
edge blanking time as shown in Figure 52. This is due to
dynamic characteristics of the MOSFET. To avoid triggering
thecurrentlimitinnormaloperation,thedraincurrentwaveform
should stay within the envelope shown.
Line Under-Voltage Detection (UV)
Line Feed Forward with DCMAX Reduction
At power up, UV keeps TOPSwitch-GX off until the input line
voltage reaches the under voltage threshold. At power down,
UV prevents auto-restart attempts after the output goes out of
regulation. This eliminates power down glitches caused by the
slow discharge of large input storage capacitor present in
applicationssuchasstandbysupplies.Asingleresistorconnected
from the LINE-SENSE pin (Y or R package) or MULTI-
FUNCTION pin (P or G package) to the rectified DC high
voltagebussetsUVthresholdduringpowerup. Oncethepower
supply is successfully turned on, the UV threshold is lowered to
The same resistor used for UV and OV also implements line
voltage feed forward which minimizes output line ripple and
reduces power supply output sensitivity to line transients. This
feed forward operation is illustrated in Figure 7 by the different
values of IL (Y or R package) or IM (P or G Package). Note that
for the same CONTROL pin current, higher line voltage results
in smaller operating duty cycle. As an added feature, the
maximumdutycycleDCMAX isalsoreducedfrom78%(typical)
at a voltage slightly higher than the UV threshold to 38%
(typical) at the OV threshold (see Figures 7, 11). Limiting
Oscillator
(SAW)
D
MAX
Enable from
X, L or M Pin (STOP)
Time
PI-2637-060600
Figure 10. Synchronization Timing Diagram.
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7/01
8
TOP242-249
DCMAX at higher line voltages helps prevent transformer
saturation due to large load transients in forward converter
applications. DCMAX of 38% at the OV threshold was chosen to
ensure that the power capability of the TOPSwitch-GX is not
restricted by this feature under normal operation.
open). When the TOPSwitch-GX is remotely turned on after
entering this mode, it will initiate a normal start-up sequence
with soft-start the next time the CONTROL pin reaches 5.8 V.
In the worst case, the delay from remote on to start-up can be
equal to the full discharge/charge cycle time of the CONTROL
pin, which is approximately 125 ms for a 47 µF CONTROL pin
capacitor. This reduced consumption remote off mode can
eliminateexpensiveandunreliablein-linemechanicalswitches.
It also allows for microprocessor controlled turn-on and turn-
off sequences that may be required in certain applications such
as inkjet and laser printers.
Remote ON/OFF and Synchronization
TOPSwitch-GX can be turned on or off by controlling the
current into the LINE-SENSE pin or out from the EXTERNAL
CURRENT LIMIT pin (Y or R package) and into or out from
the MULTI-FUNCTION pin (P or G package) (see Figure 11).
Inaddition,theLINE-SENSEpinhasa1Vthresholdcomparator
connected at its input. This voltage threshold can also be used
to perform remote ON/OFF control. This allows easy
implementation of remote ON/OFF control of TOPSwitch-GX
in several different ways. A transistor or an optocoupler output
connected between the EXTERNAL CURRENT LIMIT or
LINE-SENSEpins(YorRpackage)ortheMULTI-FUNCTION
pin (P or G package) and the SOURCE pin implements this
function with “active-on” (Figure 22, 29 and 36) while a
transistor or an optocoupler output connected between the
LINE-SENSEpin(YorRpackage)ortheMULTI-FUNCTION
(P or G package) pin and the CONTROL pin implements the
function with “active-off” (Figure 23 and 37).
Soft-Start
Two on-chip soft-start functions are activated at start-up with a
duration of 10 ms (typical). Maximum duty cycle starts from
0% and linearly increases to the default maximum of 78% at the
end of the 10 ms duration and the current limit starts from about
85% and linearly increases to 100% at the end of the 10ms
duration. In addition to start-up, soft-start is also activated at
each restart attempt during auto-restart and when restarting
after being in hysteretic regulation of CONTROL pin voltage
(VC), due to remote off or thermal shutdown conditions. This
effectivelyminimizescurrentandvoltagestressesontheoutput
MOSFET,theclampcircuitandtheoutputrectifierduringstart-
up. This feature also helps minimize output overshoot and
prevents saturation of the transformer during start-up.
When a signal is received at the LINE-SENSE pin or the
EXTERNAL CURRENT LIMIT pin (Y or R package) or the
MULTI-FUNCTIONpin(PorGpackage)todisabletheoutput
through any of the pin functions such as OV, UV and remote
ON/OFF,TOPSwitch-GXalwayscompletesitscurrentswitching
cycle, as illustrated in Figure 10, before the output is forced off.
The internal oscillator is stopped slightly before the end of the
current cycle and stays there as long as the disable signal exists.
When the signal at the above pins changes state from disable to
enable, the internal oscillator starts the next switching cycle.
This approach allows the use of this pin to synchronize
TOPSwitch-GX to any external signal with a frequency lower
than its internal switching frequency.
Shutdown/Auto-Restart
To minimize TOPSwitch-GX power dissipation under fault
conditions, the shutdown/auto-restart circuit turns the power
supply on and off at an auto-restart duty cycle of typically 4%
if an out of regulation condition persists. Loss of regulation
interrupts the external current into the CONTROL pin. VC
regulation changes from shunt mode to the hysteretic auto-
restart mode as described in CONTROL pin operation section.
When the fault condition is removed, the power supply output
becomes regulated, VC regulation returns to shunt mode, and
normal operation of the power supply resumes.
As seen above, the remote ON/OFF feature allows the
TOPSwitch-GX to be turned on and off instantly, on a cycle-by-
cycle basis, with very little delay. However, remote ON/OFF
can also be used as a standby or power switch to turn off the
TOPSwitch-GX and keep it in a very low power consumption
state for indefinitely long periods. If the TOPSwitch-GXis held
inremoteoffstateforlongenoughtimetoallowtheCONTROL
pin to dishcharge to the internal supply under-voltage threshold
of 4.8 V (approximately 32 ms for a 47 µF CONTROL pin
capacitance), the CONTROL pin goes into the hysteretic mode
of regulation. In this mode, the CONTROL pin goes through
alternate charge and discharge cycles between 4.8 V and 5.8 V
(see CONTROL pin operation section above) and runs entirely
off the high voltage DC input, but with very low power
consumption (160 mW typical at 230 VAC with M or X pins
Hysteretic Over-Temperature Protection
Temperature protection is provided by a precision analog
circuit that turns the output MOSFET off when the junction
temperature exceeds the thermal shutdown temperature
(140°Ctypical). Whenthejunctiontemperaturecoolstobelow
thehysteretictemperature,normaloperationresumesproviding
automatic recovery. A large hysteresis of 70 °C (typical) is
provided to prevent overheating of the PC board due to a
continuous fault condition. VC is regulated in hysteretic mode
and a 4.8 V to 5.8 V (typical) sawtooth waveform is present on
the CONTROL pin while in thermal shutdown.
Bandgap Reference
All critical TOPSwitch-GX internal voltages are derived from a
temperature-compensatedbandgapreference. Thisreferenceis
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7/01
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TOP242-249
also used to generate a temperature-compensated current
reference which is trimmed to accurately set the switching
frequency, MOSFET gate drive current, current limit, and the
lineOV/UVthresholds. TOPSwitch-GXhasimprovedcircuitry
to maintain all of the above critical parameters within very tight
absolute and temperature tolerances.
High-Voltage Bias Current Source
ThiscurrentsourcebiasesTOPSwitch-GXfromtheDRAINpin
and charges the CONTROL pin external capacitance during
start-up or hysteretic operation. Hysteretic operation occurs
duringauto-restart,remoteoffandover-temperatureshutdown.
In this mode of operation, the current source is switched on and
off with an effective duty cycle of approximately 35%. This
duty cycle is determined by the ratio of CONTROL pin charge
(IC) and discharge currents (ICD1 and ICD2). This current source
isturnedoffduringnormaloperationwhentheoutputMOSFET
is switching. The effect of the current source switching will be
seen on the DRAIN voltage waveform as small disturbances
and is normal.
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TOP242-249
Using Feature Pins
FREQUENCY (F) Pin Operation
RefertoTable2forpossiblecombinationsofthefunctionswith
example circuits shown in Figure 16 through Figure 40. A
description of specific functions in terms of the LINE-SENSE
pin I/V characteristic is shown in Figure 11 (right hand side).
The horizontal axis represents LINE-SENSE pin current with
positive polarity indicating currents flowing into the pin. The
meaning of the vertical axes varies with functions. For those
that control the on/off states of the output such as UV, OV and
remote ON/OFF, the vertical axis represents the enable/disable
states of the output. UV triggers at IUV (+50 µA typical with
30 µA hysteresis) and OV triggers at IOV (+225 µA typical with
8 µA hysteresis). Between the UV and OV thresholds, the
output is enabled. For line feed forward with DCMAX reduction,
the vertical axis represents the magnitude of the DCMAX. Line
feed forward with DC reduction lowers maximum duty cycle
from 78% at IL(DC) (+6M0AµXA typical) to 38% at IOV (+225 µA).
The FREQUENCY pin is a digital input pin available in the
Y or R package only. Shorting the FREQUENCY pin to
SOURCE pin selects the nominal switching frequency of
132 kHz (Figure 13) which is suited for most applications. For
other cases that may benefit from lower switching frequency
such as noise sensitive video applications, a 66 kHz switching
frequency (half frequency) can be selected by shorting the
FREQUENCY pin to the CONTROL pin (Figure 14). In
addition, an example circuit shown in Figure 15 may be used to
lower the switching frequency from 132 kHz in normal
operation to 66 kHz in standby mode for very low standby
power consumption.
LINE-SENSE (L) Pin Operation (Y and R Packages)
When current is fed into the LINE-SENSE pin, it works as a
voltage source of approximately 2.6 V up to a maximum
current of +400 µA (typical). At +400 µA, this pin turns into
a constant current sink. Refer to Figure 12a. In addition, a
comparator with a threshold of 1 V is connected at the pin and
is used to detect when the pin is shorted to the SOURCE pin.
EXTERNAL CURRENT LIMIT (X) Pin Operation
(Y and R Packages)
When current is drawn out of the EXTERNAL CURRENT
LIMIT pin, it works as a voltage source of approximately 1.3
V up to a maximum current of –240 µA (typical). At –240 µA,
it turns into a constant current source (refer to Figure 12a).
There are a total of four functions available through the use of
the LINE-SENSE pin: OV, UV, line feed forward with DCMAX
reduction,andremoteON/OFF. ConnectingtheLINE-SENSE
pin to the SOURCE pin disables all four functions. The LINE-
SENSE pin is typically used for line sensing by connecting a
resistor from this pin to the rectified DC high voltage bus to
implement OV, UV and DCMAX reduction with line voltage. In
this mode, the value of the resistor determines the line OV/UV
thresholds, andtheDCMAX isreducedlinearlywithrectifiedDC
highvoltagestartingfromjustabovetheUVthreshold. Thepin
canalsobeusedasaremoteon/offandasynchronizationinput.
There are two functions available through the use of the
EXTERNAL CURRENT LIMIT pin: external current limit
andremoteON/OFF. ConnectingtheEXTERNALCURRENT
LIMIT pin and SOURCE pin disables the two functions. In
high efficiency applications this pin can be used to reduce the
current limit externally to a value close to the operating peak
current, by connecting the pin to the SOURCE pin through a
resistor. The pin can also be used as a remote on/off. Table 2
shows several possible combinations using this pin. See Figure
LINE-SENSE AND EXTERNAL CURRENT LIMIT PIN TABLE*
Figure Number
16
17
18
19 20
21
22
23 24
25 26
27
28
29
✔
Three Terminal Operation
Under-Voltage
✔
✔
✔
✔
✔
✔
✔
✔
✔
✔
✔
✔
✔
Overvoltage
✔
Line Feed Forward (DCMAX
Overload Power Limiting
External Current Limit
Remote ON/OFF
)
✔
✔
✔
✔
✔
✔
✔
✔
✔
✔
✔
✔
✔
✔
*This table is only a partial list of many LINE-SENSE and EXTERNAL CURRENT LIMIT pin configurations that are possible.
Table 2. Typical LINE-SENSE and EXTERNAL CURRENT LIMIT Pin Configurations.
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TOP242-249
MULTI-FUNCTION PIN TABLE*
Figure Number
30
31
32
33
34
35
36
37
38
39
40
✔
Three Terminal Operation
Under-Voltage
✔
✔
✔
✔
✔
✔
✔
Overvoltage
✔
Line Feed Forward (DCMAX
Overload Power Limiting
External Current Limit
Remote ON/OFF
)
✔
✔
✔
✔
✔
✔
✔
✔
✔
✔
*This table is only a partial list of many MULTI-FUNCTION pin configurations that are possible.
Table 3. Typical MULTI-FUNCTION Pin Configurations.
11 for a description of the functions where the horizontal axis
(left hand side) represents the EXTERNAL CURRENT LIMIT
pin current. The meaning of the vertical axes varies with
function. For those that control the on/off states of the output
such as remote ON/OFF, the vertical axis represents the enable/
disable states of the output. For external current limit, the
vertical axis represents the magnitude of the ILIMIT. Please see
graphs in the typical performance characteristics section for the
current limit programming range and the selection of appropriate
resistor value.
TOPSwitch-GX to operate in a simple three terminal mode like
TOPSwitch-II. The MULTI-FUNCTION pin is typically used
for line sensing by connecting a resistor from this pin to the
rectifiedDChighvoltagebustoimplementOV, UVandDCMAX
reduction with line voltage. In this mode, the value of the
resistor determines the line OV/UV thresholds, and the DCMAX
is reduced linearly with rectified DC high voltage starting from
just above the UV threshold. In high efficiency applications
this pin can be used in the external current limit mode instead,
to reduce the current limit externally to a value close to the
operating peak current, by connecting the pin to the SOURCE
pinthrougharesistor. Thesamepincanalsobeusedasaremote
on/off and a synchronization input in both modes. Please refer
to Table 3 for possible combinations of the functions with
example circuits shown in Figure 30 through Figure 40. A
description of specific functions in terms of the MULTI-
FUNCTION pin I/V characteristic is shown in Figure 11. The
horizontal axis represents MULTI-FUNCTION pin current
with positive polarity indicating currents flowing into the pin.
The meaning of the vertical axes varies with functions. For
those that control the on/off states of the output such as UV, OV
and remote ON/OFF, the vertical axis represents the enable/
disable states of the output. UV triggers at IUV (+50 µA typical)
and OV triggers at IOV (+225 µA typical with 30 µA hysteresis).
Between the UV and OV thresholds, the output is enabled. For
external current limit and line feed forward with DCMAX
reduction, the vertical axis represents the magnitude of the ILIMIT
and DCMAX. Line feed forward with DCMAX reduction lowers
maximum duty cycle from 78% at IM(DC) (+60 µA typical) to 38%
at IOV (+225 µA). External current limit is available only with
negative MULTI-FUNCTION pin current. Please see graphs in
the typical performance characteristics section for the current
limit programming range and the selection of appropriate resistor
value.
MULTI-FUNCTION(M)PinOperation(PandGPackages)
The LINE-SENSE and EXTERNAL CURRENT LIMIT pin
functionsarecombinedtoasingleMULTI-FUNCTIONpinfor
P and G packages. The comparator with a 1 V threshold at the
LINE-SENSEpinisremovedinthiscaseasshowninFigure2b.
All of the other functions are kept intact. However, since some
of the functions require opposite polarity of input current
(MULTI-FUNCTION pin), they are mutually exclusive. For
example, line sensing features cannot be used simultaneously
with external current limit setting. When current is fed into the
MULTI-FUNCTION pin, it works as a voltage source of
approximately 2.6 V up to a maximum current of +400 µA
(typical). At+400µA,thispinturnsintoaconstantcurrentsink.
When current is drawn out of the MULTI-FUNCTION pin, it
works as a voltage source of approximately 1.3 V up to a
maximum current of –240 µA (typical). At –240 µA, it turns
into a constant current source. Refer to Figure 12b.
There are a total of five functions available through the use of
the MULTI-FUNCTION pin: OV, UV, line feed forward with
DCMAX reduction,externalcurrentlimitandremoteON/OFF. A
short circuit between the MULTI-FUNCTION pin and
SOURCE pin disables all five functions and forces
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TOP242-249
M Pin
X Pin
L Pin
IREM(N)
IUV
IOV
(Enabled)
(Disabled)
Output
MOSFET
Switching
Disabled when supply
output goes out of
regulation
I
ILIMIT (Default)
Current
Limit
I
DCMAX (78.5%)
Maximum
Duty Cycle
I
-22 µA
-27 µA
V
BG + VTP
VBG
Pin Voltage
I
-250
-200
-150
-100
-50
0
50
100
150
200
250
300
350
400
X and L Pins (Y or R Package) and M Pin (P or G Package) Current (µA)
Note: This figure provides idealized functional characteristics with typical performance values. Please refer to the parametric
table and typical performance characteristics sections of the data sheet for measured data.
PI-2636-040501
Figure 11. MULTI-FUNCTION (P or G package), LINE-SENSE, and EXTERNAL CURRENT LIMIT (Y or R package) Pin Characteristics.
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TOP242-249
Y and R Package
CONTROL Pin
TOPSwitch-GX
240 µA
(Negative Current Sense - ON/OFF,
Current Limit Adjustment)
VBG + VT
EXTERNAL CURRENT LIMIT (X)
LINE-SENSE (L)
(Voltage Sense)
1 V
VBG
(Positive Current Sense - Under-Voltage,
Overvoltage, ON/OFF Maximum Duty
Cycle Reduction)
400 µA
PI-2634-033001
Figure 12a. LINE-SENSE (L), and EXTERNAL CURRENT LIMIT (X) Pin Input Simplified Schematic.
P and G Package
CONTROL Pin
TOPSwitch-GX
240 µA
(Negative Current Sense - ON/OFF,
Current Limit Adjustment)
VBG + VT
MULTI-FUNCTION (M)
VBG
(Positive Current Sense - Under-Voltage,
Overvoltage, Maximum Duty
Cycle Reduction)
400 µA
PI-2548-092399
Figure 12b. MULTI-FUNCTION (M) Pin Input Simplified Schematic.
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TOP242-249
Typical Uses of FREQUENCY (F) Pin
+
+
DC
Input
DC
Input
Voltage
D
D
S
CONTROL
CONTROL
F
Voltage
C
C
S
F
-
-
PI-2655-071700
PI-2654-071700
Figure 13. Full Frequency Operation (132 kHz).
Figure 14. Half Frequency Operation (66 kHz).
+
QS can be an optocoupler output.
DC
Input
Voltage
D
S
CONTROL
C
STANDBY
F
47 kΩ
QS
RHF
20 kΩ
1 nF
-
PI-2656-040501
Figure 15. Half Frequency Standby Mode (For High Standby
Efficiency).
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15
TOP242-249
Typical Uses of LINE-SENSE (L) and EXTERNAL CURRENT LIMIT (X) Pins
+
+
VUV = IUV x RLS
VOV = IOV x RLS
For RLS = 2 MΩ
VUV = 100 VDC
RLS
2MΩ
C L
X
S
F
D
VOV = 450 VDC
DC
DC
Input
Voltage
Input
Voltage
DCMAX@100 VDC = 78%
DCMAX@375 VDC = 38%
D
S
L
D
S
L
C
S
D
CONTROL
CONTROL
C
C
X
F
-
-
PI-2618-040501
PI-2617-050100
Figure 17. Line-Sensing for Under-Voltage, Overvoltage and
Line Feed Forward.
Figure 16. Three Terminal Operation (LINE-SENSE and
EXTERNAL CURRENT LIMIT Features Disabled.
FREQUENCY Pin can be tied to SOURCE or
CONTROL Pin).
+
+
VUV = RLS x IUV
VOV = IOV x RLS
2 MΩ
2 MΩ
For Value Shown
VUV = 100 VDC
For Values Shown
VOV = 450 VDC
RLS
RLS
DC
Input
Voltage
DC
Input
Voltage
22 kΩ
30 kΩ
1N4148
D
L
D
S
M
CONTROL
CONTROL
C
C
6.2 V
S
-
-
PI-2620-040501
PI-2510-040501
Figure 19. Line-Sensing for Overvoltage Only (Under-Voltage
Disabled). Maximum Duty Cycle will be reduced at
Low Line.
Figure 18. Line-Sensing for Under-Voltage Only (Overvoltage
Disabled).
+
+
I
LIMIT = 100% @ 100 VDC
For RIL = 12 kΩ
ILIMIT
=
63% @ 300 VDC
ILIMIT = 69%
RLS
2.5 MΩ
For RIL = 25 kΩ
ILIMIT = 43%
See fig. 55 for other
DC
Input
Voltage
DC
D
S
D
resistor values (RIL)
Input
CONTROL
X
CONTROL
Voltage
C
C
S
X
RIL
RIL
6 kΩ
-
-
PI-2624-040501
PI-2623-040501
Figure 21. Current Limit Reduction with Line Voltage.
Figure 20. Externally Set Current Limit.
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TOP242-249
Typical Uses of LINE-SENSE (L) and EXTERNALCURRENT LIMIT (X) Pins (cont.)
QR can be an
optocoupler output or
can be replaced
+
+
QR can be an optocoupler
output or can be replaced by
a manual switch.
by a manual switch.
QR
ON/OFF
RMC
47 kΩ
DC
Input
Voltage
DC
Input
Voltage
D
S
45 kΩ
CONTROL
C
D
L
CONTROL
C
X
ON/OFF
QR
47 kΩ
S
-
-
PI-2621-040501
PI-2625-040501
Figure 23. Active-off Remote ON/OFF. Maximum Duty Cycle will
be reduced.
Figure 22. Active-on (Fail Safe) Remote ON/OFF.
QR can be an
+
+
QR can be an optocoupler
output or can be replaced
by a manual switch.
QR
optocoupler output
or can be replaced
by a manual switch.
ON/OFF
RMC
47 kΩ
For RIL =12 kΩ
45 kΩ
ILIMIT = 69 %
DC
Input
Voltage
DC
Input
Voltage
D
S
D
L
For RIL = 25 kΩ
CONTROL
CONTROL
ILIMIT = 43 %
C
C
X
S
X
RIL
RIL
ON/OFF
QR
-
47 kΩ
-
PI-2627-040501
PI-2626-040501
Figure 25. Active-off Remote ON/OFF with Externally Set Current
Limit.
Figure 24. Active-on Remote ON/OFF with Externally Set Current
Limit.
VUV = IUV x RLS
VOV = IOV x RLS
+
Q
R can be an optocoupler
+
output or can be replaced
by a manual switch.
RLS 2 MΩ
DCMAX@100 VDC = 78%
DCMAX@375 VDC = 38%
2 MΩ
RLS
QR
For RLS = 2 MΩ
ON/OFF
QR can be an optocoupler
output or can be replaced
by a manual switch.
47 kΩ
DC
Input
Voltage
VUV = 100 VDC
VOV = 450 VDC
D
S
L
CONTROL
DC
Input
Voltage
C
For RIL =12 kΩ
D
L
ILIMIT = 69 %
CONTROL
X
C
QR
RIL
ON/OFF
S
47 kΩ
-
-
PI-2628-040501
PI-2622-040501
Figure 27. Active-on Remote ON/OFF with LINE-SENSE and
EXTERNAL CURRENT LIMIT.
Figure 26. Active-off Remote ON/OFF with LINE-SENSE.
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TOP242-249
Typical Uses of LINE-SENSE (L) and EXTERNALCURRENT LIMIT (X) Pins (cont.)
VUV = IUV x RLS
VOV = IOV x RLS
+
+
QR can be an optocoupler
output or can be replaced by
a manual switch.
For RLS = 2 MΩ
2 MΩ
RLS
V
V
UV = 100 VDC
OV = 450 VDC
DC
Input
Voltage
DC
Input
Voltage
300 kΩ
DCMAX@100 VDC = 78%
DCMAX@375 VDC = 38%
D
S
L
D
S
L
CONTROL
CONTROL
C
C
For RIL = 12 kΩ
ILIMIT = 69%
X
See fig. 55 for other
resistor values (RIL)
to select different ILIMIT
ON/OFF
QR
RIL
12 kΩ
47 kΩ
-
-
values
PI-2640-040501
PI-2629-040501
Figure 29. Active-on Remote ON/OFF.
Figure 28. Line-Sensing and Externally Set Current Limit.
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TOP242-249
Typical Uses of MULTI-FUNCTION (M) Pin
+
+
VUV = IUV x RLS
VOV = IOV x RLS
C
D
S
S
S
M
S
For RLS = 2 MΩ
VUV = 100 VDC
VOV = 450 VDC
RLS
2 MΩ
DC
Input
DC
Input
Voltage
Voltage
DCMAX@100 VDC = 78%
DCMAX@375 VDC = 38%
D
S
M
D
S
M
C
D
S
CONTROL
CONTROL
C
C
-
-
PI-2508-081199
PI-2509-040501
Figure 30. Three Terminal Operation (MULTI-FUNCTION
Features Disabled).
Figure 31. Line Sensing for Undervoltage, Over-Voltage and
Line Feed Forward.
+
+
VUV = RLS x IUV
VOV = IOV x RLS
2 MΩ
22 kΩ
2 MΩ
For Value Shown
VUV = 100 VDC
For Values Shown
VOV = 450 VDC
RLS
RLS
DC
Input
Voltage
DC
Input
Voltage
30 kΩ
1N4148
D
S
M
D
S
M
CONTROL
CONTROL
C
C
6.2 V
-
-
PI-2510-040501
PI-2516-040501
Figure 32. Line Sensing for Under-Voltage Only (Overvoltage
Disabled).
Figure 33. Line Sensing for Overvoltage Only (Under-Voltage
Disabled). Maximum Duty Cycle will be reduced at
Low Line.
+
+
For RIL = 12 kΩ
ILIMIT = 100% @ 100 VDC
ILIMIT = 69%
ILIMIT
=
RLS 2.5 MΩ
63% @ 300 VDC
For RIL = 25 kΩ
ILIMIT = 43%
DC
Input
Voltage
DC
See fig. 55 for other
Input
resistor values (RIL)
Voltage
to select different
D
S
M
D
M
I
LIMIT values
CONTROL
CONTROL
RIL
6 kΩ
C
C
RIL
S
-
-
PI-2518-040501
PI-2517-040501
Figure 35. Current Limit Reduction with Line Voltage.
Figure 34. Externally Set Current Limit.
E
7/01
19
TOP242-249
Typical Uses of MULTI-FUNCTION (M) Pin (cont.)
+
+
QR can be an optocoupler
output or can be replaced
by a manual switch.
QR can be an optocoupler
output or can be replaced by
a manual switch.
QR
47 kΩ
DC
Input
Voltage
DC
Input
Voltage
ON/OFF
RMC
45 kΩ
M
D
S
M
D
CONTROL
CONTROL
C
QR
C
ON/OFF
47 kΩ
-
S
-
PI-2519-040501
PI-2522-040501
Figure 36. Active-on (Fail Safe) Remote ON/OFF.
Figure 37. Active-off Remote ON/OFF. Maximum Duty Cycle will
be Reduced.
+
+
QR can be an optocoupler
output or can be replaced
by a manual switch.
Q
R can be an optocoupler
output or can be replaced
by a manual switch.
For RIL = 12 kΩ
QR
ON/OFF
ILIMIT = 69 %
DC
Input
DC
Input
Voltage
47 kΩ
For RIL = 25 kΩ
Voltage
RMC
24 kΩ
RMC = 2RIL
ILIMIT = 43 %
D
S
M
RIL
QR
D
M
CONTROL
CONTROL
C
RIL
C
12 kΩ
ON/OFF
47 kΩ
-
S
-
PI-2520-040501
PI-2521-040501
Figure 38. Active-on Remote ON/OFF with Externally Set
Current Limit.
Figure 39. Active-off Remote ON/OFF with Externally Set
Current Limit.
QR can be an optocoupler
output or can be replaced
by a manual switch.
+
RLS
2 MΩ
QR
DC
Input
ON/OFF
47 kΩ
For RLS = 2 MΩ
Voltage
D
M
V
UV = 100 VDC
CONTROL
VOV = 450 VDC
C
S
-
PI-2523-040501
Figure 40. Active-off Remote ON/OFF with LINE-SENSE.
E
7/01
20
TOP242-249
margin under worst case conditions. Resistor R4 provides line
sensing, setting UV at 100 VDC and OV at 450 VDC. The
extended maximum duty cycle feature of TOPSwitch-GX
(guaranteedminimumvalueof75%vs. 64%forTOPSwitch-II)
allows the use of a smaller input capacitor (C1). The extended
maximum duty cycle and the higher reflected voltage possible
with the RCD clamp also permit the use of a higher primary to
secondary turns ratio for T1 which reduces the peak reverse
voltage experienced by the secondary rectifier D8. As a result
a 60 V Schottky rectifier can be used for up to 15 V outputs,
whichgreatlyimprovespowersupplyefficiency. Thefrequency
reduction feature of the TOPSwitch-GX eliminates the need for
any dummy loading for regulation at no load and reduces the no
load/standby consumption of the power supply. Frequency
jitterprovidesimprovedmarginforconductedEMImeetingthe
CISPR 22 (FCC B) specification.
Application Examples
A High Efficiency, 30 W, Universal Input Power Supply
ThecircuitshowninFigure41takesadvantageofseveralofthe
TOPSwitch-GX features to reduce system cost and power
supply size and to improve efficiency. This design delivers
30 W at 12 V, from an 85 to 265 VAC input, at an ambient of
50 °C, in an open frame configuration. A nominal efficiency of
80% at full load is achieved using TOP244Y.
The current limit is externally set by resistors R1 and R2 to a
value just above the low line operating peak DRAIN current of
approximately70%ofthedefaultcurrentlimit. Thisallowsuse
of a smaller transformer core size and/or higher transformer
primary inductance for a given output power, reducing
TOPSwitch-GX power dissipation, while at the same time
avoiding transformer core saturation during startup and output
transient conditions. The resistors R1 & R2 provide a signal
that reduces the current limit with increasing line voltage,
which in turn limits the maximum overload power at high input
line voltage. This function in combination with the built-in
soft-startfeatureofTOPSwitch-GX,allowstheuseofalowcost
RCD clamp (R3, C3 and D1) with a higher reflected voltage, by
safelylimitingtheTOPSwitch-GXdrainvoltage, withadequate
Output regulation is achieved by using a simple Zener sense
circuit for low cost. The output voltage is determined by the
Zener diode (VR2) voltage and the voltage drops across the
optocoupler (U2) LED and resistor R6. Resistor R8 provides
bias current to Zener VR2 for typical regulation of 5% at the
12 V output level, over line and load and component variations.
PERFORMANCE SUMMARY
Output Power:
Regulation:
Efficiency:
Ripple:
30 W
4%
≥ 79%
≤ 50 mV pk-pk
CY1
2.2 nF
C14 R15
1 nF 150 Ω
L3
3.3 µH
12 V
@ 2.5 A
R3
C3
4.7 nF
1 kV
68 kΩ
C12
220 µF
35 V
D8
MBR1060
C10
560 µF
35 V
C11
560 µF
35 V
2 W
BR1
600 V
2A
D1
UF4005
RTN
D2
1N4148
R4
2 MΩ
R6
150 Ω
L1
20 mH
1/2 W
R8
R1
C6
0.1 µF
150 Ω
T1
4.7 MΩ
C1
1/2 W
U2
LTV817A
CX1
100 nF
250 VAC
68 µF
D
L
TOPSwitch-GX
400 V
U1
TOP244Y
CONTROL
C
R5
6.8 Ω
S
X
F
F1
3.15 A
VR2
1N5240C
10 V, 2%
J1
R2
9.09 kΩ
L
C5
47 µF
10 V
N
PI-2657-040501
Figure 41. 30 W Power Supply using External Current Limit Programming and Line Sensing for UV and OV.
E
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21
TOP242-249
AHighEfficiency,Enclosed,70W,UniversalAdapterSupply
The circuit shown in figure 42 takes advantage of several of the
TOPSwitch-GX features to reduce cost, power supply size and
increase efficiency. This design delivers 70 W at 19 V, from an
85 to 265 VAC input, at an ambient of 40 °C, in a small sealed
adapter case (4” x 2.15” x 1”). Full load efficiency is 85% at 85
VAC rising to 90% at 230 VAC input.
Capacitor C11 has been added in parallel with VR1 to reduce
Zener clamp dissipation. With a switching frequency of
132 kHz a PQ26/20 core can be used to provide 70 W. To
maximize efficiency, by reducing winding losses, two output
windings are used each with their own dual 100 V Schottky
rectifier (D2 and D3). The frequency reduction feature of the
TOPSwitch-GX eliminates any dummy loading to maintain
regulation at no-load and reduces the no-load consumption of
thepowersupplytoonly520mWat230VACinput. Frequency
jittering provides conducted EMI meeting the CISPR 22
(FCC B) / EN55022B specification, using simple filter
components (C7, L2, L3 and C6) even with the output earth
grounded.
Due to the thermal environment of a sealed adapter a TOP249Y
is used to minimize device dissipation. Resistors R9 and R10
externally program the current limit level to just above the
operating peak DRAIN current at full load and low line. This
allowstheuseofasmallertransformercoresizewithoutsaturation
duringstartuporoutput loadtransients. ResistorsR9andR10also
reduce the current limit with increasing line voltage, limiting the
maximumoverloadpowerathighinputlinevoltage,removingthe
need for any protection circuitry on the secondary. Resistor R11
implements an under voltage and over voltage sense as well as
providing line feed forward for reduced output line frequency
ripple. With resistor R11 set at 2 MΩ the power supply does not
start operating until the DC rail voltage reaches 100 VDC. On
removal of the AC input the UV sense prevents the output
glitching as C1 discharges, turning off the TOPSwitch-GX when
theoutputregulationislostorwhentheinputvoltagefallstobelow
40 V, whichever occurs first. This same value of R11 sets the OV
threshold to 450 V. If exceeded, for example during a line surge,
TOPSwitch-GX stops switching for the duration of the surge
extending the high voltage withstand to 700 V without device
damage.
To regulate the output an optocoupler (U2) is used with a
secondary reference sensing the output voltage via a resistor
divider (U3, R4, R5, R6). Diode D4 and C15 filter and smooth
the output of the bias winding. Capacitor C15 (1uF) prevents
the bias voltage from falling during zero to full load transients.
Resistor R8 provides filtering of leakage inductance spikes
keeping the bias voltage constant even at high output loads.
Resistor R7, C9 and C10 together with C5 and R3 provide loop
compensation.
Due to the large primary currents, all the small signal control
components are connected to a separate source node that is
Kelvin connected to the source pin of the TOPSwitch-GX. For
improved common mode surge immunity the bias winding
common returns directly to the DC bulk capacitor (C1).
PERFORMANCE SUMMARY
D2
C7 2.2 nF
Y1 Safety
C13
0.33 µF 0.022 µF 0.01 µF
400 V 400 V 400 V
C12
C11
Output Power:
Regulation:
70 W
MBR20100
4%
Efficiency:
Ripple:
No Load Consumption:
≥ 84%
≤ 120 mV pk-pk
< 0.52 W @ 230 VAC
D3
MBR20100
VR1
P6KE-
200
C3
C14
19 V
@ 3.6 A
820 µF
0.1 µF
L1
200 µH
BR1
25 V
50 V
D1
RS805
UF4006
8A 600 V
C2
C4
RTN
820 µF
820 µF
R1
270 Ω
D4
1N4148
25 V
25 V
L2
820 µH
2A
R11
2 MΩ
1/2 W
R4
U2
31.6 kΩ
R8
4.7 Ω
PC817A
1%
C1
T1
TOPSwitch-GX
L
R2
150 µF
C15
1 µF
50 V
R5
562 Ω
1%
1 kΩ
400 V
C6
D
S
C9
0.1 µF
TOP249Y
L3
4.7 nF 50 V
X2
CONTROL
U1
75 µH
RT1
C
R9
2A
10 Ω
t°
13 MΩ
C10
1.7 A
R3
6.8 Ω
0.1 µF
R7
56 kΩ
X
F
F1
3.15 A
50 V
U3
TL431
C8
J1
R10
R6
4.75 kΩ
1%
0.1 µF
20.5 kΩ
C5
L
50 V
47 µF
16 V
All resistors 1/8 W 5% unless otherwise stated.
N
PI-2691-033001
Figure 42. 70 W Power Supply using Current Limit Reduction with Line and Line Sensing for UV and OV.
E
7/01
22
TOP242-249
AHighEfficiency,250W,250–380VDCInputPowerSupply
The circuit shown in figure 43 delivers 250 W (48 V @ 5.2 A)
at 84% efficiency using a TOP249 from a 250 to 380 VDC
input. DCinputisshown, astypicallyatthispowerlevelap.f.c.
boost stage would preceed this supply, providing the DC input
(C1 is included to provide local decoupling). Flyback topology
is still useable at this power level due to the high output voltage,
keeping the secondary peak currents low enough so that the
output diode and capacitors are reasonably sized.
is essential to limit the peak drain voltage during start-up and/
or overload conditions to below the 700 V rating of the
TOPSwitch-GX MOSFET.
The secondary is rectifed and smoothed by D2 and C9, C10 and
C11. Three capacitors are used to meet the secondary ripple
current requirement. Inductor L2 and C12 provide switching
noise filtering.
A simple Zener sensing chain regulates the output voltage. The
sum of the voltage drop of VR2, VR3 and VR4 plus the LED
drop of U2 gives the desired output voltage. Resistor R6 limits
LED current and sets overall control loop DC gain. Diode D4
and C14 provide secondary soft-finish, feeding current into the
CONTROLpinpriortooutputregulationandthusensuringthat
the output voltage reaches regulation at start-up under low line,
full load conditions. Resistor R9 provides a discharge path for
C14. CapacitorC13andR8providecontrolloopcompensation
and are required due to the gain associated with such a high
output voltage.
In this example the TOP249 is at the upper limit of its power
capability and the current limit is set to the internal maximum
by connecting the X pin to SOURCE. However, line sensing is
implemented by connecting a 2 MΩ resistor from the L pin to
the DC rail. If the DC input rail rises above 450 VDC, then
TOPSwitch-GX will stop switching until the voltage returns to
normal, preventing device damage.
Due to the high primary current, a low leakage inductance
transformer is essential. Therefore, a sandwich winding with a
copper foil secondary was used. Even with this technique the
leakage inductance energy is beyond the power capability of a
simple Zener clamp. Therefore, R2, R3 and C6 are added in
parallel to VR1. These have been sized such that during normal
operation very little power is dissipated by VR1, the leakage
energy instead being dissipated by R2 and R3. However, VR1
Sufficient heat sinking is required to keep the TOPSwitch-GX
device below 110 °C when operating under full load, low line
and maximum ambient temperature. Airflow may also be
required if a large heat sink area is not acceptable.
C7
2.2 nF Y1
D2
MUR1640CT
R2
R3
C6
C10
560 µF 560 µF
63 V 63 V
C11
L2
3 µH 8A
VR1
P6KE200
68 kΩ 68 kΩ 4.7 nF
48 V @ 5.2 A
+250 - 380 VDC
2 W
2 W
1 kV
C9
C12
560 µF
68 µF
63 V
63 V
D1
BYV26C
RTN
D2
1N4148
U2
LTV817A
R1
2 MΩ
1/2 W
R9
T1
C4
10 kΩ
1 µF
C1
50 V
22 µF
R6
400 V
100 Ω
TOPSwitch-GX
C13
150 nF
63 V
VR2 22 V
BZX79B22
D
S
L
TOP249Y
U1
D4
PERFORMANCE SUMMARY
1N4148
CONTROL
C
Output Power:
Line Regulation:
Load Regulation:
Efficiency:
250 W
1%
R4
5%
C14
22 µF
63 V
X
F
6.8 Ω
≥ 85%
VR3 12 V
BZX79B12
C3
R8
56 Ω
Ripple:
< 100 mV pk-pk
C3
0.1 µF
No Load Consumption: ≤ 1.4 W (300 VDC)
47 µF
50 V
VR4 12 V
BZX79B12
10 V
0V
All resistor 1/8 W 5% unless
otherwise stated.
PI-2692-033001
Figure 43. 250 W, 48 V Power Supply using TOP249.
E
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23
TOP242-249
Multiple Output, 60 W, 185-265 VAC Input Power Supply
Figure 44 shows a multiple output supply typical for high end
set-top boxes or cable decoders containing high capacity hard
disks for recording. The supply delivers an output power of
45Wcont./60Wpeak(thermallylimited)fromaninputvoltage
of 185 to 265 VAC. Efficiency at 45 W, 185 VAC is ≥ 75%.
Leakage inductance clamping is provided by VR1, R5 and C5,
keeping the DRAIN voltage below 700 V under all conditions.
Resistor R5 and capacitor C5 are selected such that VR1
dissipates very little power except during overload conditions.
The frequency jittering feature of TOPSwitch-GX allows the
circuit shown to meet CISPR22B with simple EMI filtering
(C1, L1 and C6) and the output grounded.
The3.3Vand5Voutputsareregulatedto 5%withouttheneed
for secondary linear regulators. DC stacking (the secondary
winding reference for the other output voltages is connected to
the cathode of D10 rather than the anode) is used to minimize
the voltage error for the higher voltage outputs.
The secondaries are rectified and smoothed by D7 to D11, C7,
C9, C11, C13, C14, C16 and C17. Diode D11 for the 3.3 V
output is a Schottky diode to maximize efficiency. Diode D10
for the 5 V output is a PN type to center the 5 V output at 5 V.
The 3.3 V and 5 V output require two capacitors in parallel to
meet the ripple current requirement. Switching noise filtering
is provided by L2 to L5 and C8, C10, C12, C15 and C18.
Resistor R6 prevents peak charging of the lightly loaded 30 V
output. The outputs are regulated using a secondary reference
(U3). Both the 3.3 V and 5 V outputs are sensed via R11 and
R10. Resistor R8 provides bias for U3 and R7 sets the overall
DC gain. Resistor R9, C19, R3 and C4 provide loop
compensation. A soft-finish capacitor (C20) eliminates output
overshoot.
Due to the high ambient operating temperature requirement
typical of a set-top box (60 °C) the TOP246Y is used to reduce
conductionlossesandminimizeheatsinksize. ResistorR2sets
the device current limit to 80% of typical to limit overload
power. Thelinesenseresistor(R1)protectstheTOPSwitch-GX
from line surges and transients by sensing when the DC rail
voltage rises to above 450 V. In this condition the
TOPSwitch-GX stops switching, extending the input voltage
withstand to 496 VAC which is ideal for countries with poor
powerquality. Athermistor(RT1)isusedtopreventpremature
failure of the fuse by limiting the inrush current (due to the
relatively large size of C2). An optional MOV (RV1) extends
the differential surge protection to 6 kV from 4 kV.
PERFORMANCE SUMMARY
Output Power:
Regulation:
3.3 V:
5 V:
12 V:
18 V:
30 V:
45 W Cont./60 W Peak
R6
10 Ω
D7
5%
5%
7%
7%
8%
≥75%
0.6 W
30 V @
0.03 A
UF4003
L2
C7
C8
3.3 µH
D8
UF5402
47 µF
10 µF
3A
18 V @
0.5 A
50 V
50 V
C9
L3
C10
Efficiency:
No Load Consumption:
D9
UF5402
330 µF
3.3 µH
100 µF
25 V
12 V @
0.6 A
3A
25 V
C11
C16
C13
C12
C6
2.2 nF
Y1
L4
390 µF
1000 µF
1000 µF
100 µF
3.3 µH
35 V
25 V
25 V
25 V
5 V @
3.2 A
5A
VR1
P6KE170
R5
68 kΩ
C14
C15
L5
2 W
1000 µF
220 µF
D10
3.3 µH
25 V
165 V
3.3 V @
3 A
BYV32-200
5A
C5
1 nF
400 V
C18
D11
MBR1045
C17
220 µF
1000 µF
16 V
D1-D4
1N4007 V
25 V
RTN
D6
1N4937
C2
L1
20 mH
0.8A
68 µF
R10
400 V
D6
1N4148
C3
R7
15.0
1 µF
150 Ω
R1
kΩ
50 V
2 MΩ
C1
0.1 µF
X1
U2
LTV817
T1
R8
1 kΩ
1/2 W
R11
9.53
kΩ
TOPSwitch-GX
D
S
L
RV1
275 V
14 mm
C19
0.1 µF
CONTROL
R9
3.3 kΩ
C
F1
3.15 A
C3
TOP246Y
U1
R3
6.8 Ω
0.1 µF
X
F
J1
50 V
RT1
U3
TL431
C5
C20
22 µF
10 V
10 Ω
.R2
9.08 kΩ
L
R12
10 k
47 µF
1.7 A
10 V
N
PI-2693-033001
Figure 44. 60 W Multiple Output Power Supply using TOP246.
E
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24
TOP242-249
Processor Controlled Supply Turn On/Off
position. Inthecaseofproductswithadiskdrive, theshutdown
procedure may include saving data or settings to the disk. After
the shutdown procedure is complete, when it is safe to turn off
the power supply, the microprocessor releases the M pin by
turning the optocoupler U4 off. If the manual switch and the
optocouplers U3 and U4 are not located close to the M pin, a
capacitorCM maybeneededtopreventnoisecouplingtothepin
when it is open.
A low cost momentary contact switch can be used to turn the
TOPSwitch-GXpoweronandoffundermicroprocessorcontrol
that may be required in some applications such as printers. The
lowpowerremoteofffeatureallowsanelegantimplementation
of this function with very few external components as shown in
Figure 45. Whenever the push button momentary contact
switch P1 is closed by the user, the optocoupler U3 is activated
to inform the microprocessor of this action. Initially, when the
power supply is off (M pin is floating), closing of P1 turns the
power supply on by shorting the M pin of the TOPSwitch-GX
to SOURCE through a diode (remote on). When the secondary
output voltage VCC is established, the microprocessor comes
alive and recognizes that the switch P1 is closed through the
switch status input that is driven by the optocoupler U3 output.
Themicroprocessorthensendsapowersupplycontrolsignalto
hold the power supply in the on-state through the optocoupler
U4. If the user presses the switch P1 again to command a turn
off, the microprocessor detects this through the optocoupler U3
and initiates a shutdown procedure that is product specific. For
example,inthecaseoftheinkjetprinter,theshutdownprocedure
may include safely parking the print heads in the storage
The power supply could also be turned on remotely through a
local area network or a parallel or serial port by driving the
optocoupler U4 input LED with a logic signal. Sometimes it is
easier to send a train of logic pulses through a cable (due to AC
coupling of cable, for example) instead of a DC logic level as
a wake up signal. In this case, a simple RC filter can be used to
generate a DC level to drive U4 (not shown in Figure 45). This
remote on feature can be used to wake up peripherals such as
printers,scanners,externalmodems,diskdrives,etc.,asneeded
from a computer. Peripherals are usually designed to turn off
automatically if they are not being used for a period of time, to
save power.
VCC
(+5 V)
+
External
Wake-up
Signal
High Voltage
DC Input
Power
Supply
ON/OFF
Control
MICRO
PROCESSOR/
CONTROLLER
100 kΩ
U2
27 kΩ
1N4148
LOGIC
INPUT OUTPUT
LOGIC
1N4148
6.8 kΩ
TOPSwitch-GX
D
S
M
U4
CONTROL
C
U3
6.8 kΩ
CM
47 µF
F
U1
U3
LTV817A
P1 Switch
Status
P1
1 nF
U4
LTV817A
-
RETURN
PI-2561-033001
Figure 45. Remote ON/OFF using Microcontroller.
E
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25
TOP242-249
In addition to using a minimum number of components,
TOPSwitch-GX provides many technical advantages in this
type of application:
sequence when it detects the first closure of the switch, and
subsequentbouncingoftheswitchhasnoeffect. Ifnecessary,
the microprocessor could implement the switch debouncing
in software during turn-off, or a filter capacitor can be used
at the switch status input.
1. Extremely low power consumption in the off mode: 80 mW
typical at 110 VAC and 160 mW typical at 230 VAC. This
is because in the remote/off mode the TOPSwitch-GX
consumes very little power, and the external circuitry does
not consume any current (either M, L or X pin is open) from
the high voltage DC input.
4. No external current limiting circuitry is needed for the
operation of the U4 optocoupler output due to internal
limiting of M pin current.
5. No high voltage resistors to the input DC voltage rail are
requiredtopowertheexternalcircuitryintheprimary. Even
the LED current for U3 can be derived from the CONTROL
pin. This not only saves components and simplifies layout,
but also eliminates the power loss associated with the high
voltage resistors in both on and off states.
2. A very low cost, low voltage/current, momentary contact
switch can be used.
3. Nodebouncingcircuitryforthemomentaryswitchisrequired.
During turn-on, the start-up time of the power supply
(typically 10 to 20 ms) plus the microprocessor initiation
time act as a debouncing filter, allowing a turn-on only if the
switch is depressed firmly for at least the above delay time.
During turn-off, the microprocessor initiates the shutdown
6. Robustdesign: Thereisnoon/offlatchthatcanbeaccidentally
triggered by transients. Instead, the power supply is held in
the on-state through the secondary side microprocessor.
E
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26
TOP242-249
Key Application Considerations
TOPSwitch-II vs. TOPSwitch-GX
Table 4 compares the features and performance differences
between TOPSwitch-GX and TOPSwitch-II. Many of the new
features eliminate the need for additional discrete components.
Other features increase the robustness of design allowing cost
savings in the transformer and other power components.
Function
TOPSwitch-II
TOPSwitch-GX Figures TOPSwitch-GX Advantages
Soft-Start
N/A*
10 ms
• Limits peak current and voltage
component stresses during start-up
• Eliminates external components
used for soft-start in most
applications
• Reduces or eliminates output
overshoot
External Current Limit
N/A*
67%
Programmable
100% to 30% of 24,25,27, • Higher efficiency
default current
limit
11,20,21, • Smaller transformer
28,34,35, • Allows power limiting (constant over-
38,39
load power independent of line
voltage
• Allows use of larger device for lower
losses, higher efficiency and smaller
heatsink
DCMAX
78%
7
• Smaller input cap (wider dynamic
range)
• Higher power capability (when used
with RCD clamp for large VOR)
• Allows use of Schottky secondary
rectifier diode for up to 15 V output
for high efficiency
Line Feed Forward with N/A*
DCMAX Reduction
78% to 38%
7,11,17,
26,27,28,
31,40
• Rejects line ripple
Line OV Shutdown
Line UV Detection
Switching Frequency
N/A*
N/A*
Single resistor
programmable
11,17,19, • Increases voltage withstand cap-
26,27,28,
31,33,40
ability against line surge
Single resistor
programmable
11,17,18, • Prevents auto-restart glitches
26,27,28,
during power down
31,32,40
100 kHz 10%
N/A*
132 kHz 6%
66 kHz 7%
13,15
14,15
• Smaller transformer
• Below start of conducted EMI limits
Switching Frequency
Option (Y and R
Packages)
• Lower losses when using RC and
RCD snubber for noise reduction in
video applications
• Allows for higher efficiency in
standby mode
• Lower EMI (second harmonic below
150 kHz)
Frequency Jitter
N/A*
N/A*
4 kHz@132 kHz 9,46
2 kHz@66 kHz
• Reduces conducted EMI
Frequency Reduction
At a Duty Cycle
below 10%
7
• Zero load regulation without dummy
load
• Low power consumption at no load
Table 4. Comparison Between TOPSwitch-II and TOPSwitch-GX. (continued on next page) *Not available
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27
TOP242-249
Function
TOPSwitch-II
TOPSwitch-GX Figures TOPSwitch-GX Advantages
Remote ON/OFF
N/A*
Single transistor
or optocoupler
11, 22, • Fast on/off (cycle by cycle)
23, 24, • Active-on or active-off control
interface or manual 25, 26, • Low consumption in remote off state
switch
27, 29, • Active-on control for fail-safe
36, 37, • Eliminates expensive in-line on/off
38, 39, switch
40
• Allows processor controlled turn
on/off
• Permits shutdown/wake-up of
peripherals via LAN or parallel port
Synchronization
N/A*
Single transistor
or optocoupler
interface
• Synchronization to external lower
frequency signal
• Starts new switching cycle on
demand
Thermal Shutdown
125 °C min.
Latched
Hysteretic 130 °C
min. Shutdown (with
75 °C hysteresis)
• Automatic recovery from thermal
fault
• Large hysteresis prevents circuit
board overheating
Current Limit Tolerance 10% (@25 °C)
7% (@25 °C)
• 10% higher power capability due to
tighter tolerance
-8% (0 °C to100 °C) -4% (0 °C to 100 °C)
DRAIN
Creepage
at Package
DIP
SMD
0.037" / 0.94 mm 0.137" / 3.48 mm
0.037" / 0.94 mm 0.137" / 3.48 mm
• Greater immunity to arcing as a
result of build-up of dust, debris and
other contaminants
TO-220 0.046" / 1.17 mm 0.068" / 1.73 mm
DRAIN Creepage at
PCB for Y and R
Packages
0.045" / 1.14 mm 0.113" / 2.87 mm
(R Package N/A*) (preformed leads)
• Preformed leads accommodate
large creepage for PCB layout
• Easier to meet Safety (UL/VDE)
Table 4 (cont). Comparison Between TOPSwitch-II and TOPSwitch-GX. *Not available
TOPSwitch-FX vs. TOPSwitch-GX
Table 5 compares the features and performance differences
betweenTOPSwitch-GX andTOPSwitch-FX. Manyofthenew
features eliminate the need for additional discrete components.
Other features increase the robustness of design allowing cost
savings in the transformer and other power components.
Function
TOPSwitch-FX
TOPSwitch-GX
TOPSwitch-GX Advantages
Light Load Operation
Cycle skipping
Frequency and Duty Cycle • Improves light load efficiency
reduction
• Reduces no-load consumption
Line Sensing/Externally Line sensing and
Line sensing and externally • Additional design flexibility allows all
Set Current Limit
(Y and R Packages)
externally set
current limit
mutually
set current limit possible
simultaneously
(functions split onto
L and X pins)
features to be used simultaneously
exclusive (M pin)
Current Limit
Programming
Range
100-40%
100-30%
• Minimizes transformer core size
in highly continuous designs
Table 5. Comparison Between TOPSwitch-FX and TOPSwitch-GX. (continued on next page)
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28
TOP242-249
Function
TOPSwitch-FX
TOPSwitch-GX
TOPSwitch-GX Advantages
P/G Package Current
Limits
Identical to Y
packages
TOP243P or G and
TOP244P or G internal
current limits reduced
• Matches device current limit to
package dissipation capability
• Allows more continuous design to
lower device dissipation (lower RMS
currents)
Y/R Package Current
Limits
100%
(R package N/A*)
90% (for equivalent RDS (ON)
)
• Minimizes transformer core size
• Optimizes efficiency for most
applications
Thermal Shutdown
125 °C min.
70 °C hysteresis
130 °C min. 75 °C
hysteresis
• Allows higher output powers in
high ambient temperature
applications
Maximum Duty Cycle
Reduction Threshold
90 µA
60 µA
• Reduces output line frequency
ripple at low line
• DMAX reduction optimized for
forward design
Line Under-Voltage
Negative (turn-off)
Threshold
N/A*
40% of positive (turn-on)
threshold
• Provides a well defined turn-off
threshold as the line voltage falls
Soft-Start
10 ms (duty cycle) 10 ms (duty cycle + current
limit)
• Gradually increasing current limit
in addition to duty cycle during soft-
start further reduces peak current
and voltage
• Further reduces component
stresses during start up
Table 5 (cont). Comparison Between TOPSwitch-FX and TOPSwitch-GX. *Not available
TOPSwitch-GX Design Considerations
applications where higher efficiency is needed or minimal heat
sinking is available.
Power Table
Datasheet power table represents the maximum practical
continuous output power based on the following conditions:
TOP242 to TOP246: 12 V output, Schottky output diode,
150 V reflected voltage (VOR) and efficiency estimates from
curvescontainedinapplicationnoteAN-29.TOP247toTOP249:
Higher output voltages used with a maximum output current of
6 A.
Input Capacitor
The input capacitor must be chosen to provide the minimum
DCvoltagerequiredfortheTOPSwitch-GXconvertertomaintain
regulation at the lowest specified input voltage and maximum
output power. Since TOPSwitch-GX has a higher DCMAX than
TOPSwitch-II, it is possible to use a smaller input capacitor.
For TOPSwitch-GX, a capacitance of 2 µF per watt is possible
for universal input with an appropriately designed transformer.
For all devices a 100 VDC minimum for 85-265 VAC and 250
VDC minimum for 230 VDC are assumed and sufficient heat
sinking to keep device temperature ≤ 100 °C. Power levels
shown in the power table for the R package device assume
6.45 cm2 of 610 g/m2 copper heat sink area in an enclosed
adapter, or 19.4 cm2 in an open frame.
Primary Clamp and Output Reflected Voltage VOR
A primary clamp is necessary to limit the peak TOPSwitch-GX
drain to source voltage. A Zener clamp requires few parts and
takes up little board space. For good efficiency, the clamp
Zener should be selected to be at least 1.5 times the output
reflectedvoltageVORasthiskeepstheleakagespikeconduction
time short. When using a Zener clamp in a universal input
application, a VOR of less than 135 V is recommended to allow
for the absolute tolerances and temperature variations of the
Zener. This will ensure efficient operation of the clamp circuit
and will also keep the maximum drain voltage below the rated
breakdown voltage of the TOPSwitch-GX MOSFET.
TOPSwitch-GX Selection
Selecting the optimum TOPSwitch-GX depends upon required
maximum output power, efficiency, heat sinking constraints
and cost goals. With the option to externally reduce current
limit, a larger TOPSwitch-GX may be used for lower power
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TOP242-249
AhighVOR isrequiredtotakefulladvantageofthewiderDCMAX
of TOPSwitch-GX. An RCD clamp provides tighter clamp
voltage tolerance than a Zener clamp and allows a VOR as high
as 150 V. RCD clamp dissipation can be minimized by
reducing the external current limit as a function of input line
voltage (see Figure 21 and 35). The RCD clamp is more cost
effective than the Zener clamp but requires more careful design
(see quick design checklist).
For 10 W or below, it is possible to use a simple inductor in
place of a more costly AC input common mode choke to meet
worldwide conducted EMI limits.
Transformer Design
Itisrecommendedthatthetransformerbedesignedformaximum
operating flux density of 3000 Gauss and a peak flux density of
4200 Gauss at maximum current limit. The turns ratio should be
chosen for a reflected voltage (VOR) no greater than 135 V when
using a Zener clamp, or 150 V (max) when using RCD clamp
with current limit reduction with line voltage (overload
protection).
Output Diode
The output diode is selected for peak inverse voltage, output
current, and thermal conditions in the application (including
heatsinking, air circulation, etc.). The higher DCMAX of
TOPSwitch-GX along with an appropriate transformer turns
ratio can allow the use of a 60 V Schoktty diode for higher
efficiency on output voltages as high as 15 V (see Figure 41. A
12 V, 30 W design using a 60 V Schottky for the output diode).
For designs where operating current is significantly lower than
the default current limit, it is recommended to use an externally
set current limit close to the operating peak current to reduce
peak flux density and peak power (see Figure 20 and 34). In
most applications, the tighter current limit tolerance, higher
Bias Winding Capacitor
Due to the low frequency operation at no-load a 1µF bias
winding capacitor is recommended.
80
70
60
50
40
30
20
-10
0
TOPSwitch-II (no jitter)
Soft-Start
Generally a power supply experiences maximum stress at start-
up before the feedback loop achieves regulation. For a period
of 10 ms the on-chip soft-start linearly increases the duty cycle
from zero to the default DCMAX at turn on. In addition, the
primary current limit increases from 85% to 100% over the
same period. This causes the output voltage to rise in an orderly
manner allowing time for the feedback loop to take control of
the duty cycle. This reduces the stress on the TOPSwitch-GX
MOSFET, clamp circuit and output diode(s), and helps prevent
transformersaturationduringstart-up. Alsosoft-startlimitsthe
amount of output voltage overshoot, and in many applications
eliminates the need for a soft-finish capacitor.
EN55022B (QP)
EN55022B (AV)
-10
-20
0.15
1
10
30
Frequency (MHz)
Figure 46a. TOPSwitch-II Full Range EMI Scan
(100 kHz, no jitter)
EMI
80
The frequency jitter feature modulates the switching frequency
over a narrow band as a means to reduce conducted EMI peaks
associated with the harmonics of the fundamental switching
frequency. This is particularly beneficial for average detection
mode. AscanbeseeninFigure46, thebenefitsofjitterincrease
with the order of the switching harmonic due to an increase in
frequency deviation.
70
60
TOPSwitch-GX (with jitter)
50
40
30
20
-10
0
The FREQUENCY pin of TOPSwitch-GX offers a switching
frequency option of 132 kHz or 66 kHz. In applications that
require heavy snubbers on the drain node for reducing high
frequency radiated noise (for example, video noise sensitive
applications such as VCR, DVD, monitor, TV, etc.), operating
at66kHzwillreducesnubberlossresultinginbetterefficiency.
Also, in applications where transformer size is not a concern,
use of the 66 kHz option will provide lower EMI and higher
efficiency. Note that the second harmonic of 66 kHz is still
below 150 kHz, above which the conducted EMI specifications
get much tighter.
EN55022B (QP)
EN55022B (AV)
-10
-20
0.15
1
10 30
Frequency (MHz)
Figure 46b. TOPSwitch-GX Full Range EMI Scan (132 kHz,
with jitter) with Identical Circuitry and
Conditions.
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TOP242-249
switching frequency and soft-start features of TOPSwitch-GX
contribute to a smaller transformer when compared to
TOPSwitch-II.
Y-Capacitor
The Y-capacitor should be connected close to the secondary
outputreturnpin(s)andthepositiveprimaryDCinputpinofthe
transformer.
Standby Consumption
Frequency reduction can significantly reduce power loss at
lightornoload,especiallywhenaZenerclampisused. Forvery
low secondary power consumption use a TL431 regulator for
feedback control. Alternately, switching losses can be
significantly reduced by changing from 132 kHz in normal
operation to 66 kHz under light load conditions.
Heat Sinking
The tab of the Y package (TO-220) is internally electrically
tied to the SOURCE pin. To avoid circulating currents, a heat
sink attached to the tab should not be electrically tied to any
primary ground/source nodes on the PC board.
When using a P (DIP-8), G (SMD-8) or R (TO-263) package,
acopperareaunderneaththepackageconnectedtotheSOURCE
pins will act as an effective heat sink. On double sided boards
(Figure 49), top side and bottom side areas connected with vias
can be used to increase the effective heat sinking area.
TOPSwitch-GX Layout Considerations
AsTOPSwitch-GXhasadditionalpinsandoperatesatmuch
higher power levels compared to previous TOPSwitch
families, the following guidelines should be carefully
followed.
In addition, sufficient copper area should be provided at the
anode and cathode leads of the output diode(s) for heat sinking.
Primary Side Connections
Use a single point (Kelvin) connection at the negative terminal
of the input filter capacitor for TOPSwitch-GX source pin and
biaswindingreturn.Thisimprovessurgecapabilitiesbyreturning
surge currents from the bias winding directly to the input filter
capacitor.
In Figures 47, 48 and 49 a narrow trace is shown between the
output rectifier and output filter capacitor. This trace acts as a
thermal relief between the rectifier and filter capacitor to
prevent excessive heating of the capacitor.
Quick Design Checklist
The CONTROL pin bypass capacitor should be located as
close as possible to the SOURCE and CONTROL pins and its
SOURCE connection trace should not be shared by the main
MOSFET switching currents. All SOURCE pin referenced
components connected to the MULTI-FUNCTION, LINE-
SENSEorEXTERNALCURRENTLIMITpinsshouldalsobe
located closely between their respective pin and SOURCE.
OnceagaintheSOURCEconnectiontraceofthesecomponents
should not be shared by the main MOSFET switching currents.
It is very critical that SOURCE pin switching currents are
returned to the input capacitor negative terminal through a
seperate trace that is not shared by the components connected
to CONTROL, MULTI-FUNCTION, LINE-SENSE or
EXTERNAL CURRENT LIMIT pins. This is because the
SOURCE pin is also the controller ground reference pin.
As with any power supply design, all TOPSwitch-GX designs
should be verified on the bench to make sure that components
specifications are not exceeded under worst case conditions.
The following minimum set of tests is strongly recommended:
1. Maximum drain voltage – Verify that peak VDS does not
exceed675Vathighestinputvoltageandmaximumoverload
output power. Maximum overload output power occurs
when the output is overloaded to a level just before the
power supply goes into auto-restart (loss of regulation).
2. Maximumdraincurrent–Atmaximumambienttemperature,
maximum input voltage and maximum output load, verify
drain current waveforms at start-up for any signs of
transformer saturation and excessive leading edge current
spikes. TOPSwitch-GX has a leading edge blanking time of
220 ns to prevent premature termination of the on-cycle.
Verify that the leading edge current spike is below the
allowed current limit envelope (see Figure 52) for the drain
current waveform at the end of the 220 ns blanking period.
Any traces to the M, L or X pins should be kept as short as
possible and away from the DRAIN trace to prevent noise
coupling. LINE-SENSE resistor (R1 in figures 47-49) should
be located close to the M or L pin to minimize the trace length
on the M or L pin side.
3. Thermal check – At maximum output power, minimum
input voltage and maximum ambient temperature, verify
that temperature specifications are not exceeded for
TOPSwitch-GX, transformer, output diodes and output
capacitors. Enough thermal margin should be allowed for
In addition to the 47 µF CONTROL pin capacitor, a high
frequency bypass capacitor in parallel may be used for better
noise immunity. The feedback optocoupler output should also
be located close to the CONTROL and SOURCE pins of
TOPSwitch-GX.
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TOP242-249
Maximize hatched copper
Safety Spacing
areas (
) for optimum
heat sinking
Y1-
Capacitor
+
Output Rectifier
Output Filter Capacitor
HV
-
Input Filter Capacitor
T
r
PRI
SEC
BIAS
a
n
s
f
PRI
S
S
D
o
r
m
e
r
TOPSwitch-GX
BIAS
TOP VIEW
S
S
C
M
Opto-
coupler
R1
DC
Out
-
+
R2
PI-2670-042301
Figure 47. Layout Considerations for TOPSwitch-GX using P or G Packages.
Safety Spacing
Y1-
Maximize hatched copper
+
Capacitor
areas (
) for optimum
heat sinking
Input Filter Capacitor
HV
Output Rectifier
Output Filter Capacitor
-
T
r
SEC
a
n
s
f
TOPSwitch-GX
D
o
r
X
L
m
e
r
C
TOP VIEW
Opto-
coupler
R1
Heat Sink
DC
Out
-
+
PI-2669-042301
Figure 48. Layout Considerations for TOPSwitch-GX using Y Package.
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TOP242-249
Output Filter Capacitors
Solder Side
Safety Spacing
Component Side
Y1-
+
Capacitor
TOP VIEW
HV
-
T
PRI
r
a
n
s
f
Input Filter
Capacitor
PRI
SEC
o
r
R1a - 1c
m
e
r
BIAS
D
S
X
L
DC
-
+
Out
C
Opto-
coupler
Maximize hatched copper
areas(
) for optimum
heat sinking
TOPSwitch-GX
PI-2734-043001
Figure 49. Layout Considerations for TOPSwitch-GX using R Package.
Design Tools
the part-to-part variation of the RDS(ON)of TOPSwitch-GXas
specified in the data sheet. The margin required can either
be calculated from the tolerances or it can be accounted for
by connecting an external resistance in series with the
DRAIN pin and attached to the same heatsink, having a
resistance value that is equal to the difference between the
measured RDS(ON) of the device under test and the worst case
maximum specification.
Up to date information on design tools can be found at the
Power Integrations Web site: www.powerint.com
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TOP242-249
ABSOLUTE MAXIMUM RATINGS(1)
LINE SENSE Pin Voltage ................................ -0.3 to 9 V
CURRENT LIMIT Pin Voltage ..................... -0.3 to 4.5 V
MULTI-FUNCTION Pin Voltage .................... -0.3 to 9 V
FREQUENCY Pin Voltage............................... -0.3 to 9 V
Storage Temperature ..................................... -65 to 150 °C
Operating Junction Temperature (2) ............... -40 to 150 °C
Lead Temperature (3) ............................................... 260 °C
DRAIN Voltage ............................................ -0.3 to 700 V
DRAIN Peak Current: TOP242 ...............................0.72 A
TOP243 ...............................1.44 A
TOP244 ...............................2.16 A
TOP245 ...............................2.88 A
TOP246 ...............................4.32 A
TOP247 ...............................5.76 A
TOP248 ...............................7.20 A
TOP249 ...............................8.64 A
Notes:
1. All voltages referenced to SOURCE, TA = 25 °C.
2. Normally limited by internal circuitry.
3. 1/16" from case for 5 seconds.
CONTROL Voltage .......................................... -0.3 to 9 V
CONTROL Current ...............................................100 mA
THERMAL IMPEDANCE
Thermal Impedance: Y Package (θJA)(1) ............... 70 °C/W
Notes:
(θJC)(2) ................ 2 °C/W
1. Free standing with no heatsink.
2. Measured at the back surface of tab.
3. Soldered to 0.36 sq. inch (232 mm2), 2oz. (610 gm/m2) copper clad.
4. Soldered to 1 sq. inch (645 mm2), 2oz. (610 gm/m2) copper clad.
5. Measured on the SOURCE pin close to plastic interface.
P or G Package:
(θJA) ...... 45 °C/W (3); 35 °C/W (4)
(θJC)(5) ......................... 11 °C/W
Conditions
(Unless Otherwise Specified)
See Figure 53
Parameter
Symbol
Min
Typ Max
Units
SOURCE = 0 V; TJ = -40 to 125 °C
CONTROL FUNCTIONS
FREQUENCY Pin
124
132
66
140
Switching
IC = 3 mA;
TJ = 25 °C
Connected to SOURCE
fOSC
Frequency
kHz
FREQUENCY Pin
Connected to CONTROL
61.5
70.5
(average)
Duty Cycle at
DC(ONSET)
ONSET of Fre-
10
30
%
quency Reduction
Switching
Frequency near
0% Duty Cycle
132 kHz Operation
66 kHz Operation
fOSC (DMIN)
kHz
15
4
132 kHz Operation
66 kHz Operation
Frequency Jitter
Deviation
∆f
kHz
Hz
2
Frequency Jitter
Modulation Rate
fM
250
IL ≤ IL (DC) or IM ≤ IM(DC)
IL or IM = 190 µA
75
28
78
38
83
50
Maximum Duty
Cycle
IC = ICD1
DCMAX
tSOFT
%
ms
TJ = 25 °C; DCMIN to DCMAX
10
15
Soft Start Time
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34
TOP242-249
Conditions
(Unless Otherwise Specified)
See Figure 53
Parameter
Symbol
Min
Typ Max
Units
SOURCE = 0 V; TJ = -40 to 125 °C
CONTROL FUNCTIONS (cont.)
PWM Gain
DCreg
IC = 4 mA; TJ = 25 °C
-28
-23
-18
%/mA
PWM Gain
Temperature Drift
%/mA/°C
-0.01
See Note A
1.2
1.6
2.0
2.6
3.0
4.0
TOP242-245
External Bias
Current
lB
lC(OFF)
ZC
mA
See Figure 7
TOP246-249
TOP242-245
TOP246-249
6.0
6.6
7.0
8.0
CONTROL
Current at 0%
Duty Cycle
TJ = 25 °C
mA
Ω
Dynamic
Impedance
IC = 4 mA; TJ = 25 °C
See Figure 51
10
15
22
Dynamic
0.18
Impedance
%/°C
kHz
Temperature Drift
Control Pin
Internal Filter Pole
7
SHUTDOWN/AUTO-RESTART
VC = 0 V
VC = 5 V
-5.0
-3.0
-3.5
-1.8
-2.0
-0.6
Control Pin
lC (CH)
mA
TJ = 25 °C
Charging Current
Charging Current
Temperature Drift
0.5
5.8
See Note A
%/°C
Auto-restart Upper
VC(AR)U
V
V
V
Threshold Voltage
Auto-restart Lower
Threshold Voltage
VC(AR)L
4.5
0.8
4.8
1.0
5.1
Auto-restart
VC(AR)hyst
Hysteresis Voltage
Auto-restart Duty
DC(AR)
4
8
%
Cycle
Auto-restart
f(AR)
1.0
Hz
Frequency
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TOP242-249
Conditions
(Unless Otherwise Specified)
See Figure 53
Parameter
Symbol
Min
Typ Max
Units
SOURCE = 0 V; TJ = -40 to 125 °C
MULTI-FUNCTION (M), LINE-SENSE (L) AND EXTERNAL CURRENT LIMIT (X) INPUTS
Line Under-Voltage
Threshold Current
and Hysteresis
(M or L Pin)
µA
µA
Threshold
Hysteresis
44
50
30
54
lUV
TJ = 25 °C
TJ = 25 °C
Line Over-Voltage
or Remote ON/
Threshold
Hysteresis
µA
µA
210
225
240
IOV
OFF Threshold
Current and Hys-
teresis (M or L Pin)
8
L Pin Voltage
Threshold
VL(TH)
V
0.5
-35
1.0
-27
5
1.6
-20
Remote ON/OFF
Negative Threshold
Current and Hyster-
esis (M or X Pin)
Threshold
Hysteresis
µA
µA
TJ = 25 °C
IREM (N)
IL (SC) or
IM (SC)
L or M Pin Short
Circuit Current
µA
300
400
520
VL, VM = VC
IX (SC) or
IM (SC)
-300
-110
1.90
2.30
1.26
1.18
1.24
1.13
-240
-90
-180
-70
Normal Mode
Auto-restart Mode
lL or lM = 50 µA
X or M Pin Short
Circuit Current
VX, VM = 0 V
µA
2.50
2.90
1.33
1.24
1.31
1.19
3.00
3.30
1.40
1.30
1.39
1.25
L or M Pin Voltage
(Positive Current)
VL, VM
VX
V
lL or lM = 225 µA
lX = -50 µA
lX = -150 µA
lM = -50 µA
lM = -150 µA
X Pin Voltage
(Negative Current)
V
V
M Pin Voltage
(Negative Current)
VM
Maximum Duty
Cycle Reduction
Onset Threshold
Current
IL (DC) or
IM (DC)
µA
40
60
75
TJ = 25 °C
Maximum Duty
Cycle Reduction
Slope
IL > IL(DC) or IM > IM (DC)
%/µA
0.25
X, L or M Pin
See Figure 70
VDRAIN = 150 V
TJ = 25 °C
0.6
1.0
1.0
1.6
Remote OFF
DRAIN Supply
Current
Floating
ID(RMT)
mA
L or M Pin Shorted
to CONTROL
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TOP242-249
Conditions
(Unless Otherwise Specified)
See Figure 53
Parameter
Symbol
Min
Typ
Max
Units
SOURCE = 0 V; TJ = -40 to 125 °C
MULTI-FUNCTION (M), LINE-SENSE (L) AND CURRENT LIMIT (I) INPUTS (cont)
From Remote On to Drain Turn-On
tR(ON)
Remote ON Delay
2.5
µs
µs
See Note B
Minimum Time Before Drain Turn-On
to Disable Cycle
Remote OFF
Setup Time
tR(OFF)
2.5
See Note B
FREQUENCY INPUT
FREQUENCY Pin
Threshold Voltage
VF
IF
2.9
40
V
See Note B
VF = VC
FREQUENCY Pin
Input Current
10
100
µA
CIRCUIT PROTECTION
TOP242 P/G
Internal; di/dt=90 mA/µs
TOP242 Y/R
0.418
0.697
0.45
0.75
0.481
0.802
See Note C
TJ= 25 °C
TOP243 P/G Internal; di/dt=150 mA/µs
TJ= 25 °C
See Note C
TOP243 Y/R
Internal; di/dt=180 mA/µs
0.837
0.930
0.90
1.00
0.963
1.070
TJ= 25 °C
See Note C
TOP244 P/G
TJ= 25 °C
Internal; di/dt=200 mA/µs
See Note C
TOP244 Y/R
Internal; di/dt=270 mA/µs
Self Protection
Current Limit
ILIMIT
1.256
1.674
2.511
3.348
4.185
5.022
1.35
1.80
2.70
3.60
4.50
5.40
1.445
1.926
2.889
3.852
4.815
5.778
A
TJ= 25 °C
See Note C
TOP245 Y/R
TJ= 25 °C
Internal; di/dt=360 mA/µs
See Note C
Internal; di/dt=540 mA/µs
See Note C
TOP246 Y/R
TJ= 25 °C
Internal; di/dt=720 mA/µs
TOP247 Y/R
TJ= 25 °C
See Note C
TOP248 Y/R
TJ= 25 °C
Internal; di/dt=900 mA/µs
See Note C
Internal;di/dt=1080 mA/µs
TOP249 Y/R
TJ= 25 °C
See Note C
0.75 x
ILIMIT(MIN)
≤ 85 VAC
(Rectified Line Input)
See
Note B
Initial Current Limit
IINIT
A
0.6 x
ILIMIT(MIN)
265 VAC
(Rectified Line Input)
See Fig. 52
Leading Edge
Blanking Time
ns
tLEB
220
IC = 4 mA
TJ = 25 °C
E
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37
TOP242-249
Conditions
(Unless Otherwise Specified)
See Figure 53
Parameter
Symbol
Min
Typ Max
Units
SOURCE = 0 V; TJ = -40 to 125 °C
CIRCUIT PROTECTION (cont)
tIL(D)
ns
°C
°C
V
IC = 4 mA
100
Current Limit Delay
Thermal Shutdown
Temperature
130
140
150
Thermal Shutdown
Hysteresis
75
Power-up Reset
Threshold Voltage
1.75
3.0
4.25
VC(RESET)
Figure 53, S1 Open
OUTPUT
TJ = 25 °C
15.6
25.7
7.80
12.9
5.20
8.60
3.90
6.45
2.60
4.30
1.95
3.22
1.56
2.58
1.30
2.15
18.0
30.0
9.00
15.0
6.00
10.0
4.50
7.50
3.00
5.00
2.25
3.75
1.80
3.00
1.50
2.50
TOP242
ID = 50 mA
TJ = 100 °C
TJ = 25 °C
TJ = 100 °C
TJ = 25 °C
TJ = 100 °C
TJ = 25 °C
TJ = 100 °C
TOP243
ID = 100 mA
TOP244
ID = 150 mA
TOP245
ID = 200 mA
ON-State
Resistance
RDS(ON)
Ω
TJ = 25 °C
TJ = 100 °C
TJ = 25 °C
TJ = 100 °C
TJ = 25 °C
TJ = 100 °C
TJ = 25 °C
TJ = 100 °C
TOP246
ID = 300 mA
TOP247
ID = 400 mA
TOP248
ID = 500 mA
TOP249
ID = 600 mA
VL, VM = Floating; IC = 4mA
VDS = 560 V; TJ = 125 °C
Off-State
IDSS
400
µA
Current
VL, VM = Floating; IC = 4mA
ID = 100 µA; TJ = 25 °C
Breakdown
BVDSS
700
V
Voltage
Rise
tR
100
50
ns
ns
Time
Measured in a Typical
Flyback Converter Application
Fall
Time
tF
E
7/01
38
TOP242-249
Conditions
(Unless Otherwise Specified)
See Figure 53
Parameter
Symbol
Min
Typ Max
Units
SOURCE = 0 V; TJ = -40 to 125 °C
SUPPLY VOLTAGE CHARACTERISTICS
DRAIN Supply
Voltage
See Note D
36
V
Shunt Regulator
Voltage
IC = 4 mA
VC(SHUNT)
5.60
5.85
50
6.10
V
Shunt Regulator
Temperature Drift
ppm/°C
Output
MOSFET Enabled
VL, VM = 0 V
TOP 242-245
TOP 246-249
1.0
1.2
1.6
2.2
2.5
3.2
lCD1
Control Supply/
Discharge Current
mA
Output
MOSFET Disabled
VL, VM = 0 V
lCD2
0.3
0.6
1.3
NOTES:
A. For specifications with negative values, a negative temperature coefficient corresponds to an increase in
magnitude with increasing temperature, and a positive temperature coefficient corresponds to a decrease in
magnitude with increasing temperature.
B. Guaranteed by characterization. Not tested in production.
C. For externally adjusted current limit values, please refer to Figure 55 (Current Limit vs. External Current Limit
Resistance) in the Typical Performance Characteristics section.
D. It is possible to start up and operate TOPSwitch-GX at DRAIN voltages well below 36 V. However, the
CONTROL pin charging current is reduced, which affects start-up time, auto-restart frequency, and auto-restart
duty cycle. Refer to Figure 67, the characteristic graph on CONTROL pin charge current (IC) vs. DRAIN voltage
for low voltage operation characteristics.
E
7/01
39
TOP242-249
t
2
t
1
HV
90%
90%
t
t
DRAIN
VOLTAGE
1
2
D =
10%
0 V
PI-2039-033001
Figure 50. Duty Cycle Measurement.
t
(Blanking Time)
LEB
120
100
80
1.3
1.2
1.1
1.0
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
I
@ 85 VAC
INIT(MIN)
60
I
@ 265 VAC
INIT(MIN)
40
I
I
@ 25 °C
@ 25 °C
LIMIT(MAX)
LIMIT(MIN)
Dynamic
Impedance
1
=
Slope
20
0
0
0
2
4
6
8
10
0
1
2
3
4
5
6
7
8
CONTROL Pin Voltage (V)
Figure 51. CONTROL Pin I-V Characteristic.
Time (µs)
Figure 52. Drain Current Operating Envelope.
Y or R Package (X and L Pin)
P or G Package (M Pin)
0-100 kΩ
S1
470 Ω
5 W
0-100 kΩ
S5
5-50 V
M
5-50 V
0-60 kΩ
40 V
L
D
CONTROL
470 Ω
C
TOPSwitch-GX
S2
F
X
S
S4
0-15 V
S3
47 µF
0.1 µF
0-60 kΩ
NOTES: 1. This test circuit is not applicable for current limit or output characteristic measurements.
2. For P and G packages, short all SOURCE pins together.
PI-2631-033001
Figure 53. TOPSwitch-GX General Test Circuit.
E
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40
TOP242-249
BENCH TEST PRECAUTIONS FOR EVALUATION OF ELECTRICAL CHARACTERISTICS
The following precautions should be followed when testing
TOPSwitch-GX by itself outside of a power supply. The
schematic shown in Figure 53 is suggested for laboratory
testing of TOPSwitch-GX.
restart mode, there is only a 12.5% chance that the CONTROL
pin oscillation will be in the correct state (drain active state) so
that the continuous drain voltage waveform may be observed.
It is recommended that the VC power supply be turned on first
and the DRAIN pin power supply second if continuous drain
voltage waveforms are to be observed. The 12.5% chance of
being in the correct state is due to the divide-by-8 counter.
Temporarily shorting the CONTROL pin to the SOURCE pin
will reset TOPSwitch-GX, which then will come up in the
correct state.
When the DRAIN pin supply is turned on, the part will be in the
auto-restartmode. TheCONTROLpinvoltagewillbeoscillating
at a low frequency between 4.8 and 5.8 V and the drain is turned
on every eighth cycle of the CONTROL pin oscillation. If the
CONTROL pin power supply is turned on while in this auto-
Typical Performance Characteristics
PI-2653-033001
1.1
1.0
0.9
0.8
0.7
0.6
0.5
0.4
0.3
Scaling Factors:
200
TOP242:
.45
TOP243 P/G: .75
TOP243 Y/R: .90
180
160
140
TOP244 P/G:
1
TOP244 Y/R: 1.35
TOP245 Y/R: 1.80
TOP246 Y/R: 2.70
TOP247 Y/R: 3.60
TOP248 Y/R: 4.50
TOP249 Y/R: 5.40
120
100
80
60
0.2
40
-250
-200
-150
-100
-50
0
IM (µA)
Figure 54. Current Limit vs. MULTI-FUNCTION Pin Current.
PI-2652-033001
1.1
1.0
0.9
200
180
Scaling Factors:
TOP242:
.45
TOP243 P/G: .75
TOP243 Y/R: .90
TOP244 P/G:
TOP244 Y/R: 1.35
TOP245 Y/R: 1.80
TOP246 Y/R: 2.70
TOP247 Y/R: 3.60
TOP248 Y/R: 4.50
TOP249 Y/R: 5.40
160
140
0.8
1
Maximum
0.7
Minimum
120
100
80
0.6
Typical
0.5
0.4
0.3
Maximum and minimum levels
are based on characterization.
60
40
0.2
0
5K
10K
15K
External Current Limit Resistor RIL (Ω)
Figure 55. Current Limit vs. External Current Limit Resistance.
20K
25K
30K
35K
40K
45K
E
7/01
41
TOP242-249
Typical Performance Characteristics (cont.)
1.2
1.0
0.8
0.6
0.4
1.1
1.0
0.9
0.2
0
-50 -25
0
25 50 75 100 125 150
-50 -25
0
25 50 75 100 125 150
Junction Temperature (°C)
Junction Temperature (°C)
Figure 56. Breakdown Voltage vs. Temperature.
Figure 57. Frequency vs. Temperature.
1.2
1.0
0.8
0.6
0.4
0.2
1.2
1.0
0.8
0.6
0.4
0.2
0
0
-50 -25
0
25 50 75 100 125 150
-50 -25
0
25 50 75 100 125 150
Junction Temperature (°C)
Junction Temperature (°C)
Figure 59. External Current Limit vs. Temperature
Figure 58. Internal Current Limit vs. Temperature.
with RIL =12 kΩ.
1.2
1.0
1.2
1.0
0.8
0.6
0.4
0.2
0
0.8
0.6
0.4
0.2
0
-50 -25
0
25 50 75 100 125 150
-50 -25
0
25 50 75 100 125 150
Junction Temperature (°C)
Junction Temperature (°C)
Figure 60. Overvoltage Threshold vs. Temperature.
Figure 61. Under-Voltage Threshold vs. Temperature.
E
7/01
42
TOP242-249
Typical Performance Characteristics (cont.)
6.0
1.6
1.4
1.2
1.0
0.8
0.6
0.4
0.2
VX = 1.33 - IXx 0.66 kΩ
-200 µA IX -25 µA
5.5
5.0
≤
≤
4.5
4.0
3.5
3.0
2.5
2.0
0
0
100
200
300
400
-240
-180
-120
-60
0
LINE-SENSE Pin Current (µA)
EXTERNAL CURRENT LIMIT Pin Current (µA)
Figure 62b. EXTERNAL CURRENT LIMIT Pin Voltage
vs. Current.
Figure 62a. LINE-SENSE Pin Voltage vs. Current.
1.6
6
5
4
3
VM = 1.37 - IMx 1 kΩ
1.4
-200 µA
≤ IM ≤ -25 µA
1.2
1.0
0.8
0.6
0.4
0.2
0
2
See
Expanded
Version
1
0
-300 -250 -200 -150 -100 -50
0
-300 -200 -100
0
100 200 300 400 500
MULTI-FUNCTION Pin Current (µA)
MULTI-FUNCTION Pin Current (µA)
Figure 63a. MULTI-FUNCTION Pin Voltage vs. Current.
Figure 63b. MULTI-FUNCTION Pin Voltage vs.
Current (Expanded).
1.2
1.0
0.8
0.6
0.4
0.2
1.2
1.0
0.8
0.6
0.4
0.2
0
0
-50 -25
0
25 50 75 100 125 150
-50 -25
0
25 50 75 100 125 150
Junction Temperature (°C)
Junction Temperature (°C)
Figure 64. Control Current Out at 0% Duty Cycle vs.
Temperature.
Figure 65. Max. Duty Cycle Reduction Onset Threshold
Current vs. Temperature.
E
7/01
43
TOP242-249
Typical Performance Characteristics (cont.)
6
I vs. DRAIN VOLTAGE
C
2
VC = 5 V
5
1.6
1.2
4
TCASE = 25 °C
TCASE = 100 °C
3
Scaling Factors:
TOP249 1.00
TOP248 0.83
TOP247 0.67
TOP246 0.50
TOP245 0.33
TOP244 0.25
TOP243 0.17
TOP242 0.08
0.8
0.4
0
2
1
0
0
2
4
6
8
10 12 14 16 18 20
0
20
40
60
80
100
DRAIN Voltage (V)
DRAIN Voltage (V)
Figure 66. Output Characteristics.
Figure 67. IC vs. DRAIN Voltage.
10000
600
Scaling Factors:
TOP249 1.00
500
TOP248 0.83
TOP247 0.67
Scaling Factors:
TOP246 0.50
1000
100
10
TOP249 1.00
TOP248 0.83
TOP247 0.67
TOP246 0.50
TOP245 0.33
TOP244 0.25
TOP243 0.17
TOP242 0.08
400
TOP245 0.33
TOP244 0.25
TOP243 0.17
300
200
100
0
TOP242 0.08
0
100 200 300 400 500 600
0
100 200 300 400 500 600
Drain Voltage (V)
DRAIN Voltage (V)
Figure 69. DRAIN Capacitance Power.
Figure 68. COSS vs. DRAIN Voltage.
1.2
1.0
0.8
0.6
0.4
0.2
0
-50
0
50
100
150
Junction Temperature (°C)
Figure 70. Remote OFF DRAIN Supply Current
vs. Temperature.
E
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44
TOP242-249
PART ORDERING INFORMATION
TOPSwitch Product Family
GX Series Number
Package Identifier
G
P
Plastic Surface Mount DIP
(242, 243 & 244 only)
Plastic DIP
Y
Plastic TO-220-7C
R
Plastic TO-263-7C (available only with TL option)
Package/Lead Options
Blank Standard Configurations
TOP 242 G - TL
TL
Tape & Reel, (G Package: 1 k min., R Package: 750 min.)
TO-220-7C
.165 (4.19)
.185 (4.70)
.400 (10.16)
.415 (10.54)
.045 (1.14)
.055 (1.40)
.146 (3.71)
.156 (3.96)
.108 (2.74) REF
.236 (5.99)
.260 (6.60)
+
.570 (14.48)
REF.
.467 (11.86)
.487 (12.37)
7° TYP.
.670 (17.02)
REF.
.860 (21.84)
.880 (22.35)
.095 (2.41)
.115 (2.92)
PIN 1 & 7
PIN 2 & 4
.026 (.66)
.032 (.81)
.040 (1.02)
.060 (1.52)
PIN 1
.010 (.25) M
.015 (.38)
.020 (.51)
.040 (1.02)
.060 (1.52)
.050 (1.27) BSC
.150 (3.81) BSC
.190 (4.83)
.210 (5.33)
.050 (1.27)
.050 (1.27)
Notes:
1. Controlling dimensions are inches. Millimeter
dimensions are shown in parentheses.
2. Pin numbers start with Pin 1, and continue
from left to right when viewed from the front.
3. Dimensions do not include mold flash or
other protrusions. Mold flash or protrusions
shall not exceed .006 (.15mm) on any side.
4. Minimum metal to metal spacing at the pack-
age body for omitted pin locations is .068
inch (1.73 mm).
.050 (1.27)
.050 (1.27)
.180 (4.58)
.200 (5.08)
.100 (2.54)
PIN 1
PIN 7
.150 (3.81)
.150 (3.81)
5. Position of terminals to be measured at a
location .25 (6.35) below the package body.
6. All terminals are solder plated.
MOUNTING HOLE PATTERN
Y07C
PI-2644-040501
E
7/01
45
TOP242-249
DIP-8B
⊕
D S .004 (.10)
Notes:
1. Package dimensions conform to JEDEC specification
MS-001-AB (Issue B 7/85) for standard dual-in-line (DIP)
package with .300 inch row spacing.
-E-
2. Controlling dimensions are inches. Millimeter sizes are
shown in parentheses.
3. Dimensions shown do not include mold flash or other
protrusions. Mold flash or protrusions shall not exceed
.006 (.15) on any side.
.245 (6.22)
.255 (6.48)
4. Pin locations start with Pin 1, and continue counter-clock-
wise to Pin 8 when viewed from the top. The notch and/or
dimple are aids in locating Pin 1. Pin 6 is omitted.
5. Minimum metal to metal spacing at the package body for
the omitted lead location is .137 inch (3.48 mm).
6. Lead width measured at package body.
Pin 1
-D-
.375 (9.53)
.385 (9.78)
7. Lead spacing measured with the leads constrained to be
perpendicular to plane T.
.057 (1.45)
.063 (1.60)
(NOTE 6)
.128 (3.25)
.132 (3.35)
0.15 (.38)
MINIMUM
-T-
SEATING
PLANE
.010 (.25)
.015 (.38)
.125 (3.18)
.135 (3.43)
.300 (7.62) BSC
(NOTE 7)
.100 (2.54) BSC
.048 (1.22)
.053 (1.35)
T E D S .010 (.25) M
P08B
.300 (7.62)
.390 (9.91)
.014 (.36)
.022 (.56)
⊕
PI-2551-101599
SMD-8B
Notes:
Heat Sink is 2 oz. Copper
As Big As Possible
⊕
D S .004 (.10)
1. Controlling dimensions are
inches. Millimeter sizes are
shown in parentheses.
2. Dimensions shown do not
include mold flash or other
protrusions. Mold flash or
protrusions shall not exceed
.006 (.15) on any side.
3. Pin locations start with Pin 1,
and continue counter-clock
Pin 8 when viewed from the
top. Pin 6 is omitted.
-E-
.372 (9.45)
.388 (9.86)
.245 (6.22)
.255 (6.48)
.420
.010 (.25)
⊕
E S
.046 .060 .060 .046
4. Minimum metal to metal
spacing at the package body
for the omitted lead location
is .137 inch (3.48 mm).
5. Lead width measured at
package body.
6. D and E are referenced
datums on the package
body.
.080
Pin 1
Pin 1
-D-
.086
.186
.286
.100 (2.54) (BSC)
.375 (9.53)
.385 (9.78)
Solder Pad Dimensions
.057 (1.45)
.063 (1.60)
(NOTE 5)
.128 (3.25)
.132 (3.35)
.004 (.10)
.032 (.81)
.037 (.94)
.048 (1.22)
°
°
.009 (.23)
0 - 8
.036 (0.91)
.044 (1.12)
.004 (.10)
.012 (.30)
.053 (1.35)
G08B
PI-2546-040501
E
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46
TOP242-249
TO-263-7C
.396 (10.06)
.415 (10.54)
.245 (6.22)
min.
.045 (1.14)
.055 (1.40)
.055 (1.40)
.066 (1.68)
.225 (5.72)
min.
.326 (8.28)
.336 (8.53)
.580 (14.73)
.620 (15.75)
.000 (0.00)
.010 (0.25)
.208 (5.28)
Ref.
.090 (2.29)
.110 (2.79)
-A-
.010 (0.25)
LD #1
.017 (0.43)
.023 (0.58)
.026 (0.66)
.032 (0.81)
.100 (2.54)
Ref.
.050 (1.27)
°
°
8 -
0
.315 (8.00)
Solder Pad
Dimensions
.165 (4.19)
.185 (4.70)
.380 (9.65)
.004 (0.10)
Notes:
.638 (16.21)
1. Package Outline Exclusive of Mold Flash & Metal Burr.
2. Package Outline Inclusive of Plating Thickness.
3. Foot Length Measured at Intercept Point Between
Datum A Lead Surface.
.128 (3.25)
R07C
.050 (1.27)
.038 (0.97)
4. Controlling Dimensions are in Inches. Millimeter
Dimensions are shown in Parentheses.
PI-2664-040501
E
7/01
47
TOP242-249
Revision
Date
Notes
-
D
E
11/00
1) Added R package (D2PAK).
7/01
2) Corrected abbreviations (s = seconds).
3) Corrected x-axis units in Figure 11 (µA).
4) Added missing external current limit resistor in Figure 25 (RIL).
5) Corrected spelling.
6) Added caption for Table 4.
7) Corrected Breakdown Voltage parameter condition (TJ = 25 °C)
8) Corrected font sizes in figures.
9) Figure 40 replaced.
10) Corrected schematic component values in Figure 44.
For the latest updates, visit our Web site: www.powerint.com
Power Integrations reserves the right to make changes to its products at any time to improve reliability or manufacturability.
Power Integrations does not assume any liability arising from the use of any device or circuit described herein, nor does it
convey any license under its patent rights or the rights of others.
The PI Logo, TOPSwitch, TinySwitch and EcoSmart are registered trademarks of Power Integrations, Inc.
©Copyright 2001, Power Integrations, Inc.
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E
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48
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POWERINT
TOP245RN-TL
TOPSwitch-GX Family Extended Power, Design Flexible, EcoSmart, Integrated Off-line Switcher
POWERINT
TOP245Y-
TOPSwitch-GX Family Extended Power, Design Flexible, EcoSmart, Integrated Off-line Switcher
POWERINT
TOP245Y-TL
TOPSwitch-GX Family Extended Power, Design Flexible, EcoSmart, Integrated Off-line Switcher
POWERINT
TOP245YN
TOPSwitch-GX Family Extended Power, Design Flexible, EcoSmart, Integrated Off-line Switcher
POWERINT
TOP245YN-
TOPSwitch-GX Family Extended Power, Design Flexible, EcoSmart, Integrated Off-line Switcher
POWERINT
TOP245YN-TL
TOPSwitch-GX Family Extended Power, Design Flexible, EcoSmart, Integrated Off-line Switcher
POWERINT
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