TOP265VG [POWERINT]

Integrated Off-Line Switcher with EcoSmart Technology for Highly Efficient Power Supplies; 集成离线式开关与EcoSmart技术的高效率电源
TOP265VG
型号: TOP265VG
厂家: Power Integrations    Power Integrations
描述:

Integrated Off-Line Switcher with EcoSmart Technology for Highly Efficient Power Supplies
集成离线式开关与EcoSmart技术的高效率电源

开关
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中文:  中文翻译
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TOP264-271  
®
TOPSwitch-JX Family  
®
Integrated Off-Line Switcher with EcoSmart Technology  
for Highly Efficient Power Supplies  
Product Highlights  
+
EcoSmart® - Energy Efficient  
Energy efficient over entire load range  
No-load consumption below 100 mW at 265 VAC  
AC  
IN  
DC  
OUT  
-
Up to 750 mW standby output power for 1 W input at 230 VAC  
D
S
V
High Design Flexibility for Low System Cost  
Multi-mode PWM control maximizes efficiency at all loads  
132 kHz operation reduces transformer and power supply size  
66 kHz option for highest efficiency requirements  
Accurate programmable current limit  
CONTROL  
C
TOPSwitch-JX  
X
F
Optimized line feed-forward for line ripple rejection  
Frequency jittering reduces EMI filter cost  
Fully integrated soft-start for minimum startup stress  
725 V rated MOSFET  
PI-5578-090309  
Figure 1. Typical Flyback Application.  
Simplifies meeting design derating requirements  
Extensive Protection Features  
Auto-restart limits power delivery to <3% during overload faults  
Output short-circuit protection (SCP)  
Output over-current protection (OCP)  
Heat transfer to both PCB and heat sink  
Optional external heat sink provides thermal impedance  
equivalent to a TO-220  
eSIP®-7C package:  
Output overload protection (OPP)  
Vertical orientation for minimum PCB footprint  
Simple heat sink mounting using clip provides thermal  
impedance equivalent to a TO-220  
Extended creepage to DRAIN pin  
Heat sink is connected to SOURCE for low EMI  
Output overvoltage protection (OVP)  
User programmable for hysteretic/latching shutdown  
Simple fast AC reset  
Primary or secondary sensed  
Line undervoltage (UV) detection prevents turn-off glitches  
Line overvoltage (OV) shutdown extends line surge withstand  
Accurate thermal shutdown with large hysteresis (OTP)  
Description  
TOPSwitch-JX cost effectively incorporates a 725 V power  
MOSFET, high voltage switched current source, multi-mode  
PWM control, oscillator, thermal shutdown circuit, fault  
protection and other control circuitry onto a monolithic device.  
Advanced Package Options  
eDIP-12 package:  
Low profile horizontal orientation for ultra-slim designs  
Output Power Table  
PCB Copper Area1  
Metal Heat Sink1  
230 VAC 15%4  
85-265 VAC  
230 VAC 15% 4  
Adapter2  
85-265 VAC  
Product5  
Product5  
Open  
Open  
Open  
Open  
Adapter2  
Adapter2  
Adapter2  
Frame3  
Frame3  
Frame3  
Frame3  
TOP264VG  
21 W  
22.5 W  
24 W  
27.5 W  
30 W  
32 W  
34 W  
36 W  
34 W  
12 W  
15 W  
17 W  
22.5 W  
TOP264EG/VG  
TOP265EG/VG  
TOP266EG/VG  
TOP267EG/VG  
TOP268EG/VG  
TOP269EG/VG  
TOP270EG/VG  
TOP271EG/VG  
30 W  
40 W  
60 W  
62 W  
20 W  
26 W  
40 W  
55 W  
70 W  
80 W  
93 W  
118 W  
43 W  
57 W  
86 W  
103 W  
112 W  
120 W  
140 W  
177 W  
TOP265VG  
TOP266VG  
TOP267VG  
TOP268VG  
TOP269VG  
TOP270VG  
TOP271VG  
36 W  
39 W  
44 W  
48 W  
51 W  
55 W  
59 W  
25 W  
28.5 W  
32 W  
36 W  
37.5 W  
41 W  
81 W  
119 W  
137 W  
148 W  
162 W  
190 W  
244 W  
19 W  
85 W  
21.5 W  
22.5 W  
24.5 W  
26 W  
105 W  
128 W  
147 W  
177 W  
43 W  
Table 1. Output Power Table.  
Notes:  
1. See Key Application Considerations section for more details.  
2. Minimum continuous power in a typical non-ventilated enclosed adapter measured at +50 °C ambient temperature.  
3. Minimum continuous power in an open frame design at +50 °C ambient temperature.  
4. 230 VAC or 110/115 VAC with doubler.  
5. Packages: E: eSIP-7C, V: eDIP-12. See Part Ordering Information section.  
www.powerint.com  
March 2010  
TOP264-271  
Section List  
Functional Block Diagram ....................................................................................................................................... 3  
Pin Functional Description ...................................................................................................................................... 3  
TOP264-271 Functional Description ........................................................................................................................ 4  
CONTROL (C) Pin Operation.................................................................................................................................... 5  
Oscillator and Switching Frequency.......................................................................................................................... 5  
Pulse Width Modulator ............................................................................................................................................ 5  
Maximum Duty Cycle ............................................................................................................................................... 6  
Error Amplifier .......................................................................................................................................................... 6  
On-Chip Current Limit with External Programmability ............................................................................................... 6  
Line Undervoltage Detection (UV)............................................................................................................................. 6  
Line Overvoltage Shutdown (OV).............................................................................................................................. 7  
Hysteretic or Latching Output Overvoltage Protection (OVP)..................................................................................... 7  
Line Feed-Forward with DCMAX Reduction ................................................................................................................ 8  
Remote ON/OFF ..................................................................................................................................................... 8  
Soft-Start................................................................................................................................................................. 9  
Shutdown/Auto-Restart (for OCP, SCP, OPP)......................................................................................................... 10  
Hysteretic Over-Temperature Protection (OTP) ....................................................................................................... 10  
Bandgap Reference ............................................................................................................................................... 10  
High-Voltage Bias Current Source.......................................................................................................................... 10  
Typical Uses of FREQUENCY (F) Pin ...................................................................................................................... 12  
Typical Uses of VOLTAGE MONITOR (V) and EXTERNAL CURRENT LIMIT (X) Pins .......................................... 13  
Application Examples .............................................................................................................................................. 15  
Low No-load, High Efficiency, 65 W, Universal Input Adapter Power Supply ..................................................................... 15  
Very low No-load, High Efficiency, 30 W, Universal Input, Open Frame, Power Supply..............................................................17  
Key Application Considerations .............................................................................................................................. 18  
TOPSwitch-JX vs.TOPSwitch-HX........................................................................................................................ . 18  
TOP264-271 Design Considerations ..................................................................................................................... 18  
TOP264-271 Layout Considerations ...................................................................................................................... 20  
Quick Design Checklist .......................................................................................................................................... 21  
Design Tools .......................................................................................................................................................... 21  
Product Specifications and Test Conditions .......................................................................................................... 23  
Typical Performance Characteristics .................................................................................................................... 30  
Package Outlines .................................................................................................................................................... 34  
Part Ordering Information ........................................................................................................................................ 35  
2
Rev. B 03/10  
www.powerint.com  
TOP264-271  
DRAIN (D)  
0
1
VC  
CONTROL (C)  
INTERNAL  
SUPPLY  
ZC  
-
SHUNT REGULATOR/  
ERROR AMPLIFIER  
+
-
+
SOFT START  
5.8 V  
4.8 V  
-
KPS(UPPER)  
INTERNAL UV  
COMPARATOR  
5.8 V  
+
-
IFB  
+
V
I (LIMIT)  
CURRENT  
LIMIT  
ADJUST  
KPS(LOWER)  
-
÷ 16  
ON/OFF  
+
SHUTDOWN/  
AUTO-RESTART  
EXTERNAL CURRENT  
LIMIT (X)  
CURRENT LIMIT  
COMPARATOR  
VBG + VT  
VOLTAGE  
MONITOR (V)  
STOP LOGIC  
HYSTERETIC  
THERMAL  
SHUTDOWN  
SOURCE (S)  
1 V  
CONTROLLED  
TURN-ON  
GATE DRIVER  
V
OVP OV/  
UV  
STOP SOFT  
LINE  
SENSE  
DCMAX  
START  
DCMAX  
DMAX  
OSCILLATOR  
WITH JITTER  
CLOCK  
S
R
Q
FREQUENCY (F)  
66k/132k  
F REDUCTION  
LEADING  
EDGE  
BLANKING  
F REDUCTION  
SOFT START  
IFB  
IPS(UPPER)  
IPS(LOWER)  
OFF  
PWM  
KPS(UPPER)  
KPS(LOWER)  
PI-4511-012810  
SOURCE (S)  
Figure 2. Functional Block Diagram (E and V Package).  
Pin Functional Description  
DRAIN (D) Pin:  
SOURCE (S) Pin:  
Output MOSFET source connection for high voltage power return.  
Primary side control circuit common and reference point.  
High-voltage power MOSFET DRAIN pin. 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.  
NO CONNECTION (NC) Pin:  
Internally not connected, floating potential pin.  
CONTROL (C) Pin:  
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.  
E Package (eSIP-7C)  
V Package (eDIP-12)  
S 12  
1 V  
Exposed Pad  
(Hidden)  
Internally  
Connected to  
SOURCE Pin  
EXTERNAL CURRENT LIMIT (X) Pin:  
S 11  
S 10  
S 9  
2 X  
Input pin for external current limit adjustment remote  
ON/OFF and device reset. A connection to SOURCE pin  
disables all functions on this pin.  
3 C  
4 F  
S 8  
5 NC  
S 7  
6 D  
VOLTAGE MONITOR (V) Pin:  
Input for OV, UV, line feed forward with DCMAX reduction, output  
overvoltage protection (OVP), remote ON/OFF. A connection to  
the SOURCE pin disables all functions on this pin.  
1 2 3 4 5  
V X C F S  
7
D
FREQUENCY (F) Pin:  
Input pin for selecting switching frequency 132 kHz if connected  
to SOURCE pin and 66 kHz if connected to CONTROL pin.  
PI-5568-083109  
Figure 3. Pin Configuration (Top View).  
3
www.powerint.com  
Rev. B 03/10  
TOP264-271  
VUV = IUV × RLS + VV (IV = IUV  
)
)
Auto-Restart  
+
V
OV = IOV × RLS + VV (IV = IOV  
78  
For RLS = 4 M  
Slope = PWM Gain  
4 M  
RLS  
VUV = 102.8 VDC  
VOV = 451 VDC  
DCMAX@100 VDC = 76%  
DCMAX@375 VDC = 41%  
DC  
Input  
Voltage  
D
S
V
CONTROL  
C
For RIL = 12 kΩ  
ILIMIT = 61%  
X
CONTROL  
Current  
See Figure 35 for  
other resistor values  
(RIL) to select different  
ILIMIT values.  
RIL  
12 kΩ  
-
100  
55  
Figure 4. Package Line Sense and Externally Set Current Limit.  
TOP264-271 Functional Description  
Like TOPSwitch-HX, TOP264-271 is an integrated switched  
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  
25  
power MOSFET. During normal operation the duty cycle of the  
power MOSFET decreases linearly with increasing CONTROL  
pin current as shown in Figure 5.  
CONTROL  
Current  
Full Frequency Mode  
In addition to the three terminal TOPSwitch features, such as  
the high voltage start-up, the cycle-by-cycle current limiting,  
loop compensation circuitry, auto-restart and thermal shut-  
down, the TOP264-271 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.  
132  
66  
Low  
Frequency  
Mode  
Variable  
Frequency  
Mode  
Multi-Cycle  
Modulation  
Jitter  
30  
CONTROL  
IC03 ICOFF  
ICD1 IB  
IC01  
IC02  
Current  
Three terminals, FREQUENCY, VOLTAGE-MONITOR, and  
EXTERNAL CURRENT LIMIT have been used to implement  
some of the new functions. These terminals can be connected  
to the SOURCE pin to operate the TOP264-271 in a TOPSwitch-  
like three terminal mode. However, even in this three terminal  
mode, the TOP264-271 offers many transparent features that do  
not require any external components:  
PI-5665-110609  
Figure 5. Control Pin Characteristics (Multi-Mode Operation).  
6. Hysteretic over-temperature shutdown ensures thermal fault  
protection.  
7. Packages with omitted pins and lead forming provide large  
drain creepage distance.  
1. A fully integrated 17 ms soft-start significantly reduces or  
eliminates output overshoot in most applications by sweeping  
both current limit and frequency from low to high to limit the  
peak currents and voltages during start-up.  
2. A maximum duty cycle (DCMAX) of 78% allows smaller input  
storage capacitor, lower input voltage requirement and/or  
higher power capability.  
3. Multi-mode operation optimizes and improves the power  
supply efficiency over the entire load range while maintaining  
good cross regulation in multi-output supplies.  
4. Switching frequency of 132 kHz reduces the transformer size  
with no noticeable impact on EMI.  
8. Reduction of the auto-restart duty cycle and frequency to  
improve the protection of the power supply and load during  
open loop fault, short circuit, or loss of regulation.  
9. Tighter tolerances on I2f power coefficient, current limit  
reduction, PWM gain and thermal shutdown threshold.  
The VOLTAGE-MONITOR (V) pin is usually used for line sensing  
by connecting a 4 MW resistor from this pin to the rectified DC  
high voltage bus to implement line overvoltage (OV), under-  
voltage (UV) and dual-slope line feed-forward with DCMAX  
reduction. In this mode, the value of the resistor determines the  
OV/UV thresholds and the DCMAX is reduced linearly with a dual  
slope to improve line ripple rejection. In addition, it also  
provides another threshold to implement the latched and  
5. Frequency jittering reduces EMI in the full frequency mode at  
high load condition.  
4
Rev. B 03/10  
www.powerint.com  
TOP264-271  
hysteretic output overvoltage protection (OVP). The pin can  
also be used as a remote ON/OFF using the IUV threshold.  
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 undervoltage comparator keeps VC within a window of  
typically 4.8 V to 5.8 V by turning the high-voltage current  
source on and off as shown in Figure 7. The auto-restart circuit  
has a divide-by-sixteen counter, which prevents the output  
MOSFET from turning on again until sixteen discharge/charge  
cycles have elapsed. This is accomplished by enabling the  
output MOSFET only when the divide-by-sixteen counter  
reaches the full count (S15). The counter effectively limits  
TOP264-271 power dissipation by reducing the auto-restart  
duty cycle to typically 2%. Auto-restart mode continues until  
output voltage regulation is again achieved through closure of  
the feedback loop.  
The EXTERNAL CURRENT LIMIT (X) pin can be used to reduce  
the current limit externally to a value close to the operating peak  
current, by connecting the pin to SOURCE through a resistor.  
This pin can also be used as a remote ON/OFF input.  
The FREQUENCY (F) pin sets the switching frequency in the full  
frequency PWM mode 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 the CONTROL pin  
instead. Leaving this pin open is not recommended.  
CONTROL (C) Pin Operation  
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 including the  
MOSFET gate driver. An external bypass capacitor 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 rectified DC high voltage is applied to the DRAIN pin  
during start-up, the MOSFET is initially off, and the CONTROL  
pin capacitor is charged through a switched high voltage  
current source connected internally between the DRAIN and  
CONTROL 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  
drain peak current and switching frequency from a low starting  
value to the maximum drain peak current at the full frequency  
over approximately 17 ms. If no external feedback/supply  
current is fed into the CONTROL pin by the end of the soft-start,  
the high voltage current source is turned off and the CONTROL  
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 undervoltage lockout  
threshold). When the externally fed current charges the CONTROL  
pin to the shunt regulator voltage of 5.8 V, current in excess of  
the consumption of the chip is shunted to SOURCE through an  
NMOS current mirror as shown in Figure 2. The output current  
of that NMOS current mirror 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.  
Oscillator and Switching Frequency  
The internal oscillator linearly charges and discharges an  
internal capacitance between two voltage levels to create a  
triangular waveform for the timing of the pulse width modulator.  
This oscillator sets the pulse width modulator/current limit latch  
at the beginning of each cycle.  
The nominal full switching frequency of 132 kHz was chosen to  
minimize transformer size while keeping the fundamental EMI  
frequency below 150 kHz. The FREQUENCY pin, when shorted  
to the CONTROL pin, lowers the full switching frequency to  
66 kHz (half frequency), which may be preferable in some cases  
such as noise sensitive video applications or a high efficiency  
standby mode. Otherwise, the FREQUENCY pin should be  
connected to the SOURCE pin for the default 132 kHz.  
To further reduce the EMI level, the switching frequency in the  
full frequency PWM mode is jittered (frequency modulated) by  
approximately 2.5 kHz for 66 kHz operation or 5 kHz for  
132 kHz operation at a 250 Hz (typical) rate as shown in Figure 6.  
The jitter is turned off gradually as the system is entering the  
variable frequency mode with a fixed peak drain current.  
Pulse Width Modulator  
The pulse width modulator implements multi-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 5).  
The feedback error signal, in the form of the excess current, is  
filtered by an RC network with a typical corner frequency of  
7 kHz to reduce the effect of switching noise in the chip supply  
current generated by the MOSFET gate driver.  
To optimize power supply efficiency, four different control  
modes are implemented. At maximum load, the modulator  
operates in full frequency PWM mode; as load decreases, the  
modulator automatically transitions, first to variable frequency  
PWM mode, then to low frequency PWM mode. At light load,  
the control operation switches from PWM control to multi-cycle-  
modulation control, and the modulator operates in multi-cycle-  
modulation mode. Although different modes operate differently  
to make transitions between modes smooth, the simple  
relationship between duty cycle and excess CONTROL pin  
current shown in Figure 5 is maintained through all three PWM  
When a fault condition such as an open loop or shorted output  
prevents the flow of an external current into the CONTROL pin,  
the capacitor on the CONTROL pin discharges towards 4.8 V.  
At 4.8 V, auto-restart is activated, which turns the output  
5
www.powerint.com  
Rev. B 03/10  
TOP264-271  
Maximum Duty Cycle  
The maximum duty cycle, DCMAX, is set at a default maximum  
value of 78% (typical). However, by connecting the VOLTAGE-  
MONITOR to the rectified DC high voltage bus through a resistor  
with appropriate value (4 MW typical), the maximum duty cycle  
can be made to decrease from 78% to 40% (typical) when input  
line voltage increases from 88 V to 380 V, with dual gain slopes.  
fOSC  
+
Switching  
Frequency  
fOSC  
-
4 ms  
Error Amplifier  
VDRAIN  
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-  
compensated bandgap reference. The CONTROL pin dynamic  
impedance ZC sets the gain of the error amplifier. 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 becomes the feedback  
current IFB for the pulse width modulator.  
Time  
Figure 6. Switching Frequency Jitter (Idealized VDRAIN Waveforms).  
modes. Please see the following sections for the details of the  
operation of each mode and the transitions between modes.  
Full Frequency PWM mode: The PWM modulator enters full  
frequency PWM mode when the CONTROL pin current (IC)  
reaches IB. In this mode, the average switching frequency is  
kept constant at fOSC (pin selectable 132 kHz or 66 kHz). Duty  
cycle is reduced from DCMAX through the reduction of the on-time  
when IC is increased beyond IB. This operation is identical to the  
PWM control of all other TOPSwitch families. TOP264-271 only  
operates in this mode if the cycle-by-cycle peak drain current  
stays above kPS(UPPER) × ILIMIT(set), where kPS(UPPER) is 55% (typical)  
and ILIMIT(set) is the current limit externally set via the X pin.  
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  
to temperature related changes in RDS(ON) of the output MOSFET.  
The default current limit of TOP264-271 is preset internally.  
However, with a resistor connected between EXTERNAL  
CURRENT LIMIT (X) pin and SOURCE pin, current limit can be  
programmed externally to a lower level between 30% and 100%  
of the default current limit. By setting current limit low, a larger  
TOP264-271 than 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 second resistor  
connected between the EXTERNAL CURRENT LIMIT (X) pin  
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.  
Variable Frequency PWM mode: When peak drain current is  
lowered to kPS(UPPER) × ILIMIT(set) as a result of power supply load  
reduction, the PWM modulator initiates the transition to variable  
frequency PWM mode, and gradually turns off frequency jitter.  
In this mode, peak drain current is held constant at kPS(UPPER)  
ILIMIT(set) while switching frequency drops from the initial full  
frequency of fOSC (132 kHz or 66 kHz) towards the minimum  
×
frequency of fMCM(MIN) (30 kHz typical). Duty cycle reduction is  
accomplished by extending the off-time.  
Low Frequency PWM mode: When switching frequency  
reaches fMCM(MIN) (30 kHz typical), the PWM modulator starts to  
transition to low frequency mode. In this mode, switching  
frequency is held constant at fMCM(MIN) and duty cycle is reduced,  
similar to the full frequency PWM mode, through the reduction  
of the on-time. Peak drain current decreases from the initial  
value of kPS(UPPER) × ILIMIT(set) towards the minimum value of  
kPS(LOWER) × ILIMIT(set), where kPS(LOWER) is 25% (typical) and ILIMIT(set)  
is the current limit externally set via the X pin.  
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. The current limit is lower for a short period  
after the leading edge blanking time. This is due to dynamic  
characteristics of the MOSFET. During startup and fault  
conditions the controller prevents excessive drain currents by  
reducing the switching frequency.  
Multi-Cycle-Modulation mode: When peak drain current is  
lowered to kPS(LOWER) × ILIMIT(set), the modulator transitions to  
multi-cycle-modulation mode. In this mode, at each turn-on,  
the modulator enables output switching for a period of TMCM(MIN)  
at the switching frequency of fMCM(MIN) (4 or 5 consecutive pulses  
at 30 kHz) with the peak drain current of kPS(LOWER) × ILIMIT(set),  
and stays off until the CONTROL pin current falls below IC(OFF)  
.
This mode of operation not only keeps peak drain current low  
but also minimizes harmonic frequencies between 6 kHz and  
30 kHz. By avoiding transformer resonant frequency this way,  
all potential transformer audible noises are greatly suppressed.  
Line Undervoltage Detection (UV)  
At power up, UV keeps TOP264-271 off until the input line  
voltage reaches the undervoltage threshold. At power down,  
6
Rev. B 03/10  
www.powerint.com  
TOP264-271  
VUV  
VLINE  
0 V  
S14  
S14  
S15  
S13 S12  
S0  
S15 S14  
S13 S12  
S0  
S15  
S13 S12  
S0  
S15  
S15  
5.8 V  
4.8 V  
VC  
0 V  
VDRAIN  
0 V  
VOUT  
0 V  
1
2
3
2
4
Note: S0 through S15 are the output states of the auto-restart counter  
PI-4531-121206  
Figure 7. Typical Waveforms for (1) Power Up (2) Normal Operation (3) Auto-Restart (4) Power Down.  
UV prevents auto-restart attempts after the output goes out of  
regulation. This eliminates power down glitches caused by slow  
discharge of the large input storage capacitor present in  
applications such as standby supplies. A single resistor  
connected from the VOLTAGE-MONITOR pin to the rectified DC  
high voltage bus sets UV threshold during power up. Once the  
power supply is successfully turned on, the UV threshold is  
lowered to 44% 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 of each auto-restart  
cycle (S15), the UV comparator is enabled. If the UV high  
threshold is not exceeded, the MOSFET will be disabled during  
the next cycle (see Figure 7). The UV feature can be disabled  
independent of the OV feature.  
In order to reduce the no-load input power of TOP264-271  
designs, the V pin operates at very low currents. This requires  
careful layout considerations when designing the PCB to avoid  
noise coupling. Traces and components connected to the V pin  
should not be adjacent to any traces carrying switching currents.  
These include the drain, clamp network, bias winding return or  
power traces from other converters. If the line sensing features  
are used, then the sense resistors must be placed within 10 mm  
of the V pin to minimize the V pin node area. The DC bus  
should then be routed to the line sense resistors. Note that  
external capacitance must not be connected to the V pin as this  
may cause misoperaton of the V pin related functions.  
Hysteretic or Latching Output Overvoltage Protection (OVP)  
The detection of the hysteretic or latching output overvoltage  
protection (OVP) is through the trigger of the line overvoltage  
threshold. The V pin voltage will drop by 0.5 V, and the  
controller measures the external attached impedance immediately  
after this voltage drops. If IV exceeds IOV(LS) (336 mA typical)  
longer than 100 ms, TOP264-271 will latch into a permanent off  
state for the latching OVP. It only can be reset if IX exceeds IX(TH)  
= -27 mA (typ) or VC goes below the power-up-reset threshold  
(VC(RESET)) and then back to normal. If IV does not exceed IOV(LS) or  
exceeds no longer than 100 ms, TOP264-271 will initiate the line  
overvoltage and the hysteretic OVP. Their behavior will be  
identical to the line overvoltage shutdown (OV) that has been  
described in detail in the previous section. During a fault  
condition resulting from loss of feedback, output voltage will  
rapidly rise above the nominal voltage. The increase in output  
voltage will also result in an increase in the voltage at the output  
of the bias winding. A voltage at the output of the bias winding  
that exceeds of the sum of the voltage rating of the Zener diode  
connected from the bias winding output to the V pin and V pin  
voltage, will cause a current in excess of IV to be injected into  
the V pin, which will trigger the OVP feature.  
Line Overvoltage Shutdown (OV)  
The same resistor used for UV also sets an overvoltage  
threshold, which, once exceeded, will force TOP264-271 to  
stop switching instantaneously (after completion of the current  
switching cycle). If this condition lasts for at least 100 ms, the  
TOP264-271 output will be forced into off state. When the line  
voltage is back to normal with a small amount of hysteresis  
provided on the OV threshold to prevent noise triggering, the  
state machine sets to S13 and forces TOP264-271 to go  
through the entire auto-restart sequence before attempting to  
switch again. The ratio of OV and UV thresholds is preset at  
4.5, as can be seen in Figure 8. When the MOSFET is off, the  
rectified DC high voltage surge capability is increased to the  
voltage rating of the MOSFET (725 V), due to the absence of the  
reflected voltage and leakage spikes on the drain. The OV  
feature can be disabled independent of the UV feature.  
7
www.powerint.com  
Rev. B 03/10  
TOP264-271  
If the power supply is operating under heavy load or low input  
line conditions when an open loop occurs, the output voltage  
may not rise significantly. Under these conditions, a latching  
shutdown will not occur until load or line conditions change.  
Nevertheless, the operation provides the desired protection by  
preventing significant rise in the output voltage when the line or  
load conditions do change. Primary side OVP protection with  
the TOP264-271 in a typical application will prevent a nominal  
12 V output from rising above approximately 20 V under open  
loop conditions. If greater accuracy is required, a secondary  
sensed OVP circuit is recommended.  
Remote ON/OFF  
TOP264-271 can be turned on or off by controlling the current  
into the VOLTAGE-MONITOR pin or out from the EXTERNAL  
CURRENT LIMIT pin. In addition, the VOLTAGE-MONITOR pin  
has a 1 V threshold comparator connected at its input. This  
voltage threshold can also be used to perform remote ON/OFF  
control.  
When a signal is received at the VOLTAGE-MONITOR pin or the  
EXTERNAL CURRENT LIMIT pin to disable the output through  
any of the pin functions such as OV, UV and remote ON/OFF,  
TOP264-271 always completes its current switching cycle before  
the output is forced off.  
Line Feed-Forward with DCMAX Reduction  
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. Note that for the  
same CONTROL pin current, higher line voltage results in smaller  
operating duty cycle. As an added feature, the maximum duty  
cycle DCMAX is also reduced from 78% (typical) at a voltage slightly  
lower than the UV threshold to 36% (typical) at the OV threshold.  
DCMAX of 36% at high line was chosen to ensure that the power  
capability of the TOP264-271 is not restricted by this feature under  
normal operation. TOP264-271 provides a better fit to the ideal  
feed-forward by using two reduction slopes: -1% per mA for all bus  
voltage less than 195 V (typical for 4 MW line impedance) and  
-0.25% per mA for all bus voltage more than 195 V.  
As seen above, the remote ON/OFF feature can also be used as  
a standby or power switch to turn off the TOP264-271 and keep  
it in a very low power consumption state for indefinitely long  
periods. If the TOP264-271 is held in remote off state for long  
enough time to allow the CONTROL pin to discharge to the  
internal supply undervoltage threshold of 4.8 V (approximately  
32 ms for a 47 mF 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  
Voltage Monitor and External Current Limit Pin Table*  
Figure Number  
12  
13  
14  
15  
16  
17  
18  
19  
20  
21  
22  
23  
Three Terminal Operation  
Line Undervoltage (UV)  
Line Overvoltage (OV)  
Line Feed-Forward (DCMAX  
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
)
Output Overvoltage Protection (OVP)  
Overload Power Limiting (OPP)  
External Current Limit  
Remote ON/OFF  
3
3
3
3
3
3
3
3
3
3
3
3
3
Device Reset  
Fast AC Reset  
3
3
AC Brownout  
*This table is only a partial list of many VOLTAGE MONITOR and EXTERNAL CURRENT LIMIT Pin Configurations that are possible.  
Table 2. VOLTAGE MONITOR (V) Pin and EXTERNAL CURRENT LIMIT (X) Pin Configuration Options.  
8
Rev. B 03/10  
www.powerint.com  
TOP264-271  
X Pin  
V Pin  
IREM(N)  
IUV  
IOV  
IOV(LS)  
(Enabled)  
(Disabled)  
Output  
MOSFET  
Switching  
(Non-Latching) (Latching)  
Disabled when supply  
output goes out of  
regulation  
I
ILIMIT (Default)  
Current  
Limit  
I
DCMAX (78%)  
Maximum  
Duty Cycle  
I
VBG  
Pin Voltage  
I
-250  
-200  
-150  
-100  
-50  
0
25  
50  
75  
100  
125  
336  
X and V Pins 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. For a detailed description of  
each functional pin operation refer to the Functional Description section of the data sheet.  
PI-5528-060409  
Figure 8. VOLTAGE MONITOR and EXTERNAL CURRENT LIMIT (E and V package) Pin Characteristics.  
section above) and runs entirely off the high voltage DC input,  
but with very low power consumption (<100 mW typical at  
230 VAC with X pin open). When the TOP264-271 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 mF CONTROL pin capacitor. This reduced consumption  
remote off mode can eliminate expensive and unreliable in-line  
mechanical switches. 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.  
Soft-Start  
The 17 ms soft-start sweeps the peak drain current and switching  
frequency linearly from minimum to maximum value by operating  
through the low frequency PWM mode and the variable  
frequency mode before entering the full frequency mode. 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 effectively  
minimizes current and voltage stresses on the output MOSFET,  
the clamp circuit and the output rectifier during start-up. This  
feature also helps minimize output overshoot and prevents  
saturation of the transformer during start-up.  
9
www.powerint.com  
Rev. B 03/10  
TOP264-271  
Shutdown/Auto-Restart (for OCP, SCP, OPP)  
Bandgap Reference  
To minimize TOP264-271 power dissipation under fault  
conditions such as over current (OC), short circuit (SC) or over  
power (OP), the shutdown/auto-restart circuit turns the power  
supply on and off at an auto-restart duty cycle of typically 2% 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.  
All critical TOP264-271 internal voltages are derived from a  
temperature-compensated bandgap reference. This voltage  
reference is used to generate all other internal current references,  
which are trimmed to accurately set the switching frequency,  
MOSFET gate drive current, current limit, and the line OV/UV/  
OVP thresholds. TOP264-271 has improved circuitry to  
maintain all of the above critical parameters within very tight  
absolute and temperature tolerances.  
High-Voltage Bias Current Source  
This high-voltage current source biases TOP264-271 from the  
DRAIN pin and charges the CONTROL pin external capacitance  
during start-up or hysteretic operation. Hysteretic operation  
occurs during auto-restart, remote OFF and over-temperature  
shutdown. In this mode of operation, the current source is  
switched on and off, with an effective duty cycle of approxi-  
mately 35%. This duty cycle is determined by the ratio of  
CONTROL pin charge (IC) and discharge currents (ICD1 and ICD2).  
This current source is turned off during normal operation when  
the output MOSFET is switching. The effect of the current  
source switching will be seen on the DRAIN voltage waveform  
as small disturbances and is normal.  
Hysteretic Over-Temperature Protection (OTP)  
Temperature protection is provided by a precision analog circuit  
that turns the output MOSFET off when the junction temperature  
exceeds the thermal shutdown temperature (142 °C typical).  
When the junction temperature cools to below the lower  
hysteretic temperature point, normal operation resumes, thus  
providing automatic recovery. A large hysteresis of 75 °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) triangular waveform is  
present on the CONTROL pin while in thermal shutdown.  
10  
Rev. B 03/10  
www.powerint.com  
TOP264-271  
CONTROL (C)  
200 µA  
(Negative Current Sense - ON/OFF,  
Current Limit Adjustment, OVP Latch Reset)  
VBG + VT  
EXTERNAL CURRENT LIMIT (X)  
VOLTAGE MONITOR (V)  
(Voltage Sense, ON/OFF)  
1 V  
VREF  
(Positive Current Sense - Undervoltage,  
Overvoltage, ON/OFF, Maximum Duty  
Cycle Reduction, Output Over-  
voltage Protection)  
400 µA  
PI-5567-030910  
Figure 9. VOLTAGE MONITOR (V) and EXTERNAL CURRENT LIMIT (X) Pin Input Simplified Schematic.  
11  
www.powerint.com  
Rev. B 03/10  
TOP264-271  
Typical Uses of FREQUENCY (F) Pin  
+
+
DC  
Input  
DC  
Input  
Voltage  
D
D
S
CONTROL  
Voltage  
CONTROL  
F
C
C
S
F
-
-
PI-2655-071700  
PI-2654-071700  
Figure 10. Full Frequency Operation (132 kHz).  
Figure 11. Half Frequency Operation (66 kHz).  
12  
Rev. B 03/10  
www.powerint.com  
TOP264-271  
Typical Uses of VOLTAGE MONITOR (V) and EXTERNAL CURRENT LIMIT (X) Pins  
+
+
VUV = IUV × RLS + VV (IV = IUV  
)
)
V Package  
(eDIP-12)  
E Package  
(eSIP-7C)  
V
OV = IOV × RLS + VV (IV = IOV  
S 12  
S 11  
S 10  
S 9  
1 V  
For RLS = 4 M  
2 X  
VUV = 102.8 VDC  
RLS 4 MΩ  
3 C  
4 F  
VOV = 451 VDC  
V X C  
F
S
D
DC  
Input  
Voltage  
DC  
Input  
Voltage  
S 8  
5 NC  
DCMAX@100 VDC = 76%  
DCMAX@375 VDC = 41%  
S 7  
6 D  
S
D
S
V
D
C
C
S
D
D
S
V
CONTROL  
CONTROL  
C
C
X
F
-
-
PI-4717-120307  
PI-5562-082809  
Figure 13. Line-Sensing for Undervoltage, Overvoltage and Line Feed-Forward.  
Figure 12. Three Terminal Operation (VOLTAGE MONITOR and EXTERNAL  
CURRENT LIMIT Features Disabled. FREQUENCY Pin Tied to  
SOURCE or CONTROL Pin.)  
VUV = IUV × RLS + VV (IV = IUV  
)
V
OV = IOV × RLS + VV (IV = IOV)  
+
+
VUV = RLS × IUV + VV (IV = IUV  
)
For RLS = 4 M  
4 M  
VUV = 102.8 VDC  
For Values Shown  
VUV = 103.8 VDC  
VOV = 451 VDC  
Sense Output Voltage  
RLS  
RLS  
4 MΩ  
ROVP  
DC  
Input  
Voltage  
DC  
Input  
Voltage  
VROVP  
40 kΩ  
DCMAX @ 100 VDC = 76%  
DCMAX @ 375 VDC = 41%  
D
S
V
D
S
V
CONTROL  
CONTROL  
C
C
6.2 V  
ROVP >3kΩ  
-
-
PI-4720-120307  
PI-4719-120307  
Figure 14. Line-Sensing for Undervoltage, Overvoltage, Line Feed-Forward and  
Hysteretic Output Overvoltage Protection.  
Figure 15. Line Sensing for Undervoltage Only (Overvoltage Disabled).  
+
+
For RIL = 12 k  
V
OV = IOV × RLS + VV (IV = IOV)  
ILIMIT = 61%  
4 M  
For Values Shown  
VOV = 457.2 VDC  
For RIL = 19 kΩ  
ILIMIT = 37%  
R
LS  
DC  
Input  
Voltage  
See Figure 35 for other  
resistor values (RIL).  
DC  
Input  
Voltage  
D
S
55 kΩ  
CONTROL  
1N4148  
C
D
V
CONTROL  
C
X
RIL  
S
-
-
PI-4721-120307  
PI-5580-012210  
Figure 16. Line-Sensing for Overvoltage Only (Undervoltage Disabled). Maximum  
Duty Cycle Reduced at Low Line and Further Reduction with  
Increasing Line Voltage.  
Figure 17. External Set Current Limit.  
13  
www.powerint.com  
Rev. B 03/10  
TOP264-271  
Typical Uses of VOLTAGE MONITOR (V) and EXTERNAL CURRENT LIMIT (X) Pins (cont.)  
+
+
I
LIMIT = 100% @ 100 VDC  
QR can be an optocoupler  
output or can be replaced by  
a manual switch.  
53% @ 300 VDC  
ILIMIT  
=
RLS  
2.5 M  
DC  
Input  
Voltage  
DC  
Input  
Voltage  
D
S
D
S
CONTROL  
X
CONTROL  
C
C
X
RIL  
6 k  
ON/OFF  
QR  
47 K  
-
-
PI-5465-061009  
PI-5466-061009  
Figure 18. Current Limit Reduction with Line Voltage.  
Figure 19. Active-on (Fail Safe) Remote ON/OFF, and Latch Reset.  
VUV = IUV × RLS + VV (IV = IUV  
)
+
+
QR can be an optocoupler  
output or can be replaced  
by a manual switch.  
V
OV = IOV × RLS + VV (IV = IoV  
)
DCMAX@100 VDC = 76%  
DCMAX@375 VDC = 41%  
4 M  
RLS  
For RIL =12 k  
QR can be an optocoupler  
output or can be replaced  
by a manual switch.  
I
LIMIT = 61%  
DC  
Input  
Voltage  
DC  
Input  
Voltage  
D
S
D
S
V
For RIL = 19 kΩ  
CONTROL  
CONTROL  
I
LIMIT = 37%  
C
C
For RIL =12 k  
ILIMIT = 61%  
X
X
RIL  
RIL  
QR  
QR  
ON/OFF  
ON/OFF  
16 kΩ  
-
16 kΩ  
-
PI-5531-072309  
PI-5467-061009  
Figure 21. Active-on Remote ON/OFF with Line Sense and External  
Current Limit, and Latch Reset.  
Figure 20. Active-on Remote ON/OFF with Externally Set Current Limit,  
and Latch Reset  
VUV = IUV x RLS + VV (IV = IUV  
)
+
+
Typ. 65 VAC brownout threshold.  
V
OV = IOV x RLS + VV (IV = IoV  
)
<3 s AC latch reset time.  
Higher gain QR allows increasing R1/  
decreasing C1 for lower no-load input  
power.  
For RLS = 4 M  
4 MΩ  
RLS  
VUV = 102.8 VDC  
VOV = 451 VDC  
D
DC  
Input  
Voltage  
DCMAX @ 100 VDC = 76%  
DCMAX @ 375 VDC = 41%  
DC  
Input  
Voltage  
CONTROL  
D
S
V
C
CONTROL  
C
S
X
R1  
4 M  
For RIL = 12 kΩ  
ILIMIT = 61%  
1N4007  
RIL  
X
QR  
AC  
Input  
See Figure 35 for  
other resistor values  
(RIL) to select different  
ILIMIT values.  
RIL  
12 kΩ  
R2  
C1  
39 k47 nF  
-
-
PI-5652-110609  
Figure 22. Line Sensing and Externally Set Current Limit.  
Figure 23. Externally Set Current Limit, Fast AC Latch Reset and Brownout.  
14  
Rev. B 03/10  
www.powerint.com  
TOP264-271  
device size often results in the same or lower efficiency due to  
the larger switching losses associated with a larger MOSFET.  
Application Example  
Low No-load, High Efficiency, 65 W, Universal Input  
Adapter Power Supply  
Line Sense Resistor Values  
Increasing line sensing resistance from 4 MW to 10.2 MW to  
reduce no-load input power dissipation by 16 mW  
The circuit shown in Figure 24 shows a 90 VAC to 265 VAC  
input, 19 V, 3.42 A output power supply, designed for operation  
inside a sealed adapter case type. The goals of the design were  
highest full load efficiency, highest average efficiency (average of  
25%, 50%, 75% and 100% load points), and very low no-load  
consumption. Additional requirements included latching output  
overvoltage shutdown and compliance to safety agency limited  
power source (LPS) limits. Measured efficiency and no-load  
performance is summarized in the table shown in the schematic  
which easily exceed current energy efficiency requirements.  
Line sensing is provided by resistors R3 and R4 and sets the  
line undervoltage and overvoltage thresholds. The combined  
value of these resistors was increased from the standard 4 MW  
to 10.2 MW. This reduced the resistor dissipation, and therefore  
contribution to no-load input power, from ~26 mW to ~10 mW. To  
compensate the resultant change in the UV (turn-on) threshold  
resistor R20 was added between the CONTROL and VOLTAGE-  
MONITOR pins. This adds a DC current equal to ~16 mA into the  
V pin, requiring only 9 mA to be provided via R3 and R4 to reach  
the V pin UV (turn-on) threshold current of 25 mA and setting the  
UV threshold to 95 VDC.  
In order to meet these design goals the following key design  
decisions were made.  
PI Part Selection  
One device size larger selected than required for power  
delivery to increase efficiency  
This technique does effectively disable the line OV feature as  
the resultant OV threshold is raised from ~450 VDC to ~980 VDC.  
However in this design there was no impact as the value of  
input capacitance (C2) was sufficient to allow the design to  
withstand differential line surges greater than 2 kV without the  
peak drain voltage reaching the BVDSS rating of U1.  
The current limit programming feature of TOPSwitch-JX allows  
the selection of a larger device than needed for power delivery.  
This gives higher full load, low line efficiency by reducing the  
MOSFET conduction losses (IRMS2 × RDS(ON)) but maintains the  
overload power, transformer and other components size as if a  
smaller device had been used.  
Specific guidelines and detailed calculations for the value of  
R20 may be found in the TOPSwitch-JX Application Note (AN-47).  
Clamp Configuration – RZCD vs RCD  
An RZCD (Zener bleed) was selected over an RCD clamp to  
give higher light load efficiency and lower no-load consumption  
For this design one device size larger than required for power  
delivery (as recommended by the power table) was selected.  
This typically gives the highest efficiency. Further increases in  
Input Voltage (VAC)  
Full Power Efficiency (%)  
Average Efficiency (%)  
90  
115  
230  
C11  
1 nF  
250 VAC  
C12  
1 nF  
100 V  
R15  
33  
86.6 88.4 89.1  
89.8 89.5  
C13  
470 µF 470 µF  
25 V 25 V  
C14  
No-load Input Power (mW) 57.7 59.7 86.7  
VR2  
SMAJ250A  
T1  
RM10  
19 V, 3.42 A  
3
FL1  
C4  
C21  
10 nF  
50 V  
D5  
1000 pF  
630 V  
D1  
R5  
300 Ω  
V30100C  
GBU8J  
600 V  
FL2  
5
R6  
150 Ω  
R28  
RTN  
R11  
300 Ω  
300 Ω  
1
D4  
C10  
56 µF  
35 V  
R3  
R7  
BAV21WS-  
7-F  
R22  
C5  
5.1 M10 MΩ  
R29  
300 Ω  
1.6 kΩ  
4
2.2 nF  
D2  
RS1K  
R16  
20 kΩ  
1 kV  
C19  
6.8 nF  
50 V  
L3  
C15  
Q1  
R14  
12 mH  
470 pF  
50 V  
MMBT4403  
R24  
2.2 Ω  
20 Ω  
R4  
R8  
5.1 M10 MΩ  
R10  
100 Ω  
C2  
120 µF  
400 V  
D3  
BAV19WS  
R1  
R2  
R17  
147 kΩ  
1%  
R27  
10 kΩ  
2.2 M2.2 MΩ  
R12  
4.7 kΩ  
C9  
220 nF  
25 V  
U3B  
PS2501-  
1-H-A  
U3A  
PS2501-  
1-H-A  
C1  
R20  
191 kΩ  
1%  
330 nF  
275 VAC  
VR1  
ZMM5244B-7  
Q2  
MMBT3904  
L4  
200 µH  
D
S
V
R25  
20 Ω  
1/8 W  
C16  
22 nF  
50 V  
CONTROL  
TOPSwitch-JX  
U1  
TOP269EG  
C
F1  
4 A  
R13  
6.8 Ω  
1/8 W  
R19  
20 kΩ  
X
F
L
C6  
100 nF  
50 V  
R9  
11 kΩ  
1%  
C7  
90 - 265  
VAC  
C22  
100 nF  
50 V  
47 µF  
16 V  
U2  
R18  
LMV431AIMF  
1%  
N
10 kΩ  
1%  
PI-5667-030810  
Figure 24. Schematic of High Efficiency 19 V, 65 W, Universal Input Flyback Supply With Low No-load.  
15  
www.powerint.com  
Rev. B 03/10  
TOP264-271  
The clamp network is formed by VR2, C4, R5, R6, R11, R28,  
R29 and D2. It limits the peak drain voltage spike caused by  
leakage inductance to below the BVDSS rating of the internal  
TOPSwitch-JX MOSFET. This arrangement was selected over a  
standard RCD clamp to improve light load efficiency and  
no-load input power.  
To minimize the dissipation from the bias winding under no-load  
conditions the number of bias winding turns and value of C10  
was adjusted to give a minimum voltage across C10 of ~9 V.  
This is the minimum required to keep the optocoupler biased.  
To minimize the dissipation of the secondary side feedback  
circuit Q2 was added to form a Darlington connection with U3B.  
This reduced the feedback current on the secondary to ~1 mA.  
The increased loop gain (due to the hFE of the transistor) was  
compensated by increasing the value of R16 and the addition of  
R25. A standard 2.5 V TL431 voltage reference was replaced  
with the 1.24 V LMV431 to reduce the supply current requirement  
from 1 mA to 100 mA.  
In a standard RCD clamp C4 would be discharged by a parallel  
resistor rather than a resistor and series Zener. In an RCD clamp  
the resistor value is selected to limit the peak drain voltage  
under full load and overload conditions. However under light or  
no-load conditions this resistor value now causes the capacitor  
voltage to discharge significantly as both the leakage inductance  
energy and switching frequency are lower. As the capacitor has  
to be recharged to above the reflected output voltage each  
switching cycle the lower capacitor voltage represents wasted  
energy. It has the effect of making the clamp dissipation  
appear as a significant load just as if it were connected to the  
output of the power supply.  
Output Rectifier Choice  
Higher current rating, low VF Schottky rectifier diode selected  
for output rectifier  
A dual 15 A, 100 V Schottky rectifier diode with a VF of 0.455 V  
at 5 A was selected for D5. This is a higher current rating than  
required to reduce resistive and forward voltage losses to improve  
both full load and average efficiency. The use of a 100 V Schottky  
was possible due to the high transformer primary to secondary  
turns ratio (VOR = 110 V) which was in turn possible due to the high  
voltage rating of the TOPSwitch-JX internal MOSFET.  
The RZCD arrangement solves this problem by preventing the  
voltage across the capacitor discharging below a minimum  
value (defined by the voltage rating of VR2) and therefore  
minimizing clamp dissipation under light and no-load conditions.  
Increased Output Overvoltage Shutdown Sensitivity  
Transistor Q1 and VR1 added to improve the output over-  
voltage shutdown sensitivity  
Resistors R6 and R28 provide damping of high frequency  
ringing to reduce EMI. Due to the resistance in series with VR2,  
limiting the peak current, standard power Zeners vs a TVS type  
may be used for lower cost (although a TVS type was selected  
due to availability of a SMD version). Diode D2 was selected to  
have an 800 V vs the typical 600 V rating due to its longer  
reverse recovery time of 500 ns. This allows some recovery of  
the clamp energy during the reverse recovery time of the diode  
improving efficiency. Multiple resistors were used in parallel to  
share dissipation as SMD components were used.  
During an open loop condition the output and therefore bias  
winding voltage will rise. When this exceeds the voltage of VR1  
plus a VBE voltage drop Q1 turns on and current is fed into the  
V pin. The addition of Q1 ensures that the current into the V pin  
is sufficient to exceed the latching shutdown threshold even  
when the output is fully loaded while the supply is operating at  
low line as under this condition the output voltage overshoot is  
relatively small  
Feedback Configuration  
A Darlington connection formed together with optocoupler  
transistor to reduce secondary side feedback current and  
therefore no-load input power  
Low voltage, low current voltage reference IC used on  
secondary side to reduce secondary side feedback current  
and therefore no-load input power  
Output overload power limitation is provided via the current limit  
programming feature of the X pin and R7, R8 and R9. Resistors  
R8 and R9 reduce the device current limit as a function of  
increasing line voltage to provide a roughly flat overload power  
characteristic, below the 100 VA limited power source (LPS)  
requirement. In order to still meet this under a single fault condition  
(such as open circuit of R8) the rise in the bias voltage that occurs  
during an overload condition is also used to trigger a latching  
shutdown.  
Bias winding voltage tuned to ~9 V at no-load, high line to  
reduce no-load input power  
Typically the feedback current into the CONTROL pin at high  
line is ~3 mA. This current is both sourced from the bias  
winding (voltage across C10) and directly from the output. Both  
of these represent a load on the output of the power supply.  
16  
Rev. B 03/10  
www.powerint.com  
TOP264-271  
Very Low No-load, High Efficiency, 30 W, Universal Input,  
Open Frame, Power Supply  
The size of the magnetic core is a function of the switching  
frequency. The choice of the higher switching frequency of  
132 kHz allowed for the use of a smaller core size. The higher  
switching frequency does not negatively impact the efficiency in  
TOPSwitch-JX designs due its small drain to source capacitance  
(COSS) as compared to that of discrete MOSFETs.  
The circuit shown in Figure 25 below shows an 85 VAC to  
265 VAC input, 12 V, 2.5 A output power supply. The goals of  
the design were highest full load efficiency, average efficiency  
(average of 25%, 50%, 75% and 100% load points), very low no-  
load consumption. Additional requirements included latching  
output overvoltage shutdown and compliance to safety agency  
limited power source (LPS) limits. Actual efficiency and no-load  
performance is summarized in the table shown in the schematic  
which easily exceed current energy efficiency requirements.  
Line Sense Resistor Values  
Increasing line sensing resistance from 4 MW to 10.2 MW to  
reduce no-load input power dissipation by 16 mW  
Line sensing is provided by resistors R1 and R2 and sets the  
line undervoltage and overvoltage thresholds. The combined  
value of these resistors was increased from the standard 4 MW  
to 10.2 MW. This reduced the resistor, and therefore contribution  
to no-load input power, from ~26 mW to ~10 mW. To compensate  
the resultant change in the UV threshold resistor R12 was  
added between the CONTROL and VOLTAGE-MONITOR pins.  
This adds a DC current equal to ~16 mA into the V pin, requiring  
only 9 mA to be provided via R1 and R2 to reach the V pin UV  
threshold current of 25 mA and setting the UV threshold to  
approximately 95 VDC.  
In order to meet these design goals the following key design  
decisions were made.  
PI part selection  
Ambient of 40 °C allowed one device size smaller than  
indicated by the power table  
The device selected for this design was based on the 85-265 VAC,  
Open Frame, PCB heat sinking column of power table (Table 1).  
One device size smaller was selected (TOP266V vs TOP267V)  
due to the ambient specification of 40 °C (vs the 50°C assumed  
in the power table) and the optimum PCB area and layout for  
the device heatsink. The subsequent thermal and efficiency  
data confirmed this choice. The maximum device temperature  
was 107°C at full load, 40 °C, 85 VAC, 47 Hz (worst case  
conditions) and average efficiency exceeded 83% ENERGY  
STAR and EuP Tier 2 requirements.  
This technique does effectively disable the line OV feature as  
the resultant OV threshold is raised from ~450 VDC to ~980  
VDC. However in this design there was no impact as the value  
of input capacitance (C3) was sufficient to allow the design to  
withstand differential line surges greater than 1 kV without the  
peak drain voltage reaching the BVDSS rating of U1.  
Specific guidelines and detailed calculations for the value of R12  
may be found in the TOPSwitch-JX Application Note.  
Transformer Core Selection  
132 kHz switching frequency allowed the selection of smaller  
core for lower cost  
Input Voltage (VAC)  
Full Load Efficiency (%)  
Average Efficiency (%)  
85  
115  
230  
C11  
1 nF  
250 VAC  
C12  
1 nF  
200 V  
81.25 83.94 86.21  
84.97 85.13  
R17  
22  
C14  
680 µF 680 µF  
25 V 25 V  
C15  
C16  
100 µF  
25 V  
No-load Input Power (mW) 60.8 61.98 74.74  
L2  
3.3 µH  
VR1  
P6KE180A  
12 V, 2.5 A  
6
7,8  
D8,9  
C4  
SB560  
4.7 nF  
1 kV  
11,12  
1
R5  
10 kΩ  
RTN  
C7  
47 µF  
25 V  
1/2 W  
D1  
D2  
1N4007 1N4007  
4
R1  
R3  
NCNC  
D5  
FR107  
D7  
BAV21WS-  
7-F  
5.1 M10 MΩ  
2
T1  
EF25  
R9  
10 Ω  
R18  
110 Ω  
R19  
470 Ω  
C3  
82 µF  
400 V  
VR3  
ZMM5245B-7  
R2  
R4  
C18  
47 nF  
50 V  
5.1 M10 MΩ  
D6  
BAV19WS  
R21  
86.6 kΩ  
1%  
D10  
LL4148  
U2B  
LTV817D  
L1  
R12  
191 kΩ  
1%  
14 mH  
U2A  
LTV817D  
D3  
D4  
1N4007 1N4007  
D
S
V
CONTROL  
TOPSwitch-JX  
U1  
TOP266VG  
C1  
100 nF  
275 VAC  
C
F1  
R16  
C20  
33 nF  
50 V  
3.15 A  
6.8 Ω  
X
F
C9  
100 nF  
50 V  
L
1/8 W  
R15  
14.3 kΩ  
1%  
C10  
47 µF  
25 V  
85 - 264  
VAC  
U3  
LMV431A  
1%  
R23  
10 kΩ  
1%  
N
PI-5775-030810  
Figure 25. Schematic of High Efficiency 12 V, 30 W, Universal Input Flyback Supply With Very Low No-load.  
17  
www.powerint.com  
Rev. B 03/10  
TOP264-271  
Clamp Configuration – RZCD vs RCD  
1.24 V LMV431 to reduce the supply current requirement of this  
An RZCD (Zener bleed) was selected over RCD to give higher  
light load efficiency and lower no-load consumption  
component from 1 mA to 100 mA.  
Output Rectifier Choice  
Use of high VOR allows the use of a 60 V Schottky diode for  
high efficiency and lower cost  
The clamp network is formed by VR1, C4, R5 and D5. It limits  
the peak drain voltage spike caused by leakage inductance to  
below the BVDSS rating of the internal TOPSwitch-JX MOSFET.  
This arrangement was selected over a standard RCD clamp to  
improve light load efficiency and no-load input power.  
The higher BVDSS rating of the TOPSwitch-JX of 725 V  
(compared to 600 V or 650 V rating of typical power MOSFETs)  
allowed a higher transformer primary to secondary turns ratio  
(reflected output voltage or VOR). This reduced the output diode  
voltage stress and allowed the use of cheaper and more efficient  
60 V (vs 80 V or 100 V) Schottky diodes. The efficiency  
improvement occurs due the lower forward voltage drop of the  
lower voltage diodes. Two parallel connected axial 5 A, 60 V  
Schottky rectifier diodes were selected for both low cost and  
high efficiency. This allowed PCB heat sinking of the diode for  
low cost while maintaining efficiency compared to a single  
higher current TO-220 packaged diode mounted on a heatsink.  
For this configuration the recommendation is that each diode is  
rated at twice the output current and that the diodes share a  
common cathode PCB area for heat sinking so that their  
temperatures track. In practice the diodes current share quite  
effectively as can be demonstrated by monitoring their  
individual temperatures.  
In a standard RCD clamp C4 would be discharged by a parallel  
resistor rather than a resistor and series Zener. In an RCD  
clamp the resistor value of R5 is selected to limit the peak drain  
voltage under full load and over-load conditions. However  
under light or no-load conditions this resistor value now causes  
the capacitor voltage to discharge significantly as both the  
leakage inductance energy and switching frequency are lower.  
As the capacitor has to be recharged to above the reflected  
output voltage each switching cycle the lower capacitor voltage  
represents wasted energy. It has the effect of making the  
clamp dissipation appear as a significant load just as if it were  
connected to the output of the power supply.  
The RZCD arrangement solves this problem by preventing the  
voltage across the capacitor discharging below a minimum  
value (defined by the voltage rating of VR1) and therefore  
minimizing clamp dissipation under light and no-load conditions.  
Zener VR1 is shown as a high peak dissipation capable TVS  
however a standard lower cost Zener may also be used due to  
the low peak current that component experiences.  
Output Inductor Post Filter Soft-Finish  
Inductor L2 used to provide an output soft-finish and eliminate  
a capacitor  
To prevent output overshoot during start-up the voltage  
appearing across L2 is used to provide a soft-finish function.  
When the voltage across L2 exceeds the forward drop of U2A  
and D10 current flows though the optocoupler LED and  
provides feedback to the primary. This arrangement acts to  
limit the rate of rise of the output voltage until it reaches  
regulation and eliminates the capacitor that is typically placed  
across U3 to provide the same function.  
In many designs a resistor value of less than 50 W may be used  
in series with C4 to damp out high frequency ringing and  
improve EMI but this was not necessary in this case.  
Feedback Configuration  
A high CTR optocoupler was used to reduce secondary bias  
currents and no-load input power  
Low voltage, low current voltage reference IC used on  
secondary side to reduce secondary side feedback current  
and no-load input power  
Bias winding voltage tuned to ~9 V at no-load, high line to  
reduce no-load input power  
Key Application Considerations  
TOPSwitch-JX vs. TOPSwitch-HX  
Table 4 compares the features and performance differences  
between TOPSwitch-JX and TOPSwitch-HX. 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.  
Typically the feedback current into the CONTROL pin at high  
line is ~3 mA. This current is both sourced from the bias  
winding (voltage across C10) and directly from the output. Both  
of these represent a load on the output of the power supply.  
TOP264-271 Design Considerations  
To minimize the dissipation from the bias winding under no-load  
conditions the number of bias winding turns and value of C7  
was adjusted to give a minimum voltage across C7 of ~9 V.  
This is the minimum required to keep the optocoupler biased  
and the output in regulation.  
Power Table  
The data sheet power table (Table 1) represents the maximum  
practical continuous output power based on the following  
conditions:  
1. 12 V output.  
To minimize the dissipation of the secondary side feedback  
circuit a high CTR (CTR of 300 – 600%) optocoupler type was  
used. This reduces the secondary side opto-led current from  
~3 mA to <~1 mA and therefore the effective load on the output.  
A standard 2.5 V TL431 voltage reference was replaced with the  
2. Schottky or high efficiency output diode.  
3. 135 V reflected voltage (VOR) and efficiency estimates.  
4. A 100 VDC minimum DC bus for 85-265 VAC and 250 VDC  
minimum for 230 VAC.  
5. Sufficient heat sinking to keep device temperature ≤110 °C.  
18  
Rev. B 03/10  
www.powerint.com  
TOP264-271  
TOPSwitch-HX vs. TOPSwitch-JX  
Function  
TOPSwitch-HX  
TOPSwitch-JX  
TOPSwitch-JX Advantages  
CONTROL current IC(OFF) at  
0% duty cycle  
IC(OFF) = IB + 3.4 mA  
(TOP256-258)  
IB = External bias current  
IC(OFF) = IB + 1.6 mA  
(TOP266-268)  
Reduced CONTROL current  
Better no-load performance (<0.1 W)  
Better standby performance  
eDIP-12 package  
Not available  
Available  
66/132 kHz frequency option for DIP style heatsink  
less designs  
Better thermal performance for increased power  
capability over DIP-8 package  
Breakdown voltage BVDSS  
Fast AC reset  
Min. 700 V at TJ = 25 °C  
Min. 725 V at TJ = 25 °C  
Simplifies meeting customer derating requirements  
(e.g. 80%)  
Extended line surge withstand  
3 External transistor circuits  
using the V pin  
1 External transistor circuit  
using the X pin  
Saves 5 components  
Table 4.  
Comparison Between TOPSwitch-HX and TOPSwitch-JX.  
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 18). The RCD  
clamp is more cost effective than the Zener clamp but requires  
more careful design (see Quick Design Checklist).  
6. Power levels shown in the power table for the V 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.  
The provided peak power depends on the current limit for the  
respective device.  
Output Diode  
The output diode is selected for peak inverse voltage, output  
current, and thermal conditions in the application (including heat  
sinking, air circulation, etc.). The higher DCMAX of TOP264-271,  
along with an appropriate transformer turns ratio, can allow the  
use of a 80 V Schottky diode for higher efficiency on output  
voltages as high as 15 V.  
TOP264-271 Selection  
Selecting the optimum TOP264-271 depends upon required  
maximum output power, efficiency, heat sinking constraints,  
system requirements and cost goals. With the option to  
externally reduce current limit, TOP264-271 may be used for  
lower power applications where higher efficiency is needed or  
minimal heat sinking is available.  
Bias Winding Capacitor  
Due to the low frequency operation at no-load, a bias winding  
capacitance of 10 mF minimum is recommended. Ensure a  
minimum bias winding voltage of >9 V at zero load for correct  
operation and output voltage regulation.  
Input Capacitor  
The input capacitor must be chosen to provide the minimum  
DC voltage required for the TOP264-271 converter to maintain  
regulation at the lowest specified input voltage and maximum  
output power. Since TOP264-271 has a high DCMAX limit and an  
optimized dual slope line feed forward for ripple rejection, it is  
possible to use a smaller input capacitor. For TOP264-271, a  
capacitance of 2 mF per watt is possible for universal input with  
an appropriately designed transformer.  
Soft-Start  
Generally, a power supply experiences maximum stress at  
start-up before the feedback loop achieves regulation. For a  
period of 17 ms, the on-chip soft-start linearly increases the  
drain peak current and switching frequency from their low  
starting values to their respective maximum values. 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 TOP264-271 MOSFET, clamp  
circuit and output diode(s), and helps prevent transformer  
saturation during start-up. Also, soft-start limits the amount of  
output voltage overshoot and, in many applications, eliminates  
the need for a soft-finish capacitor. Note that as soon as the  
loop closes the soft-start function ceases even if this is prior to  
the end of the 17 ms soft-start period.  
Primary Clamp and Output Reflected Voltage VOR  
A primary clamp is necessary to limit the peak TOP264-271 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 reflected  
voltage VOR, as this keeps the leakage spike conduction 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 TOP264-271 MOSFET. A high VOR is required to take full  
advantage of the wider DCMAX of TOP264-271. An RCD (or  
RCDZ) clamp provides tighter clamp voltage tolerance than a  
EMI  
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  
19  
www.powerint.com  
Rev. B 03/10  
TOP264-271  
frequency. This is particularly beneficial for average detection  
mode. As can be seen in Figures 26 and 27, the benefits of jitter  
increase with the order of the switching harmonic due to an  
increase in frequency deviation. The FREQUENCY pin offers a  
switching frequency option of 132 kHz or 66 kHz. In applications  
that require heavy snubber on the drain node for reducing high  
frequency radiated noise (for example, video noise sensitive  
applications such as VCRs, DVDs, monitors, TVs, etc.), operating  
at 66 kHz will reduce snubber loss, resulting in better efficiency.  
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.  
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.  
be located closely between their respective pin and SOURCE.  
Once again, the SOURCE connection trace of these components  
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 separate trace  
that is not shared by the components connected to CONTROL,  
VOLTAGE MONITOR or EXTERNAL CURRENT LIMIT pins. This  
is because the SOURCE pin is also the controller ground  
reference pin. Any traces to the V, X or C pins should be kept  
as short as possible and away from the DRAIN trace to prevent  
noise coupling. VOLTAGE MONITOR resistors (RLS in Figures  
13, 14, 18, 21, 22, 25, 29) and primary side OVP circuit  
components VZOV/ROV in Figures (28, 29) should be located close  
to the V pin to minimize the trace length on the V pin side.  
Resistors connected to the V or X pin should be connected as  
close to the bulk cap positive terminal as possible while routing  
these connections away from the power switching circuitry. In  
addition to the 47 mF CONTROL pin capacitor, a high frequency  
bypass capacitor (CBP) in parallel should be used for better noise  
immunity. The feedback optocoupler output should also be  
Transformer Design  
It is recommended that the transformer be designed for  
maximum 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 an  
RCD clamp with current limit reduction with line voltage (overload  
protection). 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 17).  
80  
70  
60  
50  
40  
30  
Standby Consumption  
Frequency reduction can significantly reduce power loss at light  
or no load, especially when a Zener clamp is used. For very low  
secondary power consumption, use a TL431 regulator for  
feedback control. A typical TOP264-271 circuit automatically  
enters MCM mode at no load and the low frequency mode at  
light load, which results in extremely low losses under no-load  
or standby conditions.  
20  
-10  
0
EN55022B (QP)  
EN55022B (AV)  
-10  
-20  
0.15  
1
10  
30  
High Power Designs  
Frequency (MHz)  
The TOP264-271 family contains parts that can deliver up to  
162 W. High power designs need special considerations.  
Guidance for high power designs can be found in the Design  
Guide for TOP264-271 (AN-47).  
Figure 26. Fixed Frequency Operation Without Jitter.  
80  
70  
60  
TOPSwitch-JX (with jitter)  
TOP264-271 Layout Considerations  
50  
40  
30  
20  
-10  
0
The TOP264-271 has multiple pins and may operate at high  
power levels. The following guidelines should be carefully  
followed.  
Primary Side Connections  
Use a single point (Kelvin) connection at the negative terminal of  
the input filter capacitor for the SOURCE pin and bias winding  
return. This improves surge capabilities by returning surge  
currents from the bias winding directly to the input filter  
capacitor. 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 VOLTAGE MONITOR  
(V pin) or EXTERNAL CURRENT LIMIT (X pin) pins should also  
EN55022B (QP)  
EN55022B (AV)  
-10  
-20  
0.15  
1
10  
30  
Frequency (MHz)  
Figure 27. TOPSwitch-JX Full Range EMI Scan (132 kHz With Jitter) With  
Identical Circuitry and Conditions.  
20  
Rev. B 03/10  
www.powerint.com  
TOP264-271  
located close to the CONTROL and SOURCE pins of TOP264-271  
and away from the drain and clamp component traces. The  
primary side clamp circuit should be positioned such that the loop  
area from the transformer end (shared with DRAIN) and the clamp  
capacitor is minimized. The bias winding return node should be  
connected via a dedicated trace directly to the bulk capacitor  
and not to the SOURCE pins. This ensures that surge currents  
are routed away from the SOURCE pins of the TOPSwitch-JX.  
of the V pin to minimize the V pin node area. The DC bus  
should then be routed to the line sense resistors. Note that  
external capacitance must not be connected to the V pin as this  
may cause misoperaton of the V pin related functions. As with  
any power supply design, all TOP264-271 designs should be  
verified on the bench to make sure that components specifi-  
cations are not exceeded under worst-case conditions. The  
following minimum set of tests is strongly recommended:  
Y Capacitor  
1. Maximum drain voltage – Verify that peak VDS does not  
exceed 675 V at highest input voltage and maximum  
overload 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. Maximum drain current – At maximum ambient temperature,  
maximum input voltage and maximum output load, verify  
drain current waveforms at start-up for any signs of trans-  
former saturation and excessive leading edge current spikes.  
TOP264-271 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 32) for the drain current waveform  
at the end of the 220 ns blanking period.  
3. Thermal check – At maximum output power, both minimum  
and maximum voltage and ambient temperature; verify that  
temperature specifications are not exceeded for TOP264-  
271, transformer, output diodes and output capacitors.  
Enough thermal margin should be allowed for the part-to-  
part variation of the RDS(ON) of TOP264-271, as specified in  
the data sheet. The margin required can either be calculated  
from the values in the parameter table or it can be accounted  
for by connecting an external resistance in series with the  
DRAIN pin and attached to the same heat sink, 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.  
The Y capacitor should be connected close to the secondary  
output return pin(s) and the positive primary DC input pin of the  
transformer. If the Y capacitor is returned to the negative end of  
the input bulk capacitor (rather than the positive end) a dedicated  
trace must be used to make this connection. This is to “steer”  
leakage currents away from the SOURCE pins in case of a  
common-mode surge event.  
Heat Sinking  
The exposed pad of the E package (eSIP-7C) and the V package  
(eDIP-12) is internally electrically tied to the SOURCE pin. To  
avoid circulating currents, a heat sink attached to the exposed  
pad should not be electrically tied to any primary ground/source  
nodes on the PC board. On double sided boards, topside and  
bottom side areas connected with vias can be used to increase  
the effective heat sinking area. In addition, sufficient copper  
area should be provided at the anode and cathode leads of the  
output diode(s) for heat sinking. In Figure 28, 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  
In order to reduce the no-load input power of TOP264-271  
designs, the V pin operates at very low current. This requires  
careful layout considerations when designing the PCB to avoid  
noise coupling. Traces and components connected to the V pin  
should not be adjacent to any traces carrying switching currents.  
These include the drain, clamp network, bias winding return or  
power traces from other converters. If the line sensing features  
are used, then the sense resistors must be placed within 10 mm  
Design Tools  
Up-to-date information on design tools can be found at the  
Power Integrations website: www.powerint.com  
21  
www.powerint.com  
Rev. B 03/10  
TOP264-271  
DC  
OUT  
Maximize Copper Area  
for Optimum Heat Sinking  
RLS1  
RPL1  
J2  
CB  
U2  
ROV  
DB  
U3  
T1  
HF LC  
Post-Filter  
C16  
C18  
VZOV  
R12  
Output Filter  
Capacitors  
U1  
RIL  
R16  
CBP  
Transformer  
L2  
C10  
C17  
D8  
Output  
Rectifiers  
J1  
D9  
D5  
C3  
R5  
DC  
IN  
Y-  
Capacitor  
VR1  
C11  
C4  
Clamp Circuit  
Input Filter  
Capacitor  
PI-5752-012510  
Figure 28. Layout Considerations for TOPSwitch-JX Using V-Package and Operating at 132 kHz.  
Isolation Barrier  
Clamp  
Circuit  
Y-  
Input Filter  
Capacitor  
Capacitor  
C6  
R7  
T1  
C16  
R12  
R6  
HS1  
D5  
J1  
C4  
+
HV  
-
D8  
HS2  
Output  
Rectifier  
Transformer  
Output Filter  
Capacitors  
VR1  
U1  
D
CBP  
S
V
C9  
R8  
C17  
F
X
RIL  
C
L3  
RLS2  
HF LC  
Post-Filter  
RLS1  
RPL1  
CB  
C18  
DB  
U4  
ROV  
RPL2  
R10  
C19  
C21  
R20  
VZOV  
R9  
J2  
R17  
R13  
U2  
JP2  
R15  
R21  
DC  
OUT  
-
+
PI-5793-030910  
Figure 29. Layout Considerations for TOPSwitch-JX Using E-Package and Operating at 132 kHz.  
22  
Rev. B 03/10  
www.powerint.com  
TOP264-271  
Absolute Maximum Ratings(2)  
DRAIN Pin Peak Voltage..........................................................-0.3 V to 725 V  
DRAIN Pin Peak Current: TOP264.......................................................2.08 A  
DRAIN Pin Peak Current: TOP265........................................................2.72 A  
DRAIN Pin Peak Current: TOP266.......................................................4.08 A  
DRAIN Pin Peak Current: TOP267........................................................5.44 A  
DRAIN Pin Peak Current: TOP268.......................................................6.88 A  
DRAIN Pin Peak Current: TOP269........................................................ 7.73 A  
DRAIN Pin Peak Current: TOP270........................................................9.00 A  
DRAIN Pin Peak Current: TOP271........................................................ 11.10 A  
CONTROL Pin Voltage...................................................................-0.3 V to 9 V  
CONTROL Pin Current.............................................................................100 mA  
VOLTAGE MONITOR Pin Voltage............................................-0.3 V to 9 V  
CURRENT LIMIT Pin Voltage................................................-0.3 V to 4.5 V  
FREQUENCY Pin Voltage ...........................................................-0.3 V to 9 V  
Storage Temperature ...........................................................-65 °C to 150 °C  
Operating Junction Temperature................................... -40 °C to 150 °C  
Lead Temperature(1)......................................................................................260 °C  
Notes:  
1. 1/16 in. from case for 5 seconds.  
2. Maximum ratings specified may be applied one at a time  
without causing permanent damage to the product. Exposure  
to Absolute Maximum Rating conditions for extended periods  
of time may affect product reliability.  
Thermal Resistance  
Thermal Resistance: E Package  
Notes:  
(qJA) ................................................................105 °C/W(1) 1. Free standing with no heatsink.  
(qJC) ....................................................................2 °C/W(2) 2. Measured at the back surface of tab.  
3. Soldered to 0.36 sq. in. (232 mm2), 2 oz. (610 g/m2) copper clad.  
4. Soldered to 1 sq. in. (645 mm2), 2 oz. (610 g/m2) copper clad.  
V Package  
(qJA) ........................................68 °C/W(3), 58 °C/W(4)  
(qJC) ....................................................................2 °C/W(2)  
Conditions  
SOURCE = 0 V; TJ = -40 to 125 °C  
Parameter  
Symbol  
Min  
Typ  
Max  
Units  
See Figure 32  
(Unless Otherwise Specified)  
Control Functions  
FREQUENCY Pin  
Switching Frequency  
in Full Frequency  
Mode (average)  
119  
132  
66  
145  
Connected to SOURCE  
fOSC  
TJ = 25 °C  
kHz  
FREQUENCY Pin  
59.4  
72.6  
Connected to CONTROL  
132 kHz Operation  
66 kHz Operation  
5
Frequency Jitter  
Deviation  
kHz  
Hz  
Df  
2.5  
Frequency Jitter  
Modulation Rate  
fM  
250  
78  
IV ≤ IV(DC)  
75  
30  
83  
VV = 0 V  
Maximum Duty Cycle  
Soft-Start Time  
DCMAX  
IC = ICD1  
%
IV = 95 mA  
tSOFT  
TJ = 25 °C  
17  
ms  
TOP264-265  
TOP266-268  
TOP269-271  
TOP264-265  
TOP266-268  
TOP269-271  
-62  
-54  
-50  
-61  
-60  
-57  
-50  
-44  
-40  
-51  
-50  
-48  
-40  
-34  
-30  
-41  
-40  
-38  
TJ = 25 °C  
IB < IC < IC01  
See Note C  
PWM Gain  
DCreg  
%/mA  
TJ = 25 °C  
IC IC01  
See Note A  
PWM Gain  
Temperature Drift  
See Note B  
-0.01  
%/mA/°C  
mA  
TOP264-265  
TOP266-268  
TOP269-271  
0.8  
0.9  
1.0  
1.4  
1.5  
1.6  
2.0  
2.1  
2.2  
External Bias Current  
IB  
66 kHz Operation  
23  
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Rev. B 03/10  
TOP264-271  
Conditions  
Parameter  
Symbol  
SOURCE = 0 V; TJ = -40 to 125 °C  
(Unless Otherwise Specified)  
Min  
Typ  
Max  
Units  
mA  
Control Functions (cont.)  
External Bias Current  
TOP264-265  
0.9  
1.2  
1.5  
1.5  
1.8  
2.1  
2.9  
3.1  
3.3  
3.1  
3.4  
3.8  
21  
2.1  
2.4  
2.8  
3.9  
4.1  
4.3  
4.1  
4.4  
4.8  
25  
IB  
132 kHz Operation  
66 kHz Operation  
132 kHz Operation  
TOP266-268  
TOP269-271  
TOP264-265  
TOP266-268  
TOP269-271  
TOP264-265  
TOP266-268  
TOP269-271  
CONTROL Current at  
0% Duty Cycle  
IC(OFF)  
mA  
Dynamic Impedance  
ZC  
IC = 2.5 mA; TJ = 25 °C, See Figure 31  
13  
50  
W
Dynamic Impedance  
Temperature Drift  
0.18  
7
%/°C  
CONTROL Pin Internal  
Filter Pole  
kHz  
%
Upper Peak Current to  
Set Current Limit Ratio  
TJ = 25 °C  
See Note C  
kPS(UPPER)  
kPS(LOWER)  
55  
25  
60  
Lower Peak Current to  
Set Current Limit Ratio  
TJ = 25 °C  
See Note C  
%
Multi-Cycle-  
Modulation Switching  
Frequency  
fMCM(MIN)  
TJ = 25 °C  
TJ = 25 °C  
30  
kHz  
Minimum Multi-Cycle-  
Modulation On Period  
TMCM(MIN)  
135  
ms  
Shutdown/Auto-Restart  
VC = 0 V  
-5.0  
-3.0  
-3.5  
-1.8  
-1.0  
-0.6  
CONTROL Pin  
Charging Current  
IC(CH)  
TJ = 25 °C  
mA  
VC = 5 V  
Charging Current  
Temperature Drift  
See Note B  
0.5  
5.8  
4.8  
%/°C  
Auto-Restart  
Upper Threshold  
Voltage  
VC(AR)U  
V
V
Auto-Restart Lower  
Threshold Voltage  
VC(AR)L  
4.5  
0.8  
5.1  
Voltage Monitor (V) and External Current Limit (X) Inputs  
Auto-Restart  
VC(AR)hyst  
1.0  
2
V
Hysteresis Voltage  
Auto-Restart Duty  
DC(AR)  
4
%
Cycle  
Auto-Restart  
f(AR)  
0.5  
Hz  
Frequency  
Line Undervoltage  
Threshold Current and  
Hysteresis (V Pin)  
Threshold  
Hysteresis  
Threshold  
Hysteresis  
22  
25  
14  
112  
4
27  
mA  
mA  
mA  
mA  
IUV  
TJ = 25 °C  
TJ = 25 °C  
Line Overvoltage  
Threshold Current and  
Hysteresis (V Pin)  
107  
117  
IOV  
24  
Rev. B 03/10  
www.powerint.com  
TOP264-271  
Conditions  
SOURCE = 0 V; TJ = -40 to 125 °C  
Parameter  
Symbol  
Min  
Typ  
Max  
Units  
(Unless Otherwise Specified)  
Voltage Monitor (V) and External Current Limit (X) Inputs (cont.)  
Output Overvoltage  
Latching Shutdown  
Threshold Current  
IOV(LS)  
TJ = 25 °C  
269  
336  
403  
mA  
V Pin Remote  
ON/OFF Voltage  
VV(TH)  
TJ = 25 °C  
0.8  
-35  
1.0  
-27  
5
1.6  
-20  
V
X Pin Remote ON/OFF  
and Latch Reset  
Negative Threshold  
Current and Hysteresis  
Threshold  
Hysteresis  
VV = VC  
IREM (N)  
TJ = 25 °C  
mA  
V Pin Short Circuit  
Current  
IV(SC)  
TJ = 25 °C  
VX = 0 V  
IV = IOV  
300  
400  
500  
mA  
mA  
Normal Mode  
-260  
-95  
-200  
-75  
-140  
-55  
X Pin Short Circuit  
Current  
IX(SC)  
Auto-Restart Mode  
V Pin Voltage  
(Positive Current)  
VV  
TOP264-TOP271  
IV = IOV  
2.83  
0.2  
3.0  
0.5  
3.25  
V
V
V Pin Voltage Hysteresis  
(Positive Current)  
VV(hyst)  
1.23  
1.15  
1.30  
1.22  
1.37  
1.29  
IX = -50 mA  
X Pin Voltage  
(Negative Current)  
VX  
V
IX = -150 mA  
Maximum Duty Cycle  
Reduction Onset  
Threshold Current  
IC ≥ IB, TJ = 25 °C  
18.9  
22.0  
24.2  
IV(DC)  
mA  
-1.0  
-0.25  
0.6  
IV(DC) < IV <48 mA  
IV ≥48 mA  
Maximum Duty Cycle  
Reduction Slope  
TJ = 25 °C  
%/mA  
X or V Pin Floating  
1.0  
1.6  
Remote-OFF DRAIN  
Supply Current  
ID(RMT)  
VDRAIN = 150 V  
mA  
V Pin Shorted to  
CONTROL  
1.0  
From Remote-ON to Drain  
Turn-On  
66 kHz  
132 kHz  
66 kHz  
3.0  
1.5  
3.0  
1.5  
Remote-ON Delay  
tR(ON)  
ms  
ms  
See Note C  
Minimum Time Before Drain  
Turn-On to Disable Cycle  
See Note C  
Remote-OFF  
Set-up Time  
tR(OFF)  
132 kHz  
Frequency Input  
FREQUENCY Pin  
Threshold Voltage  
VF  
IF  
See Note B  
TJ = 25 °C  
2.9  
55  
V
FREQUENCY Pin  
Input Current  
VF = VC  
10  
90  
mA  
25  
www.powerint.com  
Rev. B 03/10  
TOP264-271  
Conditions  
SOURCE = 0 V; TJ = -40 to 125 °C  
Parameter  
Symbol  
Min  
Typ  
Max  
Units  
(Unless Otherwise Specified)  
Circuit Protection  
TOP264E/V  
1.209  
1.581  
2.371  
2.800  
3.023  
3.236  
1.30  
1.70  
2.55  
3.01  
3.25  
3.48  
1.391  
1.819  
2.728  
3.222  
3.478  
3.723  
di/dt = 270 mA/ms  
TJ = 25 °C  
TOP265E/V  
di/dt = 350 mA/ms  
TJ = 25 °C  
TOP266E/V  
di/dt = 530 mA/ms  
TJ = 25 °C  
TOP267E/V  
Self Protection  
Current Limit  
(See Note C)  
di/dt = 625 mA/ms  
TJ = 25 °C  
ILIMIT  
A
TOP268E/V  
di/dt = 675 mA/ms  
TJ = 25 °C  
TOP269E/V  
di/dt = 720 mA/ms  
TJ = 25 °C  
TOP270E/V  
3.906  
4.808  
4.20  
5.17  
4.494  
5.532  
di/dt = 870 mA/ms  
TJ = 25 °C  
TOP271E/V  
di/dt = 1065 mA/ms  
TJ = 25 °C  
0.70 ×  
ILIMIT(MIN)  
Initial Current Limit  
Power Coefficient  
IINIT  
See Note C  
A
0.9 × I2f  
0.9 × I2f  
I2f  
I2f  
1.2 × I2f  
1.2 × I2f  
IX ≤ - 165 mA  
TJ = 25 °C,  
See Note E  
PCOEFF  
A2kHz  
IX ≤ - 117 mA  
Leading Edge  
Blanking Time  
tLEB  
tIL(D)  
TJ = 25 °C, See Figure 32  
220  
100  
142  
ns  
ns  
°C  
Current Limit Delay  
Thermal Shutdown  
Temperature  
135  
150  
Thermal Shutdown  
Hysteresis  
75  
°C  
V
Power-Up Reset  
Threshold Voltage  
VC(RESET)  
Figure 33 (S1 Open Condition)  
1.75  
3.0  
4.25  
26  
Rev. B 03/10  
www.powerint.com  
TOP264-271  
Conditions  
SOURCE = 0 V; TJ = -40 to 125 °C  
Parameter  
Symbol  
Min  
Typ  
Max  
Units  
(Unless Otherwise Specified)  
Output  
TJ = 25 °C  
TJ = 100 °C  
TJ = 25 °C  
TJ = 100 °C  
TJ = 25 °C  
TJ = 100 °C  
TJ = 25 °C  
TJ = 100 °C  
TJ = 25 °C  
TJ = 100 °C  
TJ = 25 °C  
TJ = 100 °C  
TJ = 25 °C  
TJ = 100 °C  
TJ = 25 °C  
TJ = 100 °C  
5.4  
8.35  
4.1  
6.25  
9.70  
4.70  
7.30  
3.20  
4.75  
2.30  
3.60  
1.95  
2.90  
1.70  
2.60  
1.40  
2.10  
1.20  
1.80  
TOP264  
ID = 150 mA  
TOP265  
ID = 200 mA  
6.3  
2.8  
TOP266  
ID = 300 mA  
4.1  
2.0  
TOP267  
ID = 400 mA  
3.1  
ON-State  
Resistance  
RDS(ON)  
W
1.7  
TOP268  
ID = 500 mA  
2.5  
1.45  
2.25  
1.20  
1.80  
1.05  
1.55  
TOP269  
ID = 600 mA  
TOP270  
ID = 700 mA  
TOP271  
ID = 800 mA  
TJ ≤ 85 °C, See Note F  
18  
36  
DRAIN Supply Voltage  
V
OFF-State Drain  
Leakage Current  
VV = Floating, Device Not Switching,  
IDSS  
470  
mA  
VDS = 580 V, TJ = 125 °C  
Breakdown  
Voltage  
VV = Floating, Device Not Switching,  
BVDSS  
725  
V
TJ = 25 °C, See Note G  
Rise Time  
Fall Time  
tR  
tF  
100  
50  
ns  
ns  
Measured in a Typical Flyback  
Converter Application  
Supply Voltage Characteristics  
TOP264-265  
66 kHz  
Operation  
0.6  
0.9  
1.1  
0.8  
1.2  
1.5  
1.2  
1.4  
1.6  
1.4  
1.7  
2.1  
2.0  
2.3  
2.5  
2.1  
2.4  
2.9  
TOP266-268  
TOP269-271  
TOP264-265  
TOP266-268  
TOP269-271  
Output  
MOSFET  
Enabled  
VX, VV =  
0 V  
ICD1  
Control Supply/  
Discharge Current  
mA  
132 kHz  
Operation  
Output MOSFET Disabled  
VX, VV = 0 V  
ICD2  
0.3  
0.5  
1.2  
27  
www.powerint.com  
Rev. B 03/10  
TOP264-271  
NOTES:  
A. Derived during test from the parameters DCMAX, IB and IC(OFF) at 132 kHz.  
B. 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.  
C. Guaranteed by characterization. Not tested in production.  
D. For externally adjusted current limit values, please refer to Figures 34 and 35 (Current Limit vs. External Current Limit Resistance)  
in the Typical Performance Characteristics section. The tolerance specified is only valid at full current limit.  
E. I2f calculation is based on typical values of ILIMIT andfOSC, i.e. ILIMIT(TYP)2 × fOSC, where fOSC = 66 kHz or 132 kHz depending on F pin  
connection. See fOSC specification for detail.  
F. The device will start up at 18 VDC drain voltage. The capacitance of electrolytic capacitors drops significantly at temperatures  
below 0 °C. For reliable start up at 18 V in sub zero temperatures, designers must ensure that circuit capacitors meet recom-  
mended capacitance values.  
G. Breakdown voltage may be checked against minimum BVDSS specification by ramping the DRAIN pin voltage up to but not  
exceeding minimum BVDSS  
.
28  
Rev. B 03/10  
www.powerint.com  
TOP264-271  
t
2
t
1
HV  
90%  
90%  
t
t
DRAIN  
VOLTAGE  
1
2
D =  
10%  
0 V  
PI-2039-033001  
Figure 30. 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
INIT(MIN)  
60  
40  
Dynamic  
Impedance  
1
=
Slope  
20  
0
0
5
6
7
8
9
0
1
2
3
4
5
6
7
8
CONTROL Pin Voltage (V)  
Time (µs)  
Figure 31. CONTROL Pin I-V Characteristic.  
Figure 32. Drain Current Operating Envelope.  
(X and V Pins)  
S1  
470  
5 W  
0-300 kΩ  
5-50 V  
40 V  
V
D
CONTROL  
470 Ω  
C
S2  
F
X
S
S4  
0-15 V  
S3  
0-60 kΩ  
47 µF  
0.1 µF  
NOTES: 1. This test circuit is not applicable for current limit or output characteristic measurements.  
Figure 33. TOPSwitch-JX General Test Circuit.  
29  
www.powerint.com  
Rev. B 03/10  
TOP264-271  
Typical Performance Characteristics  
PI-5581-090309  
1.1  
1
1.1  
1
Maximum  
0.9  
0.8  
0.7  
0.6  
0.5  
0.9  
0.8  
0.7  
0.6  
0.5  
0.4  
0.3  
0.2  
0.1  
0
Typical  
Minimum  
0.4  
t
Normalized Current Limit  
0.3  
Notes:  
1. Maximum and Minimum levels are  
based on characterization.  
2. TJ = 0 OC to 125 OC.  
0.2  
0.1  
0
-200  
-150  
-100  
-50  
0
IX (µA)  
Figure 34. Normalized Current Limit vs. X Pin Current.  
PI-5582-090309  
1.1  
1
1.1  
1
Notes:  
1. Maximum and Minimum levels are  
based on characterization.  
2. TJ = 0 OC to 125 OC.  
3. Includes the variation of X pin voltage.  
0.9  
0.8  
0.7  
0.6  
0.5  
0.4  
0.3  
0.9  
0.8  
0.7  
0.6  
0.5  
0.4  
0.3  
0.2  
0.1  
0
s)  
Maximum  
µ
Typical  
N
Normalized Current Limit (A)  
0.2  
Minimum  
15  
0.1  
0
0
5
10  
20  
25  
30  
35  
40  
45  
RIL ( k)  
Figure 35. Normalized Current Limit vs. External Current Limit Resistance.  
30  
Rev. B 03/10  
www.powerint.com  
TOP264-271  
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)  
Figure 37. Frequency vs. Temperature.  
Junction Temperature (°C)  
Figure 36. Breakdown Voltage 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 39. External Current Limit vs. Temperature with RIL = 10.5 kW.  
Figure 38. Internal Current Limit vs. Temperature.  
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)  
Figure 41. Undervoltage Threshold vs. Temperature.  
Junction Temperature (
°
C)  
Figure 40. Overvoltage Threshold vs. Temperature.  
31  
www.powerint.com  
Rev. B 03/10  
TOP264-271  
Typical Performance Characteristics (cont.)  
6
5.5  
5
1.6  
1.4  
1.2  
1.0  
0.8  
0.6  
0.4  
0.2  
VX = 1.354 - 1147.5 × IX + 1.759 × 106 ×  
(IX)2 with -180 µA < IX < -25 µA  
4.5  
4
3.5  
3
2.5  
2
0
-200  
0
100  
200  
300  
400  
500  
-150  
-100  
-50  
0
VOLTAGE-MONITOR Pin Current (µA)  
EXTERNAL CURRENT LIMIT Pin Current (µA)  
Figure 42. VOLTAGE-MONITOR Pin vs. Current.  
Figure 43. EXTERNAL CURRENT LIMIT Pin Voltage vs. Current.  
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 45. Maximum Duty Cycle Reduction Onset Threshold  
Current vs. Temperature.  
Figure 44. Control Current Out at 0% Duty Cycle vs. Temperature.  
5
4
1
VC = 5 V  
0.5  
0
3
-0.5  
Scaling Factors:  
TOP271 1.62  
TOP270 1.42  
-1  
-1.5  
-2  
2
TOP269 1.17  
TOP268 1.00  
TOP267 0.85  
TOP266 0.61  
TOP265 0.42  
TOP264 0.32  
1
TCASE = 25 °C  
TCASE = 100 °C  
0
-2.5  
0
2
4
6
8
10 12 14 16 18 20  
0
20  
40  
60  
80  
100  
Drain Voltage (V)  
Drain Pin Voltage (V)  
Figure 46. Output Characteristics.  
Figure 47. IC vs. DRAIN Voltage.  
32  
Rev. B 03/10  
www.powerint.com  
TOP264-271  
Typical Performance Characteristics (cont.)  
500  
10000  
Scaling Factors:  
TOP271 1.62  
TOP270 1.42  
TOP269 1.17  
TOP268 1.00  
TOP267 0.85  
TOP266 0.61  
TOP265 0.42  
TOP264 0.32  
Scaling Factors:  
TOP271 1.62  
TOP270 1.42  
TOP269 1.17  
TOP268 1.00  
TOP267 0.85  
TOP266 0.61  
TOP265 0.42  
TOP264 0.32  
400  
300  
132 kHz  
1000  
100  
10  
200  
100  
0
66 kHz  
0
100 200 300 400 500 600  
0
100 200 300 400 500 600 700  
Drain Pin Voltage (V)  
Figure 48. COSS vs. DRAIN Voltage.  
Drain Pin Voltage (V)  
Figure 49. DRAIN Capacitance Power.  
1.2  
1.0  
0.8  
0.6  
0.4  
0.2  
0
-50 -25  
0
25 50 75 100 125 150  
Junction Temperature (°C)  
Figure 50. Remote OFF DRAIN Supply Current vs. Temperature.  
33  
www.powerint.com  
Rev. B 03/10  
TOP264-271  
eSIP-7C (E Package)  
C
2
0.403 (10.24)  
0.397 (10.08)  
0.264 (6.70)  
Ref.  
0.081 (2.06)  
0.077 (1.96)  
A
B
Detail A  
2
0.290 (7.37)  
Ref.  
0.325 (8.25)  
0.320 (8.13)  
0.198 (5.04) Ref.  
0.519 (13.18)  
Ref.  
0.207 (5.26)  
0.187 (4.75)  
Pin #1  
I.D.  
0.016 (0.41)  
Ref.  
0.140 (3.56)  
0.120 (3.05)  
3
4
0.047 (1.19)  
0.118 (3.00)  
SIDE VIEW  
0.070 (1.78) Ref.  
0.033 (0.84)  
0.028 (0.71)  
0.010 M 0.25 M C A B  
6×  
0.100 (2.54)  
0.050 (1.27)  
0.016 (0.41)  
0.011 (0.28)  
3
6×  
0.020 M 0.51 M C  
FRONT VIEW  
BACK VIEW  
0.100 (2.54)  
10° Ref.  
All Around  
0.050 (1.27)  
0.050 (1.27)  
0.020 (0.50)  
0.060 (1.52)  
Ref.  
0.021 (0.53)  
0.019 (0.48)  
PIN 1  
0.048 (1.22)  
0.046 (1.17)  
0.019 (0.48) Ref.  
0.155 (3.93)  
0.059 (1.50)  
0.378 (9.60)  
Ref.  
0.023 (0.58)  
0.027 (0.70)  
PIN 7  
END VIEW  
0.059 (1.50)  
Notes:  
DETAIL A  
1. Dimensioning and tolerancing per ASME Y14.5M-1994.  
0.100 (2.54)  
0.100 (2.54)  
2. Dimensions noted are determined at the outermost  
extremes of the plastic body exclusive of mold flash,  
tie bar burrs, gate burrs, and interlead flash, but including  
any mismatch between the top and bottom of the plastic  
body. Maximum mold protrusion is 0.010 [0.25] per side.  
MOUNTING HOLE PATTERN  
(not to scale)  
3. Dimensions noted are inclusive of plating thickness.  
4. Does not include inter-lead flash or protrusions.  
5. Controlling dimensions in inches [mm].  
PI-4917-042010  
34  
Rev. B 03/10  
www.powerint.com  
TOP264-271  
eDIP-12 (V Package)  
0.004 [0.10] C A  
12×  
2
Seating Plane  
C
0.400 [10.16]  
0.016 [0.41]  
0.011 [0.28]  
Pin #1 I.D.  
(Laser Marked)  
0.316 [8.03]  
Ref.  
A
0.010 [0.25] Ref.  
0.059 [1.50]  
Ref, typ.  
2X  
6
1
1
2
3
4
5
6
0.004 [0.10] C B  
7
0.412 [10.46]  
Ref.  
2
0.400 [10.16]  
8
0.213 [5.41]  
Ref.  
0.350 [8.89]  
0.306 [7.77]  
Ref.  
0.059 [1.50]  
Ref, typ.  
0.436 [11.08]  
0.406 [10.32]  
B
12 11 10  
9
8
7
7
12  
3
12×  
4
0.023 [0.58]  
0.018 [0.46]  
Detail A  
°
°
4
5
TOP VIEW  
0.104 [2.65] Ref.  
0.010 (0.25) M C A B  
END VIEW  
BOTTOM VIEW  
0.092 [2.34]  
0.086 [2.18]  
Notes:  
0.356 [9.04]  
Ref.  
1. Dimensioning and tolerancing  
per ASME Y14.5M-1994.  
0.019 [0.48]  
Ref.  
0.049 [1.23]  
0.046 [1.16]  
2. Dimensions noted are determined  
at the outermost extremes of the plastic  
body exclusive of mold flash, tie bar  
burrs, gate burrs, and interlead flash,  
but including any mismatch between the  
top and bottom of the plastic body.  
3. Dimensions noted are inclusive of  
plating thickness.  
4. Does not include inter-lead flash or  
protrusions.  
5. Controlling dimensions in inches (mm).  
6. Datums A & B to be determined at Datum H.  
7. Measured with the leads constrained to be  
perpendicular to Datum C.  
0.022 [0.56]  
Ref.  
0.192 [4.87]  
Ref.  
H
0.031 [0.80]  
0.028 [0.72]  
0.020 [0.51]  
Ref.  
0.070 [1.78]  
0.028 [0.71]  
Ref.  
SIDE VIEW  
DETAIL A (Not drawn to scale)  
8. Measured with the leads unconstrained.  
9. Lead numbering per JEDEC SPP-012.  
PI-5556-122109  
Part Ordering Information  
• TOPSwitch Product Family  
• JX Series Number  
• Package Identifier  
E
Plastic eSIP-7C  
Plastic eDIP-12  
V
• Pin Finish  
G
Halogen Free and RoHS Compliant  
Tape & Reel and Other Options  
Blank Standard Configurations  
TOP 264  
E
G - TL  
35  
www.powerint.com  
Rev. B 03/10  
Revision  
Notes  
Date  
A
B
B
Release data sheet.  
Added eDIP parts.  
Page 4 “latching” changed to “hysteretic”. Table 4 updated.  
01/10  
01/10  
03/10  
For the latest updates, visit our website: 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. POWER INTEGRATIONS MAKES  
NO WARRANTY HEREIN AND SPECIFICALLY DISCLAIMS ALL WARRANTIES INCLUDING, WITHOUT LIMITATION, THE IMPLIED  
WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, AND NON-INFRINGEMENT OF THIRD PARTY RIGHTS.  
Patent Information  
The products and applications illustrated herein (including transformer construction and circuits external to the products) may be covered  
by one or more U.S. and foreign patents, or potentially by pending U.S. and foreign patent applications assigned to Power Integrations. A  
complete list of Power Integrations patents may be found at www.powerint.com. Power Integrations grants its customers a license under  
certain patent rights as set forth at http://www.powerint.com/ip.htm.  
Life Support Policy  
POWER INTEGRATIONS PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT DEVICES OR  
SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT OF POWER INTEGRATIONS. As used herein:  
1. A Life support device or system is one which, (i) is intended for surgical implant into the body, or (ii) supports or sustains life, and (iii)  
whose failure to perform, when properly used in accordance with instructions for use, can be reasonably expected to result in significant  
injury or death to the user.  
2. A critical component is any component of a life support device or system whose failure to perform can be reasonably expected to cause  
the failure of the life support device or system, or to affect its safety or effectiveness.  
The PI logo, TOPSwitch, TinySwitch, LinkSwitch, DPA-Switch, PeakSwitch, EcoSmart, Clampless, E-Shield, Filterfuse, StakFET, PI Expert  
and PI FACTS are trademarks of Power Integrations, Inc. Other trademarks are property of their respective companies.  
©2010, Power Integrations, Inc.  
Power Integrations Worldwide Sales Support Locations  
World Headquarters  
5245 Hellyer Avenue  
Germany  
Japan  
Taiwan  
. .  
Rueckertstrasse 3  
D-80336, Munich  
Germany  
Phone: +49-89-5527-3910  
Fax: +49-89-5527-3920  
e-mail: eurosales@powerint.com Phone: +81-45-471-1021  
Fax: +81-45-471-3717  
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Nei Hu Dist.  
Taipei, Taiwan 114, R.O.C.  
Phone: +886-2-2659-4570  
Fax: +886-2-2659-4550  
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San Jose, CA 95138, USA.  
Main: +1-408-414-9200  
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Phone: +1-408-414-9665  
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