LT3799EMSE-1#PBF [Linear]
LT3799-1 - Offline Isolated Flyback LED Controller with Active PFC; Package: MSOP; Pins: 16; Temperature Range: -40°C to 85°C;
| 型号： | LT3799EMSE-1#PBF |
| 厂家： | 
Linear |
| 描述： | LT3799-1 - Offline Isolated Flyback LED Controller with Active PFC; Package: MSOP; Pins: 16; Temperature Range: -40°C to 85°C 驱动 功率因数校正 光电二极管 接口集成电路 |
| 文件： | 总20页 (文件大小：827K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
LT3799-1
Offline Isolated Flyback
LED Controller with Active PFC
FeaTures
DescripTion
TheLT®3799-1isanisolatedflybackcontrollerwithpower
factor correction specifically designed for driving LEDs.
The controller operates using critical conduction mode
allowing the use of a small transformer. Using a novel
current sensing scheme, the controller is able to deliver a
well regulated current to the secondary side without using
an opto-coupler. A strong gate driver is included to drive
an external high voltage MOSFET. Utilizing an onboard
multiplier, the LT3799-1 typically achieves power factors
of 0.97. The FAULT pin provides notification of open and
short LED conditions. The LT3799-1 offers improved line
regulation over the LT3799, but is not designed for use
with a TRIAC dimmer.
n
Isolated PFC LED Driver with Minimum Number of
External Components
n
V and V
Limited Only by External Components
IN
OUT
n
n
n
n
n
n
Active Power Factor Correction (Typical PFC > 0.97)
Low Harmonic Content
No Opto-Coupler Required
Accurate Regulated LED Current (±±5 Typical)
Open LED and Shorted LED Protection
Thermally Enhanced 16-Lead MSOP Package
applicaTions
n
Offline 4W to 100W+ LED Applications
n
High DC V LED Applications
IN
The LT3799-1 uses a micropower hysteretic start-up to
efficiently operate at offline input voltages, with a third
winding to provide power to the part. An internal LDO
provides a well regulated supply for the part’s internal
circuitry and gate driver.
L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks and
True Color PWM is a trademark of Linear Technology Corporation. All other trademarks are the
property of their respective owners. Patents pending.
Typical applicaTion
20W LED Driver
LED Current vs Input Voltage
1.20
1.15
100k
100k
90V
TO 150V
AC
20Ω
1.10
4:1:1
0.22µF
499k
499k
4.7pF
1.05
1.00
10µF
2k
DCM
1A
100k
0.95
0.90
0.85
0.80
V
IN
V
FB
170V
IN_SENSE
4.99k
560µF
× 2
LT3799-1
6.34k
40.2k
V
REF
90
100
110
120
130
140
150
20W
20Ω
33V
LED
100k
V
(V
IN AC
)
32.4k
CTRL3
CTRL2
CTRL1
GATE
37991 TA01b
POWER
SENSE
INTV
CC
0.05Ω
100k
NTC
4.7µF
15.8k
2.2nF
GND
–
+
FAULT
FAULT CT COMP COMP
37991 TA01a
0.1µF
0.1µF
37991fa
1
For more information www.linear.com/LT3799-1
LT3799-1
absoluTe MaxiMuM raTings
pin conFiguraTion
(Note 1)
TOP VIEW
V , FAULT .................................................................32V
IN
1
2
3
4
5
6
7
8
V
IN_SENSE
CTRL1
CTRL2
CTRL3
16
15
14
13
12
11
10
9
SENSE
GATE
GATE, INTV ...........................................................12V
CC
–
V
17
GND
CTRL1, CTRL2, CTRL3, V
, COMP ................4V
INTV
CC
NC
REF
IN_SENSE
FAULT
+
FB, CT, V
COMP ,...................................................3V
CT
V
REF,
IN
+
COMP
DCM
FB
–
SENSE......................................................................0.4V
DCM.......................................................................±3mA
Maximum Junction Temperature .......................... 12±°C
Operating Temperature Range (Note 2)
COMP
MSE PACKAGE
16-LEAD PLASTIC MSOP
θ
JA
= ±0°C/W, θ = 10°C/W
JC
EXPOSED PAD (PIN 17) IS GND, MUST BE SOLDERED TO PCB
LT3799-1E.......................................... –40°C to 12±°C
LT3799-1I........................................... –40°C to 12±°C
Storage Temperature Range .................. –6±°C to 1±0°C
orDer inForMaTion
(http://www.linear.com/product/LT3799-1#orderinfo)
LEAD FREE FINISH
LT3799EMSE-1#PBF
LT3799IMSE-1#PBF
TAPE AND REEL
PART MARKING*
37991
PACKAGE DESCRIPTION
TEMPERATURE RANGE
LT3799EMSE-1#TRPBF
LT3799IMSE-1#TRPBF
16-Lead Plastic MSOPE
16-Lead Plastic MSOPE
–40°C to 12±°C
–40°C to 12±°C
37991
Consult LTC Marketing for parts specified with wider operating temperature ranges. *The temperature grade is identified by a label on the shipping container.
For more information on lead free part marking, go to: http://www.linear.com/leadfree/
For more information on tape and reel specifications, go to: http://www.linear.com/tapeandreel/
elecTrical characTerisTics The l denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at TA = 25°C. VIN = 18V, INTVCC = 11V, unless otherwise noted.
PARAMETER
CONDITIONS
MIN
22.2
11.8
TYP
23
MAX
24.2
13.0
UNITS
V
IN
V
IN
V
IN
V
IN
V
IN
V
IN
Turn-On Voltage
V
V
Turn-Off Voltage
12.3
10.7
2±.0
Hysteresis
V
– V
V
TURNON
TURNOFF
Shunt Regulator Voltage
Shunt Regulator Current Limit
Quiescent Current
I = 1mA
V
1±
±±
mA
Before Turn-On
After Turn-On
6±
70
7±
µA
µA
INTV Quiescent Current
Before Turn-On
After Turn-On
12
1.±
16
2.1
20
2.6
µA
mA
CC
V
V
Linear Range
0
1.3
V
IN_SENSE
l
l
Voltage
0µA Load
200µA Load
1.97
1.9±
2
1.98
2.03
2.03
V
V
REF
+
–
, CTRL1 = 1V, CTRL2 = 2V, CTRL3 = 2V
Error Amplifier Voltage Gain
∆V
/∆V
100
±0
V/V
COMP
COMP
Error Amplifier Transconductance
∆I = ±µA
µmhos
37991fa
2
For more information www.linear.com/LT3799-1
LT3799-1
elecTrical characTerisTics The l denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at TA = 25°C. VIN = 18V, unless otherwise noted.
PARAMETER
CONDITIONS
MIN
TYP
MAX
600
±2±
106
UNITS
nA
FB Pin Bias Current
(Note 3), FB = 1V
100
CTRL1/CTRL2/CTRL3 Pin Bias Current
Max SENSE Current Limit Threshold
SENSE Input Bias Current
Current Loop Voltage Gain
CT Pin Charge Current
CTRL1/CTRL2/CTRL3 = 1V
nA
96
100
1±
mV
µA
Current Out of Pin, SENSE = 0V
+
–
∆V
CTRL
/∆V
, 1000pF Cap from COMP to COMP
21
V/V
µA
SENSE
10
CT Pin Discharge Current
CT Pin Low Threshold
200
240
1.2±
100
1.2±
4±
nA
Falling Threshold
Rising Threshold
mV
V
CT Pin High Threshold
CT Pin Low Hysteresis
mV
V
FB Pin High Threshold
1.22
1.29
DCM Current Turn-On Threshold
Maximum Oscillator Frequency
Minimum Oscillator Frequency
Back-Up Oscillator Frequency
Linear Regulator
Current Out of Pin
µA
+
COMP = 1.2V, V
= 1V
300
2±
kHz
kHz
kHz
IN_SENSE
IN_SENSE
+
COMP = 0V, V
20
INTV Regulation Voltage
9.8
10
7±0
2±
10.4
V
mV
mA
mA
CC
Dropout (V – INTV
)
INTV = –10mA, Below V Turn-Off Voltage
11±0
IN
CC
CC
IN
Current Limit
Current Limit
Gate Driver
Below Undervoltage Threshold
Above Undervoltage Threshold
12
80
120
t GATE Driver Output Rise Time
C = 3300pF, 105 to 905
20
20
ns
ns
V
r
L
t GATE Driver Output Fall Time
f
C = 3300pF, 905 to 105
L
GATE Output Low (V
)
OL
0.0±
GATE Output High (V
)
OH
INTV
V
CC
– 0.0±
Note 1: Stresses beyond those listed under Absolute Maximum Ratings
may cause permanent damage to the device. Exposure to any Absolute
Maximum Rating condition for extended periods may affect device
reliability and lifetime.
to 12±°C operating junction temperature range are assured by design,
characterization and correlation with statistical process controls. The
LT3799-1I is guaranteed to meet performance specifications from –40°C
to 12±°C operating junction temperature.
Note 2: The LT3799-1E is guaranteed to meet performance specifications
Note 3: Current flows out of the FB pin.
from 0°C to 12±°C junction temperature. Specifications over the –40°C
37991fa
3
For more information www.linear.com/LT3799-1
LT3799-1
Typical perForMance characTerisTics
VIN Start-Up Voltage
vs Temperature
Input Voltage Hysteresis
vs Temperature
VIN IQ vs Temperature
24.0
23.5
23.0
22.5
22.0
140
120
100
80
12.0
11.6
11.2
10.8
10.4
10.0
V
V
= 24V
= 12V
IN
IN
60
40
20
0
–50
0
25
TEMPERATURE (°C)
50
75 100 125
–50
0
25
50
75 100 125
–50
0
25
TEMPERATURE (°C)
50
75 100
125
–25
–25
–25
TEMPERATURE (°C)
37991 G01
37991 G02
37991 G03
VREF vs Temperature
VREF vs VIN
Current Limit vs Temperature
2.100
2.075
2.050
2.025
2.000
1.975
1.950
1.925
1.900
2.100
2.075
2.050
2.025
2.000
1.975
1.950
1.925
1.900
120
100
80
60
40
20
0
MAX I
LIM
NO LOAD
NO LOAD
200µA LOAD
200µA LOAD
MIN I
25
LIM
50
14
18 20 22 24 26 28 30 32
(V)
16
–50
0
25
50
75 100 125
–50
0
75 100 125
–25
–25
V
TEMPERATURE (°C)
TEMPERATURE (°C)
IN
37991 G05
37991 G04
37991 G06
Maximum Oscillator Frequency
vs Temperature
Minimum Oscillator Frequency
vs Temperature
375
350
325
300
275
250
225
70
60
50
40
30
20
10
–50
0
25
50
75 100 125
–50
0
25
50
75 100 125
–25
–25
TEMPERATURE (°C)
TEMPERATURE (°C)
37991 G07
37991 G08
37991fa
4
For more information www.linear.com/LT3799-1
LT3799-1
Typical perForMance characTerisTics
CT Pin Charge Current
vs Temperature
CT Pin Discharge Current
vs Temperature
CT Pin Low Threshold
vs Temperature
200
190
180
170
160
150
12
10
8
0.4
0.3
0.2
0.1
0
6
4
2
0
–50
0
25
50
75 100 125
–25
–50
0
25
50
75 100 125
–50
0
25
50
75 100 125
–25
–25
TEMPERATURE (°C)
TEMPERATURE (°C)
TEMPERATURE (°C)
37991 G10
37991 G09
37991 G11
CT Pin High Threshold
vs Temperature
INTVCC vs Temperature
INTVCC vs VIN
1.5
1.4
1.3
1.2
1.1
1.0
10.6
10.4
10.2
10.0
9.8
10.25
10.20
10.15
10.10
10.05
10.00
9.95
NO LOAD
PART ON
10mA LOAD
9.6
PART OFF
14 16 18 20 22 24 26 28 30 34
9.4
–50
0
25
50
75 100 125
–25
50
–50
0
25
75 100 125
10
12
–25
TEMPERATURE (°C)
TEMPERATURE (°C)
V
(V)
IN
37991 G12
37991 G13
37991 G14
Maximum Shunt Current
vs Temperature
VIN Shunt Voltage vs Temperature
26.00
25.75
25.50
25.25
25.00
24.75
24.50
30
25
20
15
10
5
I
= 10mA
SHUNT
0
–50
0
25
50
75 100 125
–25
–50
0
25
50
75 100 125
–25
TEMPERATURE (°C)
TEMPERATURE (°C)
37991 G15
37991 G16
37991fa
5
For more information www.linear.com/LT3799-1
LT3799-1
Typical perForMance characTerisTics
LED Current vs Input Voltage
LED Current vs Input Voltage
LED Current vs Input Voltage
1.20
1.15
1.10
1.05
1.00
0.95
0.90
0.85
0.80
1.20
1.15
1.10
1.05
1.00
0.95
0.90
0.85
0.80
1.20
1.15
1.10
1.05
1.00
0.95
0.90
0.85
0.80
PAGE 17 SCHEMATIC:
OPTIMIZED FOR 220V
PAGE 17 SCHEMATIC:
OPTIMIZED FOR 120V
PAGE 17 SCHEMATIC:
UNIVERSAL
170 180 190 200 210 220 230 240 250 260 270
(V
90 110 130 150 170 190 210 230 250 270
90
100
110
120
130
140
150
V
)
V
(V )
IN AC
V
(V
IN AC
)
IN AC
37991 G19
37991 G20
37991 G18
Power Factor vs Input Voltage
Power Factor vs Input Voltage
Power Factor vs Input Voltage
1.00
0.99
0.98
0.97
0.96
0.95
0.94
0.93
0.92
0.91
1.00
0.99
0.98
0.97
0.96
0.95
0.94
0.93
0.92
0.91
1.00
0.99
0.98
0.97
0.96
0.95
0.94
0.93
0.92
0.91
PAGE 17 SCHEMATIC:
OPTIMIZED FOR 120V
PAGE 17 SCHEMATIC:
OPTIMIZED FOR 220V
PAGE 17 SCHEMATIC:
UNIVERSAL
0.90
0.90
0.90
90
100
110
120
(V
130
140
150
170 180 190 200 210 220 230 240 250 260 270
(V
90 110 130 150 170 190 210 230 250 270
V
)
V
)
V
(V )
IN AC
IN AC
IN AC
37991 G21
37991 G22
37991 G23
Efficiency vs Input Voltage
Efficiency vs Input Voltage
Efficiency vs Input Voltage
100
95
90
85
80
75
70
65
60
100
95
90
85
80
75
70
65
60
100
95
90
85
80
75
70
65
60
PAGE 17 SCHEMATIC:
OPTIMIZED FOR 120V
PAGE 17 SCHEMATIC:
OPTIMIZED FOR 220V
PAGE 17 SCHEMATIC:
UNIVERSAL
170 180 190 200 210 220 230 240 250 260 270
(V
90 110 130 150 170 190 210 230 250 270
90
100
110
120
(V
130
140
150
V
)
V
)
V (V )
IN AC
IN AC
IN AC
37991 G24
37991 G25
37991 G26
37991fa
6
For more information www.linear.com/LT3799-1
LT3799-1
pin FuncTions
CTRL1,CTRL2,CTRL3(Pin1,Pin2,Pin3):CurrentOutput
Adjustment Pins. These pins control the output current.
The lowest value of the three CTRL inputs is compared to
the negative input of the operational amplifier. Due to the
uniquenatureoftheLT3799-1controlloop, themaximum
V (Pin 11): Input Voltage. This pin supplies current to
IN
the internal start-up circuitry and to the INTV LDO. This
CC
pinmustbelocallybypassedwithacapacitor. A2±Vshunt
regulator is internally connected to this pin.
NC (Pin 12): No Connection.
currentdoesnotdirectlycorrespondtotheV
voltages.
CTRL
INTV (Pin 13): Regulated Supply for Internal Loads
CC
V
(Pin 4): Voltage Reference Output Pin, Typically 2V.
REF
and GATE Driver. Supplied from V and regulates to 10V
IN
This pin drives a resistor divider for the CTRL pin, either
foranalogdimmingorfortemperaturelimit/compensation
of LED load. Can supply up to 200µA.
(typical). INTV must be bypassed with a 4.7µF capacitor
CC
placed close to the pin.
GATE (Pin 14): N-Channel MOSFET Gate Driver Output.
FAULT (Pin 5): Fault Pin. An open-collector pull-down on
FAULT asserts if FB is greater than 1.2±V with the CT pin
higher than 1.2±V.
Switches between INTV and GND. This pin is pulled to
CC
GND during shutdown state.
SENSE (Pin 15): The Current Sense Input for the Control
CT (Pin 6): Timer Fault Pin. A capacitor is connected be-
tween this pin and ground to provide an internal timer for
faultoperations.Duringstart-up,thispinispulledtoground
and then charged with a 10µA current. Faults related to
the FB pin will be ignored until the CT pin reaches 1.2±V.
If a fault is detected, the controller will stop switching and
begintodischargetheCTcapacitorwitha200nApull-down
current. When the pin reaches 240mV, the controller will
start to switch again.
Loop. Kelvin connect this pin to the positive terminal of
the switch current sense resistor, R , and the source
SENSE
of the N-channel MOSFET. The negative terminal of the
current sense resistor should be connected to the GND
plane close to the IC.
V
(Pin16):LineVoltageSensePin.Thepinisused
IN_SENSE
for sensing the AC line voltage to perform power factor
correction. Connect the output of a resistor divider from
the line voltage to this pin. The voltage on this pin should
be between 1.2±V to 1.±V at the maximum input voltage.
+
–
COMP , COMP (Pin 7, Pin 8): Compensation Pins for
Internal Error Amplifier. Connect a capacitor between
these two pins to compensate the internal feedback loop.
GND (Exposed Pad Pin 17): Ground. The exposed pad
of the package provides both electrical contact to ground
and good thermal contact to the printed circuit board.
The exposed pad must be soldered to the circuit board
for proper operation.
FB (Pin 9): Voltage Loop Feedback Pin. FB is used to
detect open LED conditions by sampling the third winding
voltage. An open LED condition is reported if the CT pin
and the FB pin are higher than 1.2±V.
DCM(Pin10):DiscontinuousConductionModeDetection
Pin. Connect a capacitor and resistor in series with this
pin to the third winding.
37991fa
7
For more information www.linear.com/LT3799-1
LT3799-1
block DiagraM
V
IN
D2
D1
R3
T1
+
–
V
OUT
OUT
•
R4
R5
R1
R2
C3
C2
C1
L1A
L1B
L1C
C7
V
R10
N:1
9
10
16
11
FB
DCM
V
V
IN
IN_SENSE
S&H
A3
CT
FAULT
DETECTION
6
5
1.22V
+
–
A8
C4
INTV
CC
13
FAULT
R7
C5
+
–
ONE
SHOT
A2
CURRENT
COMPARATOR
+
–
R8
600mV
–
A1
+
+
–
A7
COMP
S
S
R
DRIVER
GATE
SENSE
GND
7
14
15
17
M1
R6
Q
C6
1M
A5
MASTER
LATCH
SW1
COMP
A4
8
1
2
3
4
CTRL1
CTRL2
CTRL3
–
+
+
+
A6
LOW OUTPUT
MULTIPLIER
CURRENT
OSCILLATOR
V
REF
37991 BD
37991fa
8
For more information www.linear.com/LT3799-1
LT3799-1
operaTion
The LT3799-1 is a current mode switching controller IC
designed specifically for generating an average current
outputinanisolatedflybacktopology.Thespecialproblem
normally encountered in such circuits is that information
relating to the output voltage and current on the isolated
secondary side of the transformer must be communi-
cated to the primary side in order to maintain regulation.
Historically, this has been done with an opto-isolator.
The LT3799-1 uses a novel method of using the external
MOSFETs peak current information from the sense resis-
tor to calculate the output current of a flyback converter
without the need of an opto-coupler. In addition, it also
detects open LED conditions by examining the third wind-
ing voltage when the main power switch is off.
The LT3799-1 employs a micropower hysteretic start-up
featuretoallowtheparttoworkatanycombinationofinput
and output voltages. In the Block Diagram, R3 is used to
standoffthehighvoltagesupplyvoltage. TheinternalLDO
starts to supply current to the INTV when V is above
CC
IN
23V. The V and INTV capacitors are charged by the
IN
CC
current from R3. When V exceeds 23V and INTV is
IN
CC
in regulation at 10V, the part will began to charge the CT
pin with 10µA. Once the CT pin reaches 340mV, switch-
ing begins. The V pin has 10.7V of hysteresis to allow
IN
for plenty of flexibility with the input and output capacitor
values. The third winding provides power to V when its
IN
voltage is higher than the V voltage. A voltage shunt is
IN
provided for fault protection and can sink up to 1±mA of
current when V is over 2±V.
IN
Power factor has become an important specification for
lighting. A power factor of one is achieved if the current
drawn is proportional to the input voltage. The LT3799-1
modulates the peak current limit with a scaled version of
the input voltage. This technique provides power factors
of 0.97 or greater.
During a typical cycle, the gate driver turns the external
MOSFET on and a current flows through the primary
winding. This current increases at a rate proportional
to the input voltage and inversely proportional to the
magnetizing inductance of the transformer. The control
loop determines the maximum current and the current
comparator turns the switch off when the current level
is reached. When the switch turns off, the energy in the
core of the transformer flows out the secondary winding
through the output diode, D1. This current decreases at a
rate proportional to the output voltage. When the current
decreases to zero, the output diode turns off and voltage
across the secondary winding starts to oscillate from the
parasitic capacitance and the magnetizing inductance of
the transformer. Since all windings have the same voltage
across them, the third winding rings too. The capacitor
connected to the DCM pin, C1, trips the comparator, A2,
which serves as a dv/dt detector, when the ringing occurs.
This timing information is used to calculate the output
The Block Diagram shows an overall view of the system.
The external components are in a flyback topology con-
figuration. The third winding senses the output voltage
and also supplies power to the part in steady-state opera-
tion. The V pin supplies power to an internal LDO that
IN
generates10VattheINTV pin.Thenovelcontrolcircuitry
CC
consists of an error amplifier, a multiplier, a transmission
gate, a current comparator, a low output current oscillator
and a master latch, which will be explained in the follow-
ing sections. The part also features a sample-and-hold
to detect open LED conditions, along with a FAULT pin. A
comparator is used to detect discontinuous conduction
mode (DCM) with a cap connected to the third winding.
The part features a 1.9A gate driver.
37991fa
9
For more information www.linear.com/LT3799-1
LT3799-1
operaTion
current (description to follow). The dv/dt detector waits
for the ringing waveform to reach its minimum value and
then the switch turns back on. This switching behavior is
similartozerovoltswitchingandminimizestheamountof
energy lost when the switch is turned back on, improving
efficiency as much as ±5. Since this part operates on the
edge of continuous conduction mode and discontinuous
conduction mode, this operating mode is called critical
conduction mode (or boundary conduction mode).
In a flyback topology, the secondary winding current is N
times the primary winding current, where N is the primary
to secondary winding ratio. Instead of taking the area of
the triangle, think of it as a pulse width modulation (PWM)
waveform. During the flyback time, the average current
is half the peak secondary winding current and zero dur-
ing the rest of the cycle. The equation for expressing the
output current is:
I
= 0.± • I • N • D´
PK
OUT
whereD´isequaltothepercentageofthecyclerepresented
by the flyback time.
Primary-Side Current Control Loop
The CTRL1/CTRL2/CTRL3 pins control the output current
of the flyback controller. To simplify the loop, assume
the V
pin is held at a constant voltage above
I
PK(sec)
IN_SENSE
SECONDARY
DIODE CURRENT
1V, eliminating the multiplier from the control loop. The
error amplifier, A±, is configured as an integrator with
the external capacitor, C6. The COMP node voltage is
+
converted to a current into the multiplier with the V/I
converter, A6. Since A7’s output is constant, the output
of the multiplier is proportional to A6 and can be ignored.
The output of the multiplier controls the peak current with
its connection to the current comparator, A1. The output
of the multiplier is also connected to the transmission
gate, SW1. The transmission gate, SW1, turns on when
the secondary current flows to the output capacitor. This
is called the flyback period (when the output diode D1 is
on). The current through the 1M resistor gets integrated
byA±. ThelowestCTRLinputisequaltothenegativeinput
of A± in steady state.
SWITCH
WAVEFORM
T
FLYBACK
37991 F01
T
PERIOD
Figure 1. Secondary Diode Current and Switch Waveforms
The LT3799-1 has access to both the primary winding
current, the input to the current comparator, and when
the flyback time starts and ends. Now the output current
can be calculated by averaging a PWM waveform with the
height of the current limit and the duty cycle of the flyback
time over the entire cycle. In the feedback loop previously
described, the input to the integrator is such a waveform.
The integrator adjusts the peak current until the calculated
output current equals the control voltage. If the calculated
outputcurrentislowcomparedtothecontrolpin,theerror
Acurrentoutputregulatornormallyusesasenseresistorin
series with the output current and uses a feedback loop to
control the peak current of the switching converter. In this
isolatedcasetheoutputcurrentinformationisnotavailable,
so instead the LT3799-1 calculates it using the informa-
tion available on the primary side of the transformer. The
output current may be calculated by taking the average of
the output diode current. As shown in Figure 1, the diode
current is a triangle waveform with a base of the flyback
time and a height of the peak secondary winding current.
+
amplifier increases the voltage on the COMP node, thus
increasing the current comparator input.
37991fa
10
For more information www.linear.com/LT3799-1
LT3799-1
operaTion
When the V
voltage is connected to a resistor di-
CT Pin and Faults
IN_SENSE
viderofthesupplyvoltage,thecurrentlimitisproportional
tothesupplyvoltageifCOMP isheldconstant.Theoutput
The CT pin is a timing pin for the fault circuitry. When the
input voltages are at the correct levels, the CT pin sources
10µA ofcurrent. When theCT pin reaches340mV, thepart
begins to switch. The output voltage information from the
FB pin is sampled but ignored until the CT pin reaches
1.2±V. When this occurs, if the FB pin is above 1.2±V, the
fault flag pulls low. The FAULT pin is meant to be used
+
of the error amplifier is multiplied with the V
pin
IN_SENSE
voltage. If the LT3799-1 is configured with a fast control
loop, slower changes from the V pin will not
IN_SENSE
interfere with the current limit or the output current. The
+
COMP pin will adjust to the changes of the V
.
IN_SENSE
The only way for the multiplier to function properly is to
set the control loop to be an order of magnitude slower
with a large pull-up resistor to the INTV pin or another
CC
supply. The CT pin begins to sink 200nA of current. When
theCTpingoesbelow240mV, thepartwillre-enableitself,
begin to switch, and start to source 10µA of current to the
CT pin but not remove the fault condition. When the CT
pin reaches 1.2±V and FB is below 1.2±V, the FAULT pin
will no longer pull low and switching will continue. If not
below 1.2±V, the process repeats itself.
thanthefundamentalfrequencyoftheV
signal. In
IN_SENSE
the offline case, the fundamental frequency of the supply
voltage is 120Hz, so the control loop unity gain frequency
needs to be set less than approximately 120Hz. Without a
large amount of energy storage on the secondary side, the
output current is affected by the supply voltage changes,
but the DC component of the output current is accurate.
Programming Output Current
Start-Up
The maximum output current depends on the supply
voltage and the output voltage in a flyback topology.
The LT3799-1 uses a hysteretic start-up to operate from
high offline voltages. A resistor connected to the supply
voltage protects the part from high voltages. This resis-
With the V
pin connected to 1V and a DC supply
IN_SENSE
voltage, the maximum output current is determined at
the minimum supply voltage, and the maximum output
voltage using the following equation:
tor is connected to the V pin on the part and also to a
IN
capacitor. When the resistor charges the part up to 23V
and INTV is in regulation at 10V, the part begins to
CC
N
IOUT(MAX) = 2 •(1−D)•
charge the CT pin to 340mV and then starts to switch.
The resistor does not provide power for the part in steady
state, but relies on the capacitor to start-up the part, then
42 •RSENSE
where
the third winding begins to provide power to the V pin
IN
VOUT •N
VOUT •N+ V
along with the resistor. An internal voltage clamp is at-
D =
tached to the V pin to prevent the resistor current from
IN
IN
allowing V to go above the absolute maximum voltage
IN
The maximum control voltage to achieve this maximum
output current is 2V • (1-D).
of the pin. The internal clamp is set at 2±V and is capable
of 28mA (typical) of current at room temperature. But,
ideally, the resistor connected between the input supply
It is suggested to operate at 9±5 of these values to give
margin for the part’s tolerances.
and the V pin should be chosen so that less than 10mA
is being shunted by this internal clamp.
IN
37991fa
11
For more information www.linear.com/LT3799-1
LT3799-1
operaTion
When designing for power factor correction, the output
currentwaveformisgoingtohaveahalfsinewavesquared
shape and will no longer be able to provide the above
currents. By taking the integral of a sine wave squared
over half a cycle, the average output current is found to
be half the value of the peak output current. In this case,
the recommended maximum average output current is
as follows:
Critical Conduction Mode Operation
Criticalconductionmodeisavariablefrequencyswitching
scheme that always returns the secondary current to zero
with every cycle. The LT3799-1 relies on boundary mode
and discontinuous mode to calculate the critical current
because the sensing scheme assumes the secondary
current returns to zero with every cycle. The DCM pin
uses a fast current input comparator in combination with
a small capacitor to detect dv/dt on the third winding. To
eliminate false tripping due to leakage inductance ringing,
a blanking time of between 600ns and 2.2±µs is applied
after the switch turns off, depending on the current limit.
The detector looks for 40µA of current through the DCM
pin due to falling voltage on the third winding when the
secondary diode turns off. This detection is important
since the output current is calculated using this com-
parator’s output. This is not the optimal time to turn the
N
IOUT(MAX) = 2•(1−D)•
• 47.±5
42 •RSENSE
where
VOUT •N
VOUT •N+ V
D =
IN
The maximum control voltage to achieve this maximum
output current is (1-D) • 47.±5.
switch on because the switch voltage is still close to V
IN
For control voltages below the maximum, the output cur-
rent is equal to the following equation:
+ V
•ꢀN and would waste all the energy stored in the
OUT
parasitic capacitance on the switch node. Discontinuous
ringing begins when the secondary current reaches zero
and the energy in the parasitic capacitance on the switch
node transfers to the input capacitor. This is a second-
order network composed of the parasitic capacitance on
the switch node and the magnetizing inductance of the
primary winding of the transformer. The minimum volt-
age of the switch node during this discontinuous ring is
N
IOUT = CTRL •
42 •RSENSE
The V
pin supplies a 2V reference voltage to be used
REF
with the control pins. To set an output current, a resistor
divider is used from the 2V reference to one of the control
pins. The following equation sets the output current with
a resistor divider:
V
– V
•ꢀN. The LT3799-1 turns the switch back on
IN
OUT
at this time, during the discontinuous switch waveform,
by sensing when the slope of the switch waveform goes
from negative to positive using the dv/dt detector. This
switching technique may increase efficiency by ±5.
⎛
⎜
⎝
⎞
2N
• RSENSE
R1=R2
− 1
⎟
42 • I
⎠
OUT
where R1 is the resistor connected to the V pin and the
REF
CTRL pin and R2 is the resistor connected to the CTRL
pin and ground.
37991fa
12
For more information www.linear.com/LT3799-1
LT3799-1
operaTion
Sense Resistor Selection
Errors Affecting Current Output Regulation
The resistor, R
, between the source of the external
Thereareafewfactorsaffectingtheregulationofcurrentin
amanufacturingenvironmentalongwithsomesystematic
issues. The main manufacturing issues are the winding
turns ratio and the LT3799-1 control loop accuracy. The
winding turns ratio is well controlled by the transformer
manufacturer’swindingequipment,butmosttransformers
do not require a tight tolerance on the winding ratio. We
have worked with transformer manufacturers to specify
±15errorfortheturnsratio.JustlikeanyotherLEDdriver,
the part is tested and trimmed to eliminate offsets in the
control loop and an error of ±35 is specified at 805 of
the maximum output current. The error grows larger as
the LED current is decreased from the maximum output
current. At half the maximum output current, the error
doubles to ±65.
SENSE
N-channelMOSFETandGNDshouldbeselectedtoprovide
anadequateswitchcurrenttodrivetheapplicationwithout
exceeding the current limit threshold .
For applications without power factor correction, select a
resistor according to:
2(1−D)N
IOUT • 42
RSENSE
=
• 9±5
where
VOUT •N
VOUT •N+ V
D =
IN
For applications with power factor correction, select a
resistor according to:
Thereareanumberofsystematicoffsetsthatmaybeelimi-
natedbyadjustingthecontrolvoltagefromtheidealvoltage.
It is difficult to measure the flyback time with complete
accuracy. If this time is not accurate, the control voltage
needs to be adjusted from the ideal value to eliminate the
offset but this error still causes line regulation errors. If
the supply voltage is lowered, the time error becomes a
smaller portion of the switching cycle period so the offset
becomes smaller and vice versa. This error may be com-
pensated for at the primary supply voltage, but this does
notsolvetheproblemcompletelyforothersupplyvoltages.
Another systematic error is that the current comparator
cannot instantaneously turn off the main power device.
This delay time leads to primary current overshoot. This
overshoot is less of a problem when the output current is
close to its maximum, since the overshoot is only related
to the slope of the primary current and not the current
level. The overshoot is proportional to the supply voltage,
so again this affects the line regulation.
2(1−D)N
IOUT • 42
RSENSE
=
• 47.±5
where
VOUT •N
D =
VOUT •N+ V
IN
Minimum Current Limit
The LT3799-1 features a minimum current limit of ap-
proximately75ofthepeakcurrentlimit.Thisisnecessary
when operating in critical conduction mode since low
current limits would increase the operating frequency to a
very high frequency. The output voltage sensing circuitry
needs a minimum amount of flyback waveform time to
sense the output voltage on the third winding. The time
needed is 3±0ns. The minimum current limit allows the
useofsmallertransformerssincethemagnetizingprimary
inductance does not need to be as high to allow proper
time to sample the output voltage information.
37991fa
13
For more information www.linear.com/LT3799-1
LT3799-1
operaTion
Universal Input
this energy by avalanching. Therefore the MOSFET needs
protection.Atransientvoltagesuppressor(TVS)anddiode
arerecommendedforallofflineapplicationandconnected,
as shown in Figure 3. The TVS device needs a reverse
The LT3799-1 easily operates over the universal input
range of 90V to 26±V , but is not limited to this range.
AC
AC
Applications with input voltages above ±00V can be
AC
breakdownvoltagegreaterthan(V
+V )*NwhereV
OUT
f OUT
implementedwiththeLT3799-1.Outputcurrentregulation
is the output voltage of the flyback converter, V is the
f
error may be minimized by using two application circuits
secondary diode forward voltage, and N is the turns ratio.
for the wide input range: one optimized for 120V and
AC
anotheroptimizedfor220V .Thefirstapplicationpictured
AC
in the Typical Applications section shows three options:
V
SUPPLY
universal input, 120V , and 220V . The circuit varies by
AC
AC
threeresistors.IntheTypicalPerformanceCharacteristics
section, the LED Current vs V graphs show the output
IN
current line regulation for all three circuits.
GATE
Selecting Winding Turns Ratio
Boundarymodeoperationgivesalotoffreedominselecting
the turns ratio of the transformer. We suggest to keep the
37991 F03
duty cycle low, lower N , at the maximum input voltage
PS
Figure 3. Clamp
since thedutycyclewillincreasewhenthe ACwaveformis
decreases to zero volts. A higher N increases the output
PS
current while keeping the primary current limit constant.
Although this seems to be a good idea, it comes at the
expense of a higher RMS current for the secondary-side
diodewhichmightnotbedesirablebecauseoftheprimary
sideMOSFET’ssuperiorperformanceasaswitch.Ahigher
NPSdoesreducethevoltagestressonthesecondary-side
diode while increasing the voltage stress on the primary-
side MOSFET. If switching frequency at full output load is
kept constant, the amount of energy delivered per cycle by
Transformer Design Considerations
Transformer specification and design is a critical part of
successfully applying the LT3799-1. In addition to the
usual list of caveats dealing with high frequency isolated
power supply transformer design, the following informa-
tion should be carefully considered. Since the current on
the secondary side of the transformer is inferred by the
current sampled on the primary, the transformer turns
ratio must be tightly controlled to ensure a consistent
output current.
the transformer also stays constant regardless of the N .
PS
Therefore, the size of the transformer remains the same at
practical N ’s. Adjusting the turns ratio is a good way to
PS
A tolerance of ±±5 in turns ratio from transformer to
transformercouldresultinavariationofmorethan±±5in
outputregulation.Fortunately,mostmagneticcomponent
manufacturers are capable of guaranteeing a turns ratio
tolerance of 15 or better. Linear Technology has worked
with several leading magnetic component manufacturers
to produce predesigned flyback transformers for use with
theLT3799-1. Table1showsthedetailsofseveralofthese
transformers.
find an optimal MOSFET and diode for a given application.
Switch Voltage Clamp Requirement
Leakage inductance of an offline transformer is high due
to the extra isolation requirement. The leakage inductance
energy is not coupled to the secondary and goes into
the drain node of the MOSFET. This is problematic since
400V and higher rated MOSFETs cannot always handle
37991fa
14
For more information www.linear.com/LT3799-1
LT3799-1
operaTion
Table 1. Predesigned Transformers—Typical Specifications, Unless Otherwise Noted
TARGET
TRANSFORMER SIZE
L
N
P
R
R
SEC
APPLICATION
PRI
PSA
S
PRI
PART NUMBER (L × W × H)
(µH)
400
2000
2000
300
600
600
400
100
460
±00
(N :N :N )
(mΩ)
(mΩ)
126
16±
2±
MANUFACTURER
Coilcraft
(V /I
OUT OUT
)
A
JA4429
21.1mm × 21.1mm × 17.3mm
1:0.24:0.24
6.67:1:1.67
20:1.0:±.0
6:1.0:1.0
4:1:0.71
2±2
22V/1A
10V/0.4A
3.8V/1.1A
18V/±A
7±08110210
7±0813002
7±0811330
7±0813144
7±0813134
7±0811291
7±0813390
7±0811290
X-11181-002
1±.7±mm × 1±mm × 18.±mm
1±.7±mm × 1±mm × 18.±mm
43.2mm × 39.6mm × 30.±mm
16.±mm × 18mm × 18mm
16.±mm × 18mm × 18mm
31mm × 31mm × 2±mm
±100
6100
1±0
Würth Elektronik
Würth Elektronik
Würth Elektronik
Würth Elektronik
Würth Elektronik
Würth Elektronik
Würth Elektronik
Würth Elektronik
Premo
2±
2400
18±0
±±0
420
10±
1230
688
±60
80
28V/0.±A
14V/1A
8:1:1.28
1:1:0.24
8±V/0.4A
90V/1A
43.18mm × 39.6mm × 30.48mm
31mm × 31mm × 2±mm
1:1:0.22
1±0
1:1:0.17
600
12±V/0.32A
30V/0.±A
23.±mm × 21.4mm × 9.±mm
72:16:10
1000
Loop Compensation
the R
should be chosen to limit the temperature rise
DS(ON)
of the MOSFET. The drain of the MOSFET is stressed to
• N + V during the time the MOSFET is off and
The current output feedback loop is an integrator con-
figuration with the compensation capacitor between the
negative input and output of the operational amplifier.
This is a one-pole system therefore a zero is not needed
in the compensation. For offline applications with PFC,
the crossover should be set an order of magnitude lower
than the line frequency of 120Hz or 100Hz. In a typical
application, the compensation capacitor is 0.1µF.
V
OUT
PS
IN
the secondary diode is conducting current. But in most
applications,theleakageinductancevoltagespikeexceeds
thisvoltage. Thevoltageofthisstressisdeterminedbythe
switch voltage clamp. Always check the switch waveform
with an oscilloscope to make sure the leakage inductance
voltage spike is below the breakdown voltage of the MOS-
FET. A transient voltage suppressor and diode are slower
thantheleakageinductancevoltagespike,thereforecausing
a higher voltage than calculated.
In non-PFC applications, the crossover frequency may
be increased to improve transient performance. The
desired crossover frequency needs to be set an order
of magnitude below the switching frequency for optimal
performance.
The secondary diode stress may be as much as
V
+ 2 • V /N due to the anode of the diode ringing
OUT
IN PS
with the secondary leakage inductance. An RC snubber
in parallel with the diode eliminates this ringing, so that
MOSFET and Diode Selection
the reverse voltage stress is limited to V
With a high N and output current greater than 3A, the
+ V /N .
OUT
IN PS
Withastrong1.9Agatedriver,theLT3799-1caneffectively
PS
drive most high voltage MOSFETs. A low Q MOSFET is
g
I
through the diode can become very high and a low
RMS
recommendedtomaximizeefficiency.Inmostapplications,
forward drop Schottky is recommended.
37991fa
15
For more information www.linear.com/LT3799-1
LT3799-1
operaTion
Discontinuous Mode Detection
Protection from Open LED and Shorted LED Faults
The discontinuous mode detector uses AC-coupling to
detect the ringing on the third winding. A 10pF capacitor
with a ±00Ω resistor in series is recommended in most
designs. Depending on the amount of leakage inductance
ringing, an additional current may be needed to prevent
falsetrippingfromtheleakageinductanceringing.Aresis-
The LT3799-1 detects output overvoltage conditions
by looking at the voltage on the third winding. The third
windingvoltageisproportionaltotheoutputvoltagewhen
the main power switch is off and the secondary diode is
conducting current. Sensing the output voltage requires
delivering power to the output. Using the CT pin, the part
turns off switching when a overvoltage condition occurs
andrecheckstoseeiftheovervoltageconditionhascleared,
asdescribedin“CTPinandFaults”intheOperationsection.
This greatly reduces the output current delivered to the
output but a Zener is required to dissipate 25 of the set
output current during an open LED condition. The Zener
diode’s voltage needs to be 105 higher than the output
voltage set by the resistor divider connected to the FB pin.
Multiple Zener diodes in series may be needed for higher
outputpowerapplicationstokeeptheZener’stemperature
within the specification.
tor from INTV to the DCM pin adds this current. Up to
CC
an additional 100µA of current may be needed in some
cases. The DCM pin is roughly 0.7V, therefore the resistor
value is selected using the following equation:
10V −0.7V
R =
I
where I is equal to the additional current into the DCM pin.
Power Factor Correction/Harmonic Content
The LT3799-1 attains high power factor and low harmonic
content by making the peak current of the main power
switch proportional to the line voltage by using an internal
multiplier. A power factor of >0.97 is easily attainable for
most applications by following the design equations in
thisdatasheet.Withproperdesign,LT3799-1applications
meet IEC 6100-3-2 Class C harmonic standards.
During a shorted LED condition, the LT3799-1 operates at
the minimum operating frequency. In normal operation,
the third winding provides power to the IC, but the third
winding voltage is zero during a shorted LED condition.
This causes the part’s V UVLO to shutdown switching.
IN
The part starts switching again when V has reached its
IN
turn-on voltage.
37991fa
16
For more information www.linear.com/LT3799-1
LT3799-1
Typical applicaTions
Universal 20W LED Driver
L2
800µH
L1
33mH
BR1
R6
C1
0.068µF
R7
D2
C5
90V
TO 265V
AC
20Ω
100k
4:1:1
R3
R8
100k
C4
4.7pF
499k
C2
0.22µF
R4
499k
R13
2k
10µF
D3
R4
100k
1A
D4
V
DCM
IN
Z1
V
FB
IN_SENSE
170V
R15
4.99k
R5
3.48k
4.02k
C10
560µF
× 2
LT3799-1
D1
R16
20Ω
V
REF
20W
R18
100k
R16
R9
LED
Z2
33V
CTRL3
CTRL2
CTRL1
GATE
M1
BR1: DIODES, INC. HD06
D1: CENTRAL SEMICONDUCTOR CMR1U-06M
D2,D3: DIODES INC. BAV20W
DR: CENTRAL SEMICONDUCTOR CMR1U-02M
Z1: FAIRCHILD SMBJ170A
32.4k
40.2k
POWER
SENSE
R
INTV
CC
S
100k
NTC
C9
4.7µF
0.05Ω
C8
2.2nF
R10
14.3k
Z2: CENTRAL SEMICONDUCTOR CMZ5937B
T1: COILCRAFT JA4429-AL
GND
+
–
M1: FAIRCHILD FDPF15N65
FAULT
FAULT CT COMP
COMP
37991 TA02
C7, 0.1µF
Component Values for Input Voltage Ranges
R5 (Ω)
R10 (Ω)
1±.8k
R (Ω)
C2 (µF)
0.22
S
Optimized for 110V
Optimized for 220V
Universal
6.34k
3.48k
3.48k
0.0±
0.07±
0.0±
24.9k
0.1
14.3k
0.22
Universal Input 4W LED Driver
L1
3.3mH
C1
33nF
R20, 10k
L1
3.3mH
BR1
R21, 10k
R6
R7
90V
TO 270V
AC
D2
C5
20Ω
100k
20:5:1
R3
L2, 3.3mH
R8
100k
C4
4.7pF
499k
C2
68nF
R4
499k
R13
10k
10µF
D3
R4
1A
D4
V
DCM
IN
100k
Z1
V
FB
IN_SENSE
150V
R15
4.99k
R5
LT3799-1
C10
1500µF
3.48k
BR1: DIODES, INC. HD06
D1
4W
D1: CENTRAL SEMICONDUCTOR CMMR1U-06
D2,D3: CENTRAL SEMICONDUCTOR BAV20W
D4: CENTRAL SEMICONDUCTOR CMSH2-40L
Z1: DIODES, INC SMAJ150
Z2: CENTRAL SEMICONDUCTOR CMZ5919B
T1: WÜRTH ELEKTRONIK WE-750813002
M1: INFINEON SPU04N60C3
LED
R16
20Ω
V
REF
POWER
R18
100k
M1
CTRL3
CTRL2
CTRL1
GATE
Z2
5.6V
R9
40.2k
SENSE
R
S
INTV
CC
C9
4.7µF
0.3Ω
C8
2.2nF
R10
22.1k
GND
+
–
FAULT
FAULT CT COMP
COMP
37991 TA03
C7, 0.1µF
C6
0.068µF
37991fa
17
For more information www.linear.com/LT3799-1
LT3799-1
package DescripTion
Please refer to http://www.linear.com/product/LT3799-1#packaging for the most recent package drawings.
MSE Package
16-Lead Plastic MSOP, Exposed Die Pad
(Reference LTC DWG # 05-08-1667 Rev F)
BOTTOM VIEW OF
EXPOSED PAD OPTION
2.845 ±0.102
(.112 ±.004)
2.845 ±0.102
(.112 ±.004)
0.889 ±0.127
(.035 ±.005)
1
8
0.35
REF
5.10
(.201)
MIN
1.651 ±0.102
(.065 ±.004)
1.651 ±0.102
(.065 ±.004)
3.20 – 3.45
(.126 – .136)
0.12 REF
DETAIL “B”
CORNER TAIL IS PART OF
THE LEADFRAME FEATURE.
FOR REFERENCE ONLY
DETAIL “B”
16
9
0.305 ±0.038
0.50
(.0197)
BSC
NO MEASUREMENT PURPOSE
4.039 ±0.102
(.159 ±.004)
(NOTE 3)
(.0120 ±.0015)
TYP
0.280 ±0.076
(.011 ±.003)
RECOMMENDED SOLDER PAD LAYOUT
16151413121110
9
REF
DETAIL “A”
0.254
(.010)
3.00 ±0.102
(.118 ±.004)
(NOTE 4)
0° – 6° TYP
4.90 ±0.152
(.193 ±.006)
GAUGE PLANE
0.53 ±0.152
(.021 ±.006)
1 2 3 4 5 6 7 8
DETAIL “A”
0.86
(.034)
REF
1.10
(.043)
MAX
0.18
(.007)
SEATING
PLANE
0.17 – 0.27
(.007 – .011)
TYP
0.1016 ±0.0508
(.004 ±.002)
MSOP (MSE16) 0213 REV F
0.50
(.0197)
BSC
NOTE:
1. DIMENSIONS IN MILLIMETER/(INCH)
2. DRAWING NOT TO SCALE
3. DIMENSION DOES NOT INCLUDE MOLD FLASH, PROTRUSIONS OR GATE BURRS.
MOLD FLASH, PROTRUSIONS OR GATE BURRS SHALL NOT EXCEED 0.152mm (.006") PER SIDE
4. DIMENSION DOES NOT INCLUDE INTERLEAD FLASH OR PROTRUSIONS.
INTERLEAD FLASH OR PROTRUSIONS SHALL NOT EXCEED 0.152mm (.006") PER SIDE
5. LEAD COPLANARITY (BOTTOM OF LEADS AFTER FORMING) SHALL BE 0.102mm (.004") MAX
6. EXPOSED PAD DIMENSION DOES INCLUDE MOLD FLASH. MOLD FLASH ON E-PAD SHALL
NOT EXCEED 0.254mm (.010") PER SIDE.
37991fa
18
For more information www.linear.com/LT3799-1
LT3799-1
revision hisTory
REV
DATE
DESCRIPTION
PAGE NUMBER
A
2/16
Amended Current Limit Undervoltage Threshold.
3
37991fa
Information furnished by Linear Technology Corporation is believed to be accurate and reliable.
However, no responsibility is assumed for its use. Linear Technology Corporation makes no representa-
19
tion that the interconnection of its circuits as described herein will not infringe on existing patent rights.
LT3799-1
Typical applicaTion
90V to 305V AC Input 108W LED Driver
L3
150µH
L1
C1
L2
10mH
D3
D4
D1
D2
10mH
0.47µF
90V
TO 305V
AC
R5
R1
D5
C3
20Ω
249k
T1
R10
R2
249k
C21
4.7pF
R7
499k
C2
0.47µF
22µF
R11
499k
2k
D6
3A
R3
100k
D8
V
DCM
IN
V
FB
IN_SENSE
C10
1000µF
R9
10k
220V
Z4
Z2
R4
4.32k
R6
200k
R12
3.09k
C13
2.2nF
LT3799-1
Z3
40V
C9
10µF
D9
D7
V
REF
R25
17.8Ω
CTRL3
CTRL2
CTRL1
R18
100k
R19
40.2k
GATE
M1
108W
LED
SENSE
POWER
INTV
CC
R20
16.9k
R8
15m
C20
2.2nF
INTV
CC
C8
4.7µF
FAULT
FAULT
CT
+
–
37991 TA04
GND COMP COMP
D1, D2, D3, D4: IN4005
D5, D6: DIODES INC. BAV20W
C7
0.1µF
C6
10nF
D7: CENTRAL SEMICONDUCTOR CMR1U-10M
T1: WÜRTH ELEKTRONIK-750811351
M1: INFINEON SPP17N80C3
Z4: LITTLE FUSE SMCJ220CA
Z2: FAIRCHILD SEMICONDUCTOR SMBJ130A
Z3: FAIRCHILD SEMICONDUCTOR SMCJ40A
D9: CENTRAL SEMICONDUCTOR CMR1U-02M
D8: DIODES INC SBR10U300CT
relaTeD parTs
PART NUMBER
DESCRIPTION
COMMENTS
LT37±±/LT37±±-1/ High Side 60V, 1MHz LED Controller with 3000:1
LT37±±-2 True Color PWM™ Dimming
V
SD
: 4.±V to 40V, V
= 60V, Dimming: 3000:1 True Color PWM,
IN
OUT(MAX)
I
< 1µA, 3mm × 3mm QFN-16 and MSOP-16E Packages
LT37±6/LT37±6-1/ High Side 100V, 1MHz LED Controller with 3000:1
V
SD
: 6V to 100V, V
= 100V, Dimming: 3000:1 True Color PWM,
IN
OUT(MAX)
LT37±6-2
True Color PWM Dimming
I
< 1µA, 3mm × 3mm QFN-16 and MSOP-16E Packages
LT3743
Synchronous Step-Down 20A LED Driver with
Three-State LED Current Control
V : ±.±V to 36V, Dimming: 10000:1 True Color PWM, I < 1µA,
IN SD
±mm × 8mm QFN-±2 Package
V : 3V to 30V, Dimming: 3000:1 True Color PWM, I < 1µA,
IN
LT3±18
LT3±17
LT3741
2.3A, 2.±MHz High Current LED Driver with 3000:1
Dimming
SD
4mm × 4mm QFN-16 Package
V : 3V to 30V, Dimming: 3000:1 True Color PWM, I < 1µA,
IN
1.3A, 2.±MHz High Current LED Driver with 3000:1
Dimming
SD
4mm × 4mm QFN-16 Package
V : 6V to 36V, Average Current Mode Control, I < 1µA,
IN
High Power, Constant-Current, Constant-Voltage
Synchronous Step-Down Controller
SD
4mm × 4mm QFN-20 and TSSOP-20E Packages
37991fa
LT 0216 REV A • PRINTED IN USA
LinearTechnology Corporation
1630 McCarthy Blvd., Milpitas, CA 9±03±-7417
20
●
●
LINEAR TECHNOLOGY CORPORATION 2012
(408)432-1900 FAX: (408) 434-0±07 www.linear.com/LT3799-1
相关型号：
LT3799EMSE-1#TRPBF
LT3799-1 - Offline Isolated Flyback LED Controller with Active PFC; Package: MSOP; Pins: 16; Temperature Range: -40°C to 85°C
Linear
LT3799IMSE#PBF
LT3799 - Offline Isolated Flyback LED Controller with Active PFC; Package: MSOP; Pins: 16; Temperature Range: -40°C to 85°C
Linear
LT3799IMSE#TRPBF
LT3799 - Offline Isolated Flyback LED Controller with Active PFC; Package: MSOP; Pins: 16; Temperature Range: -40°C to 85°C
Linear
LT3799IMSE-1#TRPBF
LT3799-1 - Offline Isolated Flyback LED Controller with Active PFC; Package: MSOP; Pins: 16; Temperature Range: -40°C to 85°C
Linear
LT3800EFE#PBF
LT3800 - High-Voltage Synchronous Current Mode Step-Down Controller; Package: TSSOP; Pins: 16; Temperature Range: -40°C to 85°C
Linear
LT3800EFE#TRPBF
LT3800 - High-Voltage Synchronous Current Mode Step-Down Controller; Package: TSSOP; Pins: 16; Temperature Range: -40°C to 85°C
Linear
©2020 ICPDF网 联系我们和版权申明