LT3798

1

3798f

External Components

TYPICAL APPLICATION

FEATURES

DESCRIPTION

Isolated No Opto-Coupler

Flyback Controller

with Active PFC

lated flyback controller that combines active power factor

correction (PFC) with no opto-coupler required for output

voltage feedback into a single-stage converter. A LT3798

based design can achieve a power factor of greater than 0.97

by actively modulating the input current, allowing compli-

ance with most Harmonic Current Emission requirements.

The LT3798 is well suited for a wide variety of off-line

applications. The input range can be scaled up or down,

depending mainly on the choice of external components.

Efficiencies higher than 86% can be achieved with output

power levels up to 100W. In addition, the LT3798 can easily

be designed into high DC input applications.

Universal Input 24W PFC Bus Converter

APPLICATIONS

L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear

Technology Corporation. All other trademarks are the property of their respective owners.

Protected by U.S. Patents, including 5438499 and 7471522.

3798 TA01a

EN/UVLO

DCM

FB

CTRL2

CTRL1

OVP

GATE

SENSE

GND

LT3798

VC

560μ

F

×

2

4.7pF

10μ

F

2.2nF

4:1:1

2.2μF

0.1μF

20Ω

20Ω

0.05Ω

499k

499k

95.3k

1M

D2

Z1

Z2

D1

D4

22pF

D3

100k

100k

4.99k

90.9k

CTRL3

90V

TO 265V

AC

0.1μF

40.2k

100k

16.5k

221k

4.7μF

2k

24V

1A

0

23.50

24.25

24.00

23.75

24.50

0.6

0.8

1

0.2

0.4

3798 TA01b

VAC = 265V

VAC = 220V

VAC = 120V

VAC = 90V