Pin List Table

Number

Name

Function

1

D/ST

MOSFET drain pin and input of the startup current

2

S/GND

MOSFET source and GND pin for the Control Part

3

VCC

Supply voltage input and Overvoltage protection (OVP) signal input

4

OCP

Overcurrent Protection, quasi-resonant signal input pin, and

Overvoltage Protection (OVP) signal input

5

FB

Feedback signal input and Overload Protection (OLP) signal input

6

NC

No connection

7

OVP

Overvoltage Protection (OVP) signal input

Functional Block Diagram

Functional Block Diagram

Pin-out Diagrams

2

3

4

6

1

5

7

D/ST

S/GND

VCC

OCP

FB

NC

OVP

(LF 3052)

(LF 3051)

(LF 3054)

1

2

3

4

5

6

7

D/ST

S/GND

VCC

OCP

FB

NC

OVP

2

4

6

1

3

5

7

D/ST

S/GND

VCC

OCP

FB

NC

OVP

S/GND

TSD

LEB

D/ST

STARTUP

Reg

Bias

UVLO

VCC

OCP

OVP

OVP

OSC

OCP

Detection

Bottom

Reg

Control

Feedback

OLP

①

②

③

④

Drv

FB

⑥

Q

S

R

⑤

NC

Control Part

January 28, 2013

8

SANKEN ELECTRIC CO., LTD.

LC5540LF-DS

Single-Stage Power Factor Corrected

Off-Line Switching Regulator ICs

LC5540LF

Series