3

SANKEN ELECTRIC CO., LTD.

28103.30-5

Quasi-Resonant Topology

Primary Switching Regulators

STR-W6735

0

20

40

60

80

100

0

255075

100

125

150

10.00

20.00

0.10

1.00

0.01

100.00

10

100

1000

1

0.1

ms

Current

limit

due

to R

DS(on)

Refer to figure 1 for MOSFET SOA

temperature derating coefficient

Figure 1 – MOSFET Safe Operating Area

Derating Curve

Figure 2 – MOSFET Safe Operating Area

Drain Current versus Voltage

D

S/GND

OCP/BD

FB

Start

Stop

Burst

R

S

Q

Reg&

Iconst

OVP

DRIVE

Reg

Protection

latch

S

R Q

FB

OCP

BSD

BD

Bottom Selector

Counter

SS/OLP

OLP

Delay

S

R

Q

OSC

MaxON

Soft Start

Burst

Control

Burst

Control

4

+

-

+

-

+

-

+

-

1

3

6

7

5

Terminal List Table

Number

Name

Description

Functions

1

D

Drain

MOSFET drain

2

NC

Clipped

No connection

3

S/GND

Source/ground terminal

MOSFET source and ground

4

VCC

Power supply terminal

Input of power supply for control circuit

5

SS/OLP

Soft Start/Overload Protection terminal

Input to set delay for Overload protection and Soft Start operation

6

FB

Feedback terminal

Input for Constant Voltage Control and Burst (intermittent) Mode

oscillation control signals

7

OCP/BD

Overcurrent Protection/Bottom Detection

Input for overcurrent detection and bottom detection signals