Rev. E 09/09

2

LNK623-626

www.powerint.com

Pin Functional Description

DRAIN (D) Pin:

This pin is the power MOSFET drain connection. It provides

internal operating current for both start-up and steady-state

operation.

BYPASS (BP) Pin:

This pin is the connection point for an external bypass capacitor

for the internally generated 6 V supply.

FEEDBACK (FB) Pin:

During normal operation, switching of the power MOSFET is

controlled by this pin. This pin senses the AC voltage on the

bias winding. This control input regulates the output voltage

based on the flyback voltage of the bias winding.

SOURCE (S) Pin:

This pin is internally connected to the output MOSFET source

for high voltage power and control circuit common returns.

Figure 2

Functional Block Diagram.

Figure 3.

Pin Configuration.

PI-5197-110408

SOURCE

(S)

LEADING

EDGE

BLANKING

+

-

+

-

+

-

DRAIN

(D)

BYPASS

(BP)

FEEDBACK

(FB)

SOURCE

(S)

FB

OUT

Reset

6 V

5 V

t

SAMPLE-OUT

V

ILIMIT

I

LIM

V

TH

V

ILIMIT

6.5 V

Drive

I

LIM

DC

MAX

t

SAMPLE-OUT

DC

MAX

FB

Current Limit

Comparator

STATE

MACHINE

SAMPLE

DELAY

THERMAL

SHUTDOWN

OSCILLATOR

FAULT

Auto-Restart

Open-Loop

DQ

REGULATOR

6 V

PI-5198-071608

3a

3b

D

S

BP

S

S

FB

P Package (DIP-8C)

D Package (SO-8C)

8

5

7

1

4

2

S

6

D

S

BP

S

S

FB

8

5

7

1

4

2

S

6