Rev. L 10/20

2

LNK603-606/613-616

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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/MULTI-FUNCTIONAL PROGRAMMABLE (BP/M) Pin:

This pin has multiple functions:

1. It is the connection point for an external bypass capacitor for the

internally generated 6 V supply.

2. It is a mode selection for the cable drop compensation for

LNK61X series.

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 both the output voltage in CV mode and output

current in CC mode based on the flyback voltage of the bias winding.

The internal inductance correction circuit uses the forward voltage on

the bias winding to sense the bulk capacitor voltage.

SOURCE (S) Pin:

This pin is internally connected to the output MOSFET source for

high-voltage power and control circuit common returns.

Figure 3.

Functional Block Diagram.

Figure 4. Pin Configuration.

PI-4908-012915

SOURCE

(S)

LEADING

EDGE

BLANKING

+

-

+

-

+

-

DRAIN

(D)

REGULATOR

6 V

BYPASS

(BP/M)

FEEDBACK

(FB)

SOURCE

(S)

FB

OUT

Reset

6 V

5 V

t

SAMPLE-OUT

t

SAMPLE-INPUT

V

ILIMIT

I

LIM

V

ILIMIT

V

TH

t

SAMPLE-OUT

t

SAMPLE-INPUT

V

ILIMIT

6.5 V

Drive

I

LIM

DC

MAX

DC

MAX

FB

Current Limit

Comparator

STATE

MACHINE

CABLE DROP

COMPENSATION

SAMPLE

DELAY

THERMAL

SHUTDOWN

OSCILLATOR

FAULT

Auto-Restart

Open-Loop

INDUCTANCE

CORRECTION

CONSTANT

CURRENT

D Q

PI-3491-020615

D

S

BP/M

S

S

FB

P Package (DIP-8C)

G Package (SMD-8C)

D Package (SO-8C)

8

5

7

1

4

2

S

6

FB

BP/M

D

1

2

4

8

7

6

5

S

S

S

S