HF01B00/01/02/03/04

–OFF LINE HIGH VOLTAGE QUASI RESONANT REGULATOR

HF01B00/01/02/03/04 Rev. 1.2

www.MonolithicPower.com

5

4/9/2013

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PIN FUNCTIONS

Pin #

Name

Description

1

VSD

Valley switching detector of the auxiliary flyback signal. It ensures Discontinuous Conduction

Mode (DCM) operation with valley switching over the entire input/load range. This pin also

offers OVP detection.

2

Supply voltage pin. Typically connect a 22

μF bulk capacitor and a 0.1uF ceramic capacitor

and the IC starts switching; when it falls back to 8V, the high voltage current source turns on

again and the IC stops switching.

3

N/C

Not connected. This pin ensures adequate creepage distance.

4

D

Drain of the internal MOSFET. Input for the start up high voltage current source.

5

S

Source of the internal MOSFET. Input of the primary current sense signal.

6

S

Source of the internal MOSFET. Input of the primary current sense signal.

7

GND

The IC Ground.

8

FB

This pin sets the primary peak current limit, by directly connecting an optocoupler to this pin

to close the feedback loop. A feedback voltage of 3.7V on this pin will trigger an Over Load

Protection while 0.5V will trigger a Burst Mode operation. The regulator leaves Burst Mode

Operation and enters normal operation when the FB voltage reaches 0.7V