HF01B00/01/02/03/04–OFF LINE HIGH VOLTAGE QUASI RESONANT REGULATOR
PIN FUNCTIONS
Pin #
Name
Description
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.
1
VSD
Supply voltage pin. Typically connect a 22μF bulk capacitor and a 0.1uF ceramic capacitor
to this Pin. When VCC is charged to 12V, the internal high voltage current source turns off
and the IC starts switching; when it falls back to 8V, the high voltage current source turns on
again and the IC stops switching.
2
VCC
3
4
5
6
7
N/C
D
Not connected. This pin ensures adequate creepage distance.
Drain of the internal MOSFET. Input for the start up high voltage current source.
Source of the internal MOSFET. Input of the primary current sense signal.
Source of the internal MOSFET. Input of the primary current sense signal.
The IC Ground.
S
S
GND
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
8
FB
HF01B00/01/02/03/04 Rev. 1.2
www.MonolithicPower.com
5
4/9/2013
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