HA16178P Datasheet, PDF (15/25 Pages) Renesas Technology Corp – Power Factor Correction Controller IC

HA16178P/FP
3. Soft Start
This function prevents applying excessive stress on external components and overshooting of the PFC output voltage (B
+ voltage) when start up. The pulse width is gradually widening from 0% duty cycle. During soft-start operation, the
SS and CAO signals lower with link. The duty cycle is controlled by the CAO signal.
The soft-start time can be set by an external capacity.
PFC-ON
SS
1.75 V
CAO ^SS
CAO
CT
OUT
PFC output voltage
Figure 3 Soft-Start Operation Waveform
REJ03D0903-0100 Rev.1.00 Jun 12, 2007
Page 15 of 24