M51995AP/AFP

REJ03D0835-0300 Rev.3.00 Jun 06, 2008

Page 31 of 40

2. Application circuit to make the OVP-reset time fast

OVP-reset time fast.

+

+

To main

transformer

R1

GND

R2

The time constant of

this part should be short

M51995A

Figure 27 Example Circuit Diagram to Make the OVP-Reset-Time Fast

3. OVP setting method using the induced third winding voltage on fly back system

For the over voltage protection (OVP), the induced fly back type third winding voltage can be utilized, as the

induced third winding voltage depends on the output voltage. Figure 28 shows one of the example circuit diagram.

+

Main

transformer

third winding

OVP

GND

470

Ω

M51995A

Figure 28 OVP Setting Method Using the Induced Third Winding Voltage on Fly Back System