基于AP3706的反激式变换器设计

AP3706/08N uses Pulse Frequency ModulaTIon

(PFM) method to realize DisconTInuous ConducTIon

Mode (DCM) operaTIon for flyback power supplies;

uses Primary Side Regulation (PSR) to provide Constant

Voltage (CV) and Constant Current (CC) regulation.

The principle of PFM is different from that of

Pulse Width Modulation (PWM), so the design steps of

the transformer for PFM operation is also different

from that for PWM operation. In the other side,

AP3706/08N uses PSR to provide CV/CC regulation

without requiring opto-coupler and loop compensation,

which makes the design of transformer more critical

than that with PWM. The following design steps

focus on the transformer design. Some design guides

to select diodes and transistor are also included.