Flyback switching power supply circuit

The utility model provides a flyback switching power supply circuit, can be used to provides the power supply that the multichannel keeps apart for direct current motor drive, including PWM control circuit, the NMOS pipe, a transformer, the first output circuit, the 2nd output circuit, the 3rd output circuit and optoelectronic isolation feedback circuit, an output circuit includes first diode andfirst condenser, the 2nd output circuit includes second diode and the second capacitor, the 3rd output circuit includes third diode and third capacitor, the transformer includes primary, a secondary coil and the 2nd secondary coil, PWM control circuit's inside contains the reduction voltage circuit. The utility model provides a power is kept apart to the multichannel, just need not transformer winding and provides working power supply for PWM control circuit, and circuit structure is simple, with low costs, small, stability is good and easy maintenance. 本实用新型提供种反激式开关电源电路，可用于为直流电机驱动器提供多路隔离的供电电源，包括PWM控制电路、NMOS管、变压器、第输出电