PWM type high frenquency switch power supply constant voltage/constant current controller

The utility model relates to a PWM typed high frequency switch power supply constant voltage and constant current controller. Wherein, an antiphase end of a voltage comparator is connected with a feedback voltage. A homophase end is connected with a set voltage. A feedback circuit which comprises a resistance and a capacitance is connected between the output end and the antiphase end. An antiphase end of a current comparator is connected with a feedback current. A homophase end is connected with a set current. A feedback circuit which comprises a resistance and a capacitance is connected between the output end and the antiphase end. The output ends of the voltage comparator and the current comparator are connected together. The output ends are connected with a voltage reference through a pull-up resistance, connected with the ground through a capacitance and connected with the input end of a triangular wave comparator of the PWM chip. The controller adopts the structure of parallel connection of voltage and current double control ring. When working in the constant voltage condition, the voltage ring works. When reaching the constant current point, the controller is automatically cut over to the constant current working condition and the current ring works. Therefore, the precision of voltage regulation and current regulation is enhanced.