CONSTANT VOLTAGE CONSTANT CURRENT CONTROLLER AND CONTROL METHOD THEREOF

摘要

The present invention relates to a constant voltage constant current (CVCC) controller, and associated control methods. In one embodiment, a CVCC controller for a flyback converter can include: (i) a current controller configured to generate an error signal by comparing an output current feedback signal against a reference current; (ii) a voltage controller configured to receive an output voltage feedback signal and a reference voltage, and to generate a control signal; (iii) a selector configured to control the flyback converter to operate in a first or a second operation mode based on the control signal, and to further generate a constant voltage or a constant current control signal based on the error signal; and (iv) a pulse-width modulation (PWM) controller configured to generate a PWM control signal to control a main switch, and to maintain the output voltage and/or current of the flyback converter as substantially constant.

主权项

1. A constant voltage constant current (CVCC) controller configured for a flyback converter, said CVCC controller comprising:
a) a current controller configured to generate an error signal by calculating a difference between an output current feedback signal and a reference current; b) a voltage controller configured to receive an output voltage feedback signal and a reference voltage, and to generate a control signal; c) a selector configured to receive said error signal and said control signal, and to control said flyback converter to operate in a first operation mode or a second operation mode based on said control signal, wherein said selector is configured to generate a constant voltage control signal based on said error signal when said flyback converter is operating in said first operation mode, and wherein said selector is configured to generate a constant current control signal based on said error signal when said flyback converter is operating in said second operation mode; and d) a pulse-width modulation (PWM) controller configured to generate a PWM control signal to control a main switch of said flyback converter, wherein said PWM controller is configured to generate a constant voltage signal based on said constant voltage control signal to maintain an output voltage of said flyback converter as substantially constant when said flyback converter operates in said first operation mode, and wherein said PWM controller is configured to generate a constant current signal based on said constant current control signal to maintain an output current of said flyback converter as substantially constant when said flyback converter operates in said second operation mode.