Flyback converter system and feedback controlling apparatus and method for the same

摘要

A flyback converter system and feedback controlling apparatus and method of operating the same are disclosed. The feedback controlling apparatus for the flyback converter system includes a primary feedback loop unit for generating a primary feedback signal, and a secondary feedback loop unit for generating a secondary feedback signal, a loop selector. In light-load conditions, the loop selector supplies the primary feedback signal to a PWM controller for feedback control, and the secondary feedback loop unit is disabled by a power monitor to save electrical energy.

主权项

1. A flyback converter system, comprising:
a transformer unit comprising a primary winding, a secondary winding and an auxiliary winding, which are magnetically coupled to each other; a switch unit electrically connected to the primary winding; a pulse width modulation (PWM) control unit electrically connected to the switch unit; a primary feedback loop unit electrically connected to the auxiliary winding and generating a primary feedback voltage signal according to an induced voltage of the auxiliary winding; a secondary feedback loop unit electrically connected to the secondary winding and generating a secondary feedback voltage signal according to an output voltage of the secondary winding; a loop selector operatively connected to the primary feedback loop unit and the secondary feedback loop unit, and electrically connected to the PWM control unit; and a power monitor electrically connected to the secondary winding and electrically isolated with the loop selector, the power monitor configured to generate a feedback selection signal according to a power level output by the flyback converter system; wherein the feedback selection signal turns off a switch connected between the secondary feedback loop and an output port of the flyback converter system to cut electric power supplied to the secondary feedback loop in light-load condition; wherein the loop selector is controlled by the feedback selection signal to select the primary feedback voltage signal as a feedback input signal in light-load condition and to select the secondary feedback voltage signal as the feedback input signal in full-load condition; wherein the primary winding and the auxiliary winding are located at a primary side, and the secondary winding is located at a secondary side.