An embodiment of the invention provides a feedback control circuit and a feedback control method. The feedback control circuit comprises a voltage comparator, a correction voltage generator and a processor. The voltage comparator receives mid-point voltage and correction voltage, performs comparison on the mid-point voltage and the correction voltage and outputs a reference voltage pulse wave signal. The correction voltage generator is used for generating the correction voltage and transmitting the correction voltage to a switch driving circuit and a voltage comparator. The processor compares the pulse wave width of the reference voltage pulse wave signal with the pulse wave width of a preset fixed voltage pulse wave signal and outputs a control signal to the correction voltage generator for performing fine adjustment on the voltage value of the correction voltage. The switch driving circuit performs adjustment according to the voltage value of the correction voltage and furthermore outputs a set of switch driving signals to a switch adjusting circuit for adjusting switch starting time and switch stopping time.