Patent ID: 8258824
Filing Date: 2012-09-04
Classification: H02M,H03K,Y02B

Abstract:
1. A control method of a heterodyne dual-slope feedback circuit, comprising: starting a power supply system; providing a fixed charge current source to charge a first charge capacitor with a fixed current and generating a first charge slope; driving an outer loading and judging whether said outer loading is light loading; providing a feedback error voltage (Vfb) to a second terminal of a feedback error amplifier; driving a variable charge current source to generate a first current, which utilizes the control of said feedback error amplifier to drive said variable charge current to generate said first current; charging a second charge capacitor voltage (Vrp comparing said first charge slope and said second charge slope, which utilizes a heterodyne method to determine a cross time of said first charge slope and said second charge slope, and do a discharging process when said first charge slope and said second charge slope crossover; and outputting a first PWM control signal, which utilizes a charge-discharge frequency according to said first charge slope and said second charge slope to generate said first PWM control signal.