Patent ID: 7729140

Claim:
A sampling method used for sampling a measured signal related to a switch in a converter circuit, comprising steps of: (a) providing a first working pulse signal which has a pulse-width duty ratio D in a switching period T s ; (b) setting a first adjusting period comprising first N successive switching periods of the first working pulse signal with at least a pulse duty ratio of the first working pulse signal in the first adjusting period is D, wherein N is a natural number larger than 1; (c) providing a second working pulse signal which has second N successive switching periods corresponding to the first N successive switching periods with their pulse-width duty ratio D 1 , D 2 , . . . , D N respectively to drive the switch in the converter circuit and generating the measured signal, wherein the sum of D 1 , D 2 , . . . , D N substantially equals to N·D and the second N successive switching periods constitute a second adjusting period; (d) setting one pulse of the second working pulse signal in the second adjusting period as a sampling pulse; and (e) sampling the measured signal at a predetermined sampling time point in the sampling pulse for producing a sampling value of the converter circuit.