Patent ID: 8890552
Filing Date: 2014-11-18
Classification: G01R,H02M

Abstract:
1. A sensing circuit for a flyback converter including a transformer to convert an input voltage into an output voltage, the sensing circuit comprising: a first sampling and holding circuit sampling and holding a current sense signal at a first time point to generate a first signal, wherein the current sense signal is a function of a primary current the transformer; a second sampling and holding circuit sampling and holding the current sense signal at a second time point after the first time point to generate a second signal; and a subtraction circuit connected to the first and second sampling and holding circuits to subtract the first signal from the second signal to generate a third signal for determining a variation of the current sense signal from the first time point to the second time point; wherein the first and the second time points have a time difference therebetween, which is set according to propagation delay.