Method for sensing output current of fly-back converter

Abstract

A method for sensing an output current Iout of the fly-back converter has steps of sensing a voltage US of the switching node to obtain a time period TSW of a switching cycle of the fly-back converter and a time period TOFF of a OFF stage of the switching cycle; and then calculating the output current Iout according to a formula I out = k  T OFF 2 T SW , wherein k is a predictable constant. By the method, a user just need to sense the voltage US of the switching node of the fly-back converter, and then the output current Iout of the fly-back converter is obtained by the formula without using a sensing resistor to sense any current in the fly-back converter.

Dependencies are inferred from the claim text.