Malfunction detecting circuit and malfunction detecting method for detecting malfunction of current-sensing resistor, and power converting system applying the malfunction detecting circuit

摘要

A malfunction detecting circuit for detecting malfunction of a current sensing resistor includes a reference-voltage generating circuit and a comparing circuit, wherein the reference-voltage generating circuit is utilized to generate a reference voltage signal varying with the on time period of a power switch of a power converting system. The comparing circuit compares a sensing voltage signal corresponding to a current flowing through the current sensing resistor with the reference voltage signal to generate a comparing result indicating whether the malfunction occurs.