Input and output overvoltage protection in a power converter

摘要

A controller for use in a power converter includes a gate drive circuit coupled to generate a control signal to switch a power switch of the power converter. A zero current detection circuit is coupled to a multifunction pin coupled to receive a multifunction signal that is representative of an input voltage of the power converter when the power switch is on, and representative of an output voltage of the power converter when the power switch is off. The zero current detection circuit is coupled to generate a zero current detection signal. An overvoltage detection circuit is coupled to receive the multifunction signal and a state signal representative of a state of the power switch to generate in response to the state signal and the multifunction signal a line overvoltage signal and an output over voltage signal coupled to be received by the gate drive circuit.

主权项

1. A controller for use in a power converter, comprising:
a gate drive circuit coupled to generate a control signal to switch a power switch of the power converter to control a transfer of energy of from an input of the power converter through an energy transfer element to an output of the power converter; a zero current detection circuit coupled to a multifunction pin coupled to receive a multifunction signal from the power converter, wherein the multifunction signal is representative of an input voltage of the power converter when the power switch is on, and wherein the multifunction signal is representative of an output voltage of the power converter when the power switch is off, wherein the zero current detection circuit is coupled to generate in response to the multifunction signal a zero current detection signal coupled to be received by the gate drive circuit; and an overvoltage detection circuit coupled to the multifunction pin to receive the multifunction signal from the power converter, wherein the overvoltage detection circuit is further coupled to the gate drive circuit to receive a state signal representative of a state of the power switch, wherein the overvoltage detection circuit is coupled to generate in response to the state signal and the multifunction signal a line overvoltage signal and an output overvoltage signal coupled to be received by the gate drive circuit, wherein the gate drive circuit is coupled to disable switching of the power switch in response to the output overvoltage signal or the line overvoltage signal.