Latch-up protection circuit for integrated circuits biased with multiple power supplies and its method

摘要

A latch-up protection circuit for an integrated circuit powered through a first power rail and a second power rail is disclosed, the integrated circuit having at least one semiconductor bulk of a conductivity type. The latch-up protection circuit comprises a control circuit and a switch circuit. The control circuit is connected to the first power rail and the second power rail for detecting a relative voltage therebetween and generating a first control signal and a second control signal. The switch circuit connected to the first power rail and the control circuit. When the relative voltage is greater than a first predetermined value, the switch circuit in response to the first control signal electrically connects the first power rail with the at least one semiconductor bulk. When the relative voltage is smaller than the first predetermined value, the switch in response to the first control signal electrically disconnects the first power rail from the at least one semiconductor bulk.