Method and apparatus for reducing gate leakage of low threshold transistors during low power mode in a multi-power-domain chip

Abstract

A circuit for reducing gate leakage current in a switchable power domain of a CMOS (complementary metal oxide semiconductor) integrated circuit chip includes a first transistor having a drain electrode coupled to a first terminal of a power switch having a second terminal coupled to a first reference voltage, the first transistor having a gate electrode, a body electrode, and a source electrode. The source electrode and body electrodes are coupled to a second reference voltage. The first transistor has a relatively high first gate leakage current that flows from its gate electrode to its body electrode if the power switch is open and a voltage of the gate electrode of the first transistor representing a first logic level exceeds a voltage of the body electrode by more than a first predetermined amount. A first circuit produces a relatively low voltage on the gate electrode of the first transistor representing a second logic level to substantially reduce the first gate leakage current when reduced power consumption of the chip is needed.