Patent ID: 7952389
Filing Date: 2011-05-31
Classification: H03K

Abstract:
1. A level shift circuit for transmitting a signal from a circuit operated by a first power supply to another circuit operated by a second power supply, comprising: a first inverter of the second power supply system having an output node coupled to a first output terminal and having an input node coupled to a second output terminal; a second inverter of the second power supply system having an output node coupled to said second output terminal and an input node coupled to said first output terminal; a first switch coupled between said first output terminal and a ground; a second switch coupled between said second output terminal and the ground; and a barrier gate circuit that receives an input signal of a first power supply system and a standby signal, wherein when said standby signal indicates a first state, said barrier gate circuit sets one of said first and second switches to an on-state and sets the other of said first and second switches to an off-state based on a logic level of said input signal, and wherein when said standby signal indicates a second state, said barrier gate circuit keeps both of said first and second switches in off-states holding said first and second output terminals at a constant voltage.