US Patent 11004480 Leakage current reduction in a dual rail device

A device for reducing leakage current includes a memory cell array, a power switch and a core logic. The memory cell array is electrically connected to a first power rail which supplies a first voltage level. The core logic circuitry is electrically connected to a second power rail via the power switch when the power switch is turned on. The second power rail supplies a second voltage level which is lower than the first voltage level. The power switch is to be turned off by the first voltage level supplied to a gate terminal of the power switch, to thereby disconnect the core logic circuitry in a sleep state from the second power rail.