Standby mode state retention logic circuits

Abstract

A retention mode sequential logic circuit has no balloon latch, and all its P-channel transistors are disposed in a single N-well. In one example, the circuit is a retention flip-flop that has an active high retention signal input and an active low reset input. In another example, the circuit is a retention flip-flop that has an active low retention signal input and an active low reset input. In a multi-bit retention register example, one common clock and reset signal generation logic circuit drives multiple pairs of latches. Each retention mode logic circuit described has a low transistor count, is implemented with a single N-well, exhibits low retention mode power consumption, is not responsive to a reset signal in the retention mode, and has a fast response time when coming out of retention mode operation.