Patent ID: 7564282

Claim:
A bi-stable flip-flop device having an active mode in which the device is electrically powered and an inactive mode, the flip-flop device comprising: a chain of inverters controlled by a clock signal, the chain of inverters including a master inverter and a slave inverter; storage means for storing a state of the flip-flop device in the active mode; and retention means for storing the state of the flip-flop device in the inactive mode, wherein the flip-flop device comprises a continuously powered bi-stable structure that integrates the retention means and a part of the storage means, the bi-stable structure comprising a single isolation switch that is connected to the inverter chain and controlled by a standby logic signal that is representative of whether the flip-flop device is in the active mode or the inactive mode, the single isolation switch is directly connected to the input of the master inverter or the input of the slave inverter, and in the active mode the bi-stable structure operates as a feedback loop.