US Patent 7626434 Low leakage state retention circuit

In general, in one aspect, the disclosure describes an apparatus comprising a low leakage latch to store a state of a circuit during inactive periods. The state is transferred to the low leakage latch upon receipt of an inactive pulse. A buffer is used to receive the state from an output of the low leakage latch and to isolate the state. State restore circuitry is used to restore the state to the circuit when the circuit returns to an active mode. The state restore circuitry is used to receive the isolated state and to restore the state upon receipt of an active pulse.