1 Energy Recycling Circuit for Leakage Power Reduction

As leakage constitutes an increasingly significant portion of new high performance processors ’ power consumption, effective leakage reduction techniques are essential. Sleep transistor technique can effectively reduce the static leakage current during idle mode, but a large amount of energy is still wasted at the virtual rail nodes and the time constant for the circuit to settle to sleep/low-leakage mode is usually large due to the presence of large decoupling capacitors associated with these nodes. This paper proposes a energy recycling circuit which can recycle the energy on the virtual rail nodes back to the global supply while at the same time, speed up the sleep-mode convergence process so that additional leakage energy can be saved, resulting in a higher possible sleep-wakeup activity factor. Index term – energy recycling, decoupling capacitor, leakage, sleep transistor