Analysis and optimization of gate leakage current of power gating circuits

Power gating is widely accepted as an efficient way to suppress subthreshold leakage current. Yet, it suffers from gate leakage current, which grows very fast with scaling down of gate oxide. We try to understand the sources of leakage current in power gating circuits and show that input MOSFETs plays a crucial role in determining total gate leakage current. It is also shown that the choice of a current switch in terms of polarity, threshold voltage, and size has a significant impact on total leakage current. From the observation of the importance of input MOSFETs, we propose the power optimization of power gating circuits through input control