Bootstrap circuits are very common when NMOS (or NPN) devices are used on the ... You need a way to drive the gate voltage in excess of the source or emitter end by at least the threshold voltage.

transistor-level strategies such as the leakage control NMOS transistor (LCNT) method have provided substantive leakage power minimisation, recording reductions of nearly 48.4% in CMOS circuits [4 ...