LOW POWER CMOS
first of all in mos,power is negligibly consumed in steady state(after switching),compared to say bjt where power is consumed even during ON times as mostly the bjts are not allowed to fully saturate to reduce switching time. Again current thru mos is directly related to width to length ratio of channel.This can be suitably scaled to reduce current, hence power consumption. In CMos the largest contributor to wastege of power is dynamic charging/discharging of mos capacitor.