Sources of power dissipation in digital CMOS circuits

1. Switching power (Dynamic Power)
2. Short circuit power
3. Leakage power

AvgPower = P(switching) + P(short-circuit) + P(leakage)

Switching Power
* Consists of Activity factor(alpha)
* The load capacitance
* Voltage Swing through which the capacitance
* power supply voltage Vdd

Short Circuit power
* Current flows between Vdd and Ground (Isc) . Flow of current when both P (pullup) and N (pull down ) network are on simultaneously during an output transition

Leakage Power
* Current due to leakage through reverse biased PN junctions and sub-threshold conduction of MOSFET's