Tuesday, 8 September 2015

Power Dissipation in CMOS

 There are three types of power dissipation in CMOS
1. Dynamic power is dissipated only when switching
2. Leakage current is permanent and results in a continuous loss
3. Short circuit

Ptotal = Pswitching + Pshort-circuit + PLeakage
Where,
Pswitching = CLoad  * (VDD ^2)  * f
Pshort-circuit = tsc * VDD * Isc 
PLeakage = VDD * Ileakage

Where, CLoad  = Capacitive loading due to pin and nets
             VDD = Supply Volatage
             tsc =  short circuit time in cmos
             Isc = short circuit current from pmos to nmos
             Ileakage = leakage current












where leakage power is also a funtion of Vdd, Vth and W/L ratio



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