power consumption in CMOS

[vlsitechnology]

When BJT is driving NMOS then wt will be the power consumption ??? and which power do we call ? dynamic, static, or shortcircuit power??

And also tell me when BJT is on do the current flows in NMOS???? if yes how and if no why and how??


Or the direct question is How CMOS is better in Power consumption compare to BJT?? Circuit level can anyone explain????

Please it is very important question asked by INTEL.........

 

[lordsathish]

Hi...
Static power disipation is the power dissipated when the inputs are not changing...
In CMos we use complementary devices for the pull up and pull down network...
So when either is on the other is off... so naturally there is no direct path between Vdd and Gnd... Only path exists between the output and Vdd or the output and Gnd...
Whereas in BJT when the BJT is in saturation the Vcc is connect to the Gnd through Rc and the output resistance of the BJT... so it has static power dissipation...
If you connect a BJT's output to the input of a CMOS gate there will be no power dissipation in the CMOS gate as its gate has infinite ip imedance and does not draw any current... However there is static power dissipation in the BJT connected...