Lowpower querry : Which signals consumer power in the design?

[nitint08]

Which signals consumer power in the design?
a) all active signals(i.e. having strengths 0 or 1),
b) all unknown signals having value X and
c) all high impedence signals having values Z.

 

[qieda]

Hi,

If your design is running then
toggling signals consumes power in a design.
because power is consumed due to the cross current, when you are in the transition phase of a logic gate.
(power is also consumed for toggling signals due to the capacity reloading)

Therefore a high ohmic signal may lead to a power consumption, because it could hold the receiving gate in the transition phase and we will have cross current.

In a design you will not have a X (you only will have a X in a simulator (means unknown), in reality it is always defined)


regards

 

[FvM]

Signals are an abstraction and don't consume power. It's like asking how much weight has a soul.

You have to refer to logic devices of a particular technology. quieda answered the question under the (reasonable) assumption that you're dealing with CMOS logic devices.