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Simulators >> Circuit Simulators >> Dynamic, Short circuit power power consumption of CMOS inverter
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Message started by nvrk on Jan 31^st, 2013, 10:49pm

Title: Dynamic, Short circuit power power consumption of CMOS inverter
Post by nvrk on Jan 31^st, 2013, 10:49pm

Hi All,
I want to measure static, dynamic, short circuit powers consumed by cmos inverter individually. Acoarding to my knowledge, staic power can be measured by applying DC inpput at the input of the circuit. For Dynamic and short circuit powers , we have to apply inputs such that it is switching. Now I need help to measure dynamic nad short circuits powers seperately. Please help me on this regard.

Title: Re: Dynamic, Short circuit power power consumption of CMOS inverter
Post by rfidea on Feb 2^nd, 2013, 4:47am

Put a current measuring device in series with the power supply of your inverter, for example an iprobe from analogLib if you are using Virtuoso. Then run a transient analysis with an toggling input. Calculate the average and peak current in the iprobe.

Title: Re: Dynamic, Short circuit power power consumption of CMOS inverter
Post by nvrk on Feb 3^rd, 2013, 1:10am

Thanks for your information. I will check

Title: Re: Dynamic, Short circuit power power consumption of CMOS inverter
Post by nvrk on Feb 3^rd, 2013, 10:58pm

I mesured the currne and found average. After that I did vdd*average current. But this power is nearly same as the power i measured using average of instant power.(thjis i got from tran-tran option from ADE in spectre). So i want how much short circuit power is consumed by cmos inverter. Can any body clarify me.
Thanks

Title: Re: Dynamic, Short circuit power power consumption of CMOS inverter
Post by Geoffrey_Coram on Feb 8^th, 2013, 6:19am

Since vdd is constant, then I would certainly expect the average instantaneous power to be equal to vdd * the average current.

What is your definition of short-circuit power? I think there's something about the current that passes through both devices when the input is mid-rail. Although perhaps you want the current that travels through both channels during a switching event, as opposed to the current that's used to charge the gate capacitances for the same event.

Title: Re: Dynamic, Short circuit power power consumption of CMOS inverter
Post by nvrk on Feb 17^th, 2013, 10:35pm

Hi Geoffrey_Coram ,
First of all I would like to thank for your reply.
I want to measure the power that consumed by the CMOS inverter when both devices (PMOS and NMOS) are ON during rising and falling transitions of input singnal. That power only I am treating as Short circuit power. Now how to calculate that power is my question. I feel if we calculate the current that passes from vdd to ground during input rise and fall transitions, then we can use some formule to find power consumption.Can you please help me how to find short circuit power. If you know any alternate method please help me.
Thanks

Title: Re: Dynamic, Short circuit power power consumption of CMOS inverter
Post by raja.cedt on Feb 18^th, 2013, 12:12am

hello,
do you want to simulate or calculate? Please remember short circuit power is a function of input rise and fal time as well.

Title: Re: Dynamic, Short circuit power power consumption of CMOS inverter
Post by nvrk on Feb 18^th, 2013, 5:31am

Hi,
I want to measure short circuit power through simulation. I am doing simulation using cadence spectre. can you please give me some idea..

Thanks for your concern

Title: Re: Dynamic, Short circuit power power consumption of CMOS inverter
Post by andresk on Mar 25^th, 2013, 12:35pm

Hello nvrk, maybe the below mentioned links will be helpful to you
http://www.eng.auburn.edu/~xugefu1/D&TSeminar/files/PowerAnalysis_Jins.ppt
http://www.eng.auburn.edu/~agrawvd/THESIS/ALEXANDER/thesis.pdf
http://people.bu.edu/rknepper/sc571/chapter4_b.ppt
https://smartech.gatech.edu/bitstream/handle/1853/31652/wunderlich_richard_b_200912_masters.pdf

Title: Re: Dynamic, Short circuit power power consumption of CMOS inverter
Post by nvrk on Mar 25^th, 2013, 9:12pm

Hi andresk,
I am very thankful for your support. I will read the stuff you sent.