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Design >> RF Design >> input impedance of voltage multiplier
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Message started by sriniv1422 on Aug 18^th, 2006, 7:16am

Title: input impedance of voltage multiplier
Post by sriniv1422 on Aug 18^th, 2006, 7:16am

Hi all ,
Iam trying to simulate the Modified Greinacher voltage multiplier circuit( capacitor-diode series ) for RFID tags. This is being used for Livestock IDentification.

The specs are as follows:
load current: 50uA
input power : 600uW.@50ohm.

Iam using a matching network followed buy a two stage mulyiplier circuit.

Iam trying to calculate the input impedace of the voltage multiplier ciruit , so that I can design the matching network.

could you please let me know , what simulation techniques could be used to estimate the real and imaginary part of the input impedance.

I have tried injecting an AC current and measuing the voltage .But these give me wrong results.

Could you please let me know , how to set up the simulation , so that input impedance can be calculated after the circuit has reached steady state.

I would really appreciate any info regarding this.

thanks
srinivasan.

Title: Re: input impedance of voltage multiplier
Post by gmadhavareddy on Sep 11^th, 2006, 1:03pm

Hi,
I am also doing the same type of analysis. I also not geting proper results with schottky diodes with standard specifications.
We can solve only with proper schottky diodes(means well modeled)

Bye
Madhav

Title: Re: input impedance of voltage multiplier
Post by gmadhavareddy on Sep 13^th, 2006, 5:36am

Hi Srinivasan,

I am also doing thesis on same project. I want to discuss with you some other things realted to input impedance.
Could u give your contact?( mail id or phone no)

Regards,
Madhav

Title: Re: input impedance of voltage multiplier
Post by gmadhavareddy on Sep 13^th, 2006, 9:40am

Hi,
I dont know exactly wich simulator u r using. I asked my supervisor may be it will help u.
U have to do large signal transient analysis for calculating input impedance.
Zin(1harmonic)= Vin(1st harmonic)/Iin(1 st harmonic).

I want to know wether u r using schottky diodes for votage multiplier or it is sufficient for Ordinary MOS transistor?

Regards,
Madhav

Title: Re: input impedance of voltage multiplier
Post by Ken Kundert on Sep 13^th, 2006, 10:23am

If you use Spectre, you can use its "Fourier Analyzer" to do this calculation for you. Use "spectre -h fourier" and specify both sets of inputs.

-Ken

Title: Re: input impedance of voltage multiplier
Post by sriniv1422 on Sep 14^th, 2006, 2:19pm

ken

thank you. i will try this out.

srinivasan