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input impedance of voltage multiplier
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.

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gmadhavareddy New Member Offline Posts: 5	Re: input impedance of voltage multiplier Reply #1 - 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
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gmadhavareddy New Member Offline Posts: 5	Re: input impedance of voltage multiplier Reply #2 - 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
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gmadhavareddy

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Re: input impedance of voltage multiplier
Reply #3 - 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

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Ken Kundert Global Moderator Offline Posts: 2386 Silicon Valley	Re: input impedance of voltage multiplier Reply #4 - 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
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sriniv1422 New Member Offline Posts: 2	Re: input impedance of voltage multiplier Reply #5 - Sep 14^th, 2006, 2:19pm ken thank you. i will try this out. srinivasan
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