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charge redistribution converter (Read 4418 times)
novice_designer
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charge redistribution converter
Oct 06th, 2006, 9:42am
 
Hi, Can someone tell me how to simulate a charge-redistribution converter? i am trying to use MIM capacitor models in the cap-array. How can i observe charge-redistribution in simulation? i am using Cadence spectre for simulations.
Thanks!
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loose-electron
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Re: charge redistribution converter
Reply #1 - Oct 6th, 2006, 3:19pm
 
A bit better definition of what you are trying to do would be appreciated.

Are we talking charge redistribution as in charge pumping to get to a higher voltage? Or what?

tnx,
Jerry
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Jerry Twomey
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Re: charge redistribution converter
Reply #2 - Oct 9th, 2006, 7:55am
 
Hello Jerry
I appreciate your response.
What i would like to know is:
How do I do the basic simulations to study the working of a charge-redistribution converter. It is not to pump voltage but to just study how the A/D conversion takes place.
What I have is a comparator and a capacitor array (binary weighted).

So basically when you sample the input voltage(Vin) and go into hold mode, the top plate of the capacitors should have -Vin. Then I connect each bottom plate of the capacitor to Vref.
Now my question is what kind of signals can I use for simulations?

I hope this is clearer. Else please let me know and I will elaborate further.
Thanks.
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loose-electron
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Re: charge redistribution converter
Reply #3 - Oct 11th, 2006, 10:48pm
 
OK, an ADC that works by charge sharing (redistribution) methods.

Essentially a switched capacitors structure.

Why don't you build a model out of behavioral structures, ideal switches, and others, to model and simulate the device?
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Jerry Twomey
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Re: charge redistribution converter
Reply #4 - Oct 12th, 2006, 6:29pm
 
I am trying to perform a circuit level implementation.
I am using DC input (Vin) as a starting point. In the hold mode, the voltage at the top-plate of the capacitors (which is connected to the input of the comparator) should be -Vin.  However, in my simulations the top-plate voltage in the hold mode is at zero. This is where I am kind of stuck and dont know as to why the voltage is at zero and not -Vin.
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Re: charge redistribution converter
Reply #5 - Oct 19th, 2006, 9:16pm
 
Hi,

If paste the schematic, it is easy to get detail answers for your problem.


Yawei
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