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Design >> Mixed-Signal Design >> charge redistribution converter
https://designers-guide.org/forum/YaBB.pl?num=1160152932

Message started by novice_designer on Oct 6^th, 2006, 9:42am

Title: charge redistribution converter
Post by novice_designer on Oct 6^th, 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!

Title: Re: charge redistribution converter
Post by loose-electron on Oct 6^th, 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

Title: Re: charge redistribution converter
Post by novice_designer on Oct 9^th, 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.

Title: Re: charge redistribution converter
Post by loose-electron on Oct 11^th, 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?

Title: Re: charge redistribution converter
Post by novice_designer on Oct 12^th, 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.

Title: Re: charge redistribution converter
Post by ywguo on Oct 19^th, 2006, 9:16pm

Hi,

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

Yawei