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Design >> Mixed-Signal Design >> z-domain model of chopper stabilization integrator
https://designers-guide.org/forum/YaBB.pl?num=1236682100

Message started by sun on Mar 10^th, 2009, 3:48am

Title: z-domain model of chopper stabilization integrator
Post by sun on Mar 10^th, 2009, 3:48am

Hi,
I'm want to simulate a 2nd order sigma delta modulator which uses chopper stabilization tech at the first integrator by simulink.
I have tried to place a product before and after the first integrator to emulate chopper switch, but it failed. So I want to use z-domain transfer function to replace product.
Do you have any ideal about how to model the integrator with chopper stabilization?

Sun

Title: Re: z-domain model of chopper stabilization integrator
Post by thechopper on Mar 10^th, 2009, 6:25pm

Hi Sun,

I never saw a chopper stabilization z-domain model before. Chopper-stabilization is a continous-time modulation technique which does not involve sampling. Therefore z-domain modeling for it does not look natural to me since is NOT a discrete time system (which are the systems that can be modeled in z-domain).
Is the product box you put before and after your integrator in Matlab
synchronized with the clock?

Regards
Tosei

Title: Re: z-domain model of chopper stabilization integrator
Post by sun on Mar 11^th, 2009, 5:39am

HdrChopper wrote on Mar 10^th, 2009, 6:25pm:

Hi Tosei,
Thands for your reply.
The products box that I put in simulink model are synchronized with clock. But I realized that putting products before and after the first integrator is wrong. In fact, the chopper switches should be placed before and after the opamp but the integrator. It seem to be difficult to model chopper stabilization in simulink.
now, I have realized a sigma delta modulator with chopper stabilization in veriloga. but if you have some idea to do it in simulink, I'm glad to know that.

Regards

Sun