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pss gives wrong time domain waveform (Read 4501 times)
ywguo
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pss gives wrong time domain waveform
Jul 28th, 2014, 4:58am
 
Hi Guys,

PSS gives wrong time domain waveform when I run pstb for a buck model. Transient analysis shows the model works. The following is the test bench of the buck model. What's wrong with my simulation?  I think the default engine for pss analysis is newton-shooting, too.

Yawei
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buck_sim.png
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ywguo
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Re: pss gives wrong time domain waveform
Reply #1 - Jul 28th, 2014, 5:09am
 
The following is simulation result, where the red line is transient analysis result and the blue line is the pss-tran result.
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buck_sim_001.png
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raja.cedt
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Re: pss gives wrong time domain waveform
Reply #2 - Jul 28th, 2014, 6:17am
 
hi ywguo,
Would be nice if you can show schematic one level below. Did you check PSS log file??

Thanks,
Raj.
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ywguo
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Re: pss gives wrong time domain waveform
Reply #3 - Jul 28th, 2014, 10:39pm
 
Hi Raja,

The following is the schematic of buck, which is DUT in the previous test bench. Thank you.


Yawei
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buck.png
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ywguo
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Re: pss gives wrong time domain waveform
Reply #4 - Jul 30th, 2014, 5:41pm
 
I got the answer. The pss analysis is not in the argument list of initial_step in the opamp model.

Code:
analog begin
@(initial_step ("dc","ac","tran","noise","stb"))
  begin
  Vhi=V(vdd);
  Vlo=V(gnd);
  v_th=(Vhi-Vlo)/2;
  end 



Best Regards,
Yawei
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