Stats

  • Locked Locked
  • Replies 2
  • Subscribers 125
  • Views 15144
  • Members are here 0
This discussion has been locked.
You can no longer post new replies to this discussion. If you have a question you can start a new discussion

simulating pulse width variation

svilen

 Hi,

I have a circuit that basically produces pulses with a pulse width depending on a control voltage. I use spectre to simulate it. I need to simulate the variation of the pulse width w.r.t. power supply variations. My idea was (and I may be wrong here) to perform pss-pac simulation having an ac voltage at the supply. For that I created a veriloga block which I included in the circuit. That block measures the pulse-width and outputs that value as an output voltage. The problem is that if I use last_crossing in combination with @ cross for better accuracy, pss doesn't like it and says there are hidden states. If I use only last_crossing then simulation goes through but the pulse-width the pss extracts is wrong.
I would appreciate if someone can suggest a way to perform that pulse-width measurement.
Thank you in advance.

Parents

  • A couple of thoughts. First of all seeing the code would help, because there's no reason why @cross necessarily causes a hidden state problem - it depends what you do inside the @cross.

    Anyway though, the pss result would not change dependent on the ac source - this is because the PSS is only done on the large signal conditions - and so the small signal would not impact the PSS results.

    Regards,

    Andrew.

Reply

  • A couple of thoughts. First of all seeing the code would help, because there's no reason why @cross necessarily causes a hidden state problem - it depends what you do inside the @cross.

    Anyway though, the pss result would not change dependent on the ac source - this is because the PSS is only done on the large signal conditions - and so the small signal would not impact the PSS results.

    Regards,

    Andrew.

Children
No Data

Community Guidelines

The Cadence Design Communities support Cadence users and technologists interacting to exchange ideas, news, technical information, and best practices to solve problems and get the most from Cadence technology. The community is open to everyone, and to provide the most value, we require participants to follow our Community Guidelines that facilitate a quality exchange of ideas and information. By accessing, contributing, using or downloading any materials from the site, you agree to be bound by the full Community Guidelines.