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Parameters - getting from DC analysis to TR analysis

JohnWard

PSPICE: I'm modelling a pressure sensor and have set up some parameters (including "Pressure") which model the device sensitivity and outputs vs pressure, temperature etc using formulae in the parameter definitions. This runs as a DC simulation, and I can sweep the parameters as desired - so far so good.

 However, I need to be able to run TR analysis which means being able to introduce a stimulus (eg. VSIN) to drive the circuit. I can't seem to work out how to 'map' the output of a stimulus (which is a voltage, or a current) to drive a parameter formula. There must be some way of doing this, but it's not obvious what it is. Help appreciated!

 Thanks, John.

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  • JohnWard

    Thanks for your reply. I agree this is the way to add a stimulus, but I think I didn't explain my problem well enough.

     I have a set of complex formulae added to 'parameters' which take various variables such as 'pressure' and 'temp' and calculate sensor output characteristics. The values of these calcs can be used to drive various pieces of circuit input by using them in {brackets} as component values etc.

    However, what I need to be able to do is drive something like 'pressure' from a sinewave source eg. VSIN or VSRC (ot VSTIM). The output from any of these sources is a voltage, and the value of this voltage cannot be used as far as I can see in a formula in a parameter. What I'm saying is you can go from a parameter to a voltage (or current), but not the other way.

    I guess I could use a circuit element that is driven from a parameter rather than a voltage (ie. change from using POT to some Epart equivalent circuit), but I'm not sure that the parameter calculations are re-visited at every time step in the sim, I suspect they are done at the beginning after the DC bias point calculation.

Reply
  • JohnWard

    Thanks for your reply. I agree this is the way to add a stimulus, but I think I didn't explain my problem well enough.

     I have a set of complex formulae added to 'parameters' which take various variables such as 'pressure' and 'temp' and calculate sensor output characteristics. The values of these calcs can be used to drive various pieces of circuit input by using them in {brackets} as component values etc.

    However, what I need to be able to do is drive something like 'pressure' from a sinewave source eg. VSIN or VSRC (ot VSTIM). The output from any of these sources is a voltage, and the value of this voltage cannot be used as far as I can see in a formula in a parameter. What I'm saying is you can go from a parameter to a voltage (or current), but not the other way.

    I guess I could use a circuit element that is driven from a parameter rather than a voltage (ie. change from using POT to some Epart equivalent circuit), but I'm not sure that the parameter calculations are re-visited at every time step in the sim, I suspect they are done at the beginning after the DC bias point calculation.

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