# PSPICE time and voltage dependant parts and circuits

1. ## PSPICE time and voltage dependant parts and circuits

Hi again people. I just was doing some tests and it seems it is not possible, but I want to listen to some other voices.
I want to know if it is possible to make that an ABM part could be time and voltage dependant. I have already built some parts, and the equations that defined their behaviors were written in function of voltage OR time. When I re-wrote them in function of BOTH variables, they reproduce the transient results but not the DC sweeps results.

Is there anything I can do to solve this? Thanks in advance, I hope to be clear.

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2. ## Re: PSPICE time and voltage dependant parts and circuits

It's unclear what you are trying to achieve. There's no time variable in DC sweep.

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3. ## Re: PSPICE time and voltage dependant parts and circuits

Hi again. Sorry for the late response. The situation is like this:
I have a system whose current output depends in the input voltage and in time. This means that, for example, when I increment the input (DC) voltage, the current output increases its amplitude. But, when I feed this system with a constant DC voltage, I can see oscilations along the time.

Now I´m trying to model some aspects of this system, and that´s why I asked about this dual-dependance on some ABM parts in PSPICE.

There are some curious aspects about my implementation attemps:

I have this equation for a voltage-dependant current source:
{5e-10*SIN(pi*TIME*V(D, S))}

When I make a transient simulation with a constant voltage, I can see the correct time-dependant analysis. But when I make a DC Sweep, I see very different results that when I make this analysis but without the *TIME term in the equation.

The evidence should be demonstrating that the duality I would like to implement is not possible, but I want to be sure of this.

Thanks, and I hope I´ve been clear enough now.

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4. ## Re: PSPICE time and voltage dependant parts and circuits

Implementing an analog behavior model with TIME variable dependency means to include an independent source to the model. Although the option is provided by the PSpice ABM syntax, it's not genuine behavior modeling. I didn't yet experience a simulation case where a similar combination seemed useful. If there's a time dependency to be modeled, it can be better implemented by an additional time dependent signal feed to the ABM block.

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