Designing a Circuit in PSPICE for Fast Bidirectional Switching

Click For Summary

Discussion Overview

The discussion revolves around designing a circuit in PSPICE for fast bidirectional switching. Participants explore various components suitable for achieving low power dissipation and fast switching times, while also considering the feasibility of modeling these components in PSPICE for eventual physical implementation on a breadboard.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • Justin is considering using an ideal voltage controlled switch model "S" with a vpulse to control bidirectional current, aiming for fast switching times under a microsecond.
  • There is uncertainty about whether to use a BJT, FET, IGBT, or another component entirely for the switching mechanism.
  • One participant inquires about the availability of a relay macro in PSPICE, suggesting that relays might be an option.
  • Justin expresses concern about power dissipation, stating it should be below 10mW at currents around 30-40mA, and questions the feasibility of using a relay given the required fast switching times.
  • Another participant suggests using an analog switch made from complementary CMOS transistors as a more suitable alternative to relays for fast switching.
  • Justin notes that the analog switches he has found only support maximum voltage swings of around 5V, which is insufficient for his requirement of 40V.
  • A later reply proposes constructing a custom analog switch using high-voltage CMOS transistors, similar to how solid-state relays are made, to meet the voltage requirements.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the best component to use for the circuit. There are multiple competing views regarding the suitability of relays versus analog switches, and the discussion remains unresolved regarding the optimal solution for the specified requirements.

Contextual Notes

Participants express limitations in finding suitable part models in PSPICE and the challenges of achieving low power dissipation while meeting voltage and switching time requirements. The discussion reflects ongoing exploration and refinement of ideas without definitive conclusions.

JustinH
Messages
9
Reaction score
0
Hi,
I'm designing a circuit in pspice and having some trouble with the switching. In my circuit in pspice I'm using an ideal voltage controlled switch model "S" and using a vpulse to control it. My current through the switch needs to be bidirectional, and maxing around 80mA with an average around 30-40mA. The switching time should be fast compared to a microsecond.

I'm not sure whether to use a BJT, a FET, an IGBT, a combination, or perhaps something else altogether.

I want something that I can model in pspice, and then be able to build on a breadboard.

Let me know if anything comes to mind.

Thanks,
Justin
 
Engineering news on Phys.org
Does PSPICE have a relay macro? Microcap 8 does. Is there anything about relays in the PSPICE Help menu?
 
To be honest, finding part models in pspice is more than a hassle. Are you saying that I should use a relay? I forgot to mention, the switch that I use has to have low power dissipation at the currents I'm working with. Ideally the power dissipation should be below 10mW, not sure if this is feasible.
Thanks,
Justin
 
Well, if you want fast switching times on the order of a microsecond, then I guess a relay would be a non-physical model to use in your simulation. You should use something more like what you will use in the real circuit. Look for an Analog Switch (which is made out of several complimentary CMOS transistors generally).
 
Thanks for the help, analog switches look promising.
Justin
 
Hmm, slight problem, I've been looking at analog switches, and they seem to fit the bill pretty well except the ones I've looked at have maximum voltage swings across the in and out terminals of around 5V. I need something that can handle voltage swings around 40V. I'll keep looking, but let me know if there's another device that will satisfy this requirement.
Thanks,
Justin
 
One option would be to look at how an analog switch is typically constructed (with the complementary CMOS pass devices), and make your own with high-voltage CMOS transistors. I think that's basically how solid state relays are made, and they accommodate higher voltages.
 

Similar threads

Series motors, switched to parallel
  • · Replies 15 ·
Replies
15
Views
2K
Spark plug/Igniter/Spark gap in PSpice
  • · Replies 7 ·
Replies
7
Views
8K
High-Power Switching using MOSFETs
  • · Replies 14 ·
Replies
14
Views
4K
Designing a PWM Switch with RC Circuit and Schmitt Trigger for 50 Hz Frequency
  • · Replies 11 ·
Replies
11
Views
4K
Switching between parallel and series connections (solar)
  • · Replies 31 ·
2
Replies
31
Views
5K
Computer Programs to help design circuits to hook up to a Raspberry Pi
  • · Replies 3 ·
Replies
3
Views
2K
What is causing error code 16492 in PSpice?
  • · Replies 1 ·
Replies
1
Views
5K
How Can I Design a Muting Circuit for a Tube Amp to Eliminate Switching Pops?
  • · Replies 20 ·
Replies
20
Views
6K
Designing a PSPICE Ring Oscillator with CMOS Inverters | Homework Help
  • · Replies 5 ·
Replies
5
Views
4K
Enlighten me about the differences of IGBT and MOSFET please
  • · Replies 2 ·
Replies
2
Views
2K