Inverter doesn't output properly.

Thread Starter

Runs212

Joined Mar 12, 2015
57
Ideally, the LT Spice simulation works but when I replace the ideal mosfets with the model I intend to use, it outputs incorrectly. What might be the problem?
 

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Roderick Young

Joined Feb 22, 2015
408
Do you have a graphical version of your schematic also?

Knowing nothing else, I would say there are two things to check:
  • The ideal mosfet may have a very low or nonexistent \(V_{th}\), while the real one needs more voltage to turn on. Maybe you can temporarily tamper with the \(V_{th}\) in your real device model and see if that has any effect.
  • The ideal mosfet has zero gate capacitance, so can be driven through (say) a 1k or more resistor, and will turn on instantly. Your real mosfet may be taking too long or not turning on at all. To check if this is the issue, try using your ideal mosfet in simulation, but put 1000 pF or 10000 pF from its gate to source, and see if that messes up the output the same way.
 

Thread Starter

Runs212

Joined Mar 12, 2015
57
I had so much issues with the full bridge inverter so decided to use the half bridge inverter. Please see schematic in attachment. I designed my circuit alike though using an CD4007 to generate an inverted signal. My Voltage output was 0.8V compared to ~6V on the simulation. I'd appreciate some clarification here per what i'm missing or doing wrong. I do have present an update on the progress of this project.
 

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ScottWang

Joined Aug 23, 2012
7,399
I had so much issues with the full bridge inverter so decided to use the half bridge inverter. Please see schematic in attachment. I designed my circuit alike though using an CD4007 to generate an inverted signal. My Voltage output was 0.8V compared to ~6V on the simulation. I'd appreciate some clarification here per what i'm missing or doing wrong. I do have present an update on the progress of this project.
I already said that you need a p type mosfet, the CD4007 can't driving the Vgs of N ch mosfet to make Vds get into the saturated situation.

If you don't need more current and this may works for you.
 
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