This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

Looking for the most efficient MOSFET for Pure Sine inverter output

Other Parts Discussed in Thread: LM324, OPA548, TINA-TI, LM1875, LM675

I am looking for suggestions for which MOSFET to provide a 15V 60Hz AC waveform I have tested a few different typically available BJT's and other parts, but I hear that these NexFETs are more efficient. I am not sure how that is, but would like to see a suggestion for an N-Channel and P-Channel pair to produce about 5A.

 

  • Curt, 

    What are the input conditions? 

  • I have a 15 +/- power supply so right now I was planning to come off a LM324 at 14VAC peak to peak at 60Hz and only 20mA. But the LM324 may not be able to provide the current necessary for the gate. So I am open to a suggestion about what I can use to drive the MOSFET also.

    The circuit right now is based on an OPA548 but it produces too much heat. It is a long story about the other chips and topologies I have tried, but it all comes down to too much heat.

  • Curt, 

    So what is the max voltage the FET will see? What will be the switching frequency of the FET? Can you send me a circuit diagram / topology? 

  • I have attached the working Tina-TI file. I am not an EE and do not have any industry background. I would appreciate advice you could give.

    The goal of this circuit is to input a 5VAC wave form from a voltage divider, and thus has no power. I need an output at 69VAC rms at 20-60Hz to feed an old fashioned analog volt meter. This will take maybe 3 watts. The output must be accurate so the feedback is taken from the far side of the step up transformer. 

    The problem has been the heat. Heat makes things inaccurate and increases the physical size.

    Is there any advice what so ever you can provide on this? Any topologies you would suggest, or chips I may try? I do have working versions of this using OPA548, LM675, LM1875. All produce lots of heat. I am just looking for the way to make this produce less.

    5661.LM324withPNP.TSC

  • I had not looked into how a MOSFET works, and now see that the MOSFET is not the solution for this application.