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High Speed Single Supply OpAmp for Voltage Feedback Config. in MOSFET Gate Driver AEC

Inam Shah
Intellectual 290 points
Other Parts Discussed in Thread: LM7171, LM7171QML-SP, LM7171QML, THS4041-Q1, THS4041

Dear Members,

I am a searching for a single supply high speed OpAmps to drive a MOSFET Push-Pull Stage of an Inverter Gate Drive.

The OpAmps are to be configured in voltage feedback configuration to drive the MOSEFTs to switch variable currents from 0 - 21A.

Previously, I used LM7171 for this purpose, which are unfortunately not Automotive Qualified.

Could you please suggest the alternate to LM7171 OpAmps which are additionally AEC qualified or any other suitable OpAmp for this application.

Thanks

  • 0
    TI__Genius 14036 points
    Hi Inam,

    Would you be able to use the LM7171QML and LM7171QML-SP versions of the part?

    Best regards,

    Sean
  • 0
    TI__Genius 15975 points
    Hi Inam,

    I think the THS4041-Q1 is the closest equivalent to the LM7171 that is Automotive Qualified. Would it be possible for you to explain in more details or provide the end application as to why you need an automotive qualified equivalent for the LM7171? It might be that the military equivalent or the LM7171QML would be sufficient for your application.

    Best Regards,
    Rohit
  • 0 in reply to Sean Cashin
    Intellectual 290 points

    Hi Sean,

    Thank you for your reply. Unfortunately, I am working exclusively with Automotive Qualified components.

    Greetings,

    Inam

  • 0 in reply to Rohit Bhat
    Intellectual 290 points

    Hi Rohit,

    Thank you for your reply.

    The End Application is a Gate Drive of an IGBT Module in Totem Pole configuration in automotive applications.

    The OpAmp drives the Mosfet to control the charging/ discharging current of an IGBT in voltage feedback configuration.

    I am only allowed to use automotive qualified componenets for this application and I already have used LM7171 for non-automotive application. This is the reason I am searching closest possible match.

    I had found THS4041-Q1 on your website in high speed OpAmps.

    Although it is Single Supply suitable and works well with single positive supply, it doesn't work however with single negative supply.

    I simulate the OpAmp with Spice modell given on your website in LtsSpice.

    best Regards,

    Inam

  • 0 in reply to Inam Shah
    TI__Genius 14036 points
    Hi Inam,

    Voltage is just a measure of potential between two points. An Op Amp will not know the difference between V+=15V /V- =0V and V+=0V /V- =-15V, as long as the inputs and outputs stay within their ranges referenced from the same points as the rails. This is often a problem with spice models however. Can you provide a simulation where the THS4041 is not working on a single negative supply? Also, the ML and SP verification requirements are often more stringent than Q100 requirements, what qualifications do you feel are lacking from these versions of the part?

    Best regards,

    Sean