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TPS56528: Best driver for very low impedance loads

Renan Santos Adriano
Genius 17710 points
Part Number: TPS56528

Hello Team,

My customer is trying to send a 40kHz sinusoid to a very low impedance load (25mOhms) with as much current/power as possible. TPS56528 Buck Converter Evaluation Module came to mind as a possible solution for a quick prototype to test the idea. Could you please let me know if you also recommended the TPS56528 or if there are better components that you can recommend?

Regards,

Renan

  • 0
    TI__Genius 13401 points

    Hi

    Young will reply you next Monday

    Shuai

  • 0
    TI__Genius 9280 points

    Hi Renan,

    It's possible to use a buck to generate a sinusoid signal .

    May i check the background of this application ? Why need a buck for this ? and any other requirement for the sinusoid signal ?

    a standard sinusoid ? how about the peak and valley ,offset ? also about the freq accuracy ?

    BRs,

    Young

  • 0 in reply to Young Zhao
    TI__Genius 17710 points

    Hello Young,

    Good day.

    The load is a coil with a resistance of approximately 0.1 Ohms and 5uH. This is why I was thinking of a buck, since I don’t want to get into complicated designs with power Triacs or power transistors. I could achieve it with a High Voltage amplifier, but these are very expensive  Having a sinusoidal signal is not essential. Even a square or whatever wave would do. Greater power is more important than frequency accuracy (F=40kHz, you can be off a lot, and it would still be OK). On the other hand, the offset is better small since it would heat the coil needlessly. It would be best if I could disable it when not active. Feeding 100W would be a dream (1kV). Any suggestions?

    Appreciate your help.

    Regards,

    Renan

  • 0 in reply to Renan Santos Adriano
    TI__Genius 13401 points

    Hi 

    Young will reply you tomorrow!

    Shuai

  • 0 in reply to Renan Santos Adriano
    TI__Genius 9280 points

    Hi Renan,

    Pls let me know if anything I missed.

    You may want to using the inductor as the loading for buck and so using the switching signal (SW pin of convertor ) to drive the inductor / coil , correct ?

    and SW signal would be a square wave , is it also can be acceptable ? 

    regarding the 100W, how much current you are expecting and how about the voltage ?

    BRs,

    Young

  • 0 in reply to Young Zhao
    TI__Genius 17710 points

    Hello Young,

    Please see below:

    You may want to using the inductor as the loading for buck and so using the switching signal (SW pin of convertor ) to drive the inductor / coil , correct ?

    Yes.

     SW signal would be a square wave , is it also can be acceptable ? 

    Yes.

     regarding the 100W, how much current you are expecting and how about the voltage?

    Around 10V, the load might be a bit higher due to cabling and connectors: which chip is best for my application?

    Regards,

    Renan

  • 0 in reply to Renan Santos Adriano
    TI__Genius 9280 points

    Hi Renan,

    If stress the inductor with 10V, meaning the Vin should be around 10V. Regarding the output voltage of the buck, it depends on the duty you needed. 

    If the duty is small, you may needs a larger loading capability buck to support 100W. So you need a >10A buck at least .

    Below link can give you some solutions.

    Step-down (buck) regulators product selection | TI.com (>16Vin<=30Vin, >=10A single buck )

    BRs,

    Young