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PMP8928: Change Vout- voltage

Roy Chou1
Genius 13405 points

Part Number: PMP8928

Hi Team,

I see that we have PMP8928 reference design. And my question is that how to change the negative output voltage? Thank you.

In addition, we need output negative voltage with sink current function. Output current should be 10A. (Vin = 12V-24V) Do we have another appropriate solution can be used?

Regards,

Roy

  • 0
    TI__Expert 5745 points

    Hi Roy,

    I have reached out to the original designer and he will get back to you with more details. 

    The output voltage is controlled by the resistor divider R19 and R20. What do you need to change the voltage to? 

    Care needs to be taken because the FETs will see the input voltage + the output voltage. So if you change the input range to 24V, you will need to use higher voltage FETs.

    Thanks,

    Robert 

  • 0 in reply to Robert Taylor1
    TI__Intellectual 2825 points

    Hi Roy,

    The only concern I see about sinking current would be at start up.  The TPS40170 disables the low side FET during start up into a pre-biased output, so it will not be able to sink current during startup.  Once startup is complete, it should be able to sink current.  If you can tell us the output voltage needed, then we can check to see if we have any other designs that are closer to these requirements.

    thanks,

    Brian