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TPS92520-Q1: Can 92520 discharge the output capacitor if we don't add the discharge resistor when power off?

zhiyuan zhang
Intellectual 620 points
Part Number: TPS92520-Q1

If we don't add output resistor in parallel with the Cout. When power off, will the output voltage fall slowly and the LED keep on for some time?

Or if 92520 has built in discharge circuit to discharge the CAP? If yes, where can I find the information in datasheet?

  • 0
    TI__Mastermind 23116 points

    Hello Zhiyuan,

    You can add a discharger capacitor to the output to discharge it quickly, but keep in mind that it will affect the current to the LEDs and your accuracy will be affected.  

  • 0 in reply to fhoude
    Intellectual 620 points

    Hello expert,

           Thank you for your reply.If we disable the buck via SPI or UDIM PIN and keep input power on, is it possible for the low side MOS to keep on for a while to discharge the output capacitor?

  • 0 in reply to zhiyuan zhang
    TI__Mastermind 23116 points

    Hello Zhiyuan,

    It doesn't work that way.  When the channel is off the FETs are tri-stated.  You could come up with an external circuit that quickly discharges it, but the TPS92520 its self wasn't designed to do that.  You could reduce the output capacitance.  What is their design goal and do you have a schematic?  Why is it important to discharge the capacitor?  Please give us a better understanding of your requirements and questions.