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TPS23751: about action when output short circuit

ACGUY
Guru 11170 points
Part Number: TPS23751

Hello E2E,

When output shorted circuit at Vin less than 48V, the TPS23751 has retry operation (hiccup), but when Vin more than, device has not retry operation.
please let me know why different operation when output shorted by Vin High or Low.

Regards,
ACGUY

  • +1
    TI__Expert 3700 points

    Hello ACGUY,

     

    Thank you for your question.

     

    The RCS sense resistor indirectly sets the VIN threshold for when foldback occurs. When foldback occurs, the output voltage drops which then drops the Vc voltage below its UVLO which causes the DC-DC to shutdown and initiates hiccup. 

     

    If you would like for hiccup to initiate at higher VIN, I recommend you increase the RCS sense resistor. This is because at lower VIN voltages, there is a higher peak current through the sense resistor whereas at higher VIN voltages there is a lower peak current through the sense resistor. By increasing the sense resistor, you can lower the current threshold for hiccup to initiate at the VIN you would like.

     

    Please let me know if you have any additional questions about this. Thanks!

     

    Best Regards,

    Brett Colteaux