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Original question:

TPS4H160-Q1: The Off-state Output Sink Current Clarification

TPS4H160-Q1: why add 20k pull up

Elec Cheng
Expert 7055 points
Part Number: TPS4H160-Q1

Hi Expert,

I see below part in datasheet. And I have several questions

  1. What's the internal logic control? Is there a internal pull down resistor?
  2. Why we need add 20k pull up resistor? I don't understand how it "offset" leakage current. May you help clarify? Thanks.

BR,

Elec Cheng

  • 0
    TI__Genius 16390 points

    Hi Elec,

    1. The internal logic control means the control circuitry will have some parasatic resistance from VS to VOUT and also VOUT to GND. If there's no external pull-up resistor from VS to VOUT, then VOUT might be at an undefined voltage. For example, if VS to VOUT and VOUT to GND impedance is the same, then VOUT will be at VS/2, but it varies from device to device, and also related to the environment - humidity etc.

    2. A pull up resistor at the output makes output to be much closer to VS, for open-load detection to work in the off state.

    Please let me know if this makes sense to you.

    Regards,

    Yichi