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TPS53353: POL behavior when feedback resistor short or open

Jan Bob
Intellectual 280 points
Part Number: TPS53353

Dear Team,

What TPS53353 will happen when high side feedback resistor cracked(open) or low side feedback resistor short?

Is there any difference if ripple injection is implement or not?

We want to know these four situation, thanks.

1. high side R crack before power on

2. high side R crack after power on

3. low side R short before power on

4. low side R short after power on

  • 0
    TI__Intellectual 1520 points

    Hi Jan,

    For the 4 situations, the controller will hit its maximum duty cycle which will continually ramp up VOUT.  This may cause damage to your output capacitors if VOUT surpasses the capacitor rating. It can also damage the load or some other component.  Without the feedback path on the TPS53353, there is no OV/UV protection.

    As for the ripple injection question, typically, we inject about 15mV of ripple back to the feedback pin to ensure system stability.  In the case of using the POSCAP with high ESR, you may not need to implement the ripple injection.  However, I suggest you place the injection circuit as a place holder. If you are using all ceramic output capacitor, you will need the ripple injection circuit.

    Thank you.

    Amnat