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TPS82130: TPS82130 true reverse current protection

Peter W
Prodigy 20 points
Part Number: TPS82130

Hi,

In our application it can happen that a voltage of 12 V (supplied by an external source) is present at the output of the TPS82130.VOUT (it is not guaranteed that the input voltage TPS82130.VIN is always present). Under normal operating conditions, the TPS82130 is used to generate a voltage in the range of 0.9V and 3.3V (TPS82130.VIN = 12V, voltage tracking function).
To protect the TPS82130 (and the supply voltage network at TPS82130.VIN) from the possible 12V voltage at TPS82130.VOUT, we want to connect a Schottky diode directly to TPS82130.VOUT and tap the feedback voltage TPS82130.FB after this diode. We know that the diode will reduce efficiency, but this is acceptable.
Is there anything against this solution or is there a better solution for this problem?
Is there an alternative DC/DC converter with true reverse current protection, an input voltage of 12V, an output voltage range of 0.9V to 3.3V and the tolencee to an externally supplied voltage at the output of  >= 12V? 

Thanks for your help!

  • 0
    TI__Expert 4795 points

    Hi Peter,

    I think TPS82130 is PSM version and the Low Side is not allowed for reverse current, which means itself has reverse current protection. But I will let relative expert to help confirm maybe early next week. Thanks. 

  • 0
    TI__Intellectual 1125 points

     

    Hi

    The TPS82130 max output voltage is 7V, so just based on that an external 12V shall not be applied.

    PSM operation usually means that the low side FET is OFF as long as the output is much higher than the targeted voltage. However, since it is buck configuration, that can introduce a current through the high side FET body diode and to the input voltage source.

    For all these reasons, driving the output with 12V external source is NOT a good idea.

    The suggested Schottky solution should basically work although it would be a good idea to add some (low value, 1-10uF) capacitance on anode side of the diode,  in addition to a larger amount of cap on the cathode side.

    Regards