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Original question:

TPS27081A: isolation between input and output

TPS27081A: TPS27081A

Siva Periasamy
Prodigy 80 points
Part Number: TPS27081A
Other Parts Discussed in Thread: TPS22916

I see the intrinsic diode ( refer to Simplified Schematic on page 1 of datasheet) indicating Vout will feed into Vin even when the load switch is OFF.    My design looks at switching off TPS27081A when Vout is higher than Vin.  Putting a shokky diode in series is not possible due to the power dissipation.   Please provide some guidance.

thanks.

Siva

  • 0
    TI__Genius 10652 points

    Siva,

    Load switches are never designed for perfect reverse current blocking, (NCH at least). The reverse current flows through body diode even when FET is off.

    Load switch like TPS22916 has reverse current block but it only activates once there is a 500mA reverse current, which can be unacceptable in some applications.

    But, if you are really expecting higher VOUT than VIN as part of regular operation, and reverse biasing/ reverse current thru the load switch would cause potential damage or other issues, i would strognly urge you to look at Ideal Diode or eFuse. Essentially, they have 2 back-to-back FETs internally which allow for true reverse current blocking when switch is off.

    Ideal diode options

    eFuse options

    Please let me know if you have any additional questions on this. If this answered your questions, please let me know by pressing the green button.

    Best

    Dimitri

  • 0 in reply to dimitri james
    Prodigy 80 points

    Hi Dimitri

    Thanks for the pointer.

    kind regards

    Siva