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TPS62060: the state of output impedance when input voltage is zero volt.

Noriyuki Takahashi
Genius 11700 points

Part Number: TPS62060

Hi team,

Customer wants to comfirm the state of output impedance when the input voltage is zero. Is it Hi-Z?

They use this deivce at 5Vin, 3.3Vout. Then, they want to make the vout keep 3.3V at certain time after the input voltage is lost due to some reason. So they consider to add a cap on input line or output line. They aslo take care about the reverse current. Therefore, if the output impedance will become Hi-Z, they cosider to add the cap on the output. If the output is not Hi-Z, they consider to add the cap on the input.

Could you give any advice on this?

Regards,

Noriyuki Takahashi

  • +1
    TI__Mastermind 21590 points

    Hi Noriyuki,

    If the output is 3.3V and input is 0V, there will be current flowing from output to input through the back gate diode of the high side MOSFET. This can discharge the output to the forward voltage drop of this diode. What could be done is have 2 output caps and place a Schottky diode between them to prevent reverse current. This way the last output cap should still retain it's voltage after the input is turned off.

    Best regards,

    Varun