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UCD9090A: UCD9090A_Power Supply Enable

Srikanth Kacchu1
Expert 1235 points
Part Number: UCD9090A

Hi Team

Datasheet of UCD9090A says " GPIO pins that have FPWM capability (pins 10-17) should only be used as power supply enable signals if the signal is active high" under section 7.4.10.

Unfortunately I connected Power Supply Enable pins to GPIO1-4 and GPIO13-17 in my board.

What would be the impact? Please clarify soon.

Regards

Srikanth Kacchu

  • 0
    TI__Guru 65750 points

    Hello

    GPIO1-4 and GPIO13-17 does not have FPWM capability. The section 7.4.10 does not apply your case.

    GPIO5-12 are FWPM pins, which output LOW by default(during power up and initialization). if GPIO5-12 are used to drive the ENABLE of power supply and the enable is ACTIVE LOW, then the power supply could be on when GPIO512 are under default state.

    Regards

    Yihe

  • 0 in reply to yihe
    Expert 1235 points

    Hi Yihe

    Thanks for the quick response.

    I understood your explanation on FPWM GPIO pins that if regulator enable is active low, during power sequencer initialization and power up, power supply may get enabled FPWM pins aredefault low during initialization and power up.

    But I need clarification on Non-FPWM GPIO pins. Datasheet says FPWM GPIOs should only be used for power supply enable with active high state. But I have used Non-FPWM GPIOs for power supply enable. All these are connected to active high enable input pins of regulators.

    Does the datasheet means that Non-FPWM GPIOs can be used to enable power supplies with both active high state and active low state?

    Because we are understood from datasheet is that Non-FPWM GPIOs cannot be used for power supply enable and if it is used, only active low is supported.

    Please clarify.

    Regards

    Srikanth Jacchu

  • 0 in reply to Srikanth Kacchu1
    TI__Guru 65750 points

    Hi

    For those non-FPWM pins, the default states are Hi-Z. it is up to how your design and it can support either active HIGH or LOW case.

    Regards

    Yihe

  • 0 in reply to yihe
    Expert 1235 points

    Hi Yihe

    Thank you very much

    Regards

    Srikanth Kacchu