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TPS23881: GND separation

KIM Andy
Expert 2530 points
Part Number: TPS23881


Hi

We ask about GND processing of PSE ICs.
We are going to design a 40W with the TPS23881.
Do I need to completely remove GND of PSU equipment after 57V PSE GND?
There is a case that there is a problem on the board due to the existing H / W GND not separated.
Are GND1 and GND completely disconnected in the PSE EVL board configuration?

  • 0
    TI__Genius 15685 points

    Hi Kim,

    On our EVM, the PSE's ground(both AGND and DGNG) is connected to the power supply's ground. Since we have digital isolators between MCU and PSE(for I2C bus and interrupt, reset, OSS signals), we have different grounds: GND on PSE side and GND1 on MCU side.

    Thanks,

    Penny

  • 0 in reply to Penny Xu
    Expert 2530 points

    Hi
    thank you for your quick reply.

    Do you have to apply digital isolator unconditionally when developing a real board?
    If so, please tell me why.
    As you said, if the PSE side GND and MCU side GND1 are completely separated, one of the GNDs will not be connected to the building's GND. Is that correct?

  • 0 in reply to KIM Andy
    TI__Genius 15685 points

    Hi Kim,

    It is not a must have. It is depending on customer's system design. PSE needs Vpwr and VDD to have the same ground and usually customer's system has isolated power supply for MCU or CPU and they need isolators between MCU or CPU and PSE devices. This is also a good practice for surge protection. Ultimately, it is customer's call if they want to have isolated power supplies for PSEs and MCU/CPU. Thanks.

    Best regards,

    Penny