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TS3DV642 (HDMI switch) HPD voltage leakage issue

Arthur Huang
Expert 6065 points
Other Parts Discussed in Thread: TS3DV642

Hi Team,

my customer adopted TS3DV642 for HDMI, DVI switch on their mini PC system, they got a question that when their system is power off, and they connect the HDMI panel cable to their system HDMI port(connector), in this case they observed that there is 5V voltage on the HPD signal of the TS3DV642 device, since this has power dissipation during the system power off stage, so they want to know how to avoid this 5V voltage leakage on system power off stage?

Thanks.

Regards,

Arthur

  • 0
    TI__Mastermind 45625 points

    Arthur,

    When the TS3DV642 is powered off you should not see more than 10uA of leakage through the I/O path.  

    Are you seeing more leakage than what is stated in the datasheet? 

    What is the voltage being applied to the I/O path when Vcc = 0V?

    Thank you,

    Adam

  • 0 in reply to Adam Torma
    TI__Intellectual 1060 points

    Adam,

    leakage voltage was measured in Vcc.

    customer guessed Vcc leakage voltage comes from HPD.

    do you have any idea about this?

    Marco

  • 0 in reply to Marco Hsieh
    TI__Mastermind 45625 points

    Marco,

    Where is the TS3DV642 in the system?  Do you have a diagram.  From my understanding there is 5V that is sent from the HDMI source and then the HDMI sink sends that 5V back to the HDMI source on the HPD pin.  This is how the HDMI source knows that a HDMI sink was connected.  

    Are you saying that there is 5V on the HPD pin that is leaking to the Vcc pin that is at 0V??

  • 0 in reply to Adam Torma
    TI__Intellectual 1060 points
    Adam,

    yes, your understanding is correct.
    is this symptom normal??
    If yes, is there any suggestion to prevent it??
    If not, could you provide any ideal that might cause it?

    I will send you customer's schematics.
    Marco
  • 0 in reply to Marco Hsieh
    TI__Mastermind 45625 points

    Marco,

    Yes, to my understanding this is the proper operation of HDMI.  The HDMI source uses this 5V signal to know that a HDMI sink has been connected.  Why are you wanting to prevent this normal operation?  I'm going to move this post to the computer and consumer interface forum to see if we can get a comment from someone more familiar with the HDMI standard.

    Thank you,

    Adam