TPD12S520: Can I use +5V supplied from HDMI connector for 5V_SUPPLY ？

Hi Kuno Wu,

thank you for your answer.
Is it OK to always supply 5V to 5V_SUPPLY and use +5V from HDMI for (DCLK_OUT/DDAT_OUT PIN) PU?

The DDC line goes Low when HDMI is not connected, is that a problem?

Thanks,

Hotha

Hi Kuno,

I'm sorry, my explanation didn't make sense.
My concern ,when sink power off, current flowing from Source to sink through the DDC lines.（red arrow)

As one of the solutions, is it possible to use the PU of ③ to 5V of ②?

thanks,

Hi Kuno,

TPD12S521 , nice idea.

But, Unfortunately I already have a tpd12s520. (We design HDMI Sink)

I try to make the TPD12S520 circuit, ‘flooding phenomena still can‘t be solved?

5V_Sink always input, when Sink power ON.

Thanks,

Hi Hohta,

If you connect your board 5V to the connector 19pin +5V, then may be have a problem, when you connect the Sink and Source, the source should connect a 5V to the connector, then it may be conflict, and also your board 5V is connected to connector 19pin directly, not any current limit, it seems no good.

Best Regards,

Kuno

Hi Kuno,

Sorry to make you confused, I mean.

  Board 5V(5V_Sink) : for 5V_Supply

  19pin +5V: for HPD and DDC PU

Thanks,

Hohta

Hi Hohta,

Can you change to the below supply?

Board 5V(5V_Sink) : for 5V_Supply and DDC PU,

19pin +5V: for HPD -it comes from the source.

Our EVM also connect like this-https://www.ti.com/lit/ug/slvu994/slvu994.pdf?ts=1672991109045&ref_url=https%253A%252F%252Fwww.ti.com%252Fproduct%252FTPD12S520%253FkeyMatch%253DTPD12S520%2526tisearch%253Dsearch-everything%2526usecase%253DGPN

Best Regards,

Kuno

Actually it is a very old device, so the safest way is to follow our EVM.

Hi Kuno,

I know your EVM.

If Board 5V(5V_Sink) for DDC PU, When the board is powered off, current may flow from the Source device to the 5V_sink through the DDC line.

I want to stop it.

if Board 5V(5V_Sink) should to use for  DDC PU, I may separate to use Di or other.

Thanks,

Hohta

Hi Hohta,

So you connect the source 5V to DDC PU now, any problem you meet? All function is ok? If yes, I think you can do it, but I can not recommend, because this device is come from another team, and all I can know come from the datasheet and EVM, others is not recommend, sorry.

Best Regards,

Kuno

Hi Kuno,

Yes I met some problem on DDC line.
Do you know someone who has the answer?

Thanks,

Hohta

Hi Hohta,

The design engineer about this device have leaved TI, so if you meet some problem, please separate the DDC PU supply and the connector pin19 5V, just like our EVM do, thank you.

Best Regards,

Kuno