[Galaxy S III Accessories] Diim:
Charge phone by the TV

Yes that was one of the key feature of the MHL standard v1.

And that has even been enhanced with standard v2:

- Increase of charging current limit (see http://www.galaxymhl.com/)

- And that seems now possible to power supply the MHL to HDMI bridges directly by the phone without the need to connect a wall charger, according to the new Samsung "MHL 2.0 HDTV Smart Adapter" features description (http://www.samsung.com/us/mobile/cell-phones-accessories/ET-H10FAUWESTA)

Note

: To my knowledge, GS3 and GN2 have MHL v1 ports whereas GS4 has a MHL v2 port. So the behaviour may be sligthly different between those devices, what may affect our homemade adapters.

So that is theoretically possible (Probably few people have been able to try that), but for that, you'd need:

- first of all, a "MHL-enabled" display device, what is not the majority of TVs (reason why we almost all use a MHL to HDMI adapter). On the TV, the MHL compatible HDMI port should be marked with a specific purple indication.

- A real MHL cable ("Passive" so called") like that one -> http://www.kanexlive.com/mhl-cable-passive

You'll find basic description of MHL standard on the MHL consortium website.

http://www.mhlconsortium.org/home.aspx

You'll find there a list of existing MHL-enabled devices

You'll also find information about how to recognize MHL compatibles devices and port in the "Trademark and Usage guideline".

---------- Post added at 03:02 PM ---------- Previous post was at 02:13 PM ----------

Sorry, I thought you had the same setup as necomer. http://xdaforums.com/showpost.php?p=40241508&postcount=83

Now I think I've got your setup: You have bought a standard 11pin MHL to HDMI adapter, and directly modified it by soldering a USB OTG cable. Then you have tied the USB OTG sense pin on the 11 pin connector to the ground by a 40.2K resistor. And I guess you have kept the MHL sense resistor of your MHL adapter (Needed in order to have the phone enter in MHL mode).

Am I right ?

For my information, could anyone tell us what is the value of that MHL sense resistor (you know, the one you remove on your 11 to 5 pin adapter) ?

That would be interesting anyway if necomer could confirm the behaviour in the 3 cases I described.

---------- Post added at 03:12 PM ---------- Previous post was at 03:02 PM ----------

Since we try to use the phone MHL port in USB OTG mode and MHL mode at the same time, that makes definitely sense to consider the plugging and unplugging order. So I believe you are on the right way.

---------- Post added at 03:20 PM ---------- Previous post was at 03:12 PM ----------

2) -> As I said, there could be a power conflict between the USB OTG power supply (coming from the phone) and the power supply from the MHL adapter (supplied by the wall charger). To resolve that conflict, perhaps the phone is in a state where it can only output power, but not get power.

3) -> Yes As I said, your MHL adapter seems power supplied by the USB OTG power supply of the phone. -> That is great. Do you really need to connect the charger at step 4 to have that working. If not, that would be AWESOME !

---------- Post added at 03:22 PM ---------- Previous post was at 03:20 PM ----------

No, USB HUBs are devices and thus are designed to get power from the PC (or host), but not designed to forward their own power supply to the host, so there couldn't be any power conflict. (Think of the case when you connect your hub on your PC, does that harm your PC if the hub has its own power supply ?).