There are a few things I noticed and examined for two different fast charging standards:
- MediaTek PumpExpress works without any data communications with the charger. Output 2 from my USB multimeter has no data connections, so I connected the cable to output 2 to disable data communications. The multimeter shows some varying power currents, so it is possible that the communication happens via power impulses. But it needs to go up by steps of 5V,7V,9V,12V.
- Qualcomm FastCharge jumps to desired voltage (9V) two seconds after inserting, because it uses the USB dats ports as handshake gateway, which does accordingly not work, when being used with port 2 with handicapped data ports onthe USB multimeter. How can I do manual voltage requests? QuickCharge 3.0, unlike 2.0, has no fixed levels, but can freely deliver any voltage range supported by the charger.
- For Qualcomm's wireless fast charging, the wireless charging plate itself communicaties to the USB charger through the cable. Probably, there is also some communication to the phone, but I am not quite sure.
What are the technical details behind the charging standards and how they work under the hood? Are they only software-based?
Are there documentated?
Can I safely just supply 7V or 9V using a laboratory power supply, without using any of these standards?
If they are only software-based, does that mean that I can use Qualcomm's Quick Charging standard over MediaTek processors and ViceVersa?