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Google 'Strongly' Recommends Against Third-Party Fast Charging Technology On Android (techcrunch.com)
An anonymous reader quotes a report from TechCrunch: Everyone, it seems, is going the fast charging route these days. Thanks to the nearing ubiquity of USB-C on flagship devices, the feature is quickly becoming a standard -- "standard" in the sense that everyone is doing it, not so much that there's any consistency to the tech. All in all, it's a nice addition to manufacturers' newfound focus on battery life. And while Google has embraced its own version on its new Pixel devices, the company's not so keen on letting everyone implement their own version. In newly released Android Compatibility Definition papers issued for Nougat, the company stops short of an outright ban on technologies like Qualcomm's Quick Charge, though it does take a pretty clear stand, "strongly recommend[ing]" against it. At issue, among other things here, is potential compatibility issues with standard USB chargers. Google said in its latest revision of the Android Compatibility Definition Document, "Type-C devices are STRONGLY RECOMMENDED to not support proprietary charging methods that modify Vbus voltage beyond default levels, or alter sink/source roles as such may result in interoperability issues with the chargers or devices that support the standard USB Power Delivery methods. While this is called out as "STRONGLY RECOMMENDED," in future Android versions we might REQUIRE all type-C devices to support full interoperability with standard type-C chargers."
The USB power delivery spec standardizes how to increase Vbus voltage and max current. Power profile 5 increases the voltage to 20V with 5A current for 100W of power. It can be implemented on either type A, micro USB, or type C. It used to be that the USB spec only standardized up to 7.5W power draw, which became a limiter on charging time. Now that we have the new power delivery spec extension, there are zero good reasons to implement proprietary charging standards to move beyond 7.5W.
Despite this, Qualcomm is still heavily marketing its proprietary quickcharge 3.0 system to smartphone manufacturers, purely for the incremental profits on licensed wall chargers. I'm glad to see Google throwing their weight around a little in an effort to shut down what is purely a money grab.
There is a standard for faster charging. It's called USB-C, or if that isn't fast enough, USB Power Delivery. There are legitimate compatibility concerns over the various proprietary extensions that do the same things but differently.
I'm not sure what the article means by "its own version", but the official Pixel charger uses USB Power Delivery for 18W charging.
There's no inherent connection, except whatever software support the hardware might need. The guidelines/requirements here are for Google to allow hardware vendors to use the Android trademarks, qualify for Google Play apps, and so forth. Google is using that as an incentive for the third party vendors to use standard power mechanisms rather than proprietary ones.
The cable itself has a maximum current which is independent of the device, and it can be one of three values. They didn't want every USB C cable to have to be built to carry 100 Watts.
Bruce Perens.