Bitbanging Qualcomm Charge Controllers

With more and more manufacturers moving to USB-C, it seems as though the trusty USB port is getting more and more entrenched. Not that that’s a bad thing, either; having a universal standard like this is great for simplicity and interconnectability. However, if you’re still stuck with USB 2.0 ports on your now completely obsolete one-year-old phone, there’s still some hope that you can at least get rapid charging. [hugatry] was able to manipulate Qualcomm’s rapid charging protocol to enable it to work with any device.

The protocol in question is supposed to work only on supported devices. Namely, anything with a Qualcomm Snapdragon or other similar products. [hugatry] had a Qualcomm rapid charging-capable USB port, but no supported devices. What he found out after some investigation, though, was that it’s extremely easy to bitbang the protocol to request essentially any amount of power from the Qualcomm device. He didn’t even need a microcontroller to do the handshaking, only passive components.

It’s a little surprising that getting around a proprietary standard in this day in age is so straightforward (and he does note that while it worked for him, your mileage may vary), but we’re happy to see it nonetheless. [hugatry]’s process is definitely worth checking out, as is his video which you can find after the break.

14 thoughts on “Bitbanging Qualcomm Charge Controllers

  1. Don’t get me wrong, this is useful, but this article seems a little disingenuous.

    This isn’t “getting around a proprietary” method, this is directly using the proprietary method as it was designed and documented. Useful information, but the way this article reports it is misleading.

    What he did was directly follow a TI reference guide on how to build your own QC2.0 compatible charger, which isn’t that difficult because the spec was designed to allow the negotiation to be very simple.

    The hack is to have jumpers so that you can manually change voltages (again, as per spec) to switch the device into a 9v or 12V output. That’s hardly “making it work on any device”… Besides, if you need the power supply for the device, you’ll just follow the protocol directly to get the higher voltage.

  2. Sounds more like “get a fast charging capable charger to give you the goods”. The article suggests that you can get ANY USB device to USE the fast charge output of a fast charge capable charger. In reality you’d smoke the USB device because it doesn’t support 9v on a 5v line.

  3. This is pretty cool, I didn’t even know you could get anything but 5V from any USB port. But I have to wonder if “bit-bang” is the right term as everything is happening in the analog realm; just to argue semantics.

    At any rate, it’s a nice trick to have in your pocket…how common is this? Do many chargers or USB ports support it?

    1. This particular standard is Qualcomm’s Quick Charge, you’ll find Quick Charge in many modern phones that use Qualcomm’s Snapdragon series of SOC’s, Googles Nexus line up as of the Nexus 6 (Nexus 5 didn’t support Quick Charge) and of course the Pixels, pretty much any phone that uses a Snapdragon CPU from 2015 or later, but do check compatibility, if you accidentally enable 9v or 12v output while plugged into a 5v only phone and you’ll do some damage to it.

  4. i hate to HAVE to be negative…

    1) it’s not a standard, its a propietary licensed specification. When selling home-made devices, only charging can be done without the huge licensing fees.

    2) USB-C? really? it’s a port where the age-old and trusted 5v is suddenly over 2x ??? what if the fail-safe devices (Li-On charger ect) devices accidentally fail short??? you gonna buy me a new house and car bro? no? not all LiOn (internal) protection circuits can withstand 12v. arcs can bridge ANY component… check your creepage and mind the carbon…

    3) if you only have 5 mins to spare for charging, then how is it that you can spare all day to use it? charging wastes time?

    PS: i have officially changed my stance on smarty-people, from now on, if you almost kill me because your smartphone is more important then safe driving, you will get vehicle damage and your smarty-device destroyed. december season is the season for running people over and im frankly fed-up.

    1. Yes, charging wastes time, as your device is not mobile in that time (excerpt if you charge in your car while driving). And you are wrong about USB-C: It can not only deliver 2x (5v), it can deliver up to 100W at 20V :-)
      How is it said? – “If you can’t stand the heat, stay out of the kitchen.” So if you can’t bear more than 5V don’t ask for it.

  5. Now show us how to build a dongle that can jack between the USB port on high output capable chargers with a USB 2 port and Apple, Samsung and other devices that use proprietary schemes (more complex than simply shorting the data lines to pull up to an amp) to pull charge rates over one amp.

    Why? To get around paying $40 or more for a gen-you-wine charger the OEM is gouging the customer on price – and to have one charger that can handle any phone or tablet with a micro USB port.

    I’ve a couple of chargers that can kick out 2+ amps, but Samsung devices refuse to pull more than 500 ma from them.

    If this dongle can somehow test the capability of the charger and ‘pass that along’ to the phone or tablet so wimpy chargers don’t emulate a Note 7, that would be a good thing.

    1. most of my samsung devices will pull full current as long as the voltage doesn’t drop below 5 volts and the data lines are shorted together. real picky about the voltage drop in the cable.

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