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I recently bought the Litionite Falcon powerbank that has one of its outs designed for 5/9/12V. The 12V is at 1.5A which I thought would be enough for my 12V/0.8A camera. However, connecting the camera to the charger with a USB to 0.7mm jack doesn't work. Indeed, I can measure only some 5.3V coming through the USB cable which explains why the camera doesn't recognise the power.

How do I get the 12V from the powerbank to charge my camera? Do I need a special USB cable? Do I need one with a step up? Or is it enough to wire the USB differently?

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closed as off-topic by Nick Alexeev Sep 16 '18 at 6:03

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  • "Questions on the use of electronic devices are off-topic as this site is intended specifically for questions on electronics design." – Nick Alexeev
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    \$\begingroup\$ You probably need whatever plugs into the USB port to talk to it and negotiate the higher voltage. And an 0.7mm jack isn't smart enough to do that. \$\endgroup\$ – Brian Drummond Feb 1 '18 at 23:47
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    \$\begingroup\$ USB is designed as 5 volts, they won't be outputting 12V over USB unless the device asks for it somehow. Otherwise it'd be really easy to accidentally blow up your phone. \$\endgroup\$ – immibis Feb 1 '18 at 23:53
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    \$\begingroup\$ This site explains that a software protocol is needed to negotiate an increase in voltage, but the fine details are missing. You would have to program a MPU with the protocol, using the data lines to communicate. electronicdesign.com/interconnects/… \$\endgroup\$ – Sparky256 Feb 2 '18 at 0:00
  • \$\begingroup\$ Right, so if I get a step up voltage regulator, from 5V to 12V, I should be able to get it to work? Here's one I found amazon.co.uk/gp/aw/d/B01ID90K4A/… \$\endgroup\$ – David Feb 2 '18 at 0:06
  • \$\begingroup\$ Yes and no - a step-up converter can give you 12V from a 5V source, but that does not make the powerbank give out 12V, so with regards to your question - no, you wont get it to work. With regards to what you want to achieve - that might be possible. From the specs, yes. (It might depend on the load that this adapter presents to the powerbank, if the load is big and the powerbank has OCP, then it might shut down. This is designed for the purpose, so one might assume it will be OK) \$\endgroup\$ – MrGerber Feb 2 '18 at 6:11
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Your Litionite Falcon power bank uses the Qualicom proprietary Quick Charge 3.0 technology. To enable 9 or 12V, your device have to provide certain sequencing of voltage levels on D+ and D- data lines, aka "handshake". Since your camera doesn't do that, you need to make a device between your camera and the powerbank that generates the D+/D- signals.

The details of QC protocols are not publicly disclosed, and only occasional information is available on how to conduct the handshake. The most comprehensive details were eventually published in US patent Application US2014122909. If you can read the awkward patent language, you can start there.

Alternatively there are certain ICs that support the protocol, namely AP4370 by Diodes, NCP4371 by ONSemi, and CHY103 by Power Integrations. So some bits of information about actual protocol have been leaked. For example, Texas Instruments PMP9773 Reference Guide describes the protocol as follows:

According the description in the CHY100 datasheet, the processes to enter QC2.0 are: − Apply a voltage between 0.325 V and 2 V to D+ for at least 1.25 seconds − Discharge the D- voltage below 0.325 V for at least 1ms while keep the D+ voltage above 0.325 V − Apply the voltage levels in Table 3 to set the output voltage. (must keep the D+ voltage above 0.325 V)

The table of DC voltages that you need to set on on D+/D- wires looks like this:

enter image description here

To get an idea how the QC protocol has evolved to version 3.0, the following presentation can help. Version 3.0 introduces pulsing protocol, each pulse can decrement or increment VBUS by 200 mV.

So this is up to you which way to experiment with. Given your 12V@0.8A camera requirement, you probably be better off with a 5-to-12V booster from eBay.

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Found the following at this site: https://hackaday.com/2017/03/04/unlocking-12v-quick-charge-on-a-usb-power-bank/

no idea if it actually works

Sam Mallicoat says (November 13, 2017 at 4:03 pm):

It’s easy to set a QC3 supply to 12V with just two resistors and a toggle or push button switch. Here’s how: Take a 10K Ohm and a 2.2K Ohm and solder in series across the Vbus (red) to ground(black wire). The tap between the two resistors will measure about a Volt. Solder D+ (green to this tap. Then wire the D- (white) through a N.O. switch to the same tap. Apply adapter or power pack supply and wait 1.5 seconds to push the button. Presto, 12V @1.5! No need to hold the button, the supply stays at 12.

the hackaday article also links to this: http://blog.rnix.de/12v-from-a-usb-powerbank/

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Your power bank uses Quick charge technology. To enable 9 or 12V, you have to handshake between the device and power bank. Since your device doesn't do that, you need to use a middle man. You can make them yourself, or you can buy a quick charge trigger board on the usual eBay-like websites.

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    \$\begingroup\$ +1 for the words "quick charge trigger board" - those immediately bring up several relevant products, while the search terms I tried only brought me here. \$\endgroup\$ – Nobody Nov 11 '18 at 12:11

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