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I'm looking to toggle between two USB cords via a 2pdt switch. I'm not sure if this is possible but I'll elaborate.

I am building a game controller out of an XBOX One PCB using the crossbone (pictured here) PCB. This PCB can operate off a wired connection or a wireless connection. I've determined (as best as an idiot like me can) that the best way to power the PCB is via a USB power bank (similar to this one) wired to the 'USB out' as pictured next to the micro 'USB in' on the crossbone.

I'd like to wire this in a way that my USB cord can switch between powering the PCB directly or powering the power bank which will charge via USB and in turn power the USB. This will allow me to power the USB via the power bank and run wirelessly and enable me to plug the USB in before my switch to recharge the power bank. I realise I can achieve this with a 4 pole 2 throw switch however I simply don't like the style of the switches I have found and have my little heart set on a simple 2pdt rocker switch.

So here's where I have a few questions. When the power bank is being recharged via USB I'm assuming it needs to have data + and - hooked up in order to regulate or cut power once the power bank is fully charged; is this true? Is there a way I can achieve switching between these two USB supplies using a 2pdt switch? I'm assuming my circuit is going need to include something along the lines of a relay but frankly I'm in over my head here.

Any advice would be appreciated. Thank you in advance.

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  • \$\begingroup\$ You should really just use a 4pdt switch. If you must, you could use a 4pdt relay in conjunction with the switch, but that would waste power keeping the relay energized. Also, are you sure your USB power bank supports simultaneous power input and output? It's possible you won't be able to use your device while it's plugged in, depending. \$\endgroup\$ – Hearth Jun 13 '17 at 12:39
  • \$\begingroup\$ To power a simple power bank via USB you usually don't need the data lines at all. \$\endgroup\$ – JimmyB Jun 13 '17 at 13:17
  • \$\begingroup\$ Thanks guys. I hadn't taken the fact that powering a relay would waste battery into account; that's definitely something to consider. I've tested the powerbank while plugged in it still powers the PCB but I suppose I'm not entirely sure if the powerbank is being charged in that situation. I'll have to do some testing. \$\endgroup\$ – Steven Jun 13 '17 at 14:42
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I'm assuming it needs to have data + and - hooked up in order to regulate or cut power once the power bank is fully charged; is this true?

Highly unlikely. Most power banks are simple battery charging circuit's that just happen to use usb connectors, and have no usb related logic or hardware. Most of the time the usb data pins are left unconnected. This may be different for newer QC capable adapters.

Your controller is a different story. It definitely has some usb logic. Unless the xbone controllers only use wireless for data and usb power for charging. Either way, a 4 pole switch mat help, but is not ideal. Usb is a high speed differential pair signal and adding in the switch can disrupt it badly. Usb switching is normally done through ICs designed for switching these high speed signals.

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  • \$\begingroup\$ Thanks heaps for your help. Can you tell me what an ICS is? Could you perhaps recommend a product? This isn't something I had considered but it sounds like a huge flaw in my plan. \$\endgroup\$ – Steven Jun 13 '17 at 18:40
  • \$\begingroup\$ Integrated Circuits. \$\endgroup\$ – Passerby Jun 13 '17 at 20:22

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