I wish to drive a 12V stepper motor with a USB port as the source of power. However, the USB port only outputs only 5V as output. This will obviously not work.

I had thought up of several ways to overcome this. 1. chain multiple USB ports in serial to bump up voltage. 2. Use some sort of circuit ("booster") to increase the 5V to 12V

I have tried searching this issue up online, however I have seen very differing answers. Some people say that using 2 USB ports in serial will create a short circuit while other people say that this will work and is the basis of Y cables. Could someone clarify and suggest the best option to increase a 5V supply to 12V?

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    This sounds like a bad idea. You certainly can't series connect USB ports powered from the same supply. – Transistor Jul 14 '17 at 11:12

Y cables put the power connections of the USB port in parallel and allow you to get more current.

You cannot put the power connections of two USB ports in series. This will cause a short circuit.

You could use a boost converter to get 12V from 5V.

You are limited to the power available, though.

USB is limited (with exceptions) to 0.5A at 5V. That's 2.5W.

If you boost the 5V to 12, the available current goes down. The power stays the same, but the voltage goes up. Therefor, the current has to go down. At 12V, you would have less than 200mA. I doubt that is enough to power your motor.

You'd be much better off powering the motor with a 12V power supply and designing some type of interface circuit to control it via the USB port. But it doesn't sound like you have the level of knowledge designed to build something like that.

I think the best option for you would be to use a Boost Converter (There are many available and with example circuits in the datasheet).

Make sure you know :- Current Requirements Noise Requirements (if any)

If you dont feel confident enough to design and build a 12V boost converter then go to Ebay there are many cheap options availbale which work of the shelf.

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