Voltage doubler for beaglebone black fan

Question

Hi,

I've been working on a circuit that will take the 5V from the beaglebones GPIO and boost it up so that I can drive a fan, I started with getting a ICL7660 chip, and found I was getting 13V and could drive a little 12V 10mA fan quite happily but I wanted to switch to a blower which takes 900mA and it wont even start, I monitored the power into the beagle and its not even close to 1A let alone the 2A PSU I'm using so I'm guessing the chip is limited to a few mA, do any of you know of a circuit that will eliminate this problem or is it the beaglebone itself?

I dont want to run this on a separate circuit as it will be used in a situation where additional plugs are impossible

As always thanks to anyone that can help

dougw · Accepted Answer

Hi Kevin,

Voltage boost modules are readily available or you can build your own - here is an example based on an LM2577 - you can make your by following the example in the datasheet:

DC DC Auto Boost Buck Step UP Step Down Converter Module Solar Voltage LM2577 | eBay

To convert 5 Volts to 12 V at 900 mA will require at least 2160 mA from your 5 V source and probably more like 2400 mA.

If you are getting your 5 V source from the Beaglebone Black connector it will likely not be able to supply enough current due to the size of the copper traces on the PCB.