Electronic – Battery power supply for Intel Compute Stick

batteriesdc/dc converterintelpower supply

I have an update. It seems there are multiple posts on Intel's forum by people reporting bricked Compute Sticks even though they were using the factory power supply. I followed the recommendation to reset BIOS by holding the power button for 3 seconds and… it came back to life! That is the third Compute Stick, the one for which I was using the setup with the electronic switch. The previous two are still dead. So, it seems that these computers have some issues with power supply. And the voltage spikes damaged permanently the first two, while after fixing the voltage spike, the last one suffered from corrupted BIOS but it was possible to recover it.

I am using Intel Compute Stick, which basically is a single board computer, and I am experiencing problems powering it from a battery.

Intel Compute Stick

The computer is powered via a Micro USB port. It comes with a wall power supply which has 5V 3A output. I measured the actual output to be 5.16V. The maximum power consumption I measured to be 1A in my application.

Here is what my initial setup was for powering from a battery:

[16V battery] -> [5V 3A out buck converter] -> [Intel Compute Stick]

Using this setup resulted in bricking two computers. Each time, it happened while reconnecting the power supply. I hooked up an oscilloscope and observed voltage spikes when connecting the battery. To cope with this, I decided to add an electronic switch between the buck converter and the computer (Mini MOSFET Slide Switch with Reverse Voltage Protection SV from Pololu) and to make sure it is always open when connecting the battery.

So, my second setup was:

[16V battery] -> [5V 3A out buck converter] -> [MOSFET switch] -> [Intel Compute Stick]

Below are pictures from the oscilloscope, the first two are for the first setup without the switch and the rest is for the second setup. So, it all seemed to look just fine. The actual converter output is around 5.28V which is just slightly more than 5.15V and there are no voltage spikes. At this point I decided to make the final test by connecting the battery and switching the switch on until the initial welcome screen was displayed and then switching back off. I planned to try 200 such cycles, and after 130 cycles Compute Stick died…

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So, I still must be doing something wrong, but have no idea what this could be at this point. As far as I can tell, all I have at this point is constant 5V power supply from the converter and I am just opening and closing the switch.

Any ideas?

Best Answer

It looks like the Intel computer is really sensitive to overvoltage. You could use a two stage power supply for it - a buck converter to drop the voltage down to, for example, 7 volts and then a linear regulator to provide clean and spike-free 5V. The intermediate voltage (7V in my example) should be just slightly higher than the minimal requirement for the linear regulator for best efficiency (though efficiency won't be that great anyway).

I used LM338K to make a car power supply for my Viliv N5 palmtop which has the same problem.