5V stabilised supply for USB hub

Step 16 The finished board

The board is finished, all components are in position.

It was tested.

First with two rather weak penlight cells - I did not trust my handiwork that much - and the output was 5.04 volts

Elated with the success, I tried it with three good cells - an input voltage of 4.5 volts - and the output was still 5.04 volts

Then I tried the voltage from the USB port of my computer - around 5 volts, though liable to jump around on the lower two digits - and still the output held steady at the same old 5.04 volts.

So it would seem that this thing works, at least during preliminary tests.

According to the datasheet it will start at 1.9 volts and accept a maximum of 5.5 volts, and hold its output voltage steady.

It is a buck - boost converter, which means it can accept input voltages above and below its output voltage, switching between modes automatically in order to keep the voltage steady.

It could be fed from a rechargeable cell in order to maintain the USB supply voltage even when the cable is disconnected from the computer - if that is any good.