Programmable PSU

SwitchedPSU1

I need to address one more electronic designs – I need a 15A PSU for my robot. I did a vero board design earlier using 4 x DC/DC converters due to their low cost. This delivers 12A in peak which is what I need with 12 x servo’s to allow them all to operate simultaneously. But, it is rather big, so I would like to optimize the size a bit if I can.

The concept of a switched PSU is rather easy – you send PWM into a filter consisting of a coil and a capacitor as illustrated above, and you get DC current out. If you have 12V and apply 50% duty you should have 6V in average out.

I designed a 4x half-bridge driver earlier with a very small driver stage, so what I would like to test is to convert this into a programmable, switched PSU. MCU’s are cheap these days and a small STM32F030F4 costing 50 cent could do the job here. It got ADC’s, UART and PWM output needed. It is worth a try to see what we can get out of this.

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