Those who work in different places may have different definitions of the term “high voltage”. For someone working on the Raspberry Pi’s GPIO pins it might be less than 5V, someone working on a Tesla coil might consider it to be around 20kV, and a lineman might not say something like high voltage up to 115kV. What we can all agree on, though, is that getting 300 volts from a USB power supply is definitely “high voltage” that we wouldn’t normally expect to see in this kind of context, but [Aylo6061] She needed such a power source and eventually managed to create one.
In this case, the higher voltages will eventually be used for electrophoresis or electrohydration. But before getting there, [Aylo6061] He built one of the most secure circuits we’ve seen in recent memory. Every high voltage part is hidden behind double insulation, and there is complete isolation between the high and low voltage sides thanks to the flyback transformer. This has the benefit of a floating ground which reduces the risk of accidental shock. This does cause some challenges, as voltage sensing is on the high side and is difficult while maintaining insulation, so some clever tricks have been implemented to maintain the correct target output voltage.
The control circuitry is based on the RP2040 chip and is impressive in its own right, with USB isolation for the data lines as well. In addition, the project code can be found on his GitHub page. Thanks to the partial deficiency, [Aylo6061] Dedicate an entire microprocessor core to decoding digital data from the high voltage sensor circuits. For something a little less refined, less safe, and a much higher voltage output, though, take a look at this power supply that beats the output voltage by about 30kV.
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