The first option on mind was to build an H-bridge with N-channel MOSFETS (because I have a bunch of D-PAK STD22NM20N on my parts bin) for that I need to use a MOSFET driver that also have on my parts bin, one for each H-bridge, so three will be needed, each one of 20 pins a PCB was the best option for this, desinged on KiCAD and use PCBway.... that killed the idea... first I don't want to make a PCB for this, I want to use what I have on my house and parts bin, use prefboards??... the ones I have are too small... the second option was don't use the driver IC and drive the MOSFETs directly using opto isolators, but I will need two power supplies at different voltage levels, one for low side MOSFETS with at least more than 5Vcd to drive them and other at 9.5 to 10 volts for high side MOSFETS, the problem: I have only two power supplies, both are fixed voltage, one at 5 volts and the other have multiple fixed voltage levels, (3.3v, 2.5v, 1.8v, 1.2v and 19.1v)... the solution was a simple one: build a variable power supply based on one of LM350K from my parts bin and use the 19.1v for Vin needed.

On top the multiple fixed voltage power source on bottom the 5V fixed voltage PS.

These are the guts of my multiple fixed voltage PS, made with love, the PS sections from a motorola microwave ODU, hot glue and a hacksaw.

and this is my new humble variable PS based on LM350K

The next step was to make the H-Bridge with the D-PAK MOSFET, but then again another change of mind happened, this time was too late... but that history will be for the next log.