Calculate capacitor value

Or use some 74HCxx schmitt triggers to at least

The previous schematic I posted already had a scmitt-trigger (though it was interverted :see_no_evil: ) so that point was clear :wink: Latest plans incorporate a 74LVC1G17 in sot23-5. This time I am sure it is non-inverted :wink: .

When I laid my eyes on the 3D view the thought to employ an attiny1616 with some shiftregisters (74HC595) has crossed my mind. When I use an uController to control mosfets I use a 22R resistor to limit the inrush currents and a pull-down resistor. So that is 2 resistors and a freewheel diode per mosfet.

This analog variant now has one sot23-5, one resistor (0603) and 1 capacitor more than that. The costs are about the same. So the extra amount of components isnโ€™t that much of a deal. And considering I dont have to pull my programmer out of a drawrโ€ฆ analog has my preferences.

I am however slightly worried about the contact bouncing. I will propably need an extra RC filter (atleast) for that and at that point I may be inclined to take the uController approach instead.

Therefor I am going to breadboard this circuit and perform some tests. The partial simulation I managed to do in Kicad were looking good. I have opamps laying around to make a schmitt-trigger with. With an arduino I can monitor the pulse length on the output side. I only canโ€™t monitor how steep the flanks are. I am looking forward to it.

Bas

Consider also LVC2G17.
To limit power in Mosfet during switching it have to be switched as fast as possible. Using 220R in gate is the step in opposite direction (the higher current mosfet the higher its gate charge).

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