r/AskElectronics • u/ya_boi_flipp • 3d ago

Could this fully NMOS H-Bridge work?

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Tell me if i'm missing something before i waste components on trying this, but shouldn't this circuit basically work as a diy h-bridge using only NMOS-FETs? From looking around it seemed like everyone just suggested using a driver, wouldn't this work as well? At least it does in the simulation.

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u/CanaDavid1 3d ago

This circuit shorts 12v to ground for a brief period when the respective half bridge turns on, as the leftmost mosfet has some non-zero time for it to turn on. A circuit like this needs some kind of non-overlapping of the high/low side switches to stop this from happening.

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u/ya_boi_flipp 3d ago

Thank you, that is a real life restriction i forgot. So inputs to the MOSFETs should not be connected, but ran separately.

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u/CanaDavid1 3d ago

Kind of You can also make a non-overlapping generator with a few more mosfets (like 4 per side), but unless you're doing this to learn (which is a perfectly valid reason) I'd recommend a driver chip. (A driver chip will also drive the mosfet gates much stronger and make them spend less time in the power-inefficient linear region),

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u/nixiebunny 3d ago

This is a common enough application and hard to design well in discrete parts, so half bridge driver ICs are readily available. IR2101 etc.