this post was submitted on 07 Aug 2024
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Hi there

The purpose of this schematic is to control a DC motor that runs at 8V max. That is why I chose 4 N-channel mosfets in the H bridge. P-channels would not fully activate at voltages above -10Vgs but the N-channels can handle 18V at the gate.

The 5v switches represent an Arduino's digital output pins. One to turn forward, one for reverse. To prevent a failure scenario where both pins are HIGH I added a transistor that prevents current from flowing through the optocoupler on the second half bridge.

Does this circuit make sense? I'm not an electronics engineer, just a hobbyist and have doubts about how effective the gate driving circuit is of the mosfets.

Thanks!

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[โ€“] [email protected] 2 points 2 months ago* (last edited 2 months ago) (1 children)

Thanks again for the advice. I made a working prototype and attached it to my pump. The PCB is also made at home which is something I'm trying to learn.

For now I've used just optocouplers to drive the mosfets, since pulling p-type gates down to above -24V seemed like a hassle. I've ordered some IR2210 gate drivers and intend to use those with PWM later to not have to use a buck converter.

Here's a video of the pump. https://drive.google.com/file/d/1qKDBLTbYi2Fbu3UOXpxqSoj00oueWK-K/view?usp=sharing

And the pump in action. https://drive.google.com/file/d/1--HyeJGtYS5dgsjgelE6CrOm2vbBmwXU/view?usp=sharing This version has a stepper motor instead of a DC motor. Stepper motors have low speed limit which is why I'm trying to change it to DC motors.

[โ€“] [email protected] 1 points 2 months ago

No problem :) Let me know if you need any help!