Electronics > Beginners
Sanity check - FET H-Bridge circuit
danners430:
Hey folks,
Can I just ask for a quick sanity check - I've never worked with H-Bridges before, and have found it easier to simply construct my own instead of using driver ICs. This circuit I designed with shoot-through mitigation in mind, the 250r resistor effectively limiting the shoot-through current to 20mA (in theory), which is easily manageable. Does this make sense, or should I stick to having individual control over the FETs?
Just for info, all FETs are enhancement mode, and VCC is 5V.
Cheers
Alex Nikitin:
Hmm, how much current do you need for the motor to operate?
Cheers
Alex
danners430:
The motor is just there as a placeholder for now :-) it's easier to identify than the bi-colour LED that will actually take its place :-)
There will be a variety of this that will power a motor (25mA at 16V), but for that I'll get rid of the resistors and go back to directly driving each FET from 4 GPIO pins, and programmatically eliminating shoot-through by adding a few milliseconds delay between switching the P-Channel FETs off and switching the N-Channel FETs on :-)
exe:
Why not using an IC which would significantly lower BOM, protect from short-through and easier to control (with one or two pins, one for enable/disable, another one could "direction")?
danners430:
I've had a look, and honestly the only advantage seems to be PCB space... the main problem is that the motor is a point motor for a model railway, which is switched simply by reversing the current flow - I'm not 100% sure whether a traditional motor control IC would work - although I'm very open to suggestions!
If an IC would work, does anyone have any suggestions for what to look for? there's a confusing number of different types and ratings out there!
Cheers :-)
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