H-bridge motor driver

294

06:05:01

Top left transistor is #1
Top right transistor is #2
Bottom right transistor is #3
Bottom left transistor is #4
Or just start at top left and work clockwise.
If 1 and 3 are enabled then you get forward rotation
If 2 and 4 are enabled you get reverse rotation
If 3 and 4 are enabled you get brakes
If 1 and 2 are enabled you get light braking. 
If there is anything that would make this work better please let me know, I'm noticing when I increase the load level it slows down way more than it should because the voltage drop across the motor is lower.

published 8 years ago

FernandoCPF

8 years ago

I do not want to look like someone who promotes circuits ... so I leave you where I found all this

FernandoCPF

8 years ago

Inf:http://www.talkingelectronics.com/projects/H-Bridge/H-Bridge-1.html

FernandoCPF

8 years ago

Of all those I made 7 ... and I would like you to try to do. FIGUR:3,4,5,9 and 10.

AngeloAgnello

8 years ago

I don't understand why you used the four diodes - I tried to remove them and it worked.

justinmh

8 years ago

@angelo the diodes are flyback diodes, when there is no power applied and the motor is still spinning it will create an emf (electromotive force) the diodes give a place for the current to flow so it doesn't fry the transistors. Yes in the sim you could do it with out, but in real life you would want them to protect the transistors, esp if you were using a pwm as your enable signal.

justinmh

8 years ago

@fernando, I will give these a try

XDeadpool

8 years ago

J.A

virus2x

8 years ago

To improve the circuit is necessary. Replace the NPN transistors in the top plate with pnp. And add another npn transistor. Collector to the base of pnp. Emitter in the base npn

justinmh

8 years ago

@virus, I just tried that and it doesn't work as it doesn't allow there to be any voltage drop across the motor to allow it to spin, then voltage is the same on both sides. Did you actually test this out?

virus2x

8 years ago

Yes

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