DC micro motor control

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sfink06

New Member
Hi all,
I am looking to design a PCB that can control 10 micro DC motors that run at 3 V and draw 60 mA. Should I be using surface mount H-bridges, and then control the inputs with a PIC? I had trouble finding anything that looked promising in limiting the size of the board. Thanks!

birdman0_o

Active Member
Well, it wouldnt be an H bridge, because you have 10 motors, an H bridge is meant for four. Are the motors spinning at the same time? Independantly? And in one direction or two?

sfink06

New Member
All motors must be able to move in both directions, and at any given time up to 5 motors must run at the same time (it's for a robot.)

birdman0_o

Active Member
ok, both directions would require a semi H bridge.
Which PIC do you plan on using? If you require speed control, this becomes a whole new level of difficulty...

sfink06

New Member
Some dsPIC30F2011 or something in that family, has the ADC channels I need for sensors, PWM, and 12 DI/O pins.

sfink06

New Member
Is it possible to have the h-bridge multiplexed, and then use the PWM channel to control the speed? The ADC input from the sensors will be able to determine how fast each motor needs to turn.

birdman0_o

Active Member
By multiplexing the semi - H-bridge you are effectively making the max speed 10x less (divide by number of motors). How many PWM modules does your pic have?

sfink06

New Member
2 I think, the most I've seen In a pic is 8

birdman0_o

Active Member
There are PWM driver chips, I dont know the names by heart.

phoenox

New Member
birdman what do you mean by semi - h-bridge?

I thought that an h-bridge was two high side switches and two low side switches connected to one motor.

Last edited:

New Member
Ya a half H-bridge can control one motor in one direction, full is one motor in two directions. Maybe you could have one main PIC control 3-4 slave PICs with 2 PWMs each (two motors each driven by one SN754410). You would have to give each one an address and all of them would require a bunch of code though...

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Banned
birdman what are you talking about? In order to control a DC motor bidirectionally you need a full H-bridge.

New Member
Ya a half H-bridge can control one motor in one direction, full is one motor in two directions.
I'm assuming you were talking to the other birdman?
The IC shown at sparkfun has four half h-bridges in it. By connecting the motors and pins a little differently, you can make it 2 full (bidirectional) h-bridges instead.

Banned
Lol! oh no there's two of you now!
Yeah, I was responding to birdmanO o

colin55

Well-Known Member
Don't forget, you can simplify things by having a spilt supply.

sfink06

New Member
thanks all, I think I'm just going to use 6 motors now, and only make one of them bi-directional (not really enough room on the robot for a PCB with multiple H-bridges.) If anyone knows some good small form factor H-bridge IC's, preferably SMD, I'd appreciate it.

jamesmatheson

New Member
major companies have no idea what theyre selling , I keep asking for this https://photos.app.goo.gl/F3o8KCsIDwwKC47W2 and they keep asking for a parts number, I even paid $1000 to a company and they took the money and couldn't supply the product and now they posted my name everywhere on the internet and all the companies are asking for$1000 and more before I even tell them what I need,

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