H bridge

[Armadus]

I am looking for a H-bridge circuit to control a 12 VDC motor with a 10 amp draw.
I have used a TIP 120 circuit in the past, but I think it is limited to 5 amps max.
Any suggestions?

[skimask]

I am looking for a H-bridge circuit to control a 12 VDC motor with a 10 amp draw.
I have used a TIP 120 circuit in the past, but I think it is limited to 5 amps max.
Any suggestions?

Google....248,000 hits on the first try....
Without looking at the datasheets (which again, is just a single Google search away), a TIP120 handles 5 amps according to you, you need to draw 10 amps. How about a simple paralleling setup with emitter ballast resistors....
Then there's the whole heatsinking issue...

[mister_e]

Why use transistors anyways??? MOSFET have more benefits.

IRF540, IRF640, IRFZ44, RFP50N06, IRFB41N15D, HUF75339P3, RFP40N10, IRFB41N15... are the first that spring to mind.

Transistors .. well i forgot many but... TIP3055, 2N3055 :EEK: , MJ15015, MJ15025 some are way overkill and not appropriate anyways ;)

[sayzer]

I always use IRFZ44 for one direction motor control.

But we are talking about H-Bridge here.
Driving 4 Mosfets directly from PIC output (5V) will require to do extra driver level.
5V will not ignite upper mosfets of H-Bridge.

If your application allows you, you can use one IRFZ44 and one dual-contact relay.
This way, you can first set the relay for a direction and ignite IRFZ44 for motor speed control.

[Armadus]

Thanks to all for your respoonse.

As Skimask indicated I found more hits on Google and I could not possiblity look at them all.
My posting was not to save time, but hopefully get some real world application feedback on practical circuits. Unfortunately I have not always found that everything on a Google search is credible.

In regards to the posting by mister_e I am experiementing with a mosfet circuit. I am using a simple NPN and PNP transistor as a driver off the PIC.

The posting by sayzer is interesting, but in the future I may want to add speed control which I do not see as possible with the relay.

If anyone has any comments on the pros and cons and reliabiltiy of the multitude of mosfets available for this application it would be appreciated.

[sayzer]

Wo wo wo,

It is possible to have speed control with relay, as I mostly do.

The Relay is for the direction, not for the speed.

IRFZ44 is for speed control.


When the relay is OFF, your motor terminals are connected with one direction, say CW.
When the relay is ON, your motor terminals are connected with the other direction, CCW.

In both cases, motor is not running.
You can turn the motor ON, OFF or control its speed via IRFZ44.

<img src="http://www.picbasic.co.uk/forum/attachment.php?attachmentid=2517&d=1208532602">

[Armadus]

Thanks for the new information. I think that this is a superior circuit compared to the mosfet bridge using 4 transistors to trigger the four mosfets. This circuit has the elegance of simplicity, which I think will also be more reliable. Just the info I am looking for.