H-Bridge

chronister

Hello. I'm trying to design an H-bridge circuit to use to control a large motor. I'd like advice on whether or not this design will work before I build it. The schematic is here:

http://www.ornithopter.org/hbridge.gif

The components I plan to use are two P-channel MOSFETS (P1 and P2 in the schematic), two N-channel MOSFETS (N1 and N2), four schottky diodes, four 100K pull-down resistors to prevent static electricity from turning on the MOSFETS, and two 1K resistors on the inputs to protect the microcontroller.

I wasn't sure where to put the pull-down resistors for the P-channel MOSFETS. Could you please let me know if this is right?

Also, is there some way I can implement a brake, and what changes would that require?

Thanks for your comments. If this gets the approval then hopefully it will be of use to others who may be looking for a simple H-bridge circuit.

Nathan

Post Edited By Moderator (Jon Williams) : 12/12/2004 3:53:53 AM GMT

MacGeek117

chronister,

it will probably work, and yes the pull-down resistors are in the right place -bugg

MacGeek117

(on the brake), just reverse the direction of the inputs for a brief moment. -bugg

awasson

Hey Nathan,

I found a really nice set of schematics at the Nuts and Volts Magazine PDF section:
www.nutsvolts.com/stmpindx.htm

Get the one called Stamp Applications no. 23 (January 1997)
utsvolts.com/stampaps/st_ap23.pdf

The half bridge on page seven is really efficient and low on parts. It also has a break which is good. The one on page 8 has a higher parts count and isn't as efficient but it uses a single 6 volt supply.

Of course I found this after I had already built some less than stellar controllers of my own design.

Andrew