Lowest Cost H-Bridge

william chan

I need to control a small motor (0.5 amps) and also make it reversible.
Most H-bridge ICs I can find cost more than the motor itself.
Any low cost recommendations?
Can I use a ULN2003 IC to make a h-bridge?

Thanks.

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stamptrol

Lowest cost will be single DPDT relay to give forward and reverse. Probably use a MOSFET to switch the relay. Add a MOSFET for power on and off (or PWM the MOSFET) to give variable speed.

Forum member erco posted a sketch a while back if you're looking for a schematic.

Cheers,

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Tom Sisk

http://www.siskconsult.com
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Dgswaner

how about these:
http://www.solarbotics.com/products/k_cmd/

http://www.parallax.com/Store/Accessories/MotorServoControllers/tabid/160/CategoryID/35/List/0/Level/a/ProductID/491/Default.aspx?SortField=ProductName,ProductName

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"A complex design is the sign of an inferior designer." - Jamie Hyneman, Myth Buster

DGSwaner

Phil Pilgrim (PhiPi)

William,

You can't build an H-bridge from a ULN2003, since it's current-sinking only. An H-bridge consists of two current-sinking and two current-sourcing drivers. If you're designing for mass production, the cheapest way to go is probably discrete transistors: 2 PNPs and 2 NPNs (or their MOSFET equivalents) with associated resistors and diodes. Zetex makes some H-bridge transistor arrays that might make nice building blocks. The web should be replete with candidate circuits. You will want to design in some current limiting as a protection against short circuits, as well as protection against cross-conduction, which will fry an H-bridge.

-Phil

LoopyByteloose

The Tilden H-bridge with 2n2222 and 2n2907 transistors is a pretty good option.
The cost is 6 transistors and two resistors.

http://www.solarbotics.net/library/circuits/driver_tilden.html

The web site has instructions on how to 'free form' the wiring so you don't need any printed circuit board.

This is not the cleanest or most efficent design and if you want to have better power usage, you have to add a few more resistors and a couple of diodes.

If you have space on a board [noparse][[/noparse]like the SX-28 Proto board or the Propeller Proto board], you can mount your compontents with your processor.

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It's sunny and warm here. It is always sunny and warm here.... (unless a typhoon blows through).

Tropically, G. Herzog [noparse][[/noparse] 黃鶴 ] in Taiwan

Post Edited (Kramer) : 8/21/2008 8:34:49 AM GMT

jpyle

SparkFun.com A one chip solution--$2.35 They work great for low power applications!

H-Bridge Motor Driver 1A
sku: COM-00315

Description: Faster, cheaper, smaller, better, right? The SN754410 Quad Half H-Bridge is just that. Capable of driving high voltage motors using TTL 5V logic levels, the SN754410 can drive 4.5V up to 36V at 1A continuous output current! Please see datasheet for more information. This is a pin to pin compatible replacement for the L293D.


http://www.sparkfun.com/datasheets/IC/SN754410.pdf

Phil Pilgrim (PhiPi)

DigiKey carries the SN754410 for $1.65, quantity one.

BTW, something I learned just last week: have your stuff shipped from DigiKey by Priority Mail. It's faster and way cheaper than UPS, and you can get your stuff on Saturdays, too.

-Phil

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'Still some PropSTICK Kit bare PCBs left!

tedbeau

Here's a really good example of how to use a 754410 chip as a dual H bridge. Alows reversing the motors. I used this chip, along with a 556 dual timer chip supplying PWM to the enable pin of the 754410 to control a robot built out of two CD drives.

http://www.hobbyengineering.com/appHBridge1A.html

Ted