Tiny H Bridge Drivers

metron9

I have a project where i will need to drive a tiny cell phone vibrator motor both forward and reverse. The motor is connected to a sprocket using a worm gear. Any suggestions? The kickback pulsing one of these is 25V and the motor uses about 60 mA.





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Phil Pilgrim (PhiPi)

Take a look at the Zetex ZHB6790 (pdf). The external circuitry required shouldn't take up too much room. You might also consider MOSFET drivers, like the Micrel offerings. Although these are designed for surge current apps, 60mA is a low enough continuous current, they might just work. Or not. Their "on" resistance is 10 ohms. They'd be dissipating 1.2W in an SOIC-8.

-Phil

Post Edited (Phil Pilgrim (PhiPi)) : 12/5/2007 7:15:12 AM GMT

Beau Schwabe

metron9,

I've used the those Zetex parts before and they are great. They also offer some MOSFET versions to choose from.

http://www.zetex.com/3.0/3-3-2b.asp?rid=42

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Beau Schwabe

IC Layout Engineer
Parallax, Inc.

Post Edited (Beau Schwabe (Parallax)) : 12/6/2007 8:49:05 PM GMT

metron9

Thanks, those should work fine. If we buy them in big lots I will make them available for a good price. I see digikey is over 5 bucks on qty 1

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Think Inside the box first and if that doesn't work..
Re-arrange what's inside the box then...
Think outside the BOX!

Phil Pilgrim (PhiPi)

Oh, that's a pretty obscene price. The MOSFET parts are cheaper. You might also check out some NPN/PNP arrays on the DigiKey site that are less expensive still. It'll take two, but there's a Zetex unit (ZXTD4591E6TA) that goes for $0.93 (qty 1) and an NXP unit (PBSS4140DPN) that goes for $0.76 (qty 1). Both are rated for 1A.

-Phil

ChrisP

The L298 is in that pricey 5$ range but doesnt need external circuitry and is dual full bridges if that matters...
and its also good to 46 volts...


Post Edited (ChrisP) : 12/9/2007 1:37:47 AM GMT

LoopyByteloose

This is really in range for discrete components to reduce costs. The 'Tilden' Beam H-bridge uses two 2n2222 and four 2n2907 transistors with a few resistors.

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

It seems good to 60 volts. Discrete components may actually be more durible as they have more surface area to dump heat -- certainly cheaper than ICs. And, I wonder if you really need MOSfets.

There are refinements to this that will optimize power. And, you can alternatively use 4 transistors and an IC to drive the transistors. I just can't seem to Google the right reference for the optimized designs.

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Phil Pilgrim (PhiPi)

Here's a Design Idea from EDN that may help: www.edn.com/contents/images/6421440.pdf. It starts on page 5 of the pdf (p. 78 from the magazine).

-Phil