[chbot] Cheap, low voltage, high current h-bridge

[Andrew Errington]

On Fri, March 14, 2008 12:22, Hanno Sander wrote:
> Hi,
> I'm looking for a:
> - cheap (ideally <$5 with less than 5 parts)
> - low voltage (battery powered, so 6-8Volt)
> - high current (nominal ~500mA, but spikes to 1 or 2 Amps)
> H-bridge to drive a geared "rc car" motor.
>
>
> This must be a common problem for hobbyists, but I can't find a discrete
> component that fits the bill.  I've tried L293 and L298 which are cheap,
> ok on current, but terrible for low voltage- since they eat 2 Volts- which
> also heats them up over time.
>
> I'm reasonably happy with the LMD18200T, but at $14, it's not cheap, and
> with a minimum voltage of 12 volts, it doesn't do low voltage.
>
> Mass-manufactured items, like toy robots, seem to make their own
> h-bridges using FET's - is that the solution? Hanno

Take a look at the Zetex ZHB6718:

http://www.zetex.com/3.0/product_portfolio.asp?pno=ZHB6718&h=52

There may be a better/later version, and of course you need to add logic
to drive the transistors (and not to let the magic smoke out), but I think
it's a neat chip.

HTH,

A