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

[Hanno Sander]

Thanks Andrew for the ultra-fast and accurate reply.
The Zetex ZHB6718 is:
- cheap $1.30, single SO8 package for a complete 4 transistor NPN/PNP
h-bridge
- low voltage: it loses < .1V at 1Amp current
- good on current: gain is >200 at <1Amp current, meaning drive current is
<5mA.
A slight issue: on page 7, safe operating area, full copper, dc, they imply
that it's only capable of 5v, 400mV- maybe I'll have to double up to reduce
current on each one?  Had any experience with it?  Seems straightforward to
integrate- the Propeller outputs 3.3V up to 50mA, so you could connect it
directly, right?
Hanno

On Fri, Mar 14, 2008 at 4:29 PM, Andrew Errington <
a.errington at lancaster.ac.uk> wrote:

> 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
>
>
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