[chbot] H-Bridge (was Re: Sensor Information)

[Hanno Sander]

Agree with Charles- from personal experience!
Don't use the L293 for low voltage (<12V) systems!  You'll lose too much
voltage to heat the device.  Best bet is probably to make your own h-bridge
- it's not that hard...
Hanno

2009/3/25 Charles Manning <cdhmanning at gmail.com>

> I would not put the L298 high on the list because it is a common collector
> device, just like the L293.
>
> The internal configuration of these devices means that the output voltage
> does not swing all the way to the rail and you lose approx 1.5 to 2 volts in
> the driver chip. This turns into heat, but also means that your motor does
> not get driven as hard as it should meaning that it does not get enough
> Weetbix to win that Sumo competition. That is perhaps not too much of an
> issue when you're using 12V or more input, but obviously throwing away 1.5V
> or so is bad news for low voltage systems.
>
> Many modern HBridge designs are "rail to rail" and do not suffer this
> problem.
>
>
>
>
> On Wed, Mar 25, 2009 at 3:54 PM, Andrew Errington <
> a.errington at lancaster.ac.uk> wrote:
>
>> I actually like this design:
>>
>> http://www.mcmanis.com/chuck/Robotics/tutorial/h-bridge/bjt-circuit.html
>>
>> Because the opto circuit is very elegant (it combines optical isolation
>> with 'smoke-free' logic).  I've never built one as I was not able to find
>> a fast enough opto-isolator to do high-frequency PWM.   It may be that
>> that is a non-issue however.
>>
>> Good luck with whatever design you choose.
>>
>> Andrew
>>
>>
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