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 Robotics / Handy Board / 2952
2951  |  2953
Subject: 
Re: Burning hot motor driver chips.
Newsgroups: 
lugnet.robotics.handyboard
Date: 
Sun, 9 Nov 1997 16:33:55 GMT
Original-From: 
David Kott <dakott@kott.my!NoSpam!.domain>
Viewed: 
3228 times
  
> was a faulty assumption).  So I connect the steering motor to motor1 and

sounds reasonable.. which "car" BTW?  Some may be using that very same
platform and may have some timely advice for you.

> the drive motor in motor3, so each motor has it's own driver chip.  Well
> after a few cycles of the below code, the drive motor ceases to get enough
> power to move the car (the motor begins to spin if I pick the car up).

sounds like overload/overheating cutoff to me.

> Upon burning my finger, I discovered that the chip running the was
> extremely hot.  So my question is: Is this motor simply drawing too much
> current?  I thought the L293D (which is what I am using) had some sort of
> built it cut off if things got intolorable for it.  I also understand that
> the L293D can be piggy backed, but will that give me enough amperage to run
> a typical RC car motor?  Am I going to have to use an alternate driver?

This is from the Handy Board FAQ :
<---snip--->

   It is possible to wire two of these chips in parallel (e.g., two
   L293D's or one L293D and one L293B) to gain increased current-carrying
   capability. This readily done by plopping one IC on top of the other
   and individually soldering each matching pin together.

   Another way to achieve greater power-handling capability on the Handy
   Board is to use the Texas Instruments TI SN754410 Quadruple Half H
   driver, which combines the protective diodes of the L293D chip with
   the greater current capacity of the L293B chip. The SN754410 is a
   plug-and-play replacement for the L293D.

<---snip--->

*visions of a great stack of '293Ds growing out of a HB*

So, indeed, it seems that, as you say, you *can* either parallel two (more?)
chips together OR go to an enhanced pin-for-pin replacement IC.

<two_cents>

You also might want to think about heat sinking those chips.  Either a DIP
style heatsink (I *have* seen them) to affix to the back/top.. or something more
elaborate.. as I *think* the center two pins on on each side of those packages
are meant to be affixed to a heatsink/metal/large-copper-traces/whathaveyou...
but don't quote me.. I may be thinking of some other package.  (Prototyping
is an adventure, no?)

</two_cents>
                                                                       -d



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