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Topic: L293D Getting Really Hot, Really Fast (Read 1 time) previous topic - next topic

Justscary

Jimbo, I just saw the link above for the board, I don't see any probs heat sinking these chips, if it was me, I would get an allum sink the right size to go across the three processors and use heatsink compound to "glue" it on. Ok it's not ideal, but it would be better than nothing.

JimboZA

Quote
I would get an allum sink the right size to go across the three processors and use heatsink compound to "glue" it on


Yep and that's what my later post shows too Justscary.

I'm just curious though, that the 293 datasheet says the middle four pins are electrical ground and heatsink.... so is the ideal (or theoretical) plan to solder those leads to the heatsink? I can't visualise how to do that on a board where to say the least, space is at a premium.

Gluing a chunk of metal on top seems eminently sensible to me....
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Justscary

I don't think it would matter too much if you did or didn't connect the sink to the pins, I think the idea behind the data sheet specs is to show that it is the common ground and, as some heatsinks need to be earthed to stop noise, and sometimes the sink that is used is the ground, like the side of an allum enclosure, it's showing it can have a ground link there to help prevent ground loops or just bad earth.

cr0sh


But even when the 293 can handle the current in a particular set of circumstances, what are the ways of heatsinking it when it's on a board? It's not like a 298 where there's a hole in the back to attach a sink, even an ersatz nut and bolt and a chunk of metal.

With a 293 on a board, where there's probably limited access to the 4 pins, how to protect it?


I don't know if you can still buy them, but back in the day there were clip-on heatsinks for DIP ICs like the 293 (I have a 16K core memory board that has a couple on some on-board driver ICs).
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dgelman

Hello Community,

First off thank you all for your help.

I recently encountered a couple of issues which lead to me changing my design a little. I would extremely appreciate any comment on my build.

So using L293D I am limited to 0.6 A continuous current, as maximum of 16V motor voltage supply.  I decided to switch the motors, and before I purchase them I was wondering these motors (link below) will cause any same issue (over-heating).

Motor
http://www.pololu.com/catalog/product/1443

These motors run 300 mA free-run with a 5A stall current at 12V voltage supply.  My only issue with using these motors with this shield is the 5A stall current.  I don't think I will stall the motor (in regards to my application), especially with 110 oz-in torque.

BUT, 300mA free-run is still pretty close to 600mA supply.  I always went with a rule of thumb that my driver should at least be 4-5 times current provided over the motor free-run.

Would this driver and motor work nicely together? (I am planning on using 3 of them, if that means anything)

Daniel
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