l293d overheating

Discussion in 'General Electronics Chat' started by sanths, Feb 12, 2013.

  1. sanths

    Thread Starter New Member

    Feb 12, 2013
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    hi,
    i am trying to run a dc motor using l293d driver..but chip gets too hot.guide how to avoid heat ...it is very hot to touch......
     
  2. mcgyvr

    AAC Fanatic!

    Oct 15, 2009
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    motor specs?
    input voltage?
    schematic?
    blah blah blah

    or how much power is the chip dissipating?
     
  3. sanths

    Thread Starter New Member

    Feb 12, 2013
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    coil resistance 0.8 ohms,input voltage 12v
     
  4. sanths

    Thread Starter New Member

    Feb 12, 2013
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    approx 3w power it dissipates
     
  5. sanths

    Thread Starter New Member

    Feb 12, 2013
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    actually when it is free(without load ) no heat in the ic,but when i connected to motor ,its inductive load causes chip to heat.....there is any solution for this.......i am controlling this dc motor by pwm..
     
  6. sanths

    Thread Starter New Member

    Feb 12, 2013
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    whether it may cause heat due to fast switching of pwm??????
     
  7. mcgyvr

    AAC Fanatic!

    Oct 15, 2009
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    and do you have the thermal resistance of that IC "junction to ambient"
    If its 70 deg C/W thats heating it 210 deg C and hence why the hot IC..

    Clearly it needs a heatsink.
     
  8. thatoneguy

    AAC Fanatic!

    Feb 19, 2009
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    A few problems, all of which are addressed in The L293D Datasheet

    A Minor one that may help is to put a 0.1uF cap across the leads of the motor if not already present. It may not help the heating, but will cut down on electrical noise/interference.

    The max continual the L293D DIP Package can power is 600mA, PEAK (short periods, stall current, etc) is 1.2A.

    "Only 3 Watts" is actually quite a lot of power for packages without a heatsink connection/tab. Package temp raises 80ºC/Watt (Soldering iron temp for 3W if no clip-on heatsink is used).

    I'd suggest the L298N Dual H-Bridge Which can do a continual 2A, and has a large metal tab to connect a heatsink to. They sold on Amazon as "Dual H-Bridge" or "L298" motor drivers, which are already assembled, with heatsink, on a professional PC Board.

    Of course, you can use the L298N standalone, but you'll need to remember diodes to suppress EMF
     
  9. sanths

    Thread Starter New Member

    Feb 12, 2013
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    wen i am trying to use l298 i have a problem of selecting sense resistor.....if i place 0.5ohm1watt resistor motor runs but i also experienced heating in l298 too... wat kind of sense resistor i would choose....give some suggestions.....and if the sense resistor is above 10 ohm motor stops.....
     
  10. sanths

    Thread Starter New Member

    Feb 12, 2013
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    Anyone give me suggestions for alternate ic to control dc motor with pwm..........motor spec:20v,1 amp,20 w
     
  11. thatoneguy

    AAC Fanatic!

    Feb 19, 2009
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    Does the L298N heatsink get too hot to touch? It will warm up some.

    Are you using a per-built board, or a circuit of your own with the 298?
     
    Last edited: Feb 13, 2013
  12. electron_prince

    Member

    Sep 19, 2012
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    make sure that the current drawn by each motor doesn't exceed 600mA. Alternatively you can use l298. l298 support upto 2A of current.
     
  13. mcgyvr

    AAC Fanatic!

    Oct 15, 2009
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    There is a huge difference in thermal resistance with and without a heatsink.. I'd suspect a suitable heatsink is all that is needed here to solve the issue.
     
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