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l293d motor driver IC help

Discussion in 'Robotics | RC | Automation' started by pratik20990, Dec 29, 2009.

  1. pratik20990

    pratik20990 Certified CEan

    I am using L293D motor driver for line follower which has the following pin configuration-
    In this at Pin no. 8 we have to apply the voltage at which we want to drive the motors, say, 9V. I want to ask that how can we apply that voltage at a single pin when the rest of the circuit is operating at voltage less than 5V.
  2. Well, I dont get your question.. What's the problem in giving two different voltages to 2 pins in the same IC??

    Pins 1 and 9 (Enable pins) are to be connected to 5V. And pins 8 and 16 are to be connected to the same source
    which is used to run the motors. Meaning, if you use 9V to run the motors, connect the pins 8 and 16 to the
    +ve of the 9V supply . Ground the -ve of the supply. That's all.. What's confusing here??

    Oh, if you're asking how you get 9V into the ckt from nowhere, you can always use a voltage regulator. Get a 7809 and
    give 12V from a normal 12V battery to it. It'll regulate it to 9V. Give that 9V to pins 8 and 16. Is it Clear?? :):)
  3. pratik20990

    pratik20990 Certified CEan

    Thanks for your help. You have nearly understood my question but I still have some doubt.
    I am making the circuit on a breadboard which has AT89S52 IC, L293D IC and 7805 voltage regulator. I am using a 9V battery input to 7805 which converts it to 5V. Now, if I use another 9V battery to directly give input to pin 8 of L293D by its positive terminal then can I ground the negative terminal by just connecting it to ground of that same breadboard. Will the circuit be complete then and will it work?:confused:

    Please reply....:rolleyes:
  4. dossdss

    dossdss Apprentice

    i know am replying too late for the post...:eek: but it may help to those who need to read it....

    actually i want to correct that in l293D
    pin8 = that voltage at which you want to drive the motors and
    pin16= supply vtg for the chip, that is 5V. not same as pin 16.
  5. dossdss

    dossdss Apprentice

    yes the negative terminal of the other battery has to be connected to the ground of the same circuit.

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