# l293d motor driver IC help

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

1. ### pratik20990 Apprentice

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.

#1
2. ### silverscorpion Ace

Engineering Discipline:
Electronics & Telecommunications
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??

#2
3. ### pratik20990 Apprentice

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?

#3
4. ### dossdss Apprentice

Engineering Discipline:
Electronics

i know am replying too late for the post... 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.

#4
5. ### dossdss Apprentice

Engineering Discipline:
Electronics

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

#5