I need a help designing Motor Driver Circuit

medosoft

I'm designing a driver circuit for a 12V DC motor (Power Window). I'm using an L293D motor driver chip.
According to the datasheet the chip can withstand a supply voltage Vs up to 36V. I'm only using a 9V battery.
The circuit and the motor are working well. However, after a few seconds the L293D chip would overheat. If I stop it, it will not work again until it cools down, and if I leave it I'm afraid the chip would be burned
I'm sure there is nothing wrong with my connections because I've redone them many times.
Do you know the reason or the solution to the problem?!

You can get the proper chip connection from here

the_emi_guy

Are your inputs static or are they switching at some frequency?

jim hardy

as in little NEDA1604? for a car window motor?



You're way underpowered i think.

Did you heed the heatsink instructions on pages 10, 11 & 12 of datasheet?
http://www.ti.com/lit/ds/symlink/l293d.pdf

hisham.i

The driver IC that you are using can handle up to 1A, if the IC is over heating so it may be due to that the motor is consuming higher current.

Try to measure the current, and if it was greater than 1A and if your connection are all correct, use smaller motor.

Regards,
Hisham

medosoft

No, they depend on the end user pressing a push button

medosoft

No .. Power Window is the model of the motor
You can view it from here
http://www.cytron.com.my/viewProduct...29%20-%20Right

And you're probably right about the current .. unfortunately, I have to use this motor because a smaller motor will not perform the function required

hisham.i

As it is shown from the data sheet of the motor, at no load 3A, and at full load 7A.
So you have to use another driver which can support higher current, or you can make your own driver with transistors that can handle higher current.

medosoft

Can you explain more about how to use this transistor?

hisham.i

I don't have time now, read how this driver work http://www.sparkfun.com/datasheets/R...8_H_Bridge.pdf

You have to make the same concept, but with larger transistors.
And tonight i will send you explanation also.

medosoft

That's great help .. thanks a lot

hisham.i

Dc motors drivers consist of transistors that are connected in H-bridge configuration.
See the attached picture to have a look on how H-bridge looks like.

When transistors T1 and T3 are on and transistors T2 and T4 are off, current will flow from VCC2 through T1, to T3 then to ground, and the motor will rotate on some direction lets say to the anti clock wise.

When transistors T2 and T4 are on and transistors T1 and T3 are off, current will flow from VCC2 through T2, to T4 then to ground, and the motor will rotate on the opposite direction.

So you can drive your motor using this configuration but you have to choose the correct transistor that can handle the current that is required by the motor in your case 7A.

Google for H-bridge Dc motor controller, you will find a lot of schematics, and you can share your design for any information needed.

Or try to find a supplier where you can buy H-bridge that can handle this current.

Hope this helps,

Hisham

Attached Thumbnails

 

Integral

A quick google search revealed that a 9V battery is rated at about .5Ahr. This means that it will last about 4 min on a 7A load.

Hope you have a good supply of them. Your best bet is to find a 12V lead acid battery.