Understanding L293D datasheet

[Ekalvya]

 Hi. I am new to electronics, which I have found to be interesting and worthwhile and I have some trouble in understanding the entries in the L293D datasheet. Below are my doubts. Please don't mind if they are too small.

Thank you in advance

1)      In the L293D datasheet, it has been given that, L293D has over-temperature protection.

What do they mean by this? i.e. will L293D switch off automatically when it reaches a particular temperature, if yes, then how does it know the temperature, & how to know the temperature limit?

Or, is there some other thing?

2)              In the L293D datasheet, it has been given that; L293D has ‘INTERNAL CLAMP DIODES’. What do they mean by this?

3)              In the L293D datasheet, it has been given that; L293D has ‘ENABLE FACILITY’. What do they mean by this?

4)              In the L293D datasheet, it has been given that, L293D has 1.2A maximum current output per channel (non-repetitive). What do they mean by saying ‘NON-REPETITIVE’. Do they mean that 1.2A will not be available always but it may be available sometimes? If yes, then what is the use I it?

Or, simple put, how to use this information?

5)              In the L293D datasheet, it has been given that,  PUSH-PULL FOUR CHANNLE DRIVER. What does it mean?

6)              In the L293D datasheet, it has been given that, 16^th pin is used for Vss. i.e. Logic Supply voltage. What is it used for?

[AnalogKid2DigitalMan · Accepted solution]

1. Yes, it will quit driving the load when the chips internal temperature sensor exceeds the setpoint. Not sure of what that setpoint is.

2. The diodes protect the driving transistors from voltage spikes that occur when power is switched off to the motor coil.

3. When the enable input is at a logic high, the state of the outputs will match what the state of the inputs are. When enable is at a logic low, the outputs will be off regardless of what the input states are.

4. It means do not exceed that current on a repeated basis, it will probably destroy the drive transistors.

5. Push pull typically means a set of complementary transisitors that can switch the ouput to either the positive power supply or ground.

6. This voltage (Vcc1) is needed to power the internal devices within the chip. It is different from pin 8 (Vcc2) which is where the power to apply to the motor windings is connected to.

Hope this helps.

-AK2DM

[iMakeRobots]

Also, just because of 1 and 2 doesn't mean you can't damage these chips or even make them explode.  Double and triple check your circuit before powring it up.

[Ekalvya]

Hi AK2D.

Thank you very much for your Patient Reply.

I am really very happy about it.

I like your Signature, "It’s the questions that drive us.”

It is very true.

By the way, I have one more problem (Opportunity To Learn !!!) now.

I have given the connection from the PIC microcontroller to L293D to continuously run the motor.

The motor runs, but the problem is that the motor runs with less torque than its capability (i.e. when I connect it through the main supply, it runs with higher torque than the torque when I connect it through L293D), which is a serious problem  in my application.

The max. current that my motor can draw is not more than 300 mA and voltage is 12V. From spec. sheet of L293D, it should be comfortable with it.

But still I am facing the problem.

Can you help me?

[Jack avla]

hello i just wanted to ask where did u find the L293 in the multisim or is it comes with other name ?

[xainnasir]

Hi,

L293D is a dual motor driver which is used for controlling direction & speed of DC Motor. You should read L293D Pinout before starting working on it. You should also download its Proteus Simulation and simulate this IC.

Thanks.