The Novice Writer: MOTOR DRIVER (IC L293D) EXPLAINED!!

MOTOR DRIVER IC L293D

EXPLAINED!

Written By Nikhil Darji.

Dedicated To Nidhi Patel.

FEATURES:-

•Supply-Voltage Range: 4.5 V to 12 V

•Maximum Peak motor current: 1.2A

•An automatic thermal shutdown is available

•We can use two motors at a time.

• Available in 16-pin DIP, TSSOP, SOIC packages

•Continuous Output Current = 600 mA or 0.6 A

PIN DIAGRAM:-

L293D PIN CONFIGURATION:-

PIN NUMBER	PIN NAME	FUNCTION
1	Enable 1,2	Enable pin for Motor 1; active high(+5v)
2	Input 1	Input 1 for Motor 1
3	Output 1	Output 1 for Motor 1
4	Ground	Ground (0V)
5	Ground	Ground (0V)
6	Output 2	Output 2 for Motor 1
7	Input 2	Input 2 for Motor 1
8	Vcc2 (Vs)	Supply voltage for Motors; 9-12V (up to 36V)
9	Enable 3,4	Enable pin for Motor 2; active high(+5V)
10	Input 3	Input 3 for Motor 2
11	Output 3	Output 3 for Motor 2
12	Ground	Ground(0V)
13	Ground	Ground(0V)
14	Output 4	Output 4 for Motor 2
15	Input 4	Input 4 for Motor 2
16	Vcc1 (Vss)	Connected to +5V to enable IC function (4.5V to 12V)

DESCRIPTION:-

Common DC gearhead motors need current above 250mA. There are many integrated circuits like ATmega16 Microcontroller, 555 timer IC. But, IC 74 series cannot supply this amount of current. When the motor is directly connected to the o/p of the above ICs then, they might be damaged. To overcome this problem, a motor control circuit is required, which can act as a bridge circuit.

There are various ways of making H-bridge motor control circuit such as using transistor, relays and using L293D/L298.

Here we using IC L293D motor driver.

H-Bridge Circuit:-

H-bridge is an electronic circuit that allows a voltage to be applied across a load in any direction.

H-bridge circuits are frequently used in robotics and many other applications to allow DC motors to run forward & backward.

L293D Motor Driver IC:-

L293D IC is a typical Motor Driver IC which allows the DC motor to drive in any direction (forward or reverse). This IC consists of 16-pins which are used to control a set of two DC motors. As well, this IC can drive small and quiet big motors.

This L293D IC works on the basic principle of H-bridge, this motor control circuit (H-bridge) allows the voltage to be flowing in any direction.

As we know that the voltage must change the direction of being able to rotate the DC motor in both the directions.

Hence, H-bridge circuit using L293D ICs are perfect for driving a motor. Single L293D IC consists of two H-bridge circuits inside which can rotate two DC motors separately.

Generally, these circuits are used in robotics due to its size for controlling DC motors.

How to use an L293D Motor Driver IC:-

There are two power pins for this IC, one is the Vss(Vcc1) which provides the voltage for the IC to work, this must be connected to +5V.

The other is Vs(Vcc2) which provides voltage for the motors to run, based on the specification of your motor you can connect this pin to anywhere between 4.5V to 12V, here I have connected to +12V.

All the Ground pins should be grounded.

The Enable pins (Enable 1,2 and Enable 3,4) are used to Enable Input pins for Motor 1 and Motor 2 respectively.

Since in most cases we will be using both the motors both the pins are held high by default by connecting to +5V supply.

The input pins Input 1,2 are used to control the motor 1 and Input pins 3,4 are used to control the Motor 2.

The input pins are connected to the any Digital circuit or microcontroller to control the speed and direction of the motor.

You can toggle the input pins based on the following table to control your motor.