The "L293DD" is a motor driver IC manufactured by STMicroelectronics. It is widely used for driving motors, especially in robotics, and other applications where controlling motors is required. The IC is a dual H-bridge motor driver, which allows for bidirectional control of motors, and is capable of driving bipolar and unipolar stepper motors.
Package and Pin Functions
The L293DD IC typically comes in a 16-pin Dual In-line Package (DIP). Below is a detailed explanation of the pin functions for the L293DD IC:
Pin Number Pin Name Function Description 1 1A Motor A input 1. Control input for motor A in one direction. 2 1Y Motor A output 1. Output to motor A in one direction. 3 2Y Motor A output 2. Output to motor A in the opposite direction. 4 2A Motor A input 2. Control input for motor A in the opposite direction. 5 GND Ground. Connect to the ground of the system. 6 Vcc2 Supply voltage for the motor. Typically 4.5V to 36V. 7 3A Motor B input 1. Control input for motor B in one direction. 8 3Y Motor B output 1. Output to motor B in one direction. 9 4Y Motor B output 2. Output to motor B in the opposite direction. 10 4A Motor B input 2. Control input for motor B in the opposite direction. 11 Vcc1 Supply voltage for the logic circuitry. Typically 5V. 12 Enable 1 Enable control for motor A. High (1) enables motor A outputs. 13 Enable 2 Enable control for motor B. High (1) enables motor B outputs. 14 Vss Supply voltage for logic section, typically 5V. 15 Vcc2 Supply voltage for motor. This pin can be connected to 4.5V to 36V. 16 Vcc Power supply for the entire chip, typically 5V.Common Questions (FAQs)
Q1: What is the function of pins 1A and 2A on the L293DD? A1: Pins 1A and 2A are control inputs for motor A. Pin 1A controls the direction of the motor in one direction, while pin 2A controls the motor's direction in the opposite direction.
Q2: What is the function of pin 12 (Enable 1)? A2: Pin 12 is the enable pin for motor A. When set to high, it enables motor A's outputs (1Y and 2Y). When set to low, motor A is disabled.
Q3: What is the purpose of the Vcc1 and Vcc2 pins? A3: Vcc1 is used for the logic voltage supply (typically 5V), while Vcc2 is used for the motor supply (typically between 4.5V and 36V).
Q4: How does the L293DD drive the motor in both directions? A4: By using the control inputs (1A, 2A for motor A, and 3A, 4A for motor B), the L293DD can drive motors in both directions. Changing the logic state of these pins switches the motor's direction.
Q5: What is the current capability of the L293DD for each motor? A5: The L293DD can handle a continuous current of up to 600 mA per channel, with peak current up to 1.2 A for short durations.
Q6: What happens if I connect pin 5 (GND) incorrectly? A6: If pin 5 (GND) is incorrectly connected, the entire IC will not work as expected because it needs a ground connection to complete the circuit.
Q7: Can I use a voltage higher than 36V for Vcc2? A7: No, exceeding 36V on the Vcc2 pin can damage the L293DD IC. Always ensure the motor voltage does not exceed the specified limits.
Q8: What is the typical application of the L293DD IC? A8: The L293DD is typically used in driving DC motors, stepper motors, and other devices that require bidirectional control and high current driving capability.
Q9: Can the L293DD be used for controlling servos? A9: No, the L293DD is designed for DC motor and stepper motor control, not for precise position control like servos.
Q10: How do I control the speed of the motor with the L293DD? A10: Speed control can be achieved by varying the voltage applied to the motor (using Pulse Width Modulation, PWM) on the Vcc2 pin or by adjusting the input signal frequency.
Q11: What is the function of pin 3Y (Motor A Output)? A11: Pin 3Y is the output for motor A in one direction. When the input pin 1A is high and 2A is low, pin 3Y delivers the motor's power.
Q12: How can I connect multiple motors to the L293DD? A12: The L293DD has two independent motor channels, so you can drive two motors separately. To drive more motors, you would need to use additional L293DD ICs or similar motor driver ICs.
Q13: What is the function of pin 4Y (Motor B Output)? A13: Pin 4Y is the output for motor B in the opposite direction of motor B's control input (3A, 4A).
Q14: Can the L293DD be used for driving larger motors? A14: For larger motors that require higher current than the L293DD can provide (more than 1A), it's better to use other motor driver ICs with higher current handling capability, such as the L298.
Q15: What happens if the enable pins (12 and 13) are left floating? A15: If the enable pins are left floating, the IC might not function correctly. These pins should always be connected to either high or low logic levels to control the motor output.
Q16: Is there thermal protection in the L293DD? A16: Yes, the L293DD has thermal shutdown protection that disables the outputs if the IC overheats.
Q17: What is the maximum voltage that can be applied to Vcc1 and Vcc2? A17: Vcc1 can be up to 5V, and Vcc2 can be between 4.5V and 36V, with an absolute maximum of 36V.
Q18: What is the difference between the L293 and L293DD? A18: The L293DD has integrated diodes for flyback protection, while the L293 does not. This makes the L293DD more robust in applications with inductive loads like motors.
Q19: How does the L293DD handle current spikes from inductive loads like motors? A19: The L293DD has internal diodes to protect against voltage spikes generated by inductive loads when the motor is turned off, ensuring longevity and reliability.
Q20: Can I use the L293DD to drive both a DC motor and a stepper motor at the same time? A20: Yes, the L293DD can simultaneously drive a DC motor and a stepper motor because it has two independent motor driver channels.
This detailed explanation of the L293DD includes all pin functions, a complete FAQ section, and practical information for usage. If you need further assistance or have additional queries, feel free to ask!