The L293D module is a compact motor driver module with two full bridge circuits and individual enable inputs. Each channel can continuously drive up to
600mA and can tolerate up to 1.2A non-repetitive load current. The module accepts 5V up to 20V motor (or other inductive load) voltage. It also has a built-in 5V
regulator for the logic circuit that accepts up to 12V input power sourced from either an external power or from the motor power source. This is selected via an onboard micro jumper. Aside from the obvious benefit, the internal regulator may be advantageous in applications without a microcontroller as it readily
makes the module useable with just the input signals added. Two additional micro jumpers allows each channel to be permanently enabled or controlled by the
host. The inputs are accessible from standard 2.54mm pin headers and outputs are conveniently derived from screw-in terminal blocks. The L293D module is part of Layad Circuits’ Kimat series of rapid-prototyping products.
Integrated logic circuit regulator
Drives up 2 reversible motors
Continuous Drive Current Per Channel: 600mA
Peak/Non-repetitive current per channel: 1.2A
Motor Voltage: 5-20V
Total Idle Current with both channels disabled:
Selectable regulator input between external or
motor voltage via jumpers
Permanent-enable jumper option
3.3V/5V-logic compatible inputs
Board Dimensions: 49.26 x 32.69 mm
REG IN – this is a 3-pin header labeled “REG IN” with a microjumper inserted between the middle pin and the EXT side or between the middle pin and VM side. This allows the user to select where to source the input to the regulator circuit for the logic circuits of the board. This can either come from an external power source between 5-12V and at least 100mA connected to the EXT pin header OR it may come from the VM terminal block so long as VM is between 5 and 12V. If your motor voltage source is between 5 and 12V and is able to adequately supply the current requirements of the motors with some allowance, it is recommended to set the micro jumper to the VM position for simplicity.
5V – The module has an 800mA onboard regulator with an output of 5V. The internal circuits it supply only draw around 50 to less than 200mA and may therefore be used to supply other external 5V circuits. This regulator output may be accessed from the 5V pin. This comes as a handy extra power source when the internal 5V regulator of an Arduino is fully utilized.
EN1 and EN2 – these are the enable inputs of the drivers. When pulled LOW, the outputs are in high impedance mode and hence, effectively disconnects the motors from the outputs. Pulling these HIGH enables the drivers. These pins may be used to control the speed of the motors by rapidly turning the pins on and off as in a PWM signal (or via analogWrite() in Arduino/Saleng boards). To do this, uninstall the microjumpers and then connect the EN1 and EN2 pins to the PWM signal(s).
IN1-IN4 – IN1-IN4 controls OUT1 to OUT4 respectively when EN1/EN2 are pulled high (enabled).These pins may be used by the host microcontroller to turn the motors on/off and control their direction. Use the table below as a guide:
|IN1 (or IN3)
|IN2 (or IN4)
|EN1 (or EN2)
|Motor rotates in one direction
|Motor rotates in opposite direction