Dual Full-Bridge Driver L298N
L298 is an integrated monolithic circuit. It is a high voltage, high current dual full-bridge driver designed to accept standard TTL logic levels and drive inductive loads such as relays, solenoids, DC, and stepping motors. Two enable inputs are provided to enable or disable the device independently of the input signals. The emitters of the lower transistors of each bridge are connected together and the corresponding external terminal can be used for the connection of an external sensing resistor. An additional supply input is provided so that the logic works at a lower voltage.
L298 Pin Configuration
L298 is a 15-pin IC as shown in the L298 pin diagram and the function of each pin is described below.
| Pin Name | Description |
| COMMON TERMINALS | |
| 8, GND | Connected to GROUND. |
| 4, SUPPLY VOLTAGE VS | Connected to +5V. |
| 9, LOGIC SUPPLY VOLTAGE | Supply Voltage for the Logic Blocks. |
| H-BRIDGE A | |
| (1) CURRENT SENSING A | Between this pin and ground is connected the sense resistor to control the current of the load. |
| (2) OUTPUT 1, (3) OUTPUT 2 | Outputs of the H- Bridge A. The current that flows through the load connected between these two pins is monitored at pin 1. |
| (5) INPUT 1, (7) INPUT 2 | TTL Compatible Control Inputs of the Bridge A. |
| (6) ENABLE A | TTL Compatible Enable Input. The LOW state for disable. |
| H-BRIDGE B | |
| (15) CURRENT SENSING B | Between this pin and ground is connected the sense resistor to control the current of the load. |
| (13) OUTPUT 3, (14) OUTPUT 4 | Outputs of the H- Bridge B. The current that flows through the load connected between these two pins is monitored at pin 15. |
| (10) INPUT 3,(12) INPUT 4 | TTL Compatible Control Inputs of the Bridge B. |
| (11) ENABLE B | TTL Compatible Enable Input. The LOW state for disable. |
Features and Specifications
- Operating voltage range: +5 to +46V
- Maximum supply voltage:50V
- Maximum Input and Enable Voltage:+7V
- Maximum current allowed to draw through each output: 3A
- TTL control inputs
- Total power dissipation:25W
- Operating temperature: -23°C to 130°C
- Storage Temperature: -40°C to 150°C
How to Use L298 IC
To understand the working of L298 IC, consider the simple circuit configuration shown below.
Here we are using one of H-BRIGES of l298 IC. As shown in the circuit we have two push buttons Q1 and Q2 which act as control inputs for bridge A. These logic inputs are provided by a Microcontroller or Microprocessor in application circuits. The four diodes are FLYBACK diodes used for protecting the IC from inductive voltage spikes. The enable pin is pulled high through a resistor so bridge-A will be functioning all the time. If it’s pulled to ground the bridge-A will be disabled no matter the input control logic.
After all the circuit is set up we need to press the buttons Q1 and Q2 to change the flow of current between pins OUT1 and OUT2. The logic control table is given as.
| INPUTS | FUNCTION |
| Q1=HIGH, Q2=LOW | Forward Current |
| Q1=LOW,Q2=HIGH | Reverse Current |
| Q1=Q2 | Fast MOTOR stop |
So if only Q1 is pressed, the current flows from OUT1 to OUT2. With that MOTOR rotates clockwise direction. If only Q2 is pressed, the current flows from OUT2 to OUT1. With that MOTOR rotates in anti anti-clockwise direction. If both buttons are pressed or released simultaneously the MOTOR comes to a stop immediately. In this way, we can control the motor rotation using the L298 chip.
Applications of L298 High Current Dual H-Bridge Motor Driver IC:
- High Current Motor Driver IC.
- Dual H-bridge for controlling up to two motors at a time.
- Ideal for Inductive load de-coupling from the main/control unit.
- A wide voltage range allows for an adaptive voltage range control.
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