What Is a Motor Driver? L298N, L293D, DRV8833 and TB6612FNG Explained

A motor driver is a circuit that lets a low-current microcontroller control a motor’s direction and speed. It uses switching transistors to control the motor’s power supply, allowing boards such as Arduino to operate DC motors and, with suitable drivers, stepper motors. Popular options include the L298N for beginner projects, the L293D for low-current applications, and the DRV8833 or TB6612FNG for compact, efficient designs.

What Is a Motor Driver?

A motor driver is an electronic interface between a controller and a motor. An Arduino or ESP32 can generate control signals, but its GPIO pins cannot directly supply the current most motors require. A motor driver handles the motor current and lets the controller command movement.

Motor drivers commonly control:

• Direction: Forward or reverse rotation.

• Speed: By adjusting the motor’s average power using pulse-width modulation (PWM).

• Braking: On drivers that support the required braking mode.

• Multiple motors: Depending on the number of driver channels.

A driver must match the motor’s voltage and current requirements. A board that works with a small BO motor may not be suitable for a larger geared motor or a motor with a high stall current.

How Does a Motor Driver Work?

Most common hobby DC motor drivers use an H-bridge. This circuit controls the direction of current through a motor, allowing it to rotate in either direction.

H-bridge operation

An H-bridge uses four switching elements arranged around the motor. Switching one diagonal pair makes current flow in one direction; switching the opposite pair reverses it.

In one direction, the driver activates one high-side switch and the opposite low-side switch. Reversing the active pair reverses motor current. The control inputs determine which switches are enabled.

How does PWM control motor speed?

PWM rapidly switches the driver output on and off. Changing the proportion of time the signal is on—called the duty cycle—changes the average voltage applied to the motor.

For example, a 50% duty cycle means the control signal is on for half of each PWM period. It does not guarantee exactly half the motor speed: actual speed depends on load, supply voltage, motor characteristics, driver losses and the PWM frequency.

A motor driver lets the microcontroller control a motor without drawing the motor’s operating current directly from its GPIO pins.

L298N vs L293D vs DRV8833 vs TB6612FNG

These four motor drivers are common in Arduino and robotics projects, but they are not interchangeable. Their voltage limits, current capacity, power losses and board layouts differ.

The figures refer to the IC specifications, not necessarily every breakout board sold under that name. Thermal performance, PCB copper, cooling, wiring and operating conditions determine usable current.

 

1. L298N: Best for common beginner motor-driver modules

The L298N is widely used in beginner robot kits and can control two brushed DC motors or one bipolar stepper motor. Many modules include screw terminals, enable jumpers and a heatsink.

Its main drawback is efficiency. The bipolar output stage drops a noticeable amount of voltage and dissipates heat, so a motor may receive less voltage than the battery supplies. This matters particularly when running low-voltage motors from a small battery.

Choose an L298N module when its voltage range and current capability suit your motors, and you value its familiar module layout. Do not select it simply because a module advertises a high peak current.

2. L293D: Best for modest-current legacy circuits

The L293D is an older dual H-bridge IC that can drive two DC motors or one bipolar stepper. The IC is rated for 600mA continuous output current per channel, with higher short-duration peak ratings under specified conditions. It includes clamp diodes for inductive transient suppression.

 

Its limitations are the relatively low current rating and voltage loss through the output stage. It can suit small motors and educational circuits, but it may struggle with motors whose startup or stall current exceeds its limits.

3. DRV8833: Best for compact, low-voltage battery robots

The DRV8833 is a dual H-bridge driver designed for low-voltage motor applications. Its operating motor-supply range is 2.7–10.8V, making it a strong candidate for many small robots powered by a single-cell or two-cell LiPo battery, provided the motor and battery voltage requirements match.

 

The IC supports current regulation and has MOSFET outputs, which generally reduce conduction losses compared with older bipolar drivers. Its actual usable current depends on the package and breakout board's thermal design.

Consider the DRV8833 for small two-wheel robots, compact motorised projects and low-voltage battery-powered builds. Check each motor's stall current before choosing the board.

4. TB6612FNG: Best for efficient small-robot control

The TB6612FNG is another MOSFET-based dual H-bridge driver. Toshiba specifies a 2.5–13.5V motor-supply operating range and a 1.2A average output-current absolute maximum per channel. The datasheet's usable output current depends on the device and thermal conditions; it should not be treated as a blanket 1.2A continuous rating for every breakout board.

 

It is commonly used in small robots because its output stage is efficient and it supports forward, reverse, braking and stop modes. Check the breakout board's pinout, standby input and current requirements before connecting it.

Which driver is best for your robot?

• Beginner robot kit with a suitable higher-voltage supply: Consider the L298N if its losses and thermal requirements are acceptable.

• Very small, low-current motors: The L293D may work if the motor's startup and stall current stay within the IC's limits.

• Small robot using a 3.7V LiPo battery: Consider the DRV8833 or TB6612FNG, after checking motor voltage and current.

• Compact robot where efficiency matters: Compare the DRV8833 and TB6612FNG against the exact motor specifications and breakout-board ratings.

The correct choice is the driver that can handle the motor's voltage and current with adequate thermal margin—not the board with the largest headline current number.

When to Pick the DRV8833 for a 3.7V LiPo Robot

A single-cell LiPo battery has a nominal voltage of 3.7V and a fully charged voltage of 4.2V. The DRV8833's 2.7–10.8V motor-supply range makes it a potential match for this type of battery-powered robot.

 

Before choosing it, check four things:

1. Motor voltage: Confirm that the motors are designed to operate over the battery's voltage range.

2. Stall current: Check each motor's stall current at the relevant supply voltage. The driver must handle startup and stall conditions without exceeding its limits.

3. Battery capability: Ensure the battery and its protection circuitry can supply the combined motor current.

4. Board thermal rating: Check the breakout board's current rating and thermal design, not just the DRV8833 IC's peak rating.

A driver rated for a certain peak current does not necessarily support that current continuously. If a motor stalls, its current can rise sharply and cause the driver, wiring or battery to overheat.

How to Choose a Motor Driver

Use this checklist before buying a motor driver for Arduino or another microcontroller project.

Step 1: Check the motor voltage

The driver must support the motor supply voltage across the battery's operating range. Consider the battery's fully charged voltage as well as its nominal voltage.

For example, a 3.7V LiPo reaches approximately 4.2V when fully charged. A driver must support that voltage and the motor's operating requirements.

Step 2: Check running and stall current

Running current is the current a motor draws under a particular operating load. Stall current is the current it draws when the shaft is prevented from rotating.

Stall current can be much higher than normal running current. Use the motor datasheet where available and select a driver that can handle the expected operating conditions.

Step 3: Decide how many motors to control

• One brushed DC motor requires one H-bridge for bidirectional control.

• Two independent brushed DC motors typically need a dual H-bridge.

• One bipolar stepper motor can use two H-bridges.

• A brushless DC motor needs a suitable multi-phase controller or ESC, not a basic brushed DC H-bridge.

Step 4: Consider efficiency and heat

A driver with lower conduction losses can help preserve battery voltage and reduce heat. However, efficiency also depends on the motor current, PWM settings, board layout and operating conditions.

Step 5: Check the control interface

Confirm that the driver accepts the microcontroller's logic voltage and supports the control method you need, such as direction inputs, PWM or current regulation.

Common Motor Driver Mistakes

• Ignoring stall current: A motor may exceed the driver's limits during startup or if its shaft jams.

• Using an unsuitable motor supply: The battery's voltage range must fit both the motor and driver.

• Powering motors from GPIO pins: GPIO pins provide control signals; they are not motor power outputs.

• Assuming peak current is continuous current: Peak ratings apply only under specified conditions.

• Ignoring voltage drop: A driver may dissipate enough voltage that the motor receives substantially less than the battery voltage.

• Forgetting common ground: In a typical non-isolated setup, the controller and driver need a common ground for their control signals.

• Choosing a driver for the wrong motor type: A basic H-bridge for brushed DC motors is not a substitute for a brushless ESC.

Conclusion

In this blog, we explored the fundamentals of motor drivers, including motor driver ICs, DC motor driver working, and the importance of the H bridge motor driver in practical applications. We also covered different motor driver types and applications to help you choose the right solution for your project.

 

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