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What Is a Motor Driver and How Do You Choose the Right One?

What Is a Motor Driver? If you’re looking to control a motor with your Arduino, you’ll need to use a motor driver. But what is a motor driver, and how do you choose the right one?

In this article, we’ll answer those questions and more! We’ll discuss what types of motor drivers are available, what each type can do, and how to pick the right one for your project. So read on to learn everything you need to know about motor drivers!

What is the motor driver?

A motor driver is an electronic device that controls the speed and direction of an electric motor. You can use motor drivers to control small motors like toys, remote-controlled cars, or robots. Also, you can use it to control larger motors in industrial applications.

Is a Motor Driver Necessary?

The main reason for using a motor driver is to protect the microcontroller from the large currents required to drive a motor. If you tried to connect a motor directly to a microcontroller, the current flowing through the microcontroller would damage it.

The other reason for using a motor driver is that it can provide more power than the microcontroller.  Therefore, this is useful for applications where you need to move heavy loads or drive motors that require a lot of power.

How Does a Motor Driver Work?

A motor driver IC is a power amplifier. Besides, it takes a low-power signal from the microcontroller and amplifies it to provide enough power to drive the motor.

In addition, most motor drivers also have built-in protection against things like over-current and over-temperature. This protects both the microcontroller and the motor driver itself.

How to Stop the Motor (Braking)

When you want to stop the motor, you have two options:

– coasting:

this is when you remove power from the motor. The downside is that the motor will keep spinning for a while and could damage itself or whatever it’s attached to.

– braking:

this is when you apply power to the motor in the opposite direction. This will cause the motor to stop almost immediately.

However, the downside of this is that it can put a lot of stress on the motor and could damage it.

Which one you choose depends on your application. If you need to stop the motor quickly, you should use braking. If you don’t mind the motor spinning for a while after you remove power, then you can use coasting.

One way to think of it is this: if you were on a bike going down a hill, you would want to coast. But if you were on a bike going up a hill, you would want to brake.

Another thing to consider is what kind of motor you are using. If you are using a brushed DC motor, then you will need a motor driver that can handle the high currents that these motors require. If you are using a stepper motor, you will need a motor driver that can micro-step.

Types of Motor Driver

There are two main types of motor drivers: brushed and brushless.

Brushed motor drivers are typically applicable for lower-power applications like RC toys. Plus, they are also easier to use because they don’t require any special sensors or controllers.

Brushless motor drivers are common for higher-power applications like drones and electric vehicles. Besides, they are more complex to use because they require special sensors and controllers.

Besides brushed and brushless, we also have the following types:

dc motor driver

DC motors are the most common type of motors. They are common in everything from fans to hard drives. Furthermore, you can use DC motors to control the speed and direction.

servo motor driver

Servo motors are applicable in applications that require precise control, such as robots and CNC machines.

Moreover, you could use the servo motor to control its position, speed, and torque.

stepper motor driver

A stepper motor driver is a type of electric motor that converts electrical energy into mechanical energy. And you can use them to control the speed and direction.

In addition, They are applicable in applications that require precise positionings, such as printers and scanners. Also, you could use them to control the step rate and direction.

Other Types:

Besides the above types, there are also other types of electric motors, such as

Digital Stepper Driver

Digital Stepper Driver is a motor driver that uses digital signals to control the stepper motor.

Closed Loop Stepper Driver

A Closed Loop Stepper Driver is a type of motor driver that uses feedback to control the stepper motor.

Analog Stepper Driver

Analog Stepper Driver is a type of motor driver that uses analog signals to control it.

Integrated Stepper driver

An integrated motor driver is a type of motor driver that combines the features of a motor driver and a microcontroller. And this type of motor driver is often applicable in robotics applications.

BLDC motor driver

BLDC motors are brushless DC motors. And they are common in applications that require high torque and low noise, such as computer hard drives and electric vehicles.

BLDC motor drivers are getting used to controlling the speed and direction.

DC Motor Driver Circuit

In this section, we will learn some DC motor driver circuits.

DC Motor Driver Circuit Using Transistors

DC motor driver circuit

DC motor driver circuit

This is a basic DC motor driver circuit. Furthermore, it operates using a DC motor, a resistor, and a power transistor (D880).

H Bridge Circuit

H Bridge Circuit

H Bridge Circuit

The H bridge circuit is to control the speed and direction of a DC motor. In addition, you can use this circuit in applications where the DC motor needs to be driven in both directions.

Furthermore, you can use it in robotic applications. Such as changing the direction of a robot.

motor driver ic

A motor driver IC  is a specialized IC that you can use it to control motors. Also, Motor driver ICs can be useful to control DC motors, servo motors, and stepper motors.

The most frequent motor driver ICs are as follows:

– L293D

L293D is a kind of H-bridge driver IC. And you can use it to drive inductive loads such as relays, solenoids, dc, bipolar stepping motors, etc.

– L298N

L298N is also a kind of H-bridge driver IC. Besides, It gets used to drive DC motors, stepper motors, and actuators.

– A4988

– DRV8825

 DRV8825 is a micro-stepping driver IC with a built-in translator for easy operation. Moreover, you could use DRV8825 to drive bipolar stepper motors.

motor driver function

The functions of motor driver ICs include:

– supplying power to the motor

– controlling the speed and direction of the motor

– braking the motor

– protecting  the motor from damage due to excessive current

– providing a current-limiting feature

Applications of Motor Drivers

Now that we know what motor drivers are and what they do, let’s look at some of the most common applications.

One of the most common applications is in remote-controlled toys. The motor driver amplifies the signal from the microcontroller so that it can control the motors in the toy.

Another common application is hard disk drives. The motor driver here controls the spindle motor that spins the disks.

computer drives of different types

computer drives of different types

In printers, the motor driver controls both the feed motors and the print head carriage motor.

And finally, in automated assembly machines, the motor driver again controls a variety of motors, including conveyor belt motors and gripper arm motors.

Motor Driver IC Benefits 

The following are advantages:

– Firstly, it can provide more power than the microcontroller.

– Then, it has built-in protection against things like over-current and over-temperature.

– Finally, it saves space because it combines both the amplifier and the motor driver into one IC.

Disadvantages of Motor Driver ICs:

– First, they can be expensive.

– Also, you need to pay attention to the voltage and current ratings.

– In addition, some ICs can be difficult to use.

Now that you know what a motor driver is, you need to choose the right one for your project. This can be tricky because there are so many different types of motor drivers out there.

How to Choose the Right Type of Motor Driver

The following are the important  factors to consider when choosing a motor driver:

– the type of motors you are using (brushed or brushless)

First, you need to confirm whether brushed or brushless motors you are using.

If you are not sure which type of motor gets used, take a look at the datasheet.

– the voltage of  your motors

When choosing a motor driver, it is important to consider the voltage rating,  logic level, and features and capabilities.

Choose a motor driver that is rated for the voltage of your motor, can handle the logic level of your microcontroller and has the features and capabilities that you need.

When it comes to voltage, most motor drivers can handle a range of voltages. For example, the L293D can handle voltages between +36V to -36V. However, it’s important to make sure that the voltage you are using is within the specified limits of the motor driver. If you exceed the maximum voltage, you could damage the motor driver. 

The voltage rating of the motor driver is important. Most motor drivers can operate at voltages between about 0.65V and 36V. 

The features and capabilities of the motor driver are also important. So choose a motor driver that has the features and capabilities that you need for your application.

– the current rating of your motors

It is essential to choose a motor driver that can handle the amount of current your motors will draw. If you choose a driver that is not powerful enough, it will overheat and possibly damage your motor. If you choose a driver that is too powerful, you will be wasting money on excess features that you’ll never use.

This is the amount of current that the motor driver can provide to the motors. If you are using large motors that require a lot of currents, you will need to use a motor driver with a high current rating. For example, the L293D can provide up to 600mA per channel.

-Interface

When choosing a motor driver, you also need to consider the control interface. In comparison, the most common interface is an H-bridge. This type of interface allows you to control the direction and speed of the motors.

Other interfaces include L293D, L298N, and TB6612FNG. These interfaces provide different features and capabilities.

If you are using a motor driver with a microcontroller, you will also need to consider the logic level of the interface. Most microcontrollers use TTL logic, which is not compatible with many motor drivers.

You will need to use a logic-level converter if you want to use a TTL microcontroller with motor drivers.

– the amount of torque you need

While you also need to consider the torque,  you have to look at the stall torque. This is the torque required to keep the motor from moving.

The holding torque is what you need to overcome the resistance of the load. If you need to move a heavy load, you will need a motor with a high holding torque.

– the speed at which you need your motors to rotate

Also, your motor’s rotation speed should be considered. You will need to choose motor drivers that can provide the amount of power you need to rotate your motors at the speed you need.

– the size and weight of your motors

This is also an important consideration because you need to make sure that your motor drivers can support the weight and size of your motors.

– the environment in which your motors will be used (indoor or outdoor)

This is important to consider because different motor drivers are designed for different environments. If you plan on using your motors outdoors, you will need motor drivers that are weatherproof.

– the amount  of money you are willing to spend

Don’t forget to also consider the price when choosing motor drivers. Choose motor drivers that are affordable and within your budget.

When choosing motor drivers, you need to consider the type of interface, the voltage rating, and the logic level. Moreover, you also need to consider the features and capabilities of the motor drivers. Anyway, choose the motor drivers that is best suited for your application.

What Is an H-Bridge?

The H-bridge is a type of switch circuit that includes two pairs of transistors as switches. The reverse and forward operations of a DC motor get controlled by the switches. The majority of controllers get designed in this form.

Likewise, when switching on both of the transistors,  the motor will rotate in one direction. When both of the transistors are off, the motor will not operate. The transistor pairs can be on at the same time, one pair can be on while the other is off, or they can both be off.

This will cause the motor to rotate in the other direction. The speed of the motor gets increased or decreased by adjusting the amount of time that each transistor is on.

Summary

Motor drivers are ICs that can control stepper or DC motors. In contrast, there are many different types of motor drivers, each with its own advantages and disadvantages. Some common motor driver ICs include the L298N, DRV8825, and TB6612FNG.

When choosing a motor driver, you need to consider the voltage and current requirements of your motor, as well as the maximum allowable power dissipation for the chip. Furthermore, you also need to make sure that the driver can handle the required switching frequency for your motor.

Most standard MCUs can’t drive high-power motors directly, so you’ll need to use a motor driver if you want to control a high-power DC or stepper motor.

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Hommer Zhao
Hi, I am Hommer, the founder of WellPCB. So far, we have more than 4,000 customers worldwide. If you have any questions, you can feel free to contact me. I really appreciate any help you can provide.

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