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A motor is a piece of electronic equipment that transforms electrical energy into mechanical energy. Motor driver ICs make it possible to use electricity to do tasks automatically. Several varieties of electric motors are available. These are all examples of this category of DC motors, stepper motors, and Servo motors. These motors differ based on their properties and methods of operation. Selecting the appropriate motor driver ensures your engine’s smooth operation with your chosen microcontroller. Read on to learn about the function, design, and varieties of motor drivers and the required connecting hardware. Start right now!
- 1 What is a Motor Driver?
- 2 Working on an H-bridge
- 3 How Does the Motor Driver Work?
- 4 Critical Characteristics Of Motor Drivers
- 5 Choosing the Right Motor-Driver IC
- 6 Diagnostics
- 7 Why Do We Need A Motor Driver IC?
- 8 Why 4 Grounds In The IC?
- 9 Why Capacitors in The IC?
- 10 Conclusion
What is a Motor Driver?
As the name suggests, a motor driver is a tool to power motors. On the other hand, motor driver chips are useless without a microcontroller.
To connect the motor to the microcontroller, a motor driver is used. The microprocessor and the motor require very different input voltages, which is why they can’t function together. There will be more current used by the motor than by the microprocessor.
A motor driver module is necessary when connecting two devices that draw different amounts of current from the power source. A motor is used to step up or down the voltage supply as a third device.
ICs now dominate the market for motor drivers. Driver motors vary, and so do the qualities they exhibit. An H bridge circuit is required to link these motor driver ICs to the motor controller.
Working on an H-bridge
The H-bridge gets its name because four switches at the four corners easily represent it. Below is a simplified representation of an H-bridge circuit:
The circuit’s input voltage is displayed on the right side of the diagram, while the arrow on the left indicates the larger potential side. If switches S2 and S3 are closed, the circuit between switches S1 and S4 is open, and vice versa. This forms a circuit via which electricity can travel from V through S1 and the motor to S4 before departing.
This current flow would cause the motor to rotate in one direction. Due to the fact that the direction of motor rotation is governed by which motor terminals are linked to which switches, the motor can rotate either clockwise or counterclockwise.
For the sake of argument, let’s say that under these circumstances, the motor turns in a clockwise orientation.
The motor will rotate counter-clockwise if switches S3 and S2 are closed and switch S1 and S4 are left open.
The ‘STALL’ condition will occur if switches 1 and 3 are closed while switches 2 and 4 are open (The motor will break).
When the motor is given a positive voltage from both ends, the shaft of the motor stops turning.
How Does the Motor Driver Work?
To start, signals are sent from the microcontroller to the motor. The engine then interprets the received signals and takes them to the next level. The motor accepts power from two different pins. The first pin activates the driver, and power is supplied to the motor via the motor IC via the second pin.
A high input from the CPU will result in a high output from the driver IC. This clarifies why the IC does not alter the nature of the incoming signal.
To turn the motor clockwise, open switches S2 and S3 and close switches S1 and S4. In that case, S1 will open its circuit to S4 via the motor. After this period of current flow, the circuit is complete. This current will also travel to point M to point V via switches S1 and S4. This causes the motor to remain on and rotate in a clockwise direction.
To begin, we apply a voltage to the switches. Therefore, eventually, S1 and S4 will be closed switches. In addition, since we are linking two parallel switches, we have created a positive connection. Now the motor will turn counter-clockwise. We flip switches S3 and S2 to get an engine to rotate counter-clockwise.
Critical Characteristics Of Motor Drivers
There aren’t enough motor drives available to accommodate all the various electric motors. Several companies specialize in producing motor drivers for a variety of different motors. But the manufacturers make it simpler, as they supply a list of all compatible motors to motor drivers.
Most drivers, for example, can work with both DC and stepper motors. Yet, extra care should be taken when choosing a motor driver for a servo motor.
Many motor drives function without issues when connected to an Arduino driver board. A wired motor driver will not work for every wireless project. The Bluetooth controller board, as one example, is an excellent choice for a wireless project’s control board.
Voltage and Current
If you want a flawless motor driver, voltage and current are the two most crucial specs to check for. If you’re working on a project, you should know the required supply voltage and operational current. The driver you wish to use should adhere to the appropriate level of functionality.
Choosing the Right Motor-Driver IC
A motor controller is an essential component of any electrical engineer’s toolkit. Optical equipment, Robots, consumer electronics, industrial machinery, electric cars, and possibly just about every other category of items involving electricity all use these virtual electromechanical devices.
Anyone who hooked up a battery to a brushed DC motor and watched it spin will attest to how simple it is to make the motor turn. However, it may also be challenging, which is why we appreciate motor-driver integrated circuits, which make our job more accessible and achieve results that would be challenging (if not impossible) to achieve with discrete components.
To choose a suitable motor-driver IC, you must first determine the specific sort of motor you’ll be using. This article will discuss brushed DC motors, while the next will examine stepper motors. Because of their widespread use in low and medium-voltage systems, either a brushed DC motor or a stepper motor can likely provide the rotational motion your application needs.
Driving Brushed DC Motors
As previously mentioned, a voltage is all required to get a brushed DC motor to turn (assuming that the supply can deliver the required current). However, such rudimentary performance rarely suffices; hence H bridges are commonly used to power brushed DC motors (also known as a full bridge).
An electric motor can be turned on, off, or revolve in either direction with the help of low-voltage control signals when a complete bridge is used. One or more full-bridge circuits form the backbone of motor-drive ICs designed for brushed DC motors. For this reason, I prefer the phrase “constructed around,” as a chip consisting of nothing more than a whole bridge is hardly an integrated circuit, comprising only four transistors at most.
Voltage and Current
First, ensure the motor’s current and voltage specifications match your application’s. As many devices have a wide supply-voltage range, finding a suitable voltage spec is simple.
It’s not hard to find a component that can handle the current you’ll need, but there are a few specifics to remember. A problem arises because power is lost as heat when the current used to operate the motor flows over the on-state resistance of the full-bridge transistors, as shown by the formula I2R. Power loss always manifests as increasing amounts of heat. It could be a concern if this heat builds up to the point where it significantly raises the operating temperature of a critical component.
Ultimately, it all comes down to selecting an IC with sufficient current-drive capabilities and designing for adequate heat dissipation. Look for a device with an exposed thermal pad and a large copper pour with several vias if you expect your motor-drive IC to be subjected to harsh internal temperatures. To lessen power dissipation without increasing the PCB’s size, look for a driver with low on-state resistance.
An integrated circuit (IC) motor driver streamlines the connection between the H bridge (the component responsible for physical motor control) and the signals used to direct H bridge operation. Various interfaces are available with various processors, and it’s essential to consider which will work best for your needs. Some instances are as follows:
In the MAX14872 (Maxim) case: This driver accepts logic-level inputs for both forward and reverse rotation and can be disabled with an active-low enable pin. To “brake” the motor, as in swiftly stopping it, apply logic low to the forward and reverse pins.
The BD6220F (ROHM) incorporates a forward rotation input, a reverse rotation input, and a “VREF” pin for adjusting the motor-control voltage’s duty cycle. Changing the average voltage applied to the motor winding by adjusting the pulse width of the PWM signal is a straightforward method of controlling the motor’s speed using pulse-width modulation.
For the NXP MC33HB2001: This driver provides a set of logic-level inputs for directing the rotation of the motor and an SPI bus for setting parameters and checking on its health.
Motor-driver integrated circuits are not considered to be “input-only” devices. When selecting a component, you need to think about how you want to operate the motor and the kind of information about the motor you wish the system knew. One example is the MAX14872, which features a single failure pin that can indicate either an overcurrent or a thermal-shutdown condition. In comparison, the MC33HB2001 has a total of twelve status flags, which are as follows:
Most applications do not necessitate the use of twelve status flags, and a single malfunctioning pin does not provide a significant amount of input. However, after reading over the components, I have the impression that most motor-driver ICs only send a single error signal
Why Do We Need A Motor Driver IC?
Primarily, those who drive vehicles only completely autonomous robots will use ICs in their construction. To be functional, motors require a voltage and current that is significantly higher than what is necessary by microprocessors. Consequently, the central processing unit cannot provide power to the motors. This is the major function that the motor driver IC is responsible for doing.
Why 4 Grounds In The IC?
Heavy currents are managed using the motor driver integrated circuit. The IC gets hot because it has such a high flow of current. As a result, an heat sink is needed to lower the temperature. For this reason, there are four ground pins. When the pins get soldered on the PCB, we create a sizeable metallic region in the space between the grounds, which is where the heat can escape.
Why Capacitors in The IC?
The load on the DC motor is an example of an inductive one. As a result, a reverse EMF is produced whenever it is provided with a voltage. While we are using the motor, there is a possibility that the voltage will fluctuate. One example would be if we suddenly put the motor into reverse while it was already moving in a certain way. At this stage, the voltage swings are rather severe, so the integrated circuit is at risk of being damaged. As a result, we use four capacitors, each reducing the significant variation in current.
Controlling a motor is a common requirement for electrical engineers and designers. Electric cars, Robots, optical equipment, industrial machinery, consumer electronics, and possibly just about every other category of items involving electricity all use these essential electromechanical devices.
It’s not hard to make a motor spin if you hook up a battery to a brushed DC motor. The challenge of designing a motor can be daunting, which is why we turn to motor-driver integrated circuits when we need performance that would be difficult (or impossible) to achieve with discrete components.
The type of motor you intend to utilize is the primary consideration when selecting a motor-driver IC. Brushed DC and stepper motors are prevalent in low and medium-voltage systems. Thus, if your application needs rotational motion, you can probably implement the necessary functionality using one of these motors. Please share your thoughts and feedback in the section below if you have expertise with specific components that you think might be particularly valuable in a given application.
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