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Brushed DC Motors

Brushed DC (BDC) motors get their name from the brushes that are used for commutation. Because its speed and torque are proportional to the applied voltage and current, a BDC motor is easy to control. BDC motors are cost-effective, easy to design in and simple to control, making them suitable for use in a wide variety of applications. Our microcontrollers (MCUs), gate drivers and single-chip motor drivers enable you to create compact, robust and efficient brushed DC drives.

Typical Applications

  • Toys
  • Cellular phones
  • Wipers
  • Door locks
  • Window lifts
  • Antenna retractors
  • Seat adjusters
  • Anti-lock braking systems
  • Cordless hand drills
  • Electric lawnmowers

Recommended Products for Brushed DC Motor Control

ProductsOn/Off
Control
Speed
Control
(Open/Closed)
Torque
Control
Position
Control
(QEI)
Microcontrollers (MCUs)8-bit PIC® and AVR® MCUs 
High-Side Switch
Gate Driver
MIC50xx
Low-Side Switch
Gate Driver
MIC44xx
Bidirectional
Gate Drivers
ATA6823C
ATA6824C
MIC4606
Brushed Motor Control Block Diagram

Some Basics About Brushed DC Motors

How a Brushed DC Motor Works

  • Typically, the rotor, also known as the armature, has windings that terminate on a commutator
  • Brushes make and break contact with commutation segments to commutate power to the armature
  • The stator, or outer cylinder, of a permanent magnet DC motor has two or more magnets
  • The opposite polarities of the energized winding and the stator magnets attract, causing the rotor to rotate until it is aligned with the stator
  • As the rotor comes into alignment, the brushes move across the commutator contacts and energize the next winding

Brushed DC Motor Characteristics

  • Good controllability: on/off, proportional
  • Linear torque/current curve
  • Speed proportional to voltage applied
  • Requires maintenance
  • Low overloading capability
  • Low heat dissipation
BrushedDC_KeyChar_large

Implementing Brushed DC Motor Control

How It Works

The speed of the brushed DC motor is controlled by the voltage applied to the armature, and the torque by the armature current. The flux and the torque can easily be controlled separately. This is the main principle on which all the modern control methods now rely. The controller is used to regulate the torque, speed, position or direction of the motor. Control can be implemented either in open or closed loop and the system can use feedback from optical encoder and limit switches.

Microcontroller Features for Bushed DC Motor Control

Basic I/OOn/off control
Capture/Compare/Pulse-Wid Modulation (CCP)Variable speed, torque
ComparatorsOvercurrent detection and protection
Analog-to-Digital Converters (ADCs)Motor voltage, current measurement and analog control input
Programable Gain Amplifiers (PGAs)Current measurement for torque control
Quadrature Encoder Interface (QEI)Interface with optical encoders

Gate Driver Configuration

Unidirectional Low-Side Configuration

This drive can control a BDC motor in one direction and is often used in safety-critical applications.

Lowside Brushed Diagram

Unidirectional High-Side Configuration

This lowest-cost drive technique enables most applications to simply use an output pin from a PIC® or AVR® MCU to turn on the MOSFET.

Highside Brushed Diagram

Bidirectional H-Bridge Configuration

This drive can control a BDC motor in both directions.

Bi-directional H-Bridge Connguration Brushed Motor Control Diagram

Motor Control Hardware and Software Solutions

Featured Software Tools

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Motor Control Application Algorithm and Software Library

To support the development of motor applications, we provide Brushed DC motor control examples.

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MPLAB® X Integrated Development Environment (IDE)

MPLAB X Integrated Development Environment (IDE) is an expandable, highly configurable software program that incorporates powerful tools to help you discover, configure, develop, debug and qualify embedded designs for Microchip’s microcontrollers and digital signal controllers.

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MPLAB Code Configurator (MCC)

MPLAB Code Configurator (MCC) is a free, graphical programming environment that generates seamless, easy-to-understand C code to be inserted into your project.

Featured Hardware Tools