Speed Controller for 24V Brushless DC Motor

This self-contained brushless DC motor utilizes closed-loop speed control to spin at 2054 RPM for any load torque up to 118 mNm (16.7 oz-in).  The magnetic rotor position is sensed by the DRV5013 Hall-effect sensors, and theDRV8308 controller decides when to drive the CSD88537ND FETs that energize the coils.  Intelligent sinusoidal current drive minimizes torque ripple, and the system is capabile of 71% efficiency.

Features
  • Speed control delivers accurate and consistent RPM
  • Power input supports 24V to 32V and more than 5A
  • Outrunner style provides good power density in a 6x6x3 cm³ form
  • RPM and max current are set by resistors
  • Simple and reliable design
  • System has been fully tested and proven

The DRV8308 device is a three half-bridge pre-driver that drives up to 130 mA to six N-type MOSFETs with a single power supply. Aimed at sensored three-phase brushless DC motors, this pre-driver includes configurable a digital speed loop, speed controls, and commutation modes to optimize motor performance. When properly tuned, the DRV8308 device can drive motors with less than 0.1% cycle jitter and fast torque compensation.

The integrated digital speed loop allows the motor to maintain speed under variable loads with programmable gain and loop filters. The adjustable slew rates can also lower the switching noise and improve EMC.

The DRV8308 device also supports both the 120° and 180° commutation modes with the ability to adjust the delay to increase power efficiency. For high-performance systems, sinusoidal (180°) commutation mode is used to minimize acoustic noise and torque ripple. Jitter caused by non-ideal Hall placement and matching can be eliminated once constant speed is reached by switching from three Hall sensor phases to just a single Hall sensor.

In addition to advanced programmability features to tune the motor’s performance, the SPI interface also provides detailed fault reporting such as locked rotor detection, overcurrent, overtemperature, and overvoltage, as well as charge pump short and failure, to provide robust protection and intelligence to the overall system design.

Features

  • Three-phase Brushless DC Motor Controller
    • Fully Digital Speed Loop With Programmable 
      Gain and Loop Filters
    • Clock Input or PWM Inputs for Speed Control
  • Operating Supply Voltage 8.5 to 32 V
  • Drives 10- to 130-mA Gate-Drive Current to 
    6 N-Channel MOSFETs With Adjustable Slew 
    Rates
  • Supports Sensor-based Sinusoidal and Trapezoidal 
    Commutation Control With Tunable Delay
  • Flexible Configuration Methods:
    • Serial Control
    • Internal OTP Memory
    • External EEPROM
  • 5-V Linear Regulator and Switched Power Output 
    for Hall Sensors
  • SPI Control Interface
  • Low-power Standby Mode
  • Locked Rotor Detection and Restart
  • Integrated Overcurrent, Overvoltage, and 
    Overtemperature Protection
  • 6 × 6-mm QFN Package, 0.5-mm Pitch

Source: http://www.ti.com/tool/TIDA-00197#1