Application Note AN794
October 2013
This design kit provides a complete system-level solution for sensorless, brushless dc (BLDC) motors. This application note includes complete schematics, PCB layouts and firmware. This kit supports 3-phase BLDC motors that meet the following specifications:
- Trapezoidal back-EMF
- Max operating voltage of between 10 V to 24 V dc
- 24 kHz PWM frequency
- Maximum average current of 10 A
- Maximum speed not exceeding 200,000 rpm for a 2-pole BLDC motor
- Overcurrent detection capability stops the motor when average current exceeds 10 A.
- Motor Stall detect capability stops the motor when a motor stall is detected or extreme loads encountered.
- Tachometer Frequency Generator (FG) output signal
The kit aims to demonstrate the capabilities of the C8051F850 for operating BLDC motors. The unique features offered by this MCU for BLDC motor operation are:
- PWM synchronized blanking of comparator for BEMF Zero-Crossing Detection
- Automatic PWM duty cycle reduction to limit motor current during startup
- Hyperdrive mode to increase the maximum speed of some motors
The kit uses the Turnigy 450 Series 3800 kV Brushless Outrunner Helicopter Motor.
Download Application Note AN794 (2.7 Mb)
