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Rev 0.1 10/13 Copyright © 2013 by Silicon Laboratories AN794
AN794
C8051F850 BLDC REFERENCE DESIGN KIT
1. Introduction
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
1.1. Kit Contents
The kit consists of the following:
One MCU Board: MCRD-MCU-C8051F850 with the motor control firmware preprogrammed into the MCU
One Powertrain Board: MCRD-PWR-NLV-F85X
One BLDC Motor: Turnigy 450 Series 3800 kV Brushless Outrunner Helicopter Motor
One Motor Mount Board
One 8-bit MCU Kit CD
One 12 V, 5 Amp Universal Input Power Adapter
