Chip Design of Three-Phase BLDC Motor Brake Driver IC

This paper proposes a three-phase BLDC motor brake driver IC. The driver contains five major units that are hall-signal-process-unit, logic-control-unit, speed-control-unit, brake-control-unit and power-driver-unit. First, motor speed is used PWM that can be controlled by frequency instead of traditional voltage control method. Moreover, a new brake structure using frequency-to-voltage converter (FVC) is also developed. Experimental results show that this new structure can achieve PWM control and make motor turn off effectively. Eventually, we have designed this new deriver IC using TSMC CMOS 0.35μm 2P4M technology.

I. Introduction

The three-phase BLDC motor uses electronic switches instead of brushes and commutators as seen in brush DC motor. It completely eliminates the brush wear thus it has features of high efficiency and low maintaining cost. The three-phase BLDC motor is becoming more popular with the advancement in microelectronics and widely used in the spindle motor of CD-ROM and DVD-ROM [1]. The traditional speed control method for BLDC motor uses analog voltage to adjust PWM [2]. The disadvantage of such structure is that controller must contain a digital-to-analog converter (DAC) to generate analog voltage. We use a new speed control method by frequency that the motor speed can be controlled directly by controller's digital output without using a DAC.