Patent ID: 7723937
Filing Date: 2010-05-25
Classification: G11B,H02P

Abstract:
1. A motor drive control device comprising: an output stage including upper and lower power MOSFETs and a spindle output predriver, for driving a polyphase DC motor; a current detector for detecting a current flowing through the polyphase DC motor; an output drive controller which outputs a PWM signal desired in such a manner that a current instruction signal and the current detected by the current detector coincide with each other; a phase voltage detector for the polyphase DC motor; and an initial-acceleration controller, wherein the initial-acceleration controller is activated at start-up and performs initial acceleration of the polyphase DC motor by detecting a peak of voltages induced in a non-conducting phase depending on a slope of a phase current for driving the polyphase DC motor by the PWM signal and by performing switching control of a conducting phase, and wherein after the initial acceleration, a position of a rotor is detected based on a back electromotive force in each phase which is generated by rotation of the polyphase DC motor through the phase voltage detector, whereby rotation control is performed by the output drive controller.