Patent ID: 7333413

Claim:
A method for controlling angular velocity of a spindle motor, the method comprising: generating a first control signal while in a first control mode, and generating a second control signal while in a second control mode; when receiving the first control signal in the first control mode, sending a first control voltage and a second control voltage to the spindle motor, causing the spindle motor to produce a first armature current upon reception of the first pulse and produce a second armature current upon reception of the second pulse; when receiving the second control signal in the second control mode, sending a third DC signal with a third control voltage to the spindle motor, causing the spindle motor to produce a third armature current upon reception of the DC signal; outputting a first, a second, and a third test voltage corresponding to the first, the second, and the third armature currents; using the first control voltage, the second control voltage and the third control voltage with the first, the second and the third test voltages to obtain a motor coefficient and a relative angular velocity of the spindle motor for controlling the angular velocity of the spindle motor.