METHOD AND CIRCUIT FOR UNIFORM-VELOCITY CONTROL OF THREAD OFDISK DRIVE

摘要

PROBLEM TO BE SOLVED: To reduce the search delay due to a driving deviation to be generated in a set and a driving circuit in a thread by using a photocoupler in a sensor part. SOLUTION: A sensor part 201 consisting of a photocupler detects pulses with respect to the track of a disk drive and an amplifier part 203 amplifies the output of the sensor part 201 to output one pulse per 24 tracks. A delay and differentiator 205 performs the prescribed delaying of the output of the amplifier part 203 and differentiates it and a differentiator 207 delays the output of the amplifier part 203 and a triangular wave generator 211 generates a triangular wave by receiving the output of a current source generator 209. A sample-and-hold circuit 213 samples and holds the output of the triangular wave generator by the output of the differentiator 207, a forward and backward exchanger 215 allows the output of the sample and hold circuit 213 to be converted into a voltage by the input signals of a forward or backward control ends C1, C2 with respect to a frequency. An adding/subtracting unit 131 makes power consumption minimum by performing the addition/subtraction between the output of the amplifier 129 and the control signal of a thread movement control end 185 and a thread is controlled by a driving circuit 133.