MAGNETIC DISK DEVICE AND SYSTEM

摘要

PURPOSE:To effectively employ a speed control circuit or power amplifier and to reduce a packaging space and the cost without causing the reduction in a throughput by sharing plural speed control circuits for power amplifiers among actuators. CONSTITUTION:In the system composed of numerous access mechanisms A1-An, the speed control system including respectively the power amplifier for large current is composed of three sets and a position control system is composed of the respective actuator together with the power amplifier 5 for small current exclusively. A mode changing switch 4 has the switch of the top-most step for position control and the other three corresponding to three speed control systems. Since the speed servo system is prepared in three sets, upto the optional three sets of actuators A1-An (n>3) can simultaneously be accessed. The selection of Y is performed by the signal of S1.