Servo Control; Servo Control Circuit; Figure 4.6 Block Diagram Of Servo Control Circuit - Fujitsu MHA2021AT Product Manual

Theory of Device Operation

4.7 Servo Control

The actuator motor and the spindle motor are submitted to servo control. The
actuator motor is controlled for moving and positioning the head to the track
containing the desired data. To turn the disk at a constant velocity, the actuator
motor is controlled according to the servo data that is written on the data side
beforehand.

4.7.1 Servo control circuit

Figure 4.6 is the block diagram of the servo control circuit. The following
describes the functions of the blocks:

Figure 4.6 Block diagram of servo control circuit

(1) Microprocessor unit (MPU)
The MPU includes the AD converter and DSP unit, etc., and the MPU starts the
spindle motor, moves the heads to the reference cylinders, seeks the specified
cylinder, and executes calibration according to the internal operations of the
MPU.
4-14 C141-E042-01EN