4.7 Servo Control

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:

 

(1)

 

 

MPU/HDC/RDC

 

(2)

 

Head

Servo

MPU

 

burst

core

 

capture

 

Position Sense

CSR: Current Sense Resister

VCM: Voice Coil Motor

(3)

SVC

 

(4)

 

DAC

Power

VCM current

 

Amp

 

 

(7)

CSR

 

 

VCM

(5)

(6)

 

Spindle

Driver

Spindle

motor

 

motor

control

 

 

Figure 4.6 Block diagram of servo control circuit

C141-E269

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Fujitsu MHY2200BS, MHY2160BS, MHY2120BS, MHY2040BS, MHY2080BS, MHY2060BS, MHY2100BS manual Servo Control, Servo control circuit