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:

Head

(2)

Servo burst capture

(1)

MPU/HDC/RDC

MPU

core

(3)

SVC

 

(4)

 

DAC

Power

VCM current

 

Amp

 

 

(7)

CSR

Position Sense

CSR: Current Sense Resister

VCM: Voice Coil Motor

 

 

 

 

 

 

 

 

 

 

 

VCM

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

(5)

 

 

(6)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Spindle

 

 

 

Driver

 

Spindle

 

motor

 

 

 

 

 

 

 

 

motor

 

control

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Figure 4.6 Block diagram of servo control circuit

4-12

C141-E221

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Fujitsu MHV2040AS, MHV2080AS, MHV2060AS manual Servo Control, Servo control circuit
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MHV2060AS, MHV2080AS, MHV2040AS specifications

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