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1.2.4 Spindle servo system
In the spindle servo system, the following modes are available:
1) Kick
Used to accelerate the disc rotation in the setup mode.
2) Offset
a. Used in the setup mode after the kick mode, until the TBAL adjustment is completed.
b. Used during the play mode when the focus loop is unlocked, until it is locked again.
In both cases, the mode is used to keep the disc rotation approximately normal.
3) Applicable servo
CLV servo mode, used in the normal operation.
In the EFM demodulation block, by WFCK/16 sampling whether the frame sync signal and the internal frame counter
output are synchronized, a signal is created to show if they are "in-sync" or "non-sync." The status is not recognized as
asynchronous until the signal is "non-sync" for eight consecutive times; otherwise it is recognized as synchronous. In the
applicable servo mode, the leading-in servo mode is automatically selected in the asynchronous status, and the normal
servo mode in the synchronous status.
4) Brake
Used to stop the spindle motor.
In accordance with the CPU of the LSI command, the brake voltage is sent out from the servo LSI. At this time, the EFM
waveform is monitored in the LSI, and when the longest EFM pattern exceeds a certain interval (or the rotation slows
down enough), a flag is set inside the CD of the LSI, and the CPU of the LSI switches off the brake voltage. If a flag is not
set within a certain period, the CPU of the LSI shifts the mode from the brake mode to the stop mode, and retains the
mode for a certain period of time. If the mode switches to this stop mode in the eject operation, the disc will be ejected
after the period of time mentioned above elapses.
5) Stop
Used when the power is turned on and during the eject operation. In the stop mode, the voltage in both ends of the spindle
motor is 0 V.
6) Rough servo
Used in carriage feed (carriage move mode such as long search).
By obtaining the linear velocity from the EFM waveform, the "H" or "L" level is input to the spindle equalizer. In the test
mode, this mode is also used for grating confirmation.
IC201 PE5547A
EFM
SIGNAL
Fig.1.2.9 Block diagram of the spindle servo system
5
6
SPEED ERROR SIGNAL
PWM
DSP
DIG.
BLOCK
EQ
PHASE ERROR SIGNAL
CX-3195
6
7
IC301 BA5839FP
SOP
MD
16
112
26
SOM
15
7
8
M
SPINDLE
MOTOR
13
8
A
B
C
D
E
F
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