CXA1992BR
Tracking and Sled Servo
TE
TGH
TGL
GAIN
WINDOW
COMPARATOR
+
–
26 SENS2
SENS
SELECTOR
45
TEO
25
SENS1
BALH
BALL
BUFFER AMP
46
100k
150k
BALANCE
WINDOW
COMPARATOR
47k
LPFI
SLED ON/OFF
CONTROL
19
LOCK
SLED MOTOR
M
SL_O
16
DFCT
TEI
TM1
TG1
66p
47
680k
SL_M
100k
680k
15
100k
TDFCT
TM6
TM5
22µA
50
48
8.2k
3.3µ
SL_P
TM2
22µA
14
1k
1k
0.047µ
47k
ATSC
ATSC
82k
22µ
15k
TM4
TM3
100k
20k
11µA
0.022µ
TZC
100k
TA_M
TA_O
49
12
13
11µA
90k
TZC
TRACKING
COIL
10k
TGU
TG2
Tracking Phase
Compensation
9
0.033µ
TG2
470k
10
TM7
FSET
11
510k
0.015µ
The above figure shows a block diagram of the tracking and sled servo.
The capacitor connected between Pins 9 and 10 is a time constant to cut the high-frequency gain when TG2 is
OFF. The peak frequency of the tracking phase compensation is approximately 1.2kHz when a 510kΩ
resistance is connected to Pin 11. In the CXA1992AR, TG1 and TG2 are inter-linked switches.
To jump tracks in FWD and REV directions, turn TM3 or TM4 ON. During this time, the peak voltage applied to
the tracking coil is determined by the TM3 or TM4 current and the feedback resistance from Pin 12. To be
more specific,
Track jump peak voltage = TM3 (or TM4) current × feedback resistance value
The FWD and REV sled kick is performed by turning TM5 or TM6 ON. During this time, the peak voltage
applied to the sled motor is determined by the TM5 or TM6 current and the feedback resistance from Pin 15;
Sled kick peak voltage = TM5 (or TM6) current × feedback resistance
The values of the current for each switch are determined by the resistance connected between Pin 17 and VEE.
When this resistance is 60kΩ :
TM3 (or TM4) = ±11µA, and TM5 (or TM6) = ±22µA.
As is the case with the FE signal, the TE signal is switched to pass through a low-pass filter formed by the
internal resistance (100kΩ) and the capacitance connected to Pin 50.
– 24 –
SONY [ SONY CORPORATION ]
