CXA1782 SONY [Sony Corporation], CXA1782 Datasheet - Page 19

• Manufacturer Part Number: CXA1782
• Description: RF Signal Processing Servo Amplifier for CD players
• Manufacturer: SONY [Sony Corporation]

Tracking Sled Servo
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 decrease the high-frequency gain when
TG2 is OFF. The peak frequency of the tracking phase compensation is approximately 1.2kHz when a 510kΩ
resistance connected to Pin 11. In the CXA1782, 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,
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;
The values of the current for each switch are determined by the resistance connected between Pin 17 and
VEE. When this resistance is 120kΩ:
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 47.
0.047µ
100k
0.033µ
Track jump peak voltage = TM3 (or TM4) current
Sled kick peak voltage = TM5 ( or TM6) current
TM3 ( or TM4) = ±11µA, and TM5 (or TM6) = ±22µA.
470k
0.022µ
150k
42
43
44
47
45
10
46
9
BUFFER AMP
TDFCT
TEO
LPFI
TZC
TEI
TGU
TG2
ATSC
100k
TE
470k
–
+
TG2
DFCT
TZC
130mV
17mV
100k
100k
20k
1k
1k
TM1
Tracking Phase
Compensation
680k
680k
LPF
HPF
ATSC
11
– 19 –
FSET
66p
TG1
510k
0.01µ
feedback resistance
TM7
10k
feedback resistance value
TM6
TM5
TM4
TM3
22µA
22µA
11µA
11µA
90k
TA_M
TA_O
TM2
SL_O
15
16
14
12
13
SL_M
SL_P
100k
82k
TRACKING
COIL
CXA1782CQ/CR
8.2k
SLED MOTOR
3.3µ
22µ
15k
M