55
YPM-MG2196ZF
6) Focus-error amplifier
The system outputs photodetector output (A+C) and
(B+D) as FE signal (A+C)-(B+D) from Pin 28 via the dif-
ference amplifier, then via the error amplifier.
Low-frequency components of voltage FEY is:
An S curve equivalent to approximately 1.6 Vp-p is
obtained at FE output (Pin 28) by using REFO as refer-
ence. The cut-off frequency of the amplifier of the last
layer is 12.4 kHz.
7) Tracking-error amplifier
Outputs E and F from the photodetector are output as
TE signal (E-F) from Pin 24 via the difference amplifier,
then via the error amplifier.
Low-frequency components of voltage TEY is:
TE waveforms equivalent to approximately 1.5 Vp-p are
obtained at TE output (Pin 24) by using REFO as refer-
ence. The cut-off frequency of the amplifier of the last
layer is 19.5 kHz.
8) Tracking zero-cross amplifier
Tracking zero-cross signal (TEC signal) is generated by
amplifying TE waveforms (voltage at Pin 24) by a factor
of four. The signal is used for detecting the zero-cross
point of tracking error in the servo LSI UPD63702AGF.
The purposes of detecting the zero-cross point are as
follows:
(1)To be used for counting tracks for carriage move and
track jump.
(2)To be used for detecting the direction of lens move-
ment when tracking is closed. (To be used in the
tracking brake circuit mentioned later.)
The frequency range of TEC signal is from 500 Hz to
19.5 kHz.
Voltage TEC = TE level x 4
In other words, the TEC signal level is calculated as 6
Vp-p. This level exceeds the D range of the operation
amplifier, resulting in the signal to clip. However,
there shall be no problem, since the servo LSI uses
only zero-cross point.
6
5
9.3k
Ω
9.3k
Ω
20k
Ω
10k
Ω
10k
Ω
6
13
13
12
10k
Ω
10k
Ω
20k
Ω
FE VCA
38
REFOUT
C114
390pF
FE
R108
33k
Ω
28
27
17.2k
Ω
50pF
gm=1/68.8k
Ω
90k
Ω
10
11
CN101
A+C
B+D
F.BAL
REFOUT (+2.5V)
gm CONDUCTANCE
UPC2572GS
Fig. 4 Focus-error amplifier
Fig. 5
Tracking-error amplifier,
Tracking zero-cross amplifier
CN101
R117
16k
Ω
R116
16k
Ω
14
15
9
11
31k
Ω
31k
Ω
50pF
63k
Ω
C123
4.7nF
R114
10k
Ω
R113
10k
Ω
TBAL
C115
120pF
R109
68k
Ω
R115
1k
Ω
C126
15nF
TE
4R
R
F
E
23
TEC
C116
6.8nF
TE VCA
gm=1/17k
Ω
63k
Ω
37
24
5pF
TOFST
R110
130k
Ω
50pF
25
REFOUT (+2.5V)
gm CONDUCTANCE
UPC2572GS
63k
Ω
68k
Ω
TEY=(E-F) X
X
(31k
Ω
+16k
Ω
)
17k
Ω
: (TE level of pickup unit x 5.36)
20k
Ω
90k
Ω
R108
FEY=(A+C)-(B+D)X
X
X
10k
Ω
68.8k
Ω
17.2k
Ω
: (FE level of pickup unit x 5.02)
Summary of Contents for YPM-MG2196ZF
Page 3: ...3 YPM MG2196ZF ...
Page 4: ...4 YPM MG2196ZF 2 EXPLODED VIEWS AND PARTS LIST 2 1 CD MECHANISM ...
Page 17: ...17 YPM MG2196ZF ...
Page 19: ...19 1 2 3 4 1 2 3 4 D C B A SIDE B E E E E E E E E 16 1 5 8 9 A CD CORE UNIT A YPM MG2196ZF ...
Page 20: ...20 YPM MG2196ZF 1 2 3 4 1 2 3 4 D C B A CN801 PU UNIT A C D 4 2 SIDE PCB B SIDE PCB SIDE A B ...
Page 22: ...22 YPM MG2196ZF 1 2 3 4 1 2 3 4 D C B A D 4 4 MOTOR PCB B SPINDLE MOTOR M5 MOTOR PCB B D ...
Page 23: ...23 YPM MG2196ZF 1 2 3 4 1 2 3 4 D C B A D M M4 CARRIAGE 1 12 B CN864 ...
Page 28: ...28 YPM MG2196ZF 1 2 3 4 1 2 3 4 D C B A LOAD DOOR MODE E 4 9 FORDSW PCB I FORDSW PCB I SIDE A ...
Page 29: ...29 YPM MG2196ZF 5 6 7 8 5 6 7 8 D C B A I FORDSW PCB I SIDE B ...
Page 35: ...35 YPM MG2196ZF Grating waveform Ech Xch 20mV div AC Fch Ych 20mV div AC 45 0 75 60 30 90 ...