Sony DVP-S7000 (serv.man2) Service Manual ▷ View online
– 90 –
Figure 5-3.
S waveform at DVD disc
(Focus error), IC717
@ª
P
Figure 5-4.
S waveform at DVD
(dual layer) disc,
IC717
@ª
P
ADDRESS, 8-BIT
DATA, 8-BIT
TSENS
TDS
TDH
TCKL
R/W
R/W
ADDR 0
ADDR 0
TCLK
$∞P SDEN
SDEN
SCLK
(CPCK)
SDATA
(WRITE)
SDATA
(READ)
(CPDT0)
SDATA
$¢P (CPDT0)
SCLK
$£P (CPCK)
TTRN
TSENH
TDSKEW
TSENDL
TCKH
ADDR 6
ADDR 6
DATA 7
DATA 7
Figure 5-2.
TT-701 Board IC001 SSI33P3720 serial timing chart
– 91 –
The IC717 DSP: CXD2545Q on MB-75 board provides the following control in the
focus servo system.
Figure 5-5.
MB-75 Board, IC717 CXD2545Q
SERVO BLOCK
26
27
28
29
30
RFDC
SWITCH
&
BUFFER
A/D
CONVERTER
TE
SE
FE
VC
FOCUS SERVO
SERVO DSP
PWM GENERATOR
TRACKING SERVO
SLED SERVO
SERVO
INTERFACE
FOCUS PWM
GENERATOR
TRACKING PWM
GENERATOR
SLED PWM
GENERATOR
25
RFC
24
ADIO
14
TEST
16
TES2
17
TES3
21
AV
DD
40
AV
DD
23
AVss
35
AVss
41
V
DD
90
V
DD
15
Vss
65
Vss
61
XRST
SFDR
FOK
93
DFCT
92
MIRR
91
COUT
89
SRDR
TFDR
TRDR
FFDR
FRDR
MIRR
DFCT
FOK
100
2
4
6
8
10
(a) Focus search
The optical pickup lens is moved toward a disc to turn on the focus servo.
The focus servo loop is turned on when the PI (Pull IN) signal (used for FOK:
Focus OK) exceeds the specification (2.75V) and the FE signal zero-crossing is
detected.
(b) Focus gain adjustment
The gain of digital filter in the IC717 is automatically adjusted so that the focus
servo loop gain becomes optimum.
Consequently, the optimum gain for each disc to be played can be attained, besides
correction of gain variations in focus actuator (coil) and optical pickup sensor
(photodiode for focusing).
(c) Focus bias adjustment
The focus bias is added to the focus servo filter so as to minimize the jitter.
Consequently, a variation of optical pickup and disc can be automatically corrected.
– 92 –
Figure 5-6.
MB-75 Board, DVD focus drive
DVD FCS–
To Focus Actuator
6
FFDR
IC717
CXD2545Q
IC886
NJM3403
Level Shift
DSP
FRDR
5
7
9
8
13
IC892
TC74HC4053
Gain Select
IC890
BA5970FP
Buffer
Focus Drive
AMP
Level
Shift
R918
3.3K
R919
1K
12
8
10
14
FDWN
From IC1499
11
27
15
DVD FCS+
16
The FE (Focus Error) signal adjusted to proper gain in the IC717 (DSP) is output from
DSP as focus drive signal (FFDR8P, FRDR!ºP) after PWM modulation.
The FFDR and FRDR signals are shifted in level in the IC886 (OP AMP NJM3403)
and selected in gain (attenuation selection at focus search) in the IC892 (switch
IC74HC4053), then entered to the focus actuator (coil) drive IC (IC890: BA5970FP).
The IC890 amplifies voltage, transforms voltage, and amplifies current, and drives the
focus actuator (coil) with the output signals of IC890 (DVD FCS+, DVD FCS–).
(2) DVD tracking servo
Figure 5-7.
DVD tracking servo, drive
The tracking error signal output from optical pickup is entered to the IC001: SSI33P3720
A2 to D2 (1 to 4P) on the TT-701 board. The tracking error signal is detected in the
DPD (Differential Phase Detection) method.
The amplification degree and offset value of tracking error signal are set by internal
register in the IC001.
The tracking error signal TE (IC001, #•P) is output from IC001, then it is entered to the
switch IC (IC005: TC7S66F).
The switch IC shuts off tracking error signal when DVD RF signal (RFP) is below
about 200mVp-p (AC component).
OFF when RFP (CN0019)
is below 200mVp-p
DVD
CD
CD
: H
: L
: L
From IC0047
To Tracking Actuator
CN005
CN980
TT-701 BOARD
MB-75 BOARD
1
IC001
SSI33P3720
IC005
TC7S66F
IC768
TC74HC4053
2
3
4
E
Q
14
CN001
13
6
18
OFFSET
LPF
2
38
1
TE
SWITCH
4
CD/DVD
15
1
2
DVD/CD
SELECT
IC890
BA5970FP
Tracking
Drive
IC717
CXD2545Q
DSP
TFDR
TRDR
10
8
8
DPD
27
4
24
6
23
DVDTRK+
DVDTRK–
18
17
– 93 –
The tracking error signal is entered to the MB-75 board from CN005 (DPD: 8P) through
a flexible flat cable.
The tracking error (TE) signal (DPD: Differential Phase Detection signal) generated in
the IC001 is entered to the MB-75 board through a flexible flat cable.
The TE (Tracking Error) signal is entered to the IC717 (DSP: CXD2545Q) TE (@¶P)
via the switch IC, IC768 (74HC4053, switches over between CD tracking error signal
and DVD tracking error (DPD) signal).
The DSP IC provides the following control in the tracking servo system.
(a) Tracking gain adjustment
The gain of internal digital filter of IC is automatically adjusted so that the tracking
servo loop gain becomes optimum.
Consequently, the optimum gain for each disc to be played can be attained, besides
correction of gain variations in tracking actuator (coil) and optical pickup sensor
(photodiode for tracking and focusing).
(b) Tracking jump control
At one track jump or N track jump (jumping many tracks) in asearching, generation
of tracking pulses, detection of tracking zero-cross timing, control of tracking
brake, and measurement of tracking jumps are executed.
The TE (Tracking Error) signal adjusted to proper gain in the IC717 (DSP) is output
from DSP as tracking drive signal (TFDR4P, TRDR6P) after PWM modulation.
(See Figure 5-5)
The TFDR and TRDR signals are entered to the tracking actuator (coil) drive IC (IC890:
BA5970FP).
The IC890 amplifies voltage, transforms voltage, and amplifies current, and drives the
tracking actuator (coil) with the output signals of IC890 (DVD TRK+, DVD TRK–).
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