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CX-3268
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1. CIRCUIT DESCRIPTIONS
DV5U Chip
(MN2DS0018MAUB : IC1501)
2.2 2.2 2.2 2.2
14 24
25
103
104
105
106
2.2 2.2 2.2 2.2
CDMPD
DVDMP
78 LD
(CD)
65 LD
(DVD)
15
MN2DS0018MAUB is 1-chip LSI for DVD-Player. The DVD-Player system can be\
constructed by connecting this
LSI with driver IC, SDRAM, Flash-ROM, and Audio-DAC etc.
This LSI has the front end part (SODC / FE) for carrying out RF signal\
processing / servo processing / decode
processing, the AV decoder part (backend / BE) for carrying out video \
decode processing of MPEG1 / MPEG2 /
JPEG etc. and audio decode processing of DVD-Audio / Dolby Dijital2 / DT\
S / MP3 etc., and the system controller
for controlling the system built-in.
The front end part realizes various processing such as optical head sign\
al arithmetic processing, RF signal processing,
digital signal processing of DVD standard-compliant DVD-ROM play (16-8 \
demodulation, error correction), digital
signal processing of CD-DA / CD-ROM (error correction), AV decoder tra\
nsfer, servo control, spindle motor control,
and seeking control.
With MN2DS0018MAUB, the waveform of servo system of front end such as FE\
, TE, AS cannot be seen in a same
way as DVD mechanism module (LS1) CX-3250. Keep it in mind.
1.1 Analog block (MN2DS0018MAUB : IC1501) 1 Front end part (MN2DS0018MAUB : IC1501)
The functions of analog block are as below:
1. Reference power supply circuit
2. SERVO system / DPD system signal processing circuit
Gain switching amplifier and Low Pass Filter (LPF)
3. RF signal processing circuit
RF adder circuit, in-lining circuit, Variable Gain Amplifier (VGA) cir\
cuit
4. Laser power control (LPC) circuit
5. A/D converter for SERVO (10bit), DPD system comparator, PWM
1.1.1 APC circuit The optical output of laser diode (LD) has a large negative temperatur\
e character.
Consequently, if LD is driven at the rated current, a constant optical o\
utput cannot be obtained.
APC circuit is the circuit for controlling the current so that the outpu\
t becomes constant for the monitor diode (MD).
MN2DS0018MAUB has two types of APC circuit for DVD and CD built-in.
In case of DVD (CD), the LD current can be obtained by dividing the vo\
ltage measurement value between
DVDLD1 (CDLD1) and 5 V by 8.8 ohm (2.2 ohm x 4 = 8.8 ohm). In case o\
f DVD (CD), the LD current
becomes approximately 45 mA (40 mA). The voltage difference between DV\
DLD1 (CDLD1) and 5 V will be
396 mV (352 mV).
PU unit
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CX-32683
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After 10bit ADC
12
11 FE2
FE1
CN1101
115
116
VIN7 VIN8
Selector
LPF
50k Hz
Input AMP Buffer
LPF
LPF
50k Hz
G=0dB Buffer AMP
ADC drive AMP
Gain switching
6/7.5/9/10.5/
12/13.5/15/
16.5/18/19.5d
ADC
Selector
ADC
Gain switching
3dB, 9dB
Gain switching
-6dB, 0dB, 9 5dB
DV5U Chip
FE1
FE2
FE signal generation circuit
+
-
1+Pfbal0,1/0x0100
1-Pfbal0,1/0x0100 Offset cancel Fbal coarse adjustment value FE
AMP
DV5U Chip
1.1.2 FE generation circuit
Focus error (FE) generation circuit
The signals FE1 and FE2 from PU are AD-converted in IC1501 and imported.\
Then, the differential is taken by
taking the offset cancel into account and it becomes FE.
FE = (FE1) - (FE2)
