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40
MN103S86G
Write
Strategy
IC 201
CN 101
Optical
Pick-up
HOP-7531TS
LD
PD
LDD
Serial
I/F
D/A
D/A
D/A
D/A
D/A
D/A
M
P
X
IC 121
AN22112A
APC
19
A/D
ADSC
S/H
Signal
FM
126
VPD
127 FPDM
128
VREFPD
49
50
51
SH1
SH2
SH3
VGA
LPF
Ave
Erase
Space
VGA
S/H2
S/H3
S/H1
DESCRIPTION OF CIRCUIT
1. ALPC (Automatic Laser Power Control) Circuit
1-1. Block Diagram
1-2. ALPC (Automatic Laser Power Control) Circuit Operation
The ALPC block detects the laser output power of the front monitor. The power signal detected with the PD for front monitor
detection is input the voltage from the VPD pin(126Pin) or the FPDM pin(127Pin), the reference signal of the input signal is
input from the VREFPD pin(128Pin). The ALPC block generates the singals from the input laser power signals in the
following detection systems. This block has four detection paths:All average value path, multi pulse average/peak value
detection path, erase/bottom value detection path, space/playback power value detection path.