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23
1.1.9.
Laser Unit (LSU) Control Circuit
The laser control signals are described below.
nLDEN
The LSU is activated when this output signal is LOW. If an error occurs, the nLDEN output signal level
goes High and the LSU is deactivated.
goes High and the LSU is deactivated.
nVIDEO
This is the actual Data Signal. The Laser is ON when the nVIDEO output signal level is LOW.
nHSYNC
This horizontal synchronization signal transmitted from the Beam Detection Sensor sets the horizontal
position of the laser beam as it crosses the OPC Drum.
position of the laser beam as it crosses the OPC Drum.
nSTART
This is the Scanner Motor Control Signal. The Scanner Motor rotates when the nSTART output signal
level is LOW.
level is LOW.
nREADY
A Phased-Lock Loop (PLL) circuit keeps the Scanner Motor speed constant when the nREADY is at a
Low output signal level.
Low output signal level.
CLK
This is the Scanner Motor Clock.
nS/H
This is the Sample Hold Signal in order to adjust the Laser power. when the Laser switches on
compulsorily, the Laser Power is adjusted suitable level and held until next duty cycle in order to keep
the Laser Power stable .
compulsorily, the Laser Power is adjusted suitable level and held until next duty cycle in order to keep
the Laser Power stable .
Laser
Timing
Sensor
Scanner
Motor
Laser
Drive
Circuit
Scanner
Motor
Drive
Circuit
IC3
SHINE
nVIDEO
nS/H
nLDEN
nHSYNC
nSTART
LSU
+5V
Q26
IC21
IC25
C147
R215
C120
Q29
Q31
Q30
+5V
R22
R21
SC PCB
8
7
9
13
3
CN10
23
20
19
nREADY
CLK
2
1
30
163
24
21
Laser Unit Control Circuit Block Diagram
R181
2
2
4
4
3
2
1
GND
3
2
1
3
2
1
3
2
1
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