CHAPTER 2
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COPYRIGHT © 2000 CANON INC. CANOSCAN D660U REV.0 JULY 2000 PRINTED IN JAPAN (IMPRIME AU JAPON)
C. Scanning lamp/FAU lamp lighting circuit
When the scanner is powered ON, the "LAMP ON" signal is set to "H" and turns ON the lamp
control circuit to p12VI to the inverter PCB to light the scanning lamp.
The scanning lamp exposure control is performed by scanning white calibration plate which
is placed outside the image area to feedback on the output. ASIC inputs the pulse signal
(LAMP ON) according to the feedbacked signal to the lamp control circuit to ge12VI.
FAU lamp exposure control is performed by directly feedbacking the output from the FAU
lamp. When the host computer commands to use the FAU, ASIC sets "FAU INV" signal to "H".
The lamp control circuit pr12VI to FAU inverter PCB to light the FAU lamp.
Figure 2-12
ASIC
Lamp
control
circuit
Host
computer
Main PCB
CCD
drive
PCB
Inverter
PCB
GND
Scanning
lamp
LAMPON
FAUINV
12VI
GND
FAU Inverter
PCB
FAU lamp
Cold cathode
fluorescent
lamp
Cold cathode
fluorescent
lamp