Sharp FO-4500, Руководство по обслуживанию

Страница: 112 / 192

[4] Circuit description of CCD PWB
The CCD board picks up optical information from the document, con-
verts it into an electrical (analog) signal and transfers it to the control
board.
1. Block diagram
CCD
µPD3753CY
+5V
AG
VO
T
Φ
1
Φ
2
Φ
Fig.10
2. Description of blocks
1) CCD
The
µ
PD3753CY is a highly sensitive charged coupled image sensor
that consists of 2088 picture elements.
Receiving there drive signals (
φ
T,
φ
2,
φ
1) from the control board.
2) Waveforms
1.
φ
1,
φ
2 ...signals within the control board.
2
Φ
1
Φ
Fig. 11
[5] Circuit description of operation PWB
1. Block diagram
ULN2003
SEN1
SEN2
SEN3
SEN4
SEN5
SEN6
LS145
HC174
+5V
LD0 ~ LD7
LCD DRIVER
LCD
COG (LMG2022-TPR)
PANEL PWB
ULN2003
Fig. 12
2. Operational description
1) Panel PWB
The panel PWB includes the ten key scan circuit and the LED lighting
circuit.The LS145 is controlled through LD0~LD3 (4 bits) and ten key
detection is performed. The HC174 is controlled through LD0~LD5 (6
bits) to provide LED lighting information.
2) COG (LMG2022-TPR)
The COG uses the one-chip LCD driver IC to display 20 digits x 2
lines. The LCD display density is controlled with an extemal resistor.
FO-4500H
5 – 22