Ic902 (H Driver) And Ic904 (V Driver) - Epson PhotoPC 850Z Service Manual

EPSON PhotoPC 850Z
Table 2-2. CCD Pin Description (Continued)
Pin No. Symbol Pin Description
φSUB
16 Substrate Clock
17 CSUB Substrate Bias
Protection
18 VL
Transistor Bias
NOTE: ----: When the sensor reads-out.
Operating Principles
Waveform Voltage
DC Approx. 8V
Approx. 8V
(Different
DC
from every
CCD)
DC
Operating Principles of Circuit Boards

2.2.1.2 IC902 (H Driver) and IC904 (V Driver)

H Driver (IC902) and V Driver (IC904) are necessary to generate the clocks
(vertical transfer clock, horizontal transfer clock, and electronic shutter clock)
which drive the CCD.
IC902 is an inverter IC which drives the horizontal CCDs (H1 and H2). In
addition, the XV1-XV4 signals which are output from IC102 are the vertical
transfer clocks, and the XSG1 and XSG signals output from IC102 are
superimposed onto XV1 and XV3 at IC904 in order to generate a ternary pulse.
Furthermore, the XSUB signal which is output from IC102 is used as the sweep
pulse for the electronic shutter, and the RG signal which is output from IC102 is
the reset gate clock.
1A 1
1Y 2
2A 3
2Y 4
3A 5
3Y 6
GND 7
Figure 2-6. IC902 Block Diagram
Revision A
14 V
CC
13
6A
12 6Y
11 5A
10 5Y
4A
9
8 4Y
43