Circuit Description Of Cis Unit - Sharp FO 4400 - B/W Laser - All-in-One Service Manual

LB1845 (IC3) Terminal description
Pin name Pin No.
VBB 1, 14 Output stage power-supply voltage
SENSE1 2 Set current detection pins.
SENSE2 13 Connect these pins, fed back through noise filters, to E1, and E2.
E1 3 Current control pins by connecting between this pin and GND.
E2 12
DGND 4,11 Internal diode anode connection
OUT1B 6
OUT1A 7 Output pins
OUT2B 8
OUT2A 9
GND 15 Ground
RC1 27 Used to set the output off time for the switched output signals.
RC2 16 The fixed off times are set by the capacitors and resistors connected to these pins. t off
Vref1 26 Output current settings
Vref2 17 The output current is determined by the voltage (in the range 1.5 to 7.5V) input to these pins.
PHASE1 25 Output phase switching inputs.
PHASE2 18 [H] input : OUT A = high, OUT B = low
[L] input : OUT A = low, OUT B = high
ENABLE1 24 Output on/off settings
ENABLE2 19 [H] input : output OFF
[L] input : output ON
I01, I11 22, 23 Digital inputs that set the output current
I02, I12 21, 20 The output currents can be set to 1/3, 2/3, or full by setting these pins to appropriate combinations of high and low levels.
VCC 28 Logic block power supply.

[3] Circuit description of CIS unit

1. CIS
CIS is an image sensor which puts the original paper in close contact
with the full-size sensor for scanning, being a monochromatic type
with the pixel number of 1,728 dots and the main scanning density of
8 dots/mm.
It is composed of sensor, rod lens, LED light source, control circuit
and so on, and the reading line and focus are previously adjusted as
the unit.
Due to the full-size sensor, the focus distance is so short that the set
is changed from the light weight type to the compact type.
2. Waveforms
The following clock is supplied from LC272DOBT-WA6 via 74HCT244
on the control board, and AO is output.
CISSI
CISCLK
AO
Pin Description
1.2 ms
1.52 MHz
Fig. 7
5 – 15
CR
Approx. 5 V
0V
Approx. 5 V
0 V
1.5 V (TYP)
(White original paper)
FO-4400U
FO-CS1