Carriage Unit; Ccd Pwb; Dc Power Circuit - Sharp AR-M207 Service Manual

(11) Carriage unit

a. General
The carriage unit is provided with the CCD PWB, the inverter PWB, and the lamps. It scans documents and transfers AD-converted image data to the
ASIC.
b. CCD PWB
The CCD on the CCD PWB employs the color image sensor uPD8861 of 5400 pixels x 3 lines, and scans documents in the main scanning direction in
the resolution of 600dpi/US letter size.
Image data scanned by the CCD are inputted to the AFE (AD9826), and subject to CDS, amplification, and AD-conversion. Then digital data are
outputted to the MCU PWB and to the ASIC, which performs image process of the digital data.
c. Lamp inverter PWB
The transformer is controlled by the lamp control signal from the MCU PWB. The transformer output controls lighting of the cool cathode ray tube.
B. DC power circuit
The DC power circuit directly rectifies the AC power and performs switching-conversion with the DC/DC converter circuit, and rectifies and smoothes
again to generate a DC voltage.
The constant voltage control circuit is of +5VEN. +24V are of the non-control system by winding from the +5VEN winding. As shown in fig (1), +24V,
and +5V are provided with the ON/OFF function by external signals. +3.3V is outputted from 24V to the step down converter.
Refer to the block diagram.
AR-M207 M165 M162 ELECTRICAL SECTION 13-7