Epson Stylus Photo RX640 series, Service Manual

Page: 18 / 103

EPSON Stylus PHOTO RX640/650 Revision A
Operating Principles Operating Principles of Electric Circuitry 18
2.2 Operating Principles of Electric Circuitry
2.2.1 Overview
The major circuit boards of Stylus PHOTO RX640/650 are as follows:
„
Main Board: C608MAIN
„
Power Supply Board: C608PSB/C608PSE
„
Panel Board: C608PNL and C608PNL-B
„
CCD Unit Board (Scanner): C608ISN
„
USB I/F Board : I/F Board Assembly
2.2.2 Features
„
High-Speed SPC is realized without HUB, thanks to employment of USB 2.0
multi-end point.
„
An SOC incorporating the printer controller, scanner controller, PT controller
and CPU Super Macro is realized.
„
Only one CPU (SH2A by RENESAS) controls the printer, scanner and PT
section.
„
Equipped with one 64-Mbit Flash ROM (with 16-bit bus width) and one 32-
Mbit Flash ROM (with 16-bit bus width).
(Flash ROM or MASK ROM is mounted)
„
Equipped with one 256-Mbit SDRAM (16-bit bus width) for ASIC local
buses, and one 256-Mbit SDRAM (16-bit bus width) for CPU bus.
„
Low cost of logic power supply and motor drive is realized by employment of
motor drivers with built-in power supply.
„
The band width is ensured by setting the operating frequency of the local
SDRAM of SOC at 96 MHz.
„
High-speed processing is ensured because all the processing from scanning to
binarization, Microweave, and image buffer generation is carried out inside
the SOC, without via the CPU bus.
„
The size of the MW buffer is reduced to 1/3 of the conventional size by
employment of UBEC (Ultra Block Encode).
„
Equipped with a color LCD (2.5-inch low-temperature poly-silicon TFT
liquid crystal) as a standard feature.
„
Power consumption is suppressed by executing the following actions at
transition to the power save mode.
•
Lowering the supply voltage for main power
•
Cutting off the photo-electric current of the photo sensor
•
Stopping the motor drive circuit
•
Stopping the UDL clock inside the ASIC
•
Entering the CPU core low consumption mode
•
High efficiency power supply circuit
•
Stopping excitation of the printer motor
•
Stopping the head drive circuit
•
Turning off the CCD scanner power supply and stopping the excitation of the
scanner motor
•
Turning off the preview monitor
2.2.3 Circuit Board Constitution
Table 2-5. Circuit Board Constitution
Circuit Board Description
Main
Board
System section
†
Logic circuits (ASIC incorporated in the CPU core, Flash ROM
x 2, and SDRAM x 2)
†
Interface circuit (USB 2.0, USB 1.1 Host)
†
RTC circuit
†
Color LCD interface
†
Panel interface
†
IrDA circuit
Power Supply
section
†
Regulator circuit
†
Power switch circuit
†
Overvoltage protection circuit
Printer section
†
Motor control and drive circuits (PF, CR)
†
Head control and drive circuit
†
Sensor circuits (PE, PF, PW, APG, CDR 1 and 2)
Card ASIC section
†
Logic circuit (ASIC)
†
Card power supply control circuit
Scanner section
†
Scanner interface circuit
†
Motor control and drive circuit (Scanner)
†
Scanner HP detection interface circuit
†
TPU interface circuit
Panel Board
†
Power switch circuit
†
Switching circuit
†
LED circuit
ISN Board
†
CCD control and A/D conversion circuit
†
Optical sensor circuit
LCD Board
†
LCD control circuit
†
LCD module
†
SDRAM