Operating Principles Of Electric Circuitry; Overview; Features; Circuit Board Constitution - Epson Stylus PHOTO RX640 Service Manual

EPSON Stylus PHOTO RX640/650

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:
Power Supply Board:
Panel Board:
CCD Unit Board (Scanner):
USB I/F Board :

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
Operating Principles
C608MAIN
C608PSB/C608PSE
C608PNL and C608PNL-B
C608ISN
I/F Board Assembly
Operating Principles of Electric Circuitry
• 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
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)
System section
RTC circuit
Color LCD interface
Panel interface
IrDA circuit
Regulator circuit
Power Supply
Power switch circuit
section
Main
Overvoltage protection circuit
Board
Motor control and drive circuits (PF, CR)
Printer section
Head control and drive circuit
Sensor circuits (PE, PF, PW, APG, CDR 1 and 2)
Logic circuit (ASIC)
Card ASIC section
Card power supply control circuit
Scanner interface circuit
Motor control and drive circuit (Scanner)
Scanner section
Scanner HP detection interface circuit
TPU interface circuit
Power switch circuit
Panel Board
Switching circuit
LED circuit
CCD control and A/D conversion circuit
ISN Board
Optical sensor circuit
LCD control circuit
LCD Board LCD module
SDRAM
Revision A
Description
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