Epson Stylus Photo RX650 - Operating Principles of Electric Circuitry; Overview; Features; Circuit Board Constitution

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