Control Circuit - Epson 1240U Service Manual

EPSON Perfection 1240U

2.2 Control Circuit

The CPU (IC12) of this scanner is a one-tip 16-bit bus CPU operating at
20MHz. ASIC (IC10) manages input signal correction, image processing, and
controlling the CCD sensor board and USB interface. The power supply control
uses a DC/DC converter to generate 5 V and 12 V signals from the 24 V DC
input. Table 2-1 shows the major IC functions.
Table 2-1. Major ICs
IC Location
M37920 IC12
MB81F6416420-102 IC13
IS61C6416 IC17
E02A32SA IC10
A3957SLBTR IC4,5
M51953A IC11
M27C1001-10F1 IC9
IS61C256AH IC16
GP1S58V PC1
NJM2360 IC1,2
AD9822 IC19
E02A35BA IC14
SSR20.00BA CR1
NJM78M12 IC8
Operating Principles
Functions
CPU
24-bit Address Bus
16-bit Data Bus
SDRAM 4M x 16bit
SRAM 64k x 16bit
ASIC: Manages the following:
• Input image signal correction
• CCD control
• Line control
• Image processing
• Memory control
• Data in/output control
CR motor driver IC
Reset IC
PROM 4M x 8bit
SRAM 32k x 8bit
CR home position sensor
DC/DC Converter
8bit A/D Converter
USB interface control
Clock 20MHz
Regulator (12VDC)
Control Circuit
CCD Board
Image Data
(R/G/B)
Lamp
&
Inverter Board
Reset IC
(IC11)
Regulator
DC/DC
+12VDC
(IC8)
+24VDC Converter
(IC1,2)
+5VDC
+24VDC
Figure 2-5. Control Circuit Diagram
Revision A
SRAM SDRAM USB
(IC17) (IC13)
A/D 8-bit
Data
Converter
(IC19) USB
E02A34EB (IC10)
Controller
(IC14)
Address Bus
Data Bus
PROM
( IC9)
CPU (IC12)
CLK(CR1)
CR Motor H.P.
Option
CR
Sensor
Driver
Motor
( PC1)
(IC4,5)
SRAM
(IC16)
20