Control Circuit - Epson perfection 640U Service Manual

EPSON Perfection 640U

2.2 Control Circuit

The CPU (IC12) of this scanner is a one-tip 16-bit bus CPU operating at
16MHz. ASIC (IC9) 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 IC11
SDM4260CLU-6S IC6
BA033FP-E2 IC11
NJM78M05DLA-TE1 IC7
E02A32SA IC9
A3957SLBTR IC3, 4
M51953A IC10
MSM534052E IC8
CSACW48.00MX41013-T CR1
GP1S58V PC1
NJM2360 IC1, 2
NJM78M12 IC5
Operating Principles
Functions
CPU
24-bit Address Bus
16-bit Data Bus
DRAM 256k x 16bit
Regulator IC (3.3 VDC)
Regulator IC (5 VDC)
ASIC: Manages the following:
• Input image signal correction
• CCD control
• USB interface control
• Image processing
• Memory control
• Data in/output control
CR motor driver IC
Reset IC
Program ROM (512k x 8bit)
48MHz clock for E02A32SA
CR home position sensor
DC/DC Converter
3-terminal regulator (12 VDC)
Control Circuit
Figure 2-5. Control Circuit Diagram
RevIsion A
18