Electrical Circuit Operating Principles; Power Supply Board; Main Board - Epson Stylus CX4300 Service Manual

EPSON Stylus CX4300/CX4400/CX5500/CX5600/DX4400/DX4450

2.4 Electrical Circuit Operating Principles

The electric circuit of Stylus CX4300/CX4400/CX5500/CX5600/DX4400/DX4450
consists of the following boards:

Main board:

PCBA MB

Power supply board:

ASSY POWER 110V/220V
Panel board: PCBA PB
The figure below shows the block diagram of this printer.
Panel Board
Main Board
Power Off +42VDC
Power Supply Board
Figure 2-7. Electrical Circuit Block Diagram
OPERATING PRINCIPLES
CR Motor
PF Motor
Printer
Mechanism
Head Driver Board
Sensors
Scanner Motor
Scanner
Mechanism
CIS Assy.
Electrical Circuit Operating Principles
2.4.1 Power Supply Board
In the Power Supply Board of Stylus CX4300/CX4400/CX5500/CX5600/DX4400/
DX4450, the simulated oscillating stimulation flyback converter circuit method is
used, and it supplies +42 VDC to the drive line. The application of the output voltage is
described below.
AC voltage input from AC inlet first goes through filter circuit that removes high
frequency components and is then converted to DC voltage via the rectifier circuit and
the smoothing circuit. DC voltage is then led to the switching circuit and FET QF1
preforms the switching operation. By the switching operation of the primary circuit,
+42VDC is generated and stabilized at the secondary circuit.
2.4.2 Main Board
The logic circuit of the Main Board is composed of the following:
Logic line (CPU-ASIC 4 in 1, Flash-ROM and so on)
Motor control/drive circuit (CR Motor, PF Motor, Scanner Motor)
Head control/drive circuit
USB I/F circuit
Sensor circuit
Reset circuit, EEPROM circuit
Table 2-5. Main Board Major Components and Primary Functions
IC Location
Drives CPU (H8S/2674 base), internal 8 K byte x 4 RAM,
CPU-ASIC U3
24 Mhz, 3.3 V/1.8V
SDRAM U4 3.3 V drive 4M x 16 bit DRAM
Serial Flash U5 3.3 V drive 4 M bit Serial Flash that stores the program
U6 Scanner motor drive; adjusts 5 V, drives 42 V
Motor Driver
U7 CR/PF motor drive; adjusts 5 V, drives 42 V
• EEPROM
Default settings, backup for all parameters
RTC U9
• Reset function
• Timer function
DAC U10 Generates trapezoidal waveform, drives 3.3 V
Revision A
Function
30