Epson 875DC - Stylus Photo Color Inkjet Printer, Service Manual

Page: 23 / 66

EPSON Stylus PHOTO 875DC Revision A
OPERATING PRINCIPLES Overview 23
2.1.2 Power Supply Board
C364PSB/PSE, the power supply board of this printer, features the
following:
"
Logic line: +5V ± 5%, 0.95A
+3.3V ± 5%, 0.85A
"
Drive line: +42V ± 5%, 0.4A (maximum 1.4A)
"
Power supply control in the secondary power switch
!
The secondary side switching operation allows the printer to keep
supplying power to the both logic and drive lines for at least 30
seconds after the printer power is turned off.
!
If the AC plug is disconnected from the AC socket while the printer
power is on, voltage for the logic line is kept for at least 256ms.
2.1.3 USB Hub
2.1.3.1 Overview
The USB hub of this printer features the following:
"
Complies with the Universal serial bus specifications Rev. 1.0.
"
Not powered from the Vbus.
"
Self-powered hub
"
Two ports are used as the down stream ports. (Other two are not
used.)
"
Stand-alone type hub without CPU’s control
"
Vendor ID/product ID is built up to allow future support availability.
2.1.3.2 Hub Port Connection
When connecting to the USB, the hub IC (TUSB2043A) lets the printer
recognize the device in the following order:
1. Hub IC
2. Printer part
3. Card reader part