SED1354 Datasheet, PDF (311/472 Pages) Epson Company – Color Graphics LCD/CRT Controller

Epson Research and Development
Vancouver Design Center
Page 11
2.1.4 CRT Support
The SED1354 has all the necessary signals to interface to an external RAMDAC so a CRT is
supported. The Brooktree Bt481A RAMDAC is supported on the SDU1354-D9000 evaluation
board.
Refer to the Programming Notes and Examples, document number X19A-G-002-xx for
programming details.
2.1.5 Adjustable LCD BIAS Power Supply
Most color 640x480 passive LCD panels require a positive power supply to provide between +23V
and +40V (I_out = 45mA). For ease of implementation, such a power supply has been provided as an
integral part of this design. The signal VDDH can be adjusted by R16 to provide an output voltage
from +23V to +40V and is enabled / disabled by the SED1354 control signal LCDPWR.
LCDPWR is an output signal which follows a pre-defined power-up / power-down sequence
designed to protect the LCD panel from damage caused by the power supply being enabled in the
absence of control signals. Determine the panel’s specific power requirements and set the potenti-
ometer accordingly before connecting the panel.
Evaluation Board User Manual
Issue Date: 98/10/29
SDU1354-D9000
X19A-G-003-04