Hitachi, Ltd.(NYSE:HIT) today announces the release of
the HD66421 LCD controller/driver with bitmap RAM*1
provided on a chip. This device is designed for multifunction
portable telephones and other portable information equipment,
supports the large screen size of 160 x 100 dots, and achieves
four-level gray scale display or four-color display on reflective
color LCD panels for the first time in the industry. This product
can use high speed switching two plain of display, when monochrome
display mode. Sample shipments will begin in September 1998 in
Japan.
Recently, information and communication infrastructures have
been greatly improved and information can be acquired whenever and
wherever desired. In this context, a wide range of portable
information equipment has appeared on the market. There are now
strong desires for LCD displays used in these devices to be
enlarged to display even more information and to support graphical
displays to improve visual impact. To respond to these needs and
to achieve miniaturization and to reduce power consumption
required in portable information equipment, single-chip
implementations of LCD display systems, and gray scale and color
displays in the LCD controller driver circuit are required.
Hitachi is already mass producing the HD66410 LCD controller
/driver with on-chip bitmap RAM. This device is designed for use
in pagers and other multifunction portable telephone products and
can drive a 128 x 33-dot monochrome LCD in a single chip. To
further respond to these market needs, Hitachi has developed and
is releasing the HD66421.
The HD66421 includes 32k bits of bitmap RAM and an LCD drive
power supply circulation chip. At the same time as supporting a
160 x 100dot large screen display in a single chip for the first
time in the industry, the HD66421 also achieves monochrome
display, four-level gray scale display or four-color display with
reflective color LCD panels.
In monochrome display mode, two plain of display can be
selected in this mode using internal memory. These two operations
are independent of each other, thus one plain can be rewritten
while the other plain is displayed. This product can use high
speed switching two plain of display, when applications require
animated display.
Since the appearance of the displayed gray scale or colors
differs depending on the characteristics of the LCD panel used,
the HD66421 includes a 32-color palette and allows an arbitrary
four colors to be selected for optimal four-color display on the
LCD panel used. The HD66421 uses a variable pulse-width scheme to
implement the gray scale/color display, and thus achieves
four-level/four-color display without flicker or smear. The
HD66421 can also drive reflective color LCDs that use the ECB
(electrically controlled birefringence)*2 technique to
display four colors with the same drive circuit used for
monochrome displays. It is also possible to implement 160 x
200-dot displays or 320x 100-dot displays by connecting two chips
in a master/slave*3 configuration.
The HD66421 provides several power-saving features. One such
feature is a partial display mode. This modeallows only an
arbitrary 8 lines of the display to be driven, with the rest of
the display turned off. This can be used to reduce power in
standby mode. Another power-saving feature is the inclusion of the
divider resistor, voltage follower, and electronic potentiometer
circuit required for the LCD power-supply circuit. This allows
application circuits to be implemented compactly, and the
inclusion of the on-chip power-supply circuit can reduce the power
consumption of the LCD system as a whole.
The HD66421 is provided in a TCP (tape carrier package) format
to support light-weight and compact implementation of LCD display
systems. Future developments in this area will include modified
and enlarged display sizes and the incorporation of even more of
the power-supply system components into the IC itself to further
reduce the number of external components required in the
power-supply circuit.
Notes*
1.Bitmap RAM: Memory used to store the data bits corresponding
to the image to be displayed.
2. ECB (electrically controlled birefringence): Refers to LCD
panels that take advantage of the phenomenon thattransmitted light
that has been diffracted by liquid crystal molecules appears
colored. Multi-color displays can be implemented since the color
changes with the strength of the applied electric field.
Currently, panels that support 4 or 5 colors have been produced
commercially.
3. Master/slave connection: Refers to expanding the display
size by using two or more ICs with one operating as the master and
the other(s)operating as slave(s).
Application Product Examples
- Multifunction portable telephones
- Portable information equipment that includes communications
functionality
- Bi-directional pagers
Sample prices in Japan
|
Catalog No.
|
Sample Price (Yen)
|
|
HD66421TB0
|
1,200
|
Features
1. Large-screen drive circuit implemented in a single chip
The HD66421 achieves a 160 x 100-dot display in a single chip.
Although the 128 x 33-dot HD66410 currently in volume production
can display two lines with eight Japanese kanji characters in 16 x
16 dot kanji character, this new product can display six lines
with ten characters.
2. Support for gray-scale or color displays
Since the HD66421 supports arbitrary selection from a palette of
32 gray levels or colors, it supports optimal gray-level display
and can drive the reflective color LCDs that require subtle
voltage control. Also, the HD66421 uses a variable pulse-width
scheme to implement the grayscale/color display, and thus achieves
gray scale/color display without flicker or smear.
3. Support for partial displays
As a low-power mode, the HD66421 supports a mode in which only 8
line sat an arbitrary position are displayed. This mode achieves
reduced power consumption during standby by operating the LCD
drive outputs from only the logic operating power supply, which
makes the high voltage used for the LCD drive unnecessary.
Specifications
|
Item
|
Specification
|
|
Internal RAM capacity
|
32k bits (160 x 100 x 2)
|
|
Number of LCD
drive circuits
|
Segment outputs
|
160 outputs
|
|
Common outputs
|
100 outputs
|
|
Color/gray-scale display
|
Simultaneous display of four colors/gray levels from a
palette of 32 levels.
|
|
CPU interface
|
8-bit parallel 8086-compatible interface
|
|
Display duty
|
1/8, 1/64, 1/80, 1/100
|
|
Display control functions
|
Display on/off, vertical scroll, blinking, reverse
video, partial display
|
|
Oscillator circuit
|
CR oscillator (Only requires an external
resistor.)
|
|
Power-supply circuit
|
Bleeder resistor, voltage follower, electronic
potentiometer
|
|
Power-supply voltage
|
Vcc
|
2.2 V to 5.5 V
|
|
VLCD
|
6 V to 18 V
|
|
Package
|
TCP
|
WRITTEN BY Secretary's Office
All Rights Reserved,
Copyright (C)
1998, Hitachi, Ltd.
