Hitachi, Ltd. (TSE: 6501) today announced the HD66761 LCD controller driver, providing single
-chip drive for STN color graphics LCD panels with the industry's largest display screen size
of 128 x 80pixels, and capable of displaying 256 colors, for use with liquid crystal displays
on mobile communication terminals such as digital mobile phones with a built-in simple browser.
Sampleshipments will begin on May 18, 2000 in Japan.
With the HD66761, 256-color display can be achieved on landscape or portrait format color LCD
panels of up to 128 x 80 pixels, using a single chip, or up to 128 x 160 pixels, using two
chips,enabling portable mobile communication terminals to handle information distribution
services such as e-mail and WWW contents including Internet color images.
Digital mobile phones are rapidly becoming widely used not only as telephone voice terminals,
but also as data communication terminals handling information distribution services such as
e-mail and WWW contents. With the growing volume of display information involved in image
display, in addition to text-based displays such as phone numbers and kanji messages,
the trend in small LCD panels on portable phones is to color graphics display capability
and larger size.
Hitachi has previously released the four-grayscale monochrome display HD66750/751
(128 x 128 dots) and HD66752 (168 x 132 dots) as STN liquid crystal display drivers for mobile
communicationterminals. To meet the strong market demand for color display capability, Hitachi
has now developed the HD66761 LCD driver offering single-chip implementation of a 256-color
display with a 128 x 80-pixel screen size.
When using a 12 x 12-pixel kanji font, up to 60 characters (6 lines of 10 characters) can be
displayed with a single HD66761 chip, while using two chips in a coupled configuration by means
of the master-slave function makes possible a display of up to 120 characters
(12 lines of 10 characters), sufficient for longer e-mail messages. In addition, on-chip bit
operation functions*1 provide smooth processing of largeamounts of data, such as color image
data, making it possible to greatly reduce the graphics processingload on the microcomputer
software.
Larger screen sizes and color display capacity not only require a higher LCD drive voltage, but
are also associated with lower display quality and increased current dissipation.
The HD66761 has an on-chip maximum 7x step-up circuit. With color display on a 128 x 80-pixel
screen requiring an LCD drive voltage of approximately 14 V, use of the step-up circuit enables
an LCD drive voltage of approximately 15.4 V at 2.2 V power supply voltage.
To counter any decrease in display quality, the LCD drive voltage generation op-amp and step-up
circuit drive current can be controlled by software, allowing current dissipation to be held
down to the minimum necessary level while maintaining display quality. Also, since image
display involves higher LCD panel power consumption, and greater voltage fluctuations, than
text display, contrast variations are also greater. However, an on-chip voltage regulation
circuit enables the voltage to be stabilized and contrastvariations to be suppressed.
The HD66761 employs the C-pattern LCD drive method used in large LCD display systems. With
this method, the alternation frequencies of the illuminated and non-illuminated parts of
the LCD display are made uniform, reducing the crosstalk noise due to contrast variations
associated with alternation frequency deviation.
To reduce current dissipation, a partial display function is provided that enables only a part
of the screen display area to be driven. The upper and lower display areas can be driven
independently, enabling display to be performed with a lower LCD drive duty*2. For example,
when displaying seven lines of icons at the top of the screen and 17 message lines in
the center, both displays can be driven at a duty of 1/24.
Supported mounting methods are COF*3 mounting, in which the device is mounted face-down
on a flexible film substrate, and TCP*4 mounting, in which the device is connected directly
to the LCD glass.
Hitachi plans to extend the product lineup in the future with the development of models capable
of handling even larger screen sizes.
Notes: 1.Bit operation functions: Data processing functions that perform data rewriting and
computational operations in display RAM for individual display dots.
2.LCD drive duty: Ratio of the drive time for a single line on an LCD screen to the
time for one frame of which the line is a part.
3.COF (Chip On Film): A mounting method in which a die with gold bump is directly
mounted face-down on a flexible film substrate.
4.TCP (Tape Carrier Package): A package in which the chip is mounted on a thin-film
tape. Ultra-thin type mounting is possible.
< Typical Applications >
· Mobile phones handling e-mail and WWW contents services
· Mobile phones supporting high-speed data transfer (W-CDMA, GSM)
· Small PDAs, handheld GPS terminals, handheld POS terminals
· Portable digital audio players
< Prices in Japan > (For Reference)
Product Code | Shipment Form | Sample Unit Price (Yen) |
HCD66761BP | Die with gold bump | 1,600 |
HD66761TB0 | Bending TCP | 2,200 |
< Specifications >
Item | HD66761 Specifications |
Display size | 128 x 80 pixels, 256 colors |
Number of outputs | 384 segment outputs 80 common outputs |
On-chip RAM for display | 81.92 kbits |
Display functions | · Hardware color window cursor display (arbitrary rectangular area: 8 colors specifiable) · Split-screen partial display function (screen division at arbitrary line) · 4-pixel-unit horizontal scrolling |
Bit operation functions | · Write data mask function (bit units) · Bit operation function (pixel units) · Specified color comparison drawing decision function |
LCD drive duty | 1/16 to 1/80 (programmable in 8-line units) |
LCD drive bias | 1/5 to 1/10 (programmable) |
LCD drive step-up circuit output | 4x, 5x, 6x, 7x (programmable) |
Interface | 68/80-type 8/16-bit bus interface |
Write cycle | 300 ns |
Logic power supply voltage | 2.2 V to 3.6 V |
LCD drive voltage | 5 V to 15.5 V |
Shipment forms | · Die with gold bump (for COF mounting) · Bending TCP |
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