CalDriCon is an electrical digital signaling interface that for high definition
liquid crystal displays
A liquid-crystal display (LCD) is a flat-panel display or other Electro-optic modulator, electronically modulated optical device that uses the light-modulating properties of liquid crystals combined with polarizers to display information. Liq ...
(LCDs) for
high-definition televisions and mobile handsets. It was originally developed by
THine Electronics, Inc.
Outline of CalDriCon
CalDriCon is a clock separated point-to-point interface with a data rate up to 2.0 Gbit/s/lane.
CalDriCon searches the best sampling point at the receiving devices and finds the best pre-emphasis level at the transmitting devices in order to adjust.
The pre-emphasis at the transmitter enables to keep good quality of signal integrity. Because of this feature the set systems can use low-cost cables to achieve stable high-speed data transmission.
Terminating both of the transmitting side and the receiving side enables to reduce bad reflection effects from multi-drop points.
CalDriCon can reduce pin counts and cables for transmission of high-definition pixel data that resulted in lowering total costs and required space for internal interface systems.
History of developing high-speed LCD driver interfaces
In around 2000,
LCD-panels often selected high-speed driver interfaces such as mini-LVDS, developed by
Texas Instruments
Texas Instruments Incorporated (TI) is an American multinational semiconductor company headquartered in Dallas, Texas. It is one of the top 10 semiconductor companies worldwide based on sales volume. The company's focus is on developing analog ...
, and
RSDS (Reduced Swing Differential Signaling), developed by
National Semiconductor
National Semiconductor Corporation was an United States of America, American Semiconductor manufacturing, semiconductor manufacturer, which specialized in analogue electronics, analog devices and subsystems, formerly headquartered in Santa Clara, ...
.
However, as full
HD televisions were launched in 2005 and full HD with double frame rate in 2007, higher-speed demands in
high-definition televisions have required advanced technologies in driver interfaces. In such situation, new LCD driver interfaces such as Advanced PPmL and CalDriCon have appeared to solve the constraints of high-speed technologies.
Comparison among LCD driver interfaces
Among new LCD driver interfaces, CalDriCon satisfies both of high-speed requirements of 2.0 Gbit/s/lane and noise tolerances against unstable power sources and grounds as well as auto-adjustment of
skew between
clock
A clock or chronometer is a device that measures and displays time. The clock is one of the oldest Invention, human inventions, meeting the need to measure intervals of time shorter than the natural units such as the day, the lunar month, a ...
and
data
Data ( , ) are a collection of discrete or continuous values that convey information, describing the quantity, quality, fact, statistics, other basic units of meaning, or simply sequences of symbols that may be further interpreted for ...
.
{, class="wikitable"
, style="background-color:#f8f8f8" align="center" colspan="4" ,
Comparison among LCD driver interfaces
, -
! name !! mini-LVDS !! Advanced PPmL !! CalDriCon
, -
, Data rate per lane , , ~300 Mbit/s , , ~2.0 Gbit/s , , ~2.0 Gbit/s
, -
, Connection , , Bus topology , , Point-to-Point , , Point-to-Point
, -
, Signal integrity distortion by multi-drop , , Appear , , Not appear , , Not appear
, -
, Skew adjustment between clock and data , , Not available , , Not required , , Auto-adjustable
, -
, Noise tolerance for unstable power sources and ground , , Strong: driver ICs do not have PLL circuits , , Weak: driver ICs have PLL circuits , , Strong: driver ICs do not have PLL circuits
As driver ICs are generally loaded as
COF (chip-on-film), they are often affected by noises from unstable power sources and ground. While mini-LVDS and
RSDS were based on
differential signaling
Differential signalling is a method for electrically transmitting information using two complementary signals. The technique sends the same electrical signal as a differential pair of signals, each in its own conductor. The pair of conduc ...
and relatively tolerant for noise, they have faced difficulties to achieve higher-speed performance than 1 Gpbs because of no skew adjustment between clock and power.
On the other hand, many of advanced LCD driver interfaces, using
CDR (or clock data recovery) technology, remove the necessities to adjust skew between clock and data and achieved higher data rate over 1 Gbit/s. However, CDR technology requires having
PLL circuits on receiving driver
ICs. COF is easily affected by the noise of power source and ground.
CalDriCon, instead of using CDR, detects the optimal sampling points at receiving driver ICs and adjust the transmitting phase between clock and data. This feature achieves both of high-speed of 2 Gbit/s and noise tolerances in unstable power sources and ground as well solution of skew adjustment.
In addition, CalDriCon and many other advanced driver interfaces adopt Point-to-Point connection that brings much less distortion of signal integrity even in the multi-drop connection than mini-LVDS that is often affected by noise because of its
bus topology.
See also
*
Low voltage differential signaling
Low-voltage differential signaling (LVDS), also known as TIA/EIA-644, is a technical standard that specifies electrical characteristics of a differential, serial signaling standard. LVDS operates at low power and can run at very high speeds u ...
*
V-by-One HS
References
* “Trend of high-speed in LCD driver: 2 Gbps becomes available,” Nikkei Electronics (Nov.01,2010, pp. 12～pp. 13）
External links
THine Electronics
Computer buses