Reveals New LED Control Technology
October 16, 2006
Carpenter Decorating has patented a fundamentally new and different LED
lighting control method for networking color-variable decorative LED lighting.
US patent number 7,015,825, awarded in March 2006 to Carpenter Decorating, could
become one of the more significant patents as far as members of the LED lighting
community are concerned.
The patent describes a new concept in networking color-variable decorative LED
lighting. As such, it is a core technology that sits as a direct alternative to
Color Kinetics' Chromasic technology, which has been widely licensed throughout
the LED industry.
Carpenter Decorating is a 75-year-old veteran and leader in seasonal lighting
and signage. Jeffrey Callahan, the named inventor on the patent, explained to
LEDs Magazine that the technology was developed in collaboration with Philips
Semiconductors, which is now NXP.
"We worked with Philips/NXP for more than 3 years to develop the technology,"
says Callahan. "They showed great support for the core concept ideas from the
very start and contributed their IC engineering genius." Philips has already
launched an IC that enables the applications described in the 7,015,825 patent.
"Our patent covers the use of the new technology in solid-state lighting
applications, color variability, and networked lamps and fixtures," says
Callahan. "Philips [now NXP] retains its use in cellphone backlighting and other
non-solid-state lighting applications." In fact, NXP informs customers that they
must license the 7,015,825 patent if they want to develop products in the
application areas covered by the patent.
Callahan describes the technology as a "fundamentally new and different LED
lighting control method", rather than using old technologies such as DMX to dim
multicolor LED fixtures using PWM. "We have demonstrated that LED lighting
devices in numerically addressed lighting networks can be achieved using
low-level, high-drive I2C network constructs," he says.
The NXP chip in question is the PCA9633, the first IC to use the new 1 MHz Fast
Mode+ I2C logic bus (see our in-depth article for more details). Compared with
the basic I2C bus, the new standard enables much greater distances and greater
Callahan explains that the ICs are numerically addressable and can either
directly drive RGB and RGBA LEDs or interface easily to external drivers to
control much larger solid-state lighting arrays. The chips allow for individual
control of each LED connected to each output bit and can be controlled globally
or broken up into subgroups.
The older version of I2C had numerous issues relating to control distance as
well as LED driver addressing and color mixing, but these were all broken down
by the developments revealed in the patent. "No-one thought that the decades-old
I2C bus could be revamped so well into the FM+ standard, and then used so
imaginatively for wide-area color variable LED lighting control," says Callahan.
Callahan explains that master/slave FM+ I2C solid-state lighting network
topologies open up a number of new avenues for the LED luminaire dimming and
color mixing control community. These include bus bi-directionality for the
addition of lumen maintenance and color temperature sensors, and a broad host of
As more companies continue to sign licenses to gain access Color Kinetics'
patented technologies, and other companies continue to grumble about the
validity of these patents, Carpenter Decorating has made a significant
breakthrough by developing technology that uses a completely new approach to
controlling LED lighting fixtures.