The invention relates to methods for controlling the output of decorative lighting systems, for example a string of holiday lights. The patent describes the use of the I2C communications protocol, which provides high data rate and addressing capabilities both to individual LED clusters and to strings of such clusters that comprise a decorative lighting system.
The I2C protocol, says the patent, permits universal control of individual LED clusters in a decorative lighting system by way of a command controller, and advantageously permits individual controller-less and autonomous designs.
Carpenter has previously been granted another patent in related areas and has other patents pending – see Carpenter patent reveals new LED control technology and Color Kinetics responds to Carpenter article.
According to one embodiment of the invention described in US patent number 7,327,337, a decorative lighting system comprises a command controller, a plurality of lighting devices (each containing several LEDs) and a flexible cord interconnection. The command controller generally comprises a microcontroller for providing a data signal and a clock signal. The data signal typically includes instructions related to a plurality of addresses corresponding to the lighting devices. A power supply on the command controller provides a power signal for powering the pluralities of illumination devices. The flexible cord comprises at least two conductors capable of carrying the data signal, clock signal, and power signal from the command controller.
Each multi-LED illumination device contains an integrated circuit LED driver that is electrically interconnected to the command controller. The IC is responsive to the data signal, clock signal, and power signal and drives the LEDs accordingly, determining their blink rates and intensities. One variant of the IC includes a plurality of pulse-width modulation (PWM) registers that are selectable in combination to drive the LEDs to a blink rate and intensity independent of one another.