ams’s new ‘Smart Lighting Manager’ chip enables a new generation of higher-quality LED-based lamps and luminaires for smart LED lighting manufacturers. The AS7221 uses closed-loop sensing to maintain more accurate correlated color temperature (CCT) and lumen output while also lowering system bill of materials costs, contends the firm.
Integrated tri-stimulus XYZ color sensor and intelligent driver management in new AS7220 enable high accuracy closed-loop maintenance of LED outputs in industrial, commercial and high-end residential lighting products.
The AS7220 follows the launch in Jan 2017 of the AS7221 that offered full white color tuning and daylighting features. It combines a precise calibrated-for-life color sensor with an intelligent Cognitive Lighting Engine for standalone closed-loop maintenance of the output from strings of warmer and cooler white LEDs. The result is a luminaire which automatically adjusts for the color shift and lumen depreciation of LEDs as a natural result of aging, operating temperature changes and driver variation over lifetime.
The AS7220’s embedded tri-stimulus CIE XYZ color sensor enables accurate and stable CCT control. It directly maps the sensor channel data to the CIE 1931 color space. Nano-optic interference filters deposited on the die of AS7220 devices offer high stability and virtually no degradation over time and temperature.
The sensor system’s LGA package, which measures just 4.7mm x 4.5mm x 2.5mm, includes a built-in aperture with a ±20.5° field of view.
The chip is able to deliver factory-calibrated CCT values typically accurate to within .002 du’v’ (approximately 2-3 Macadam steps) across its -40 to +85 degree C operating temperature range.
The AS7220 is easy to integrate into LED lighting system designs. After the desired CCT and/or full-output lumen values are programmed into it on the production line, it autonomously implements closed-loop color and output control of the LEDs inside a luminaire or lamp.
Control of the power supplied to LED strings is implemented via either digital switching of multichannel power supplies, or through a combination of PWM current steering combined with an analog or digital output to standard single-channel 0-10V or PWM-input dimming ballasts or drivers.
“A continuing challenge in the LED lighting industry is to deliver precisely the same color and output not only over changes in operating temperature, but over the years of service life that customers expect”, said Tom Griffiths, Senior Marketing Manager at ams.
“While LEDs are well characterized for their first years of operation, longer term predictive models reveal variability in color and brightness. In addition, LEDs are evolving so fast that the same parts are unlikely to remain the cost-effective choice for the same model of luminaire even as little as one year after going into production, introducing still more variation from light to light”, he added.
The firm noted that by adding closed-loop sensing, luminaire manufacturers free themselves from these technology and supply constraints, lowering BOM costs and gaining both consistency and a wider basis for component selection, while delivering more precise lighting quality over lifetime.
The AS7220 is pre-configured for optional operation with an external ams ambient light sensor to additionally provide for autonomous daylight harvesting using standard 0-10V dimming inputs.
The chip also provides a direct interface to standard occupancy sensors to enable intelligent dimming control and energy-saving schemes.
The AS7220 Smart Lighting Manager is available now in production volumes. Unit pricing is $2.81 in order quantities of 10,000 units. An evaluation kit for the AS722x family is available.
For more technical information, visit www.ams.com/Smart-Lighting-Manager/AS7220
To view the full Press release, click here.