ams uses closed-loop sensing for tight LED light control

ams has introduced a power management IC for LED-based lamps and luminaires which uses closed-loop sensing to maintain more accurate correlated colour temperature (CCT) and lumen output.

AS7221 block diagram

Following the AS7221 smart lighting manager introduced earlier this year, this new device, the AS7220, combines a precise calibrated-for-life colour 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 colour shift and lumen depreciation of LEDs as a natural result of aging, operating temperature changes and driver variation over lifetime,” said the supplier.

Sensor-driven algorithms are used o allow for a more loosely CCT- and flux-binned range of cool-white and warm-white LEDs to achieve a high and stable quality of light.

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.