Power Electronics

Ambient Light Sensor for Intelligent Daylight Harvesting

Austriamicrosystems introduced the TSL4531 ambient light sensor family, which enables sophisticated daylight harvesting for intelligent lighting systems and luminaires. The sensor family - developed by TAOS, the leading global supplier of intelligent light sensors acquired by austriamicrosystems in 2011 - offers a wide sensitivity range from 3 lux to 220,000 lux, preventing saturation even in direct sunlight while implementing a photopic response model that spectrally matches light perception in the human eye.

The TSL4531 ambient light sensor provides a simple, direct lux output and a 16-bit digital interface. Sophisticated filters automatically reject the 50-60 Hz ripple typically produced by a building's fluorescent lighting systems, enabling the sensed light levels to more accurately measure the daylight that is entering the building.

Daylight harvesting is the next major step in the development of integrated lighting systems, enabling luminaires to dim in response to the amount of outside light that is entering a building through windows or skylights. By supplementing the working space with only the amount of light needed to maintain a uniformly lit environment, energy savings of 30% or more can be realized when compared to existing installations, which do not respond to changes in ambient light.

TSL4531 Features

  • Direct lux output
  • Approximates the human eye's spectral response in diverse lighting conditions
  • Three user-selectable integration times: 400 ms, 200 ms, and 100 ms
  • Dynamic range: 3 lux to 220,000 lux
  • Active current: 110 µA, typical
  • Power down mode: 2.2 µA, typical
  • 16-bit digital output compatible with I2C interface
  • 2 mm x 2 mm ChipLED package
  • 2.5 V supply voltage with 1.8 V logic interface
  • Rejects 50 Hz/60 Hz lighting ripple
  • Available now in volume production
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