ams TSL27721 Ambient Light Sensor

The TSL2740 includes both proximity detection and very-high sensitivity light-to-digital converter ambient light sensing (ALS) features. The proximity detection feature provides object detection using photodiode detection with reflected IR energy. The detect/release events are interrupt driven, and occur when proximity result crosses upper and/or lower threshold settings. The proximity engine features offset adjustment registers to compensate for unwanted IR energy reflection at the sensor. Proximity results are further improved by automatic ambient light subtraction. The ALS feature approximates the human eye response to light intensity under varying lighting conditions and transforms this light intensity to a digital signal output capable through a 1.8V I²C interface. The ALS sensor features 2 output channels, a visible channel and an IR channel. The visible channel has a photodiode with a photopic Interferometric UV and IR blocking filter and the IR channel has a photodiode with an IR pass filter. Each channel has a dedicated integrating data converter which converts photodiode current into a 16-bit digital output. This digital output can be interfaced with a microprocessor where illuminance in lux is derived to accurately measure ambient light to control a displays baklight.