The TSL2672 family of devices provides proximity detection when coupled with an external IR LED. The devices incorporate a constant-current LED sink driver to pulse the external IR LED and achieve very low average power consumption using the low power wait state with programmable wait time between proximity measurements. In addition, the devices are register-set and pin-compatible with the TSL2671 series and include a number of new and improved features, such as improved signal-to-noise and measurement accuracy. A proximity offset register allows compensation for optical system crosstalk between the IR LED and the sensor. To prevent false measurements, a proximity saturation bit indicates that the internal analog circuitry saturated. Interrupts have been enhanced with the addition of a sleep-after-interrupt feature that also allows for single-cycle operation.
The device is an advanced proximity sensor. The slim module incorporates an IR LED and factory calibrated LED driver. The proximity detection feature provides object detection (e.g. mobile device screen to user’s ear) by photodiode detection of reflected IR energy (sourced by the integrated LED). 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 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.