LED drivers and light sensors enable compelling displays
LED-based display backlighting continues to be the largest market for high-brightness LEDs despite the fact that the general-illumination application gets more notice.
Indeed light and proximity sensing is needed in devices based on LCDs to set the appropriate backlight level for maximum display quality without wasting power when ambient light is sufficient or when no one is present to view the display. Taos is targeting mobile devices such as smartphones and tablets with its new TSL2x72 family, although the company also expects the sensors to be used in computer-display and HDTV applications.
The new products include the TSL2572 family for digital ambient light sensing (ALS), the TSL2672 family for proximity detection, and the TSL2772 family that includes both light and proximity sensors.
To serve in mobile applications, the sensors must work in very bright environments and the new Taos products are designed for use in full sunlight at levels to 60,000 lx and beyond. “Mobile device vendors are continually striving to deliver more compelling products with an improved user experience; therefore, they demand ALS and proximity detection solutions capable of operating in a very wide range of lighting conditions,” said Jerry Koontz, TAOS Director of Marketing.
Taos uses programmable signal-gain modes, including a reduced-gain mode, to boost the dynamic range of the light sensors. Meanwhile the company boosted the signal-to-noise performance and added crosstalk-compensation technology to deliver more-accurate proximity detection. Both sensor types can be used sporadically while remaining in sleep mode much of the time to minimize power consumption – especially important in any battery-powered application.
The sensors work with any type of light source including fluorescent and at virtually any lighting level. Moreover the dual-diode architecture can provide accurate results even when mounted behind glass that can distort the spectrum.