Converters Simplify Ambient Light Sensing

Designed to ease ambient light sensing in display backlighting and keyboard illumination applications, the TSLxxxx light-to-digital converters transform light intensity into a digital signal capable of direct I2C or SMBus interfacing. Expected to extend battery life, the TSL2560 and TSL2561 allow display backlighting to be managed automatically. Both combine a visible light blocking photodiode with a broadband photodiode on a CMOS chip. This combination enables either device to be used to calculate light intensity in lux over a 20-bit dynamic range with a 16-bit resolution. Two ADCs convert the photodiode currents to an SMBus (TSL2560) or I2C (TSL2561) output that represents the irradiance measured on each channel. Shared features include the ability to measure light levels from 0.1 lux to 40,000 lux, operation from a single 2.7V to 3.3V supply, and a power consumption as low as 10.8 µW. Available in chip-scale and transfer-molded-board packages, price for either device is $1.29 each/1,000. An evaluation module with a USB interface is available for $125. TAOS INC., Plano, TX. (972) 673-0759.