Low Power Ambient Light-to-Voltage Non-Linear Converter

The ISL29102 is a low cost, light-to-voltage silicon optical sensor combining a photodiode array, a nonlinear current amplifier, and a micro-power op amp on a single monolithic IC. Similar to human eyes, the photodiode array has peak sensitivity at 550nm and spans from 400nm to 600nm, rejecting UV light and IR light. The input luminance range is from 0.3 lux to 10,000 lux. The integrated nonlinear current amplifier boosts and converts the photodiode signal in a square root fashion, extending the light input dynamic range, while maintaining excellent sensitivity at dim conditions with low lux levels. The device consumes minimal power over a wide range of ambient lux levels because the current consumption ramps at a square root fashion. A dark-current compensation circuit minimizes the effect of temperature-dependent leakage currents in the absence of light, improving the light sensitivity at low lux levels while maintaining excellent sensitivity at low lux levels. The built-in 1μA op amp gives the ISL29102 an output voltage driving advantage for heavier loads. The ISL29102 is housed in an ultra-compact 2mm x 2.1mm ODFN plastic case surface mount package. Operation is rated from -40 °C to +85 °C.