The TSL2550 is a digital light sensor with a two-wire, SMBus serial interface. It combines two photodiodes and a companding analog-to-digital converter (ADC) on a single CMOS integrated circuit to provide light measurements over an effective 12-bit dynamic range. The TSL2550 is designed for use with broad wavelength light sources. One of the photodiodes (Channel 0) is sensitive to visible and infrared light, while the second photodiode (Channel 1) is sensitive primarily to infrared light. An integrating ADC converts the photodiode currents to Channel 0 and Channel 1 digital outputs. Channel 1 digital output is used to compensate for the effect of the infrared component of ambient light on Channel 0 digital output. The ADC digital outputs of the two channels are used to obtain a value that approximates the human eye response in the commonly used unit of Lux. This device is intended primarily for use in applications in which measurement of ambient light is used to control display backlighting such as laptop computers, PDAs, camcorders, and GPS systems. Other applications include contrast control in LED signs and displays, camera exposure control, lighting controls, etc. The integrating conversion technique used by the TSL2550 effectively eliminates the effect of flicker from AC-powered lamps, increasing the stability of the measurement. |