Osram Opto Semiconductors unveils a light sensor that detects ambient brightness in the same way as the human eye. The SFH 5712 sensor offers not only standard data rates but also high-speed rates of up to 3.4MHz. Without the need for any additional control commands, an IC in the sensor automatically provides a measured value between 3-65,000 lux twice a second. The sensor has only four connections and takes up very little space, measuring just 2mm x 2mm x 0.7mm. It is controlled via an integrated I²C interface.
"The benefits of our digital ambient light sensor are obvious," said Werner Kuhlmann, development manager for silicon detectors at Osram. "The sensor digitally transmits the true lux value so there is no need for complicated formulas to calculate an appropriate value from the output signal. This saves one operation in the application. It is also insensitive to mains-power related 50-60Hz flickering that is produced for example by fluorescent lamps." With 150µA during operation and only 1.5µA in stand-by mode the sensor consumes very little power.
The SFH 5712 is primarily intended for mobile applications in which the brightness of the display is constantly adjusted according to available ambient light. This extends the interval between recharges and therefore improves the service life of the devices. The main beneficiaries are cellphones, PDAs, navigation devices, netbooks and laptops. Ambient light adjusted brightness also improves readability. A good legible display on satellite navigation devices is not just highly convenient but also an important safety aspect.
For application notes on light sensors click here.
Keywords:
image sensor
I²C interface
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