Light Sensor for Dimming Displays

June 12, 2008
Melexis announces the MLX75304, a new SensorEyeC™ series light sensor designed for dimming LCD displays. Typical applications include dimming mobile phone and notebook screens. In automotive applications the MLX75304 Light-to-Frequency SensorEyeC is specifically effective for instrument panel dimming and headlight control.The MLX75304 enables excellent screen readability under all circumstances. Under extremely low light conditions the device will adjust the display brightness for perfect reading comfort. During bright light conditions the sensor will maximize screen lighting producing the best possible visibility. The sensor’s very broad dynamic range, in excess of 100dB, makes it appropriate for all light situations.This sensor is a monolithic integrated sensor where photodiode, transimpedance amplifier and output stage are integrated onto one chip to minimize manufacturing cost. In addition, this approach produces a highly linear response and a low temperature dependency. A second cost saving benefit results from the inclusion of a frequency output, which assures high precision control under all lighting conditions while simultaneously simplifying the sensor interface. In fact, obtain a precise readout of the ambient light level the only requirement is a digital input to either a small microcontroller or counter. Because of its small 3mmx3mm SMD package and its 260°C solder reflow compatibility, the sensor is perfectly fit for high-volume PCB assembly lines.