MC8201中文资料Ambient Light Sensor数据手册ABOV规格书

描述 Description

The MC8201 integrates ALS(Ambient Light Sensor), PS(Proximity Sensor) and IR LED(Light Emitting Diode) driver in a single die, and can be merged with IR LED in a extremely small package. It is an advanced digital ambient light sensor and proximity sensor, which can transform illuminance (light intensity) to a digital signal output and detect proximity of object.
For ambient light sensing, it combines an opened photodiode and a light shielded photodiode which is used to reduce dark noise. The opened photodiode is capable of providing a photovoltaic response and coated with Infra Red cut off filter on a CMOS integrated circuit. The photovoltaic response is converted into digital counter value by the ALS ADC of 16-bit resolution. It closely approximates the human eye spectral response of visible wavelength.
In addition, the MC8201 has another opened photodiode with IR pass filter in order to detect proximity of an object. When PS is enabled, the IR LED is turned on by the built-in IR LED driver. When the IR from the LED reaches an object and gets reflected back, the opened photodiode for proximity sensing converts the reflected IR light with center frequency of 940 nm into current. The amount of current is converted into digital counter value by the PS ADC of 10-bit resolution. The counter value is inversely proportional to the square of the distance between the sensor and the object. The proximity detection feature operates well from bright sunlight to dark rooms. The wide dynamic range also allows for operation in short distance detection behind dark glass such as a cell phone. The operation voltage ranges from 2.4 V to 3.6 V.
The ALS features are ideal for reducing power consumption and adjusting brightness of display equipments like LCD, PDP, LED, virtual keyboard and portable projector, etc. The proximity detection feature is targeted esspecially for cell phones with touch screen. In cell phones, the proximity sensor can detect when a user positions the phone close to their ear and can disable the touch screen to prevent mal-functions due to touch events.