Patent ID: 8513892

Claim:
An illuminance sensor, comprising: a first photosensor outputting a current in accordance with light intensity; a second photosensor having a light receiving area different from that of said first photosensor, and outputting a current in accordance with light intensity; a first switch having a first terminal receiving the output current of said second photosensor, the first switch having second and third terminals, and the first terminal operable for connection to one of the second and third terminals based on a first control signal; a first polarity detection circuit connected to the second terminal of said first switch for detecting polarity of an input current; a charge amount detection circuit connected to an output node of said first photosensor and the third terminal of said first switch for detecting a charge amount by integrating an input current; and a computation control unit outputting said first control signal based on a detection result of said first polarity detection circuit, and outputting a digital signal indicating illuminance at a location where said first and second photosensors are installed based on a detection result of said charge amount detection circuit.