Patent ID: 7595795

Claim:
A photosensor comprising: a sensor receiving an external light and generating a sensing voltage in response to an amount of the external light received, the sensor comprising a first light receiver generating a first photovoltage in response to the amount of the external light received, and a first output unit converting the first photovoltage into the sensing voltage; a reference voltage generator blocked from the external light and generating a reference voltage, the reference voltage generator comprising a second light receiver generating a second photovoltage, and a second output unit converting the second photovoltage into the reference voltage; and a processor receiving the sensing voltage from the sensor and the reference voltage from the reference voltage generator to generate a sensor output voltage in response to a difference between the sensing voltage and the reference voltage, wherein the first output unit comprises a first switching transistor selectively outputting the first photovoltage responsive to a switching signal, and the second output unit comprises a second switching transistor selectively outputting the second photovoltage responsive to the switching signal.