Patent ID: 7859486

Claim:
An ambient light sensing circuit adapted to be electrically coupled to a first power supply for supplying a first power supply voltage and an output load coupled to a storage capacitor, the ambient light sensing circuit comprising: a transistor; a first storage capacitor coupled to the transistor and adapted to compensate for a threshold voltage of the transistor; a second storage capacitor coupled to the first storage capacitor; a photodiode coupled to the first storage capacitor and the second storage capacitor, the photodiode being adapted to change a coupling voltage of the first storage capacitor and the second storage capacitor based on ambient light incident thereon; a first switch adapted to selectively apply the first power supply voltage to the output load coupled to the transistor; a second switch including a first electrode coupled to a first electrode of the transistor, and a second electrode coupled to the output load and a first electrode of the first switch, the second switch being adapted to allow a charge stored in the storage capacitor to be discharged through the transistor based on the coupling voltage of the first storage capacitor and the second storage capacitor; and a third storage capacitor coupled to the photodiode and adapted to increase an inverse bias potential of the photodiode.