Patent ID: 8304706
Filing Date: 2012-11-06
Classification: G01J

Abstract:
1. A photodetector circuit for detecting an amount of incident light, comprising: a photoelectric element which generates more power as the amount of incident light increases, the photodetector circuit detecting the amount of incident light based on an amount of the generated power of the photoelectric element; a first P-channel metal oxide semiconductor (MOS) transistor for charging an output terminal with an ON-state current of the first P-channel MOS transistor; a second P-channel MOS transistor for charging a first node with an ON-state current of the second P-channel MOS transistor; a first N-channel MOS transistor for discharging the output terminal with an ON-state current of the first N-channel MOS transistor, a first depletion type N-channel MOS transistor for discharging the first node with an ON-state current of the first depletion type N-channel MOS transistor, wherein, when the voltage generated by the generated power of the photoelectric element is high, the first N-channel MOS transistor is turned ON, the first depletion type N-channel MOS transistor is turned OFF, the first P-channel MOS transistor is turned OFF, and the second P-channel MOS transistor is turned ON, and wherein, when the voltage generated by the generated power of the photoelectric element is low, the first N-channel MOS transistor is turned OFF, the first depletion type N-channel MOS transistor is turned ON, the first P-channel MOS transistor is turned ON, and the second P-channel MOS transistor is turned OFF.