Patent ID: 6909462
Filing Date: 2005-06-21
Classification: H04N

Abstract:
1. A photosensor circuit comprising: light-electricity converting means which converts a light signal into electricity, an n-channel MOS transistor which has a logarithmic characteristic in its weakly reversed condition and converts a sensor current generated by said light-electricity converting means into a detection voltage which has a logarithmic characteristic, a capacitor which in connection to a detection terminal of said n-channel MOS transistor, and initializing means which applied to reset voltage to a gate of said n-channel MOS transistor, thereby lowering an independence between a drain and a source to control charging and discharging of said capacitor; wherein an n-channel MOS transistor is a depletion type n-channel MOS transistor (QD a low impedance condition is created between the drain and the source of said depletion type channel MOS transistor (QD