IMAGE SENSOR FOR EXCLUDING INFLUENCE OF BUS VOLTAGE DROP OF PIXEL SOURCE FOLLOWER AMPLIFIER

摘要

PPROBLEM TO BE SOLVED: To realize a reader circuit which is not affected by a voltage drop of a current resistor caused by a bias current and bus resistance. PSOLUTION: A CMOS image sensor includes an array of pixels, a plurality of buses connected to a part of the pixels while including a photo-diode wherein each pixel receives incident light and converts the light to an electric charge (a1) and a source follower amplifier to be functioned as a voltage buffer by receiving a signal from the photo-diode (a2) to drive a photo-diode signal beyond the buses. The image sensor further includes a reader circuit for receiving and storing a signal from the amplifier, and a current source which is electrically connected to a bus terminal inverse to the reader circuit for supplying the bias current from the current source to the source follower amplifier, such that the voltage drop fault of the current resistor caused by the bias current and the bus resistance is not present in the reader circuit. PCOPYRIGHT: (C)2004,JPO