Image sensor for removing horizontal noise

Abstract

Disclosed herein is an image sensor for removing a horizontal noise. The image sensor includes a pixel array including a plurality of unit pixels located at every row or column; an analog bus located at every row or column, for transferring output signals of the pixel array; and a readout circuit for reading the output signals of the pixel array loaded on the analog bus, wherein the readout circuit includes: a plurality of first transistors having a drain connected to the column analog bus and a source connected to a supply voltage; and a second transistor having a drain connected to a gate of the second transistor and gates of the first transistors, and a source connected to the supply voltage, wherein, a size of the second transistor is larger than a size of the first transistor.

1 . An image sensor, comprising:
 a pixel array including a plurality of unit pixels located at every row or column;   an analog bus located at every row or column, for transferring output signals of the pixel array; and   a readout circuit for reading the output signals of the pixel array loaded on the analog bus,   wherein the readout circuit includes:   a plurality of first transistors having a drain connected to the column analog bus and a source connected to a supply voltage; and   a second transistor having a drain connected to a gate of the second transistor and gates of the first transistors, and a source connected to the supply voltage,   wherein, a size of the second transistor is larger than a size of the first transistor.   
     
     
         2 . The image sensor as recited in  claim 1 , wherein an amount of current flowing via the second transistor is relatively larger than a current amount flowing on the first transistor. 
     
     
         3 . The image sensor as recited in  claim 2 , wherein the first transistors are located at every row and the second transistor forms current mirrors with the first transistors. 
     
     
         4 . The image sensor as recited in  claim 2 , wherein the first transistors are located at every column and the second transistor forms current mirrors with the first transistors. 
     
     
         5 . The image sensor as recited in  claim 2 , wherein the first transistors and the second transistor are NMOS transistor. 
     
     
         6 . The image sensor as recited in  claim 2 , wherein the supply voltage is a ground voltage. 
     
     
         7 . An image sensor, comprising:
 a pixel array including a plurality of unit pixels located at every row or column;   an analog bus located at every row or column for transferring output signals of the pixel array; and   a readout circuit for reading the output signals of the pixel array loaded on the analog bus,   wherein the readout circuit includes:   a plurality of first transistors having a drain connected to the column analog bus and a source connected to a supply voltage; and   a second transistor having a drain connected to a gate of the second transistor and gates of the first transistors, and a source connected to the supply voltage,   wherein an amount of the second current is larger than an amount of the first current.   
     
     
         8 . The image sensor as recited in  claim 7 , wherein the first transistors are located at every row and the second transistor forms current mirrors with the first transistors. 
     
     
         9 . The image sensor as recited in  claim 7 , wherein the first transistors are located at every column and the second transistor forms current mirrors with the first transistors. 
     
     
         10 . The image sensor as recited in  claim 7 , wherein the first transistors and the second transistor are NMOS transistor. 
     
     
         11 . The image sensor as recited in  claim 7 , wherein the supply voltage is a ground voltage.