Patent ID: 7250897

Claim:
A complementary metal oxide semiconductor (CMOS) image sensor, comprising: an image capturing unit for capturing an analog signal corresponding to an image of a subject; an analog-digital converter for converting the analog signal into a digital signal by using a ramp signal decreasing in a fixed slope according to a reference clock; a ramp signal generation unit for providing the ramp signal to the analog-digital converter; and a control unit for providing at least one of the image capturing unit, the anolog-digital converter, and the ramp signal generation unit with control signals and outputting data through an interface, wherein the analog-digital converter includes: a chopper comparator for comparing the analog signal with the ramp signal; an input capacitor for inducing a first voltage value corresponding to a start voltage of the ramp signal in a reset mode and a second voltage value corresponding to the ramp signal decreasing according to the reference clock in a counter mode; and a counter, wherein the chopper comparator has: a plurality of inverters having a common source amplifier structure; a plurality of switches controlled by the control unit; and a plurality of capacitors, wherein at least one of the inverters includes: a current mirror circuit connected between a power voltage terminal and an output terminal; and an N-type metal oxide semiconductor (NMOS) transistor, connected between the output terminal and a ground voltage terminal, having a gate connected to an input terminal.