Image sensor controlling a conversion gain, imaging device having the same, and method of operating the same

Abstract

An image sensor includes: a first pixel connected to a column line; and a second pixel connected to the column line. Each of the first pixel and the second pixel includes: one photodiode; a first floating diffusion region; a second floating diffusion region; one first transistor connected between the one photodiode and the first floating diffusion region; a second transistor connected between the first floating diffusion region and the second floating diffusion region; a third transistor connected to the second floating diffusion region; a fourth transistor including a gate connected to the first floating diffusion region; and a fifth transistor including a drain connected to a source of the fourth transistor and a source connected to the column line. The second floating diffusion region of the first pixel and the second floating diffusion region of the second pixel are electrically connected without an intermediate transistor.