Amplifier and image sensor device including the same
An amplifier includes a first capacitor connected between an input node and a floating node, a second capacitor connected between the floating node and an output node, an amplifying element connected between a power supply voltage and the output node and operating in response to a voltage level of the floating node, a current bias source connected between the output node and a ground voltage, a first reset switch connected between the floating node and an intermediate node and operating in response to a reset bias, a second reset switch connected between the intermediate node and the output node and operating in response to the reset bias, and a reset bias generator circuit that outputs the reset bias in response to a reset signal. The reset bias is one of a reset voltage of the intermediate node, the power supply voltage, and the ground voltage.
1 . An image sensor comprising: a first substrate comprising: a first photo detector; a second photo detector; a floating diffusion node configured to connect to the first photo detector; a reset gate configured to connect to the floating diffusion node; and a source follower configured to connect to the floating diffusion node; and a second substrate comprising: a comparator configured to compare a first signal with a threshold value and to generate an on-event signal and an off-event signal, wherein the first signal is generated based on an amount of change of a light received by the second photo detector.
2 . The image sensor of claim 1 , wherein the first substrate and the second substrate are connected through a Cu-to-Cu bonding.
3 . The image sensor of claim 2 , wherein the second substrate further comprising:
an amplifier configured to receive a second signal generated based on a photo current corresponding to the light received by the second photo detector and to generate the first signal based on the second signal.
4 . The image sensor of claim 3 , wherein the amplifier further comprising:
a first node;
a second node;
a first capacitor configured to connect to the first node and the second node; and
a reset circuit configured to connect to the first node and the second node.
5 . The image sensor of claim 4 , wherein the comparator is configured to receive the first signal from the second node of the amplifier.
6 . The image sensor of claim 5 , wherein the amplifier further comprising:
a second capacitor configured to connect to the first node,
wherein the second capacitor, the first node, the first capacitor, and the second node are connected in series.
7 . The image sensor of claim 6 , further comprising:
a transistor configured to connect to the second capacitor.
8 . The image sensor of claim 2 , wherein the first photo detector is included in a first pixel,
wherein the second photo detector is included in a second pixel,
wherein the first pixel and the second pixel have the same length and the same width in a plan view.
9 . The image sensor of claim 8 , further comprising:
a third substrate comprising logic circuits and connected to the second substrate.
10 . The image sensor of claim 9 , wherein the transistor is a PMOS transistor.
11 . The image sensor of claim 10 , wherein the logic circuits are configured to control the first pixel.
12 . An image sensor comprising:
a first substrate comprising:
a first photo detector;
a second photo detector;
a floating diffusion node configured to connect to the first photo detector;
a reset gate configured to connect to the floating diffusion node; and
a source follower configured to connect to the floating diffusion node; and
a second substrate configured to receive a first signal generated based on an amount of change of a light received by the second photo detector and to generate an on-event signal and an off-event signal.
13 . The image sensor of claim 12 , wherein the second substrate further comprising:
an amplifier configured to receive the first signal and to generate a second signal;
a comparator configured to compare the second signal with a threshold value and to generate the on-event signal and the off-event signal.
14 . The image sensor of claim 13 , wherein the amplifier is configured to remove a noise generated from a leakage.
15 . The image sensor of claim 14 , wherein the amplifier comprises:
a first node;
a second node;
a reset bias generator configured to generate a reset bias; and
a reset circuit configured to connect to the first and second nodes and to receive the reset bias.
16 . The image sensor of claim 13 , wherein the amplifier comprises:
a first node;
a second node;
a first capacitor; and
a second capacitor,
wherein the first capacitor, the first node, the second capacitor, and the second node are connected in series.
17 . The image sensor of claim 16 , wherein the comparator is configured to receive the second signal from the second node of the amplifier.
18 . The image sensor of claim 17 , further comprising:
a current bias configured to connect to the first capacitor; and
a PMOS transistor configured to connect to the first capacitor and the current bias.
19 . An image sensor comprising: a first substrate comprising: a first photo detector; a second photo detector; a floating diffusion node configured to connect to the first photo detector; a reset gate configured to connect to the floating diffusion node; and a source follower configured to connect to the floating diffusion node; and a second substrate comprising: an amplifier configured to receive a first signal generated based on a photo current and to generate a second signal; and a comparator configured to compare the second signal with a threshold value, wherein the photo current is generated based on an amount of change of a light incident received by the second photo detector, wherein the amplifier is configured to remove a noise generated from a leakage, and wherein the first substrate and the second substrate are connected through a Cu-to-Cu bonding.
20 . The image sensor of claim 19 , wherein a first photo detector is included in a first pixel,
wherein a second photo detector is included in a second pixel, and
wherein the first pixel and the second pixel have the same length and the same width in a plan view.