CN-122002150-A - Image sensor and method of operating the same

Abstract

The image sensor includes a first pixel and a second pixel. The first pixel includes a first photodiode, a first transfer gate connected between the first photodiode and a first Floating Diffusion (FD) node, a first FD select gate connected between the first node and the first FD node, a first laterally overflowing integration capacitor (LOFIC) select gate connected between the first FD node and a first LOFIC node, and a first capacitor connected between the first LOFIC node and a first reset voltage. The second pixel includes a second photodiode, a second transfer gate connected between the second photodiode and a second FD node, and a second FD selection gate connected between the second node electrically connected to the first node and the second FD node.

Inventors

• XU ZHENSHUO
• ZHANG DONGNING

Assignees

• 三星电子株式会社

Dates

Publication Date

20260508

Application Date

20251023

Priority Date

20241106

Claims (20)

1. 1. An image sensor, comprising: A first pixel including a first photodiode configured to output a first output voltage corresponding to light incident on the first photodiode, and A second pixel including a second photodiode, the second pixel configured to output a second output voltage corresponding to light incident on the second photodiode, Wherein the first pixel further comprises, A first transfer gate connected between the first photodiode and a first Floating Diffusion (FD) node, A first FD selection gate connected between the first node and the first FD node, A first laterally-overflowed integrating capacitor (LOFIC) select gate connected between the first FD node and the first LOFIC node, and A first capacitor connected between the first LOFIC node and a first reset voltage, an Wherein the second pixel further comprises, A second transfer gate connected between the second photodiode and the second FD node, A second FD selection gate connected between a second node electrically connected with the first node and a second FD node, A second LOFIC select gate connected between the second FD node and the second LOFIC node, and And a second capacitor connected between the second LOFIC node and the first reset voltage.
2. 2. The image sensor of claim 1, wherein, The first capacitor includes at least one of a metal-insulator-metal (MIM) capacitor, a metal-oxide-metal (MOM) capacitor, a metal-oxide-semiconductor capacitor (MOSCAP), a polysilicon capacitor, and a DRAM capacitor, and The second capacitor includes at least one of a MIM capacitor, a MOM capacitor, a MOSCAP, a polysilicon capacitor, and a DRAM capacitor.
3. 3. The image sensor of claim 1 wherein, in response to the image sensor operating in a LOFIC mode in which the first FD selection gate and the second FD selection gate are turned off, The first LOFIC select gate and the LOFIC select gate are turned on, The first FD node is electrically connected with the first capacitor, an The second FD node is electrically connected to the second capacitor.
4. 4. The image sensor of claim 3, wherein, The first pixel may further comprise a pixel array, A first LOFIC reset gate connected between the first LOFIC node and the second reset voltage, and A first discharge switch connected between the first reset voltage and the second reset voltage, and Wherein the second pixel further comprises, A second LOFIC reset gate connected between the second LOFIC node and a second reset voltage, and And the second discharging switch is connected between the first reset voltage and the second reset voltage.
5. 5. The image sensor of claim 4 wherein, in response to the image sensor operating in the LOFIC mode, The first FD node and the first capacitor are reset by a first LOFIC reset gate and a first discharge switch, and The second FD node and the second capacitor are reset through a second LOFIC reset gate and a second discharge switch.
6. 6. The image sensor of claim 1, wherein, The first pixel may further comprise a pixel array, A first LOFIC reset gate coupled between the first LOFIC node and a third LOFIC node, A third LOFIC reset gate connected between the third LOFIC node and a second reset voltage, A first discharge switch connected between the first reset voltage and the second reset voltage, and A third capacitor connected between the third LOFIC reset node and the first reset voltage, an Wherein the second pixel further comprises: a second LOFIC reset gate coupled between the second LOFIC node and a fourth LOFIC node, A fourth LOFIC reset gate connected between the fourth LOFIC node and the second reset voltage, A second discharge switch connected between the first reset voltage and the second reset voltage, and And a fourth capacitor connected between the fourth LOFIC node and the first reset voltage.
7. 7. The image sensor of claim 1, wherein the first FD node and the second FD node are electrically connected in response to the image sensor operating in a sharing mode in which the first LOFIC select gate and the second LOFIC select gate are turned off and the first FD select gate and the second FD select gate are turned on.
8. 8. The image sensor of claim 7, wherein, The first pixel further includes a first reset gate connected between the first node and the pixel voltage, an The second pixel further includes a second reset gate connected between the second node and the pixel voltage.
9. 9. The image sensor of claim 8, wherein the first FD node and the second FD node are reset through a first reset gate and a second reset gate in response to the image sensor operating in the shared mode.
10. 10. The image sensor of claim 1, wherein, The first pixel may further comprise a pixel array, A first reset gate connected between the first node and the third FD node, an A third reset gate connected between the third FD node and the pixel voltage, an The second pixel may further comprise a pixel array, A second reset gate connected between the second node and the fourth FD node, and And a fourth reset gate connected between the fourth FD node and the pixel voltage.
11. 11. The image sensor of claim 1, wherein, The first pixel may further comprise a pixel array, A third photodiode, and A third transmission gate connected between the third photodiode and the first FD node The second pixel further includes: A fourth photodiode, and And a fourth transfer gate connected between the fourth photodiode and the second FD node.
12. 12. The image sensor of claim 1, further comprising: a third pixel including a third photodiode, the third pixel configured to output a third output voltage corresponding to light incident on the third photodiode, Wherein the third pixel further comprises, A third transfer gate connected between the third photodiode and a third FD node; A third FD selection gate connected between a third node and a third FD node electrically connected to the first node and the second node, A third LOFIC selection gate connected between the third FD node and the third LOFIC node, an And a third capacitor connected between the third LOFIC node and a third reset voltage.
13. 13. The image sensor of claim 1, wherein, The first pixel further comprises a first source follower and a first select gate connected in series between the pixel voltage and the first column line, The gate terminal of the first source follower is connected to the first FD node, The second pixel further comprises a second source follower and a second select gate connected in series between the pixel voltage and the first column line, A gate terminal of the second source follower is connected to the second FD node, an The first column line is configured to output each of a first output voltage and a second output voltage.
14. 14. The image sensor of claim 1, wherein, The first pixel further comprises a first source follower and a first select gate connected in series between the pixel voltage and the first column line, The gate terminal of the first source follower is connected to the first FD node, The second pixel further comprises a second source follower and a second select gate connected in series between the pixel voltage and the second column line, The gate terminal of the second source follower is connected to the second FD node, The first column line is configured to output a first output voltage, The second column line is configured to output a second output voltage.
15. 15. The image sensor of claim 1, further comprising: a first semiconductor die, and A second semiconductor die stacked on the first semiconductor die and configured to be electrically connected to the first semiconductor die by a connection structure, Wherein the first photodiode and the second photodiode are in a first semiconductor die, and Wherein the first capacitor and the second capacitor are in the second semiconductor die.
16. 16. A method of operating an image sensor comprising a first pixel and a second pixel, Wherein the first pixel includes a first photodiode, a first Floating Diffusion (FD) node, a first Shared Floating Diffusion (SFD) circuit connected to the first FD node, and a first lateral overflow integration capacitor (LOFIC) circuit connected to the first FD node, and Wherein the second pixel includes a second photodiode, a second FD node, a second SFD circuit connected to the second FD node and a second LOFIC circuit connected to the second FD node, The method comprises the following steps: in the sharing mode, electrically connecting the first and second FD nodes by disabling the first LOFIC circuit and enabling the first SFD circuit and performing a sensing operation on the first pixel based on the first and second FD nodes, and In the LOFIC mode, electrically connecting the first FD node and a first capacitor included in the first LOFIC circuit by disabling the first SFD circuit and enabling the first LOFIC circuit, and performing a sensing operation on the first pixel based on the first FD node and the first capacitor, wherein, During a sensing operation of the first pixel in the sharing mode, the first capacitor is electrically separated from the first FD node, and The second FD node is electrically separated from the first FD node during a sensing operation on the first pixel in the LOFIC mode.
17. 17. The method of claim 16, wherein performing a sensing operation on the first pixel in the sharing mode comprises: Electrically connecting the first FD node and the second FD node and resetting the first FD node and the second FD node during the first period; sampling a low conversion gain reset value corresponding to voltages of the first FD node and the second FD node during a second period after the first period; During a third period subsequent to the second period, electrically separating the first FD node from the second FD node, and sampling a high conversion gain reset value corresponding to a voltage of the first FD node; transmitting photoelectrons of the first photodiode of the first pixel to the first FD node during a fourth period after the third period; Sampling a high conversion gain signal value corresponding to the voltage of the first FD node during a fifth period after the fourth period; During a sixth period after the fifth period, the first FD node and the second FD node are electrically connected, and low conversion gain signal values corresponding to voltages of the first FD node and the second FD node are sampled.
18. 18. The method of claim 16, wherein performing a sensing operation on the first pixel in the LOFIC mode comprises: sampling a high conversion gain reset value corresponding to a voltage of the first FD node during a first period; Transmitting photoelectrons of the first photodiode to the first FD node during a second period subsequent to the first period; sampling a high conversion gain signal value corresponding to a voltage of the first FD node during a third period subsequent to the second period; during a fourth period after the third period, electrically connecting the first FD node and the first capacitor, and sampling a LOFIC signal value corresponding to voltages of the first FD node and the first capacitor; resetting the first FD node and the first capacitor during a fifth period after the fourth period and During a sixth period after the fifth period, a LOFIC reset value corresponding to the voltages of the first FD node and the first capacitor is sampled.
19. 19. The method of claim 16, wherein performing a sensing operation on the first pixel in the LOFIC mode comprises: during a first period, electrically connecting the first FD node and the first capacitor, and sampling a LOFIC signal value corresponding to voltages of the first FD node and the first capacitor; resetting the first FD node and the first capacitor during a second period after the first period; Sampling a LOFIC reset value corresponding to voltages of the first FD node and the first capacitor during a third period after the second period; during a fourth period after the third period, electrically separating the first FD node from the first capacitor, and sampling a high conversion gain reset value corresponding to a voltage of the first FD node; Transmitting photoelectrons of the first photodiode to the first FD node during a fifth period after the fourth period, and During a sixth period after the fifth period, a high conversion gain signal value corresponding to the voltage of the first FD node is sampled.
20. 20. An image sensor, comprising: a first photodiode; a first transfer gate connected between the first photodiode and a first Floating Diffusion (FD) node; a first Shared Floating Diffusion (SFD) circuit connected to the first FD node; a first laterally overflowing integrating capacitor (LOFIC) circuit connected to the first FD node and including a first capacitor; a first source follower including a first gate terminal connected to the first FD node, and A first select gate connected between the first source follower and the first column line, Wherein the image sensor is configured to operate in a sharing mode and a LOFIC mode such that in the sharing mode, the first SFD circuit is configured to electrically connect the first FD node to a second FD node different from the first FD node, and In the LOFIC mode, the first LOFIC circuit is configured to electrically connect the first FD node to the first capacitor.

Description

Image sensor and method of operating the same Cross Reference to Related Applications The present application claims priority from korean patent application No. 10-2024-0156129 filed in the korean intellectual property office on day 11 and 6 of 2024, the disclosure of which is incorporated herein by reference in its entirety. Technical Field Some example embodiments described herein relate to an image sensor, and more particularly, to an image sensor and/or a method of operating the same. Background The image sensor obtains image information about an external object by converting light reflected from the external object into an electrical signal. An electronic device including an image sensor may display an image in a display panel by using the obtained image information. The image sensor may be mounted in various types of electronic devices. For example, an electronic device including an image sensor may be included as a component of various types of electronic devices, such as a smart phone, a tablet Personal Computer (PC), a laptop PC, and/or a wearable device. Disclosure of Invention Some example embodiments provide an image sensor having improved performance and improved reliability and/or a method of operating the same. According to some example embodiments, an image sensor includes a first pixel including a first photodiode configured to output a first output voltage corresponding to light incident on the first photodiode, and a second pixel including a second photodiode configured to output a second output voltage corresponding to light incident on the second photodiode. The first pixel further includes a first transfer gate connected between the first photodiode and a first Floating Diffusion (FD) node, a first FD select gate connected between the first node and the first FD node, a first laterally overflowing integration capacitor (LOFIC) select gate connected between the first FD node and a first LOFIC node, and a first capacitor connected between the first LOFIC node and a first reset voltage. The second pixel further includes a second transfer gate connected between the second photodiode and the second FD node, a second FD selection gate connected between the second node electrically connected to the first node and the second FD node, a second LOFIC selection gate connected between the second FD node and the second LOFIC node, and a second capacitor connected between the second LOFIC node and the first reset voltage. Alternatively or additionally, according to some example embodiments, there is provided a method of operating an image sensor including a first pixel including a first photodiode, a first Floating Diffusion (FD) node, a first Shared Floating Diffusion (SFD) circuit connected to the first FD node, and a first laterally-overflowed integrating capacitor (LOFIC) circuit connected to the first FD node, and a second pixel including a second photodiode, a second FD node, a second SFD circuit connected to the second FD node, and a second LOFIC circuit connected to the second FD node. The operating method includes electrically connecting a first FD node and a second FD node by disabling a first LOFIC circuit and enabling a first SFD circuit and performing a sensing operation on a first pixel based on the first FD node and the second FD node in a sharing mode, and electrically connecting the first FD node and a first capacitor included in the first LOFIC circuit by disabling the first SFD circuit and enabling the first LOFIC circuit and performing a sensing operation on the first pixel based on the first FD node and the first capacitor in a LOFIC mode. The first capacitor is electrically separated from the first FD node during a sensing operation on the first pixel in the sharing mode. The second FD node is electrically separated from the first FD node during a sensing operation on the first pixel in the LOFIC mode. Alternatively or additionally, according to some example embodiments, an image sensor includes a first photodiode, a first transfer gate connected between the first photodiode and a first Floating Diffusion (FD) node, a first Shared Floating Diffusion (SFD) circuit connected to the first FD node, a first lateral overflow integrating capacitor (LOFIC) circuit connected to the first FD node and including a first capacitor, a first source follower including a first gate terminal connected to the first FD node, and a first select gate connected between the first source follower and a first column line. The image sensor is configured to operate in a sharing mode and a LOFIC mode such that in the sharing mode, the first SFD circuit electrically connects the first FD node to a second FD node different from the first FD node, and in the LOFIC mode of the image sensor, the first LOFIC circuit electrically connects the first FD node to the first capacitor. Alternatively or additionally, according to some example embodiments, the image sensor includes a first pixel including a first photodi