Active pixel sensor circuit, driving method and image sensor

Patent metadata

Field	Value
Publication number	US-10187597-B2
Application number	US-201715574458-A
Country	US
Kind code	B2
Filing date	Mar 17, 2017
Priority date	May 20, 2016
Publication date	Jan 22, 2019
Grant date	Jan 22, 2019

Abstract

The present disclosure provides an active pixel sensor circuit, a driving method, and an image sensor. The active pixel sensor circuit comprises a photosensitive device, a first storage capacitor, a second storage capacitor and a source follower transistor. The active pixel sensor circuit further comprises a reset sub-circuit, a charging control sub-circuit, a compensation control sub-circuit, a signal-reading control sub-circuit. The charging control sub-circuit controls a second pole of the photosensitive device to be connected to a second terminal of the second storage capacitor during the reset phase and the charging phase, and controls the gate of the source follower transistor to be connected to a second pole of the source follower transistor during the charging phase. The compensation control sub-circuit controls the second terminal of the second storage capacitor to be connected to a second terminal of the first storage capacitor during the reset phase and the compensation phase.

First claim

The invention claimed is:

1. An active pixel sensor circuit comprising: a photosensitive device, a first storage capacitor, a second storage capacitor, a source follower transistor, a reset sub-circuit, a charging control sub-circuit, a compensation control sub-circuit, and a signal-reading control sub-circuit, wherein
a first pole of the photosensitive device is connected to a first level line;
a first terminal of the second storage capacitor is connected to the first level line;
a gate of the source follower transistor is connected to a first terminal of the first storage capacitor, and a first pole of the source follower transistor is connected to a second level line;
the reset sub-circuit is connected to the first terminal of the first storage capacitor and a second terminal of the first storage capacitor, respectively and configured to control the first terminal of the first storage capacitor to be connected to a first reset voltage line during a reset phase, and control the second terminal of the first storage capacitor be connected to a second reset voltage line;
the charging control sub-circuit is connected to a second pole of the photosensitive device, a second terminal of the second storage capacitor, the gate of the source follower transistor and a second pole of the source follower transistor, respectively and configured to control the second pole of the photosensitive device to be connected to the second terminal of the second storage capacitor during the reset phase and a charging phase, and control the gate of the source follower transistor to be connected to the second pole of the source follower transistor during the charging phase;
the compensation control sub-circuit is connected to the second terminal of the second storage capacitor and the second terminal of the first storage capacitor, respectively and configured to control the second terminal of the second storage capacitor to be connected to the second terminal of the first storage capacitor during the reset phase and a compensation phase; and
the signal-reading control sub-circuit is connected to a photocurrent signal reading line and the second pole of the source follower transistor, respectively and configured to control the photocurrent signal reading line to be connected to the second pole of the source follower transistor during a signal reading phase.

2. The active pixel sensor circuit according to claim 1 , wherein
the reset sub-circuit is further connected to a reset control signal line and configured to control the first terminal of the first storage capacitor to be connected to the first reset voltage line under the control of a reset control signal during the reset phase, and control the second terminal of the first storage capacitor to be connected to the second reset voltage line;
the charging control sub-circuit is further connected to a first charging control signal line and a second charging control signal line, respectively and configured to control the second pole of the photosensitive device to be connected to the second terminal of the second storage capacitor under the control of a first charging control signal during the reset phase and the charging phase, and control the gate of the source follower transistor to be connected to the second pole of the source follower transistor under the control of a second charging control signal during the charging phase;
the compensation control sub-circuit is further connected to a compensation control signal line and configured to control the second terminal of the second storage capacitor to be connected to the second terminal of the first storage capacitor under the control of a compensation control signal during the reset phase and the compensation phase; and
the signal-reading control sub-circuit is further connected to a reading control signal line and configured to control the photocurrent signal reading line to be connected to the second pole of the source follower transistor under the control of a reading control signal during the signal reading phase.

3. The active pixel sensor circuit according to claim 2 , wherein the reset sub-circuit comprises:
a first reset transistor, wherein a gate of the first reset transistor is connected to the reset control signal line, a first pole of the first reset transistor is connected to the first reset voltage line, and a second pole of the first reset transistor is connected to the first terminal of the first storage capacitor; and
a second reset transistor, wherein a gate of the second reset transistor is connected to the reset control signal line, a first pole of the second reset transistor is connected to the second reset voltage line, and a second pole of the second reset transistor is connected to the second terminal of the first storage capacitor.

4. The active pixel sensor circuit according to claim 3 , wherein the charging control sub-circuit comprises:
a first charging control transistor, wherein a gate of the first charging control transistor is connected to the first charging control signal line, a first pole of the first charging control transistor is connected to the second pole of the photosensitive device, and a second pole of the first charging control transistor is connected to the second terminal of the second storage capacitor; and
a second charging control transistor, wherein a gate of the second charging control transistor is connected to the second charging control signal line, a first pole of the second charging control transistor is connected to the gate of the source follower transistor, and a second pole of the second charging control transistor is connected to the second pole of the source follower transistor.

5. The active pixel sensor circuit according to claim 4 , wherein the compensation control sub-circuit comprises a compensation control transistor, wherein a gate of the compensation control transistor is connected to the compensation control signal line, a first pole of the compensation control transistor is connected to the second terminal of the first storage capacitor, and a second pole of the compensation control transistor is connected to the second terminal of the second storage capacitor.

6. The active pixel sensor circuit according to claim 5 , wherein the signal-reading control sub-circuit comprises a signal-reading control transistor, wherein a gate of the signal-reading control transistor is connected to the reading control signal line, a first pole of the signal-reading control transistor is connected to the second pole of the source follower transistor, and a second pole of the signal-reading control transistor is connected to the photocurrent signal reading line.

7. The active pixel sensor circuit according to claim 1 , wherein the photosensitive device comprises a photodiode.

8. The active pixel sensor circuit according to claim 6 , wherein the source follower transistor, the first reset transistor, the second reset transistor, the first charging control transistor, the second charging control transistor, the compensation control transistor, and the signal-reading control transistor are all p-type transistors, a second level is a high level, and a first level is a low level.

9. A driving method of an active pixel sensor circuit for use in the active pixel sensor circuit according to claim 1 , the driving method comprising:
a reset step in which during the reset phase the reset sub-circuit controls a first reset voltage to be written into the first terminal of the first storage capacitor and controls a second reset voltage to be written into the second terminal of the first storage capacitor; the compensation control sub-circuit controls the second reset voltage to be written into the second terminal of the s

Assignees

• Boe Technology Group Co Ltd
• Beijing Boe Optoelectronics Tech Co Ltd

Inventors

• Yang Shengji
• Dong Xue
• Xue Hailin
• Chen Xiaochuan
• Wang Haisheng
• Liu Yingming
• Zhao Weijie
• Ding Xiaoliang
• Wang Chunlei
• Li Wei
• Sun Zebin

Classifications

• H04N25/77 Primary

  Pixel circuitry, e.g. memories, A/D converters, pixel amplifiers, shared circuits or shared components · CPC title

• H04N5/365

  Electricity · mapped topic

• H04N5/3745 Primary

  Electricity · mapped topic

• H04N5/378

  Electricity · mapped topic

• H04N25/78

  Readout circuits for addressed sensors, e.g. output amplifiers or A/D converters · CPC title