Imaging device and imaging system

Patent metadata

Field	Value
Publication number	US-10165214-B2
Application number	US-201615170749-A
Country	US
Kind code	B2
Filing date	Jun 1, 2016
Priority date	Jun 5, 2015
Publication date	Dec 25, 2018
Grant date	Dec 25, 2018

Abstract

An imaging device according to an exemplary embodiment includes a plurality of pixels, a differential amplifier circuit that includes a plurality of transistors forming a differential pair, and a current source configured to supply a bias current to the plurality of transistors, and is configured to receive a signal from the plurality of pixels, a capacitor element including a first terminal and a second terminal, a first switch through which the first terminal is connected to an electric path between the current source and the plurality of transistors, and a second switch through which the first terminal is connected to a voltage supply node supplied with a voltage.

First claim

What is claimed is:

1. An imaging device comprising:
a photoelectric conversion unit;
a differential amplifier circuit including a plurality of transistors forming a differential pair and a current source supplying a bias current to the plurality of transistors, and configured to receive a signal based on charge generated by the photoelectric conversion unit;
a capacitor element including a first terminal and a second terminal;
a first switch connecting the first terminal to an electric path between the current source and the plurality of transistors; and
a second switch connecting the first terminal to a voltage supply node supplied with a voltage,
wherein the first switch and the second switch operate in phases opposite to each other.

2. The imaging device according to claim 1 , wherein a timing at which the first switch transfers is synchronized with a timing at which a level of the signal changes.

3. The imaging device according to claim 1 , wherein a first voltage and a second voltage, which is different from the first voltage, are selectively supplied to the second terminal.

4. The imaging device according to claim 3 ,
wherein the first voltage is supplied to the second terminal when the first switch is ON, and
wherein the second voltage is supplied to the second terminal when the first switch is OFF.

5. The imaging device according to claim 3 , further comprising:
a third switch connecting the second terminal to a node supplied with the first voltage; and
a fourth switch connecting the second terminal to a node supplied with the second voltage.

6. The imaging device according to claim 5 ,
wherein the first switch and the third switch operate in a same phase, and
wherein the second switch and the fourth switch operate in a same phase.

7. The imaging device according to claim 3 , wherein, when the voltage supplied to the second terminal is switched from the first voltage to the second voltage, voltage of the first terminal changes in such a manner that charge current flowing into the capacitor element increases.

8. The imaging device according to claim 1 ,
wherein the plurality of transistors are N-type channel transistors, and
wherein the voltage supply node is a ground node.

9. The imaging device according to claim 8 , wherein the second terminal is connected to the ground node.

10. The imaging device according to claim 1 ,
wherein the plurality of transistors are P-type channel transistors, and
wherein the voltage supply node is a power supply node.

11. The imaging device according to claim 10 , wherein the second terminal is connected to the power supply node.

12. The imaging device according to claim 1 , wherein the voltage supplied to the voltage supply node is set in such a manner that a voltage of a source of one of the plurality of transistors is set to be a value between the voltage supplied to the voltage supply node and a voltage of a gate of the one of the plurality of transistors.

13. The imaging device according to claim 1 , wherein the differential amplifier circuit forms a comparison unit configured to compare the signal with a reference signal.

14. The imaging device according to claim 1 , wherein the differential amplifier circuit forms an inverting amplifier circuit configured to amplify the signal.

15. The imaging device according to claim 1 , further comprising a plurality of pixels each including the photoelectric conversion unit,
wherein the plurality of pixels forms a pixel array including a plurality of pixel columns, and
wherein a plurality of the differential amplifier circuits is provided for the respective plurality of pixel columns.

16. An imaging system comprising:
the imaging device according to claim 1 , and
a signal processing device configured to process a signal from the imaging device.

17. An imaging device comprising:
a photoelectric conversion unit;
a differential amplifier circuit including a plurality of transistors forming a differential pair and a current source supplying a bias current to the plurality of transistors, and configured to receive a signal based on charge generated by the photoelectric conversion unit;
a capacitor element including a first terminal and a second terminal;
a first switch connecting the first terminal to an electric path between the current source and the plurality of transistors; and
a second switch connecting the first terminal to a voltage supply node supplied with a voltage
wherein a first voltage and a second voltage, which is different from the first voltage, are selectively supplied to the second terminal.

18. The imaging device according to claim 17 , wherein a timing at which the first switch transfers is synchronized with a timing at which a level of the signal changes.

19. The imaging device according to claim 17 ,
wherein the first voltage is supplied to the second terminal when the first switch is ON, and
wherein the second voltage is supplied to the second terminal when the first switch is OFF.

20. The imaging device according to claim 17 , further comprising:
a third switch connecting the second terminal to a node supplied with the first voltage; and
a fourth switch connecting the second terminal to a node supplied with the second voltage.

21. The imaging device according to claim 20 ,
wherein the first switch and the third switch operate in a same phase, and
wherein the second switch and the fourth switch operate in a same phase.

22. The imaging device according to claim 17 , wherein, when the voltage supplied to the second terminal is switched from the first voltage to the second voltage, voltage of the first terminal changes in such a manner that charge current flowing into the capacitor element increases.

23. The imaging device according to claim 17 ,
wherein the plurality of transistors are N-type channel transistors,
wherein the voltage supply node is a ground node, and
wherein the second terminal is connected to the ground node.

24. The imaging device according to claim 17 ,
wherein the plurality of transistors are P-type channel transistors,
wherein the voltage supply node is a power supply node, and
wherein the second terminal is connected to the power supply node.

25. The imaging device according to claim 17 , wherein the voltage supplied to the voltage supply node is set in such a manner that a voltage of a source of one of the plurality of transistors is set to be a value between the voltage supplied to the voltage supply node and a voltage of a gate of the one of the plurality of transistors.

26. The imaging device according to claim 17 , wherein the differential amplifier circuit forms a comparison unit configured to compare the signal with a reference signal.

27. The imaging device according to claim 17 , wherein the differential amplifier circuit forms an inverting amplifier circuit configured to amplify the signal.

28. The imaging device according to claim 17 , further comprising a plurality of pixels each including the photoelectric conversion unit,
wherein the plurality of pixels forms a pixel array including a plurality of pixel columns, and
wherein a plurality of the differential amplifier circuits is provided for the respective plurality of pixel columns.

29. An imaging system comprising:
the imaging device according to claim 17 , and
a signal process

Assignees

• Canon Kk

Inventors

• Sakuragi Takamasa

Classifications

• H04N25/78 Primary

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

• H04N5/378 Primary

  Electricity · mapped topic