# US 11,310,488 B2 · Method of operating an image sensor, image sensor performing the same, and electronic system including the same

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- Number: US 11,310,488 B2
- Document ID: US11310488B2
- Status: Granted
- Kind: B2
- Application number: 17/018,120
- Filed: 2020-09-11
- Published: 2020-12-31
- Granted: 2022-04-19
- Earliest claimed: 2018-08-28
- Assignees: Samsung Electronics Co., Ltd.
- Applicants: Samsung Electronics Co., Ltd.
- Inventors: Hyeok-Jong Lee
- Web page: https://patentgrep.com/patent/US11310488B2

## CPC

- H04N 17/002: {for television cameras}
- H04N 25/69: SSIS comprising testing or correcting structures for circuits other than pixel cells
- H04N 25/709: Circuitry for control of the power supply
- H04N 25/76: Addressed sensors, e.g. MOS or CMOS sensors
- H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION

## Abstract

In a method of operating an image sensor, the image sensor includes a pixel array and a plurality of column driving circuits that are connected to a plurality of columns of the pixel array. A test operation is performed by applying a test pattern to the plurality of column driving circuits while changing a level of a well-bias voltage applied to a transistor included in the plurality of column driving circuits. A bias setting operation for setting the level of the well-bias voltage is performed based on a result of the test operation. An image capture operation for detecting incident light and generating a frame image is performed based on the pixel array, the plurality of column driving circuits and the well-bias voltage set by the bias setting operation.

## Claims

### Claim 1

An image sensor comprising:
a pixel array configured to generate a plurality of analog pixel signals in response to incident light;
a test pattern generator configured to generate a test pattern; and
a plurality of column driving circuits configured to convert the plurality of analog pixel signals received from the pixel array into a first plurality of digital signals or to convert the test pattern into a second plurality of digital signals based on a selection signal,
wherein the image sensor is configured to generate a test result pattern based on the second plurality of digital signals or image data based on the first plurality of digital signals, and
wherein the image sensor is configured to convert the test pattern into the second plurality of digital signals using a first number of the plurality of column driving circuits in a first test mode and to convert the test pattern into the second plurality of digital signals using a second number of the plurality of column driving circuits in a second test mode.

### Claim 2 (depends on 1)

The image sensor of claim 1, further comprising:
a comparison logic configured to compare the test result pattern with the test pattern and to generate a determination signal.

### Claim 3 (depends on 2)

The image sensor of claim 2, wherein each of the plurality of column driving circuits includes:
a comparator configured to compare one of the plurality of analog pixel signals with a ramp signal to generate a comparison signal;
a multiplexer configured to output the test pattern or the comparison signal in response to the selection signal; and
a counter configured to generate one of the first plurality of digital signals or the second plurality of digital signals based on an output of the multiplexer.

### Claim 4 (depends on 3)

The image sensor of claim 3, further comprising:
a timing controller configured to transmit a well-bias voltage to the plurality of column driving circuits and to change a level of the well-bias voltage based on the determination signal.

### Claim 5 (depends on 2)

The image sensor of claim 2, wherein each of the plurality of column driving circuits includes:
a multiplexer configured to output the test pattern or one of the plurality of analog pixel signals in response to a selection signal;
a comparator configured to compare an output of the multiplexer with a ramp signal to generate a comparison signal; and
a counter configured to generate one of the first plurality of digital signals or the second plurality of digital signals based on the comparison signal.

### Claim 6 (depends on 5)

The image sensor of claim 5, further comprising:
a timing controller configured to transmit a well-bias voltage to the plurality of column driving circuits and to change a level of the well-bias voltage based on the determination signal.

### Claim 7

An image sensor comprising:
a pixel array configured to generate a plurality of analog pixel signals in response to incident light;
a test pattern generator configured to generate a test pattern; and
a plurality of column driving circuits configured to convert the plurality of analog pixel signals received from the pixel array into a first plurality of digital signals or to convert the test pattern into a second plurality of digital signals based on a selection signal;
wherein the image sensor is configured to convert the test pattern into the second plurality of digital signals using a first number of the plurality of column driving circuits in a first test mode and to convert the test pattern into the second plurality of digital signals using a second number of the plurality of column driving circuits in a second test mode, and
wherein the first number is different from the second number.

### Claim 8 (depends on 7)

The image sensor of claim 7, wherein the image sensor is configured to convert the test pattern into the second plurality of digital signals using all of the plurality of column driving circuits in the first test mode.

### Claim 9 (depends on 7)

The image sensor of claim 7, further comprising:
a comparison logic configured to compare the second plurality of digital signals with the test pattern and to generate a determination signal to a timing controller.

### Claim 10 (depends on 9)

The image sensor of claim 9, wherein the timing controller is configured to transmit a well-bias voltage to the plurality of column driving circuits and to change a level of the well-bias voltage based on the determination signal.

### Claim 11 (depends on 10)

The image sensor of claim 10, wherein the timing controller is configured to increase the level of the well-bias voltage based on the determination signal.

### Claim 12 (depends on 10)

The image sensor of claim 10, wherein the timing controller is configured to decrease the level of the well-bias voltage based on the determination signal.