公开(公告)号：US20220264082A1

公开(公告)日：2022-08-18

申请号：US17736504

申请日：2022-05-04

Applicant: STMicroelectronics Asia Pacific Pte Ltd

Inventor： Hong Chean CHOO ,  Lookah CHUA ,  Wai Yin HNIN

IPC: H04N17/00 ,  G01R19/25 ,  G01R19/00

Abstract: An electronic device includes a pixel array having a plurality of rows with active imaging pixels, and at least one row with test pixels. Each of the test pixels includes a test voltage generation circuit generating a test voltage, a switching circuit receiving the test voltage and an image pixel output signal and passing the test voltage as output when in a test mode, a comparison circuit receiving the output from the switching circuit and an analog to digital conversion signal and asserting a counter reset signal when the output from the switching circuit and the analog to digital conversion signal are equal in voltage, and a counter beginning counting at a beginning of each test cycle within the test mode, stopping counting upon assertion of the counter reset signal, and outputting its count upon stopping counting. The count is proportional to the test voltage when in the test mode.

公开(公告)号：US20200045303A1

公开(公告)日：2020-02-06

申请号：US16514695

申请日：2019-07-17

Applicant: STMicroelectronics Asia Pacific Pte Ltd

Inventor： Hong Chean CHOO ,  Lookah CHUA ,  Wai Yin HNIN

IPC: H04N17/00 ,  G01R19/00 ,  G01R19/25

Abstract: An electronic device includes a test voltage generation circuit to generate a test voltage as a function of a regulator voltage, and a switching circuit to receive the test voltage and an image pixel output signal, and to pass the test voltage as output when in a test mode. A comparison circuit receives the output from the switching circuit and an analog to digital conversion signal, and asserts a counter reset signal when the output from the switching circuit and the analog to digital conversion signal are equal in voltage. A counter begins counting at a beginning of each test cycle within the test mode, stops counting upon assertion of the counter rest signal, and outputs its count upon stopping counting. The count is proportional to the test voltage when in the test mode.