Image sensors with testing capabilities
AssigneeSemiconductor Components Industries, LLC
InventorThapan Akavoor Sankaran
Life of this patent
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Abstract
An image sensor may include an array of imaging pixels and readout circuitry. Testing circuitry may be interposed between the imaging pixels and the readout circuitry. The testing circuitry may include first and second test rows that provide first and second respective test voltages. In a testing mode, the first test voltage may be provided to approximately half of the readout circuitry and the second the second test voltage may be provided to the remaining half of the readout circuitry. In an imaging mode, the readout circuitry may be coupled to column output lines and read out signals from the array of imaging pixels. The components that receive different test voltages may be arranged in an alternating or checkerboard pattern to ensure testing of scenarios with coupling between adjacent components.
Claims19
An image sensor comprising:
- an array of imaging pixels;
- readout circuitry configured to read out signals from the array of imaging pixels;
- a first test row that is configured to provide a first test voltage to the readout circuitry;
- and
- a second test row that is configured to provide a second test voltage that is different than the first test voltage to the readout circuitry, wherein the readout circuitry comprises a first plurality of amplifiers and analog-to-digital converters and a second plurality of amplifiers and analog-to-digital converters, wherein the first plurality of amplifiers and analog-to-digital converters is configured to receive the first test voltage, and wherein the second plurality of amplifiers and analog-to-digital converters is configured to receive the second test voltage.
An image sensor comprising:
- an array of imaging pixels;
- a plurality of column output lines coupled to the array of imaging pixels;
- readout circuitry having a first plurality of components and a second plurality of components;
- a first test row comprising switching circuitry that provides a first test voltage to the first plurality of components in a first state and that provides signals from the plurality of column output lines to the first plurality of components in a second state;
- and
- a second test row comprising switching circuitry that provides a second test voltage to the second plurality of components in the first state and that provides signals from the plurality of column output lines to the second plurality of components in a second state.
An image sensor comprising:
- an array of imaging pixels;
- readout circuitry;
- and
- circuitry configured to provide at least first and second test voltages to the readout circuitry in a first mode and to provide signals from the array of imaging pixels to the readout circuitry in a second mode, wherein the first test voltage is configured to follow a rising ramped profile during the first mode and wherein the second test voltage is configured to follow a falling ramped profile during the first mode.
Dependencies are inferred from the claim text.