Fast wafer test for event-based vision sensor
AssigneeOmniVision Technologies, Inc.
InventorsAndreas Suess, Menghan Guo
Life of this patent
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Abstract
A method for wafer testing an event-based vision sensor (EVS), the EVS sensor comprising a photodiode, a logarithmic amplifier configured to generate an amplified signal in response to voltage received by the photodiode, a first buffer, and a bitline (BL), the method including determining a performance of the logarithmic amplifier, where determining the performance includes irradiating a pixel array by sweeping irradiance, feeding an output of the pixel array into the BL, probing one or more output of the BL with an analog-to-digital converter (ADC), and monitoring the one or more outputs of the BL, wherein the performance is determined based upon the one or more outputs of the BL.
Claims20
A method for wafer testing an event-based vision sensor (EVS), the EVS sensor comprising a photodiode, a logarithmic amplifier configured to generate an amplified signal in response to voltage received by the photodiode, a first buffer, and a bitline (BL), the method comprising:
- determining a performance of the logarithmic amplifier, wherein determining the performance comprises:
- irradiating a pixel array by sweeping irradiance;
- feeding an output of the pixel array into the BL;
- probing one or more output of the BL with an analog-to-digital converter (ADC);
- and
- monitoring the one or more outputs of the BL, wherein the performance is determined based upon the one or more outputs of the BL.
A method of determining a performance of a difference detector of an event-based vision sensor (EVS), the EVS sensor comprising a photodiode, a logarithmic amplifier configured to generate an amplified signal in response to voltage received by the photodiode, a first buffer, a bitline (BL), a difference detector, a first comparator, and a second comparator, and wherein the method comprises:
- forcing a front end of the EVS to a static level;
- injecting a swept voltage to the difference detector with the BL;
- monitoring an output the EVS relative to a voltage threshold;
- and
- detecting an event when the output of the EVS switches from the first comparator to the second comparator based on the voltage threshold.
A method of determining a performance of a first comparator and a second comparator of an event-based vision sensor (EVS), the EVS sensor comprising a photodiode, a logarithmic amplifier configured to generate an amplified signal in response to voltage received by the photodiode, a first buffer, a bitline (BL), a difference detector, the first comparator, and the second comparator, wherein the method comprises:
- injecting a signal to the difference detector;
- monitoring an output the EVS relative to a voltage threshold;
- and
- detecting an event when the output of the EVS switches from the first comparator to the second comparator based on the voltage threshold.
Dependencies are inferred from the claim text.