In-Pixel Single-Slope ADC Layout for Lower Peak Current

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Solution Overview

Problem

Digital imaging systems face limitations in pixel count, density, sensitivity, and conversion speed due to high current requirements during the analog-to-digital conversion process in Solid State Area Array Imaging Devices (SSAAIDs).

Innovation Solution

Implementing a system where only half of the pixels in a Focal Plane Array conduct Analog-to-Digital Conversion (ADC) at any given time, with one group counting from the start and the other group counting from when the voltage reference equals the input signal until the end of conversion, maintaining constant current and reducing peak current consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If all pixels conduct ADC simultaneously, then conversion speed is improved, but peak current consumption increases

Engineering Contradiction:

Improveconversion speedVSAvoidpeak current consumption

Core Design Contradiction:

SpeedVSPower

Solution Approach 1:

The pixel array is divided into two distinct groups: first pixels that count from the beginning of the ramp until the ramp equals the input signal, and second pixels that count from when the ramp equals the input signal until the end of conversion. This segmentation allows current consumption to be distributed across different time intervals, reducing peak current while maintaining overall conversion speed.

Inventive Principle:

Principle #1Segmentation

2Productivity

If all pixels count simultaneously, then productivity is improved, but use of energy worsens

Engineering Contradiction:

Improvepixel array conversion throughputVSAvoidcurrent consumption

Core Design Contradiction:

ProductivityVSUse of energy by moving object

Solution Approach 1:

The pixel array operates in periodic phases where first pixels are active during an initial counting period and second pixels become active during a subsequent counting period. This periodic activation pattern ensures that all pixels ultimately complete conversion (maintaining productivity) while current draw is spread over time (reducing energy consumption).

Inventive Principle:

Principle #19Periodic action

Data Source

PatentUS11523083B2Low power in-pixel single slope analog to digital converter (ADC)

Publication Date: 2022.12.06 BAE SYSTEMS INFORMATION ANDELECTRONIC SYSTEMS INTEGRATION INC

AI summary

Techniques, systems, architectures, and methods for reducing peak power during an Analog-to-Digital Conversion (ADC) process, in embodiments on a Focal Plane Array (FPA).