Sensor Readout Integration Circuit for Flexible Range Gating
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Solution Overview
Problem
Radiation sensors, particularly those used for infrared detection, face limitations in sensitivity due to fixed integration times and susceptibility to stray light, which restrict their ability to effectively process signals and maintain high sensitivity and range without increasing system size, weight, and power.
Innovation Solution
The integration circuit device includes an amplifier, an integration capacitor, and switches that allow for flexible placement of integration intervals, enabling subinterval range gating and blanking, allowing for multiple integrations within a frame time and improving signal-to-noise ratio through techniques like time delay integration and hyper-resolution gating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If fixed integration times are used in radiation sensors, then the circuit design is simplified, but sensitivity and range are limited due to inability to effectively process signals and manage stray light
Solution Approach 1:
The patent implements dynamic integration time control through multiple switches (S1, S2, S3) that can be configured in different states to achieve variable integration intervals. The integration capacitor CINT is charged during signal integration and discharged during reset intervals, with the duration controlled by switch configurations. This allows the integration time to be dynamically adjusted between short and long intervals, enabling the system to adapt to different sensing requirements and improve sensitivity without requiring complex external timing circuits.
Solution Approach 2:
The patent employs periodic integration and reset cycles controlled by a clock signal. The integration capacitor undergoes repeated charge-discharge cycles, where signal current is integrated during designated intervals and the capacitor is reset periodically. This periodic action enables time-delay integration techniques where multiple returns can be averaged, improving signal-to-noise ratio and sensitivity while maintaining a manageable circuit design through regular, predictable operation patterns.
2Measurement precision
If integration intervals are fixed, then the sensor can process signals efficiently, but it becomes susceptible to stray light and cannot effectively average multiple returns
Solution Approach 1:
The patent implements preliminary blanking action by using switch S2 to prevent integration during known stray light periods. Before integrating useful signals, the circuit can be configured to blank out intervals where stray light or laser pulses are expected. This preliminary action protects the integration capacitor from charging during harmful periods, allowing the sensor to efficiently process only the desired signal portions while rejecting stray light, thereby improving signal-to-noise ratio without losing efficiency.
Solution Approach 2:
The patent enables continuous useful integration action through multiple integration intervals within a single frame time. By configuring the switches appropriately, the circuit can perform multiple integration cycles, each capturing useful signal returns. These continuous useful actions allow the sensor to average multiple returns and accumulate signal energy, improving sensitivity and signal-to-noise ratio while maintaining efficient use of the integration capacitor through uninterrupted charging during designated intervals.
3Measurement precision
If multiple integrations are performed within a frame time, then sensitivity and range are improved, but the switch control complexity increases
Solution Approach 1:
The patent implements multi-functionality using a small set of three switches (S1, S2, S3) that can be configured in multiple states to achieve various integration modes. The same switches enable single integration, multiple integrations, short integration, long integration, blanking, and time-delay integration techniques. This universal switch control architecture allows the circuit to perform multiple functions and achieve improved sensitivity through multiple integrations while minimizing control complexity by reusing the same hardware components for different operational modes.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution enhances the sensitivity and range of radiation sensors by enabling flexible integration times, averaging multiple returns, and effectively managing stray light, thereby improving signal processing and reducing readout noise without increasing system size or power.
Implementation Method 1
Radiation sensors such as those used to detect infrared (IR) typically include electronics including circuitry that allows for the signal current to be integrated as part of the detection signal processing
Implementation Method 2
an amplifier for receiving input from a transducer, and an integration capacitor operatively connected to the amplifier, and for integrating signal from the transducer
Data Source
AI summary
Techniques are disclosed for radiation sensors that generate current signal to provide flexible placement of one or more integration intervals between resets of an integration capacitor. With flexible timing, an embodiment of the present invention provides several modes of operation including: multiple stray light blanking interval to occur during the integration cycle; range gating for LIDAR applications; time-delay-integration (TDI) with multiple short integration periods between frame resets; and hyper-resolution gating that provides better resolution than is normally possible with a fixed gate width. Numerous variations will be apparent in light of this disclosure.