Sensor Front-End Circuitry With Stable Feedback and Low Noise

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Solution Overview

Problem

Existing photon-counting CT systems face challenges in achieving high performance with low power consumption, high count rates, and stable operation due to the two-stage front-end circuitry's higher noise and power penalties.

Innovation Solution

A two-stage front-end electronic circuitry using single-input operational transconductance amplifiers with active feedback and control circuits to buffer input signals, decouple stages, and maintain stable feedback resistance across process, voltage, and temperature variations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a two-stage front-end circuitry is used to handle large and varying input capacitance, then the circuitry can process electromagnetic radiation signals, but the noise and power consumption increase

Engineering Contradiction:

Improveinput capacitance handlingVSAvoidpower consumption

Core Design Contradiction:

Adaptability or versatilityVSUse of energy by stationary object

Solution Approach 1:

The patent implements dynamic power management by selectively enabling or disabling circuit stages based on operating conditions. The first circuit stage is enabled when input capacitance exceeds a threshold value, while the second stage operates independently when capacitance is below the threshold, thereby reducing overall power consumption while maintaining adaptability to varying input conditions

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system dynamically changes operational parameters (which circuit stage is active) based on the input capacitance level. By monitoring the input capacitance and switching between different circuit configurations, the system optimizes the balance between handling capability and power consumption

Inventive Principle:

Principle #35Parameter changes

2Adaptability or versatility

If a two-stage front-end circuitry is used to handle large and varying input capacitance, then the circuitry can process electromagnetic radiation signals, but the noise increases

Engineering Contradiction:

Improveinput capacitance handlingVSAvoidnoise

Core Design Contradiction:

Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The patent employs dynamic circuit configuration that adapts to input conditions. By selectively activating only the necessary circuit stage based on input capacitance levels, the system minimizes the number of active components, thereby reducing noise while maintaining the ability to handle varying input capacitance

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system extracts or removes the second circuit stage from active operation when input capacitance is low, using only the first stage. This selective extraction of unnecessary circuit elements reduces noise contribution while preserving full functionality when needed

Inventive Principle:

Principle #2Taking out (Extraction)

3Ease of manufacture

If feedback resistors are realized by MOS transistors biased in linear-region, then the circuit can be integrated, but the feedback resistance varies with process, voltage, and temperature

Engineering Contradiction:

ImproveintegrationVSAvoidfeedback resistance stability

Core Design Contradiction:

Ease of manufactureVSStability of the object's composition

Solution Approach 1:

The patent implements a control circuit that provides feedback to compensate for PVT variations in the MOS transistor feedback resistors. The control circuit monitors the actual feedback resistance and dynamically adjusts operating parameters to maintain the desired feedback resistance value across process, voltage, and temperature variations

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The system dynamically changes control parameters (such as gate voltages or bias currents) of the MOS transistors to compensate for PVT-induced resistance variations. By adjusting these parameters in real-time, the system maintains stable feedback resistance while preserving the integrated MOS transistor implementation

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS12489996B2Front-end electronic circuitry for an electromagnetic radiation sensor application

Publication Date: 2025.12.02 AMS INTERNATIONAL AG

AI summary

A front-end electronic circuitry for an electromagnetic radiation sensor application comprises a charge sensitive amplifier stage with a first single-input operational transconductance amplifier, and a transistor being arranged in a first feedback path of the first single-input operational transconductance amplifier, and a signal shaper stage with a second single-input operational transconductance amplifier, and an active feedback circuit being arranged in a second feedback path of the second single-input operational transconductance amplifier. The front-end electronic circuitry further comprises a control circuit having a second transistor. The control circuit is configured to provide a control signal to control the transistor of the first feedback path in dependence on a gate-source voltage of the second transistor.