CMOS Sensor Array Using Correlated Double Counting for Noise Suppression
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Solution Overview
Problem
Current LC resonant circuits for sensing electrical and magnetic signals face limitations in noise suppression and require external bias fields and complex post-processing, which hinder their portability and cost-effectiveness for applications like biosensing.
Innovation Solution
A sensor array utilizing a correlated double counting (CDC) method with a CMOS-compatible design, featuring a plurality of sensors, an active core, oscillator, frequency counter, and controller, which implements noise cancellation techniques to suppress 1/f3 phase noise without power overhead, enabling efficient detection of magnetic and electrical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional LC resonant circuits are used for sensing, then electrical and magnetic signals can be detected, but noise suppression is insufficient and external bias fields are required
Solution Approach 1:
The sensor array performs self-noise-cancellation by using the correlated double counting method, where the system itself generates reference signals to suppress its own noise without requiring external bias fields or complex external processing equipment
Solution Approach 2:
The system uses feedback from the oscillator and frequency counter to continuously monitor and adjust the sensing process, enabling real-time noise suppression through the correlated double counting algorithm that processes signals and reference measurements
2Measurement precision
If traditional sensing circuits are used, then magnetic and electrical properties can be measured, but the devices are not portable and cost-effective
Solution Approach 1:
The patent merges multiple sensing functions, noise suppression, signal processing, and data output into a single integrated sensor array fabricated on a monolithic semiconductor substrate, eliminating the need for separate external components and enabling portable, cost-effective devices
Solution Approach 2:
The system replaces complex mechanical and external field-based biasing mechanisms with an electronic integrated circuit solution that uses electronic correlation processing to achieve noise suppression, simplifying the overall system architecture for portability
3Measurement precision
If noise suppression techniques are applied, then signal-to-noise ratio improves, but power consumption increases
Solution Approach 1:
The correlated double counting method uses periodic sampling and counting operations that process signals in discrete time intervals, achieving noise suppression through temporal correlation analysis without requiring continuous high-power consumption, as the processing occurs in structured periodic cycles
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
The CDC method achieves 6 dB noise reduction, enhancing the signal-to-noise ratio and enabling hand-held, battery-powered devices for sensitive applications like biosensing without the need for external bias fields or complex processing.
Implementation Method 1
an oscillator configured to provide an oscillation signal to each of the sensors
Implementation Method 2
each of the plurality of sensors configured to measure an electrical property or a magnetic property of a specimen of interest
Data Source
AI summary
A scalable and ultrasensitive frequency-shift magnetic array scheme. The theoretical limit of the sensor noise floor is shown to be dominated by the phase noise of the sensing oscillators. To increase the sensitivity, a noise suppression technique, Correlated Double Counting (CDC), is described with no power overhead. As an implementation example, a 64-cell sensor array is designed in a standard 65 nm CMOS process. The CDC scheme achieves an additional 6 dB noise suppression. The magnetic sensing capability of the presented sensor is verified by detecting micron size magnetic particles with an SNR of 14.6 dB for a single bead and an effective dynamic range of at least 74.5 dB. Applications in biosensing are contemplated, among other possible uses. Measurement of electrical properties is also contemplated.