ISFET Array Digital Oscillation Detection for Scalable Chemical Sensing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Large-scale arrays of ISFETs used in chemical sensing and nucleic acid sequencing face challenges with high computing power requirements, analogue data processing, sensitivity to parasitic components and environmental noise, and limited scalability due to high-performance front-end interface circuitry.
Innovation Solution
A semiconductor device with a transducer that switches between ON and OFF states, using a signal generator to oscillate inputs and modulate the output signal based on chemical or electrical inputs, converting analogue signals to digital through a demodulator and encoder, thereby simplifying processing and reducing noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If large-scale arrays of ISFETs are used for chemical sensing and nucleic acid sequencing, then detection capability and scalability are improved, but computing power requirements and processing complexity increase enormously
Solution Approach 1:
The patent replaces complex analogue signal processing circuits with a digital oscillation-based detection system. Instead of using traditional analogue readout circuitry to measure continuous voltage signals from ISFETs, the system applies an oscillating voltage to the gate of each transistor and detects oscillation characteristics (frequency, amplitude, or phase changes) that correspond to ion concentration. This substitution of analogue processing with digital oscillation detection simplifies the front-end interface circuitry, reduces computing power requirements, and enables easier integration of large-scale sensor arrays while maintaining high detection capability.
2Measurement precision
If high-performance front-end interface circuitry is used for accurate analogue readout, then measurement precision is improved, but system area and power consumption increase
Solution Approach 1:
The patent replaces power-hungry high-performance analogue readout circuitry with a digital oscillation-based detection method. By applying an oscillating voltage to the ISFET gate and detecting changes in oscillation characteristics, the system achieves accurate ion concentration measurement without requiring complex analogue amplification and filtering circuits. This approach significantly reduces both system area and power consumption while maintaining measurement precision, as the digital oscillation detection can be implemented with simple voltage sources and threshold detectors.
3Loss of information
If traditional analogue signal processing is used, then continuous signal information is preserved, but sensitivity to parasitic components and environmental noise increases
Solution Approach 1:
The patent replaces vulnerable analogue signal processing with robust digital oscillation detection. Instead of measuring continuous analogue voltages that are susceptible to parasitic components and environmental noise, the system applies an oscillating voltage and detects changes in oscillation characteristics. The oscillation signal acts as a reference that can be correlated with the sensor response, enabling differentiation between true chemical signals and noise. This digital approach inherently rejects parasitic components and environmental interference while preserving the essential signal information.
4Measurement precision
If accurate analogue readout circuitry is implemented, then detection precision is improved, but integration ability and scalability are limited
Solution Approach 1:
The patent replaces integration-limited analogue readout circuitry with scalable digital oscillation detection. Each ISFET in the array can be independently addressed by applying oscillating voltages to their gates, and the oscillation responses can be read out using simple digital circuits. This approach enables easy integration of large-scale sensor arrays on a single chip, as the digital oscillation detection method requires minimal circuit area per sensor and allows for systematic expansion from small to large arrays without proportionally increasing complexity or power consumption.
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 approach simplifies signal processing, increases integration ability, and reduces noise, enabling efficient detection and scalability of chemical signals, particularly in nucleic acid sequencing, by converting chemical concentrations to digital outputs.
Implementation Method 1
Previously publications have disclosed the ability of an ION Sensitive Field Effect Transistor (ISFET) to detect chemicals proximate the sensing surface
Implementation Method 2
A signal generator oscillates one or more of said inputs to vary the switching point of the transducer
Implementation Method 3
converting analogue signals to digital through a demodulator and encoder
Data Source
AI summary
An apparatus with a transducer having a first output signal and arranged to receive an electrical input. The transducer switches the first output signal between an ON and OFF state. The apparatus has a chemical sensing surface coupled to the transducer arranged to receive a chemical input. A signal generator oscillates one or more of said inputs to vary the switching point of the transducer. The oscillating input may be the chemical input and/or the electrical input. The output signal may be a pulse whose period ON or OFF is determined by the oscillating input modulated by the chemical input.