Dual Bond Wire Thermistor Sensor Network for Wearable Health Monitoring
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional wearable sensor devices face inaccuracies in measuring thermistor resistance due to errors from offsets, current mismatches, gain variations, and digitization resolution limits, necessitating a cost-effective and efficient solution.
Innovation Solution
A wireless sensor device system with a temperature sensor network utilizing a dual bond wire system, driver and receiver devices, and a method involving either a two-step or four-step process to determine thermistor resistance, along with a dithering process to enhance ADC resolution, effectively eliminating measurement errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional temperature sensors are used to measure thermistor resistance, then the device structure is simple, but measurement precision deteriorates due to errors from offsets, current mismatches, gain variations, and digitization resolution limits
Solution Approach 1:
The temperature sensor is divided into separate functional modules: a driver device that generates excitation signals, a dual bond wire system that interfaces with the thermistor, and a receiver device that measures voltage responses. This segmentation allows each module to be optimized independently, improving measurement precision while managing complexity through modular design
Solution Approach 2:
A dual bond wire system is introduced as an intermediary between the driver device and the thermistor. This intermediary structure enables precise control and measurement of current flow through the thermistor, eliminating direct connection errors and improving resistance measurement accuracy through isolated signal paths
2Measurement precision
If conventional single bond wire system is used, then device complexity is low, but measurement precision deteriorates due to current mismatches and offset errors
Solution Approach 1:
The single bond wire connection is segmented into a dual bond wire system, where one bond wire carries the excitation current and the other carries the voltage measurement signal. This segmentation separates the current path from the voltage measurement path, eliminating current mismatch errors and improving resistance measurement precision
Solution Approach 2:
Instead of measuring both current and voltage through the same bond wire (conventional approach), the invention inverts the approach by using separate bond wires: one for current injection and another for voltage sensing. This inversion of the measurement strategy eliminates the fundamental error source of current-induced voltage drops in the bond wire itself
3Measurement precision
If standard ADC resolution is used, then device complexity is low, but measurement precision deteriorates due to digitization resolution limits
Solution Approach 1:
The system employs periodic dithering signals superimposed on the DC excitation current. This periodic modulation causes the thermistor resistance to vary periodically, allowing the ADC to capture resistance values at multiple discrete levels. By analyzing the pattern of digitized values over one complete cycle, the system achieves sub-ADC-resolution precision through temporal averaging
Solution Approach 2:
The dithering process intentionally introduces excessive small-amplitude variations in the excitation current that exceed the ADC's least significant bit. This excessive action, when averaged over a complete cycle, reveals precise resistance values that would be invisible to the ADC's coarse resolution, effectively extracting more information than the ADC's nominal resolution would suggest
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 system provides highly accurate thermistor resistance measurements by eliminating errors and improving digitization resolution, leading to reliable health monitoring of users.
Implementation Method 1
determining at least one output voltage using at least one input current flowing through the dual bond wire system
Data Source
AI summary
A method and system for determining thermistor resistance have been disclosed. The method comprises providing a temperature sensor network within a wireless sensor device, wherein the temperature sensor network includes a driver device and a receiver device, coupling the driver device to the receiver device using a dual bond wire system, determining at least one output voltage using at least one input current flowing through the dual bond wire system, and determining the thermistor resistance using the at least one output voltage. The system comprises a wireless sensor device including a temperature sensor network that comprises driver and receiver devices, and a dual bond wire system that couples the driver device to the receiver device, wherein at least one output voltage is determined using at least one input current flowing through the dual bond wire system, further wherein the thermistor resistance is determined using the at least one output voltage.