DC Impedance Estimation via Charging Time Constants
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Solution Overview
Problem
Existing impedance measurement technologies require complex circuitry and high power consumption when using alternating current signals, limiting their efficiency and practicality for applications like wearable devices.
Innovation Solution
An apparatus utilizing direct current signals with a circuitry configuration that switches between charging and discharging loops to measure time constants, allowing estimation of impedance with reduced complexity and power consumption, employing distinct resistors and control circuitry to manage switching and adjust resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If alternating current signals are used for impedance measurement, then measurement accuracy is improved, but power consumption increases and circuit complexity increases
Solution Approach 1:
The patent changes the fundamental parameter of the measurement signal from alternating current to direct current. By using DC signals and measuring time constants during charging and discharging phases, the system achieves impedance measurement without requiring complex AC signal generation and processing circuitry, thereby reducing power consumption while maintaining measurement capability
Solution Approach 2:
The patent replaces the electrical AC signal-based measurement system with a time-constant-based measurement approach using DC signals. This substitution eliminates the need for AC signal generation, synchronization, and processing circuits, significantly simplifying the overall system and reducing power consumption
2Measurement precision
If alternating current signals are used for impedance measurement, then measurement accuracy is improved, but circuit complexity increases
Solution Approach 1:
The patent extracts and eliminates the complex AC signal generation, modulation, and demodulation circuits from the impedance measurement system. By using simple DC voltage sources and measuring the time constants of RC circuits during charging and discharging, the system achieves impedance measurement with minimal circuitry
Solution Approach 2:
The patent replaces the complex electrical AC measurement system with a simpler time-constant measurement system using DC signals. The impedance information is extracted from the charging and discharging time constants of a known capacitor through a unknown impedance, eliminating the need for AC signal processing infrastructure
3Use of energy by moving object
If direct current signals are used with time constant measurement, then power consumption is reduced, but measurement precision may be compromised
Solution Approach 1:
The patent uses feedback through the capacitor charging and discharging process to extract impedance information. By measuring the time constants during charge and discharge phases and using these values to calculate impedance, the system achieves accurate measurements while maintaining low power consumption through simple DC signal usage
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
Enables accurate impedance estimation with lower power requirements and reduced circuit complexity, suitable for extended use in wearable devices, such as monitoring body composition and stress levels.
Implementation Method 1
the first circuit loop is configured to enable charging of a capacitor to enable measurement of a first time constant to be obtained where the first time constant is indicative of a charging time of the capacitor
Implementation Method 2
the second circuit loop is configured to enable discharging of the capacitor to enable measurement of a second time constant to be obtained where the second time constant is indicative of a discharging time of the capacitor
Implementation Method 3
circuitry configured to provide a direct current signal to a subject
Data Source
AI summary
The application relates to an apparatus, electronic device and method. The apparatus comprises circuitry configured to provide a direct current signal to a subject. The circuitry is configured to enable switching between a first circuit loop and a second circuit loop. The first circuit loop is configured to enable charging of a capacitor to enable measurement of a first time constant to be obtained where the first time constant is indicative of a charging time of the capacitor. The second circuit loop is configured to enable discharging of the capacitor to enable measurement of a second time constant to be obtained where the second time constant is indicative of a discharging time of the capacitor. The first time constant and the second time constant enable an impedance of the subject to be estimated.