LC Sensor Charge-Threshold Excitation for Low-Power Measurement
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Solution Overview
Problem
Inductive (LC) sensors in fluid metering applications face challenges with high power consumption and sensitivity to Power Voltage-Temperature (PVT) variations, particularly due to the use of high-speed clock sources for energy transfer, which affects measurement time and robustness.
Innovation Solution
The method involves accumulating excitation energy for the LC sensor until a charge threshold is reached, allowing for efficient energy transfer and oscillation, eliminating the need for high-speed clocks and using closed-loop control to reduce PVT sensitivity, thereby enhancing power efficiency and robustness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If high-speed clock sources are used to control energy transfer during LC sensor excitation, then measurement speed is improved, but power consumption increases
Solution Approach 1:
The patent applies periodic action by using a low-speed clock source that operates in periodic cycles - accumulating excitation energy over multiple cycles until a charge threshold is reached, then terminating accumulation and performing measurement. This periodic operation allows the system to achieve adequate measurement speed while dramatically reducing power consumption compared to continuous high-speed operation.
2Productivity
If high-speed clock sources are used for energy transfer, then excitation efficiency is improved, but power absorption increases
Solution Approach 1:
The patent applies preliminary action by pre-accumulating excitation energy in a capacitor before the actual measurement phase. The low-speed clock source charges the capacitor to a predetermined threshold level in advance, ensuring sufficient energy is available for efficient LC sensor excitation without requiring continuous high-power delivery during measurement.
Solution Approach 2:
The system uses periodic charging cycles to accumulate excitation energy, switching the capacitor between charging and measurement phases. This periodic operation allows energy to be accumulated efficiently at low power levels, then released at higher power during brief measurement windows, improving overall excitation efficiency while reducing average power absorption.
3Reliability
If closed-loop control is implemented to reduce PVT sensitivity, then measurement robustness is improved, but device complexity increases
Solution Approach 1:
The patent implements feedback by continuously monitoring the charge voltage on the capacitor during the accumulation phase and comparing it against a predetermined threshold. When the threshold is reached, the system automatically terminates the charging process and transitions to measurement mode. This simple feedback mechanism compensates for PVT variations without requiring complex control algorithms.
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 reduces power absorption, makes the system less sensitive to PVT variations, and improves robustness by allowing clock-less operation, leading to more efficient and reliable measurements.
Implementation Method 1
accumulating excitation energy for an inductive-capacitive (LC) sensor
Implementation Method 2
inductive sensing is based on an inductor-capacitor resonant circuit
Implementation Method 3
the inductor acting as a sensing coil... currents are generated in the object... The currents thus generated form a magnetic field
Data Source
AI summary
In one embodiment, an inductive/LC sensor device includes: an energy storage device for accumulating excitation energy, an LC sensor configured to oscillate using energy accumulated in the energy storage device and transferred to the LC sensor, an energy detector for detecting the energy accumulated in the energy storage device reaching a charge threshold, and at least one switch coupled with the energy detector for terminating accumulating excitation energy in the energy storage device when the charge threshold is detected having been reached by the energy detector.