LC Sensor Excitation Control Without High-Speed Clocks
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Solution Overview
Problem
Inductive (LC) sensors used in fluid metering applications face challenges such as high power consumption and sensitivity to Power Voltage-Temperature (PVT) variations, particularly due to the need for high-speed clock sources and prolonged measurement times.
Innovation Solution
A method that eliminates the need for high-speed clock sources by using closed-loop control to manage energy accumulation and transfer in LC sensors, allowing for efficient energy use and robust operation across varying conditions, employing electronic switches and reference capacitors to control energy transfer and sensing phases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If high-speed clock sources are used to control energy transfer during excitation, then measurement speed is improved, but power consumption increases
Solution Approach 1:
The patent employs periodic switching of electronic switches to transfer energy in controlled intervals between the reference capacitor and sensor capacitor, replacing continuous high-speed clock operation with periodic energy transfer cycles that achieve measurement objectives with lower average power consumption
Solution Approach 2:
The patent extracts and eliminates the high-speed clock source from the system, replacing it with a clock-less energy transfer mechanism using electronic switches that control energy movement between capacitors, thereby removing the primary source of high power consumption while maintaining measurement functionality
2Productivity
If high-speed clock sources are used for excitation, then energy transfer control is improved, but sensitivity to PVT variations increases
Solution Approach 1:
The patent implements closed-loop control where the system monitors the charging state of the sensor capacitor and adjusts the energy transfer process accordingly, using feedback signals from the sensing phase to control the discharge timing, which compensates for PVT variations and maintains reliable operation across different conditions
Solution Approach 2:
The patent changes the control parameter from fixed high-speed clock timing to dynamic energy state monitoring, where the transfer and sensing phases are controlled based on the actual charge/voltage state of capacitors, making the system adaptive to PVT variations rather than rigid to frequency variations
3Device complexity
If traditional clock-based excitation is used, then energy transfer control is simplified, but measurement time increases
Solution Approach 1:
The patent performs preliminary energy accumulation in the reference capacitor before the sensing phase, pre-charging it to the supply voltage during a dedicated charging phase, which enables faster subsequent energy transfer to the sensor capacitor and reduces total measurement time while maintaining simple control logic
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, enhances robustness against PVT variations, and enables faster measurement times without the drawbacks of traditional high-frequency clock-based systems, improving overall efficiency and reliability in LC sensor operations.
Implementation Method 1
a reference capacitor adapted for accumulating energy from a voltage source
Implementation Method 2
a sensor capacitor adapted for detecting charge as a function of the energy transferred from the reference capacitor
Data Source
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Figure 6~7
AI summary
In one embodiment, an inductive/LC sensor device includes: - energy accumulation means (Cref) for accumulating excitation energy, - an LC sensor (10) configured for oscillating energized by energy accumulated, - an energy detector (12) for detecting the energy accumulated on the energy accumulation means (Cref) reaching a charge threshold, and - at least one switch (S1, S2) coupled with the energy detector (12) for terminating accumulating excitation energy for the sensor (10) on the energy accumulation means (Cref) when the charge threshold is detected having been reached by the energy detector (12).