Two-Wire Measurement Interface With Feedback Voltage Regulation
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Solution Overview
Problem
Measuring devices with a two-wire interface, such as IEPE-type piezoelectric accelerometers, face limitations due to the incompatibility between the constant current source and the need for a low impedance voltage power supply, which requires an auxiliary power supply circuit, and the voltage excursion limitations caused by components like Zener diodes, making it difficult to correct signal disturbances.
Innovation Solution
An electronic measuring device with a two-wire interface that includes a processing stage and a regulator with a feedback loop, allowing robust compensation of the regulator's influence, and featuring a series regulator or switching regulator with an energy storage device to provide a stable voltage supply to the transducer and processing stage, thereby addressing the voltage excursion issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a Zener diode is used in series with the amplification stage to provide constant voltage, then the voltage regulation is achieved, but the voltage excursion is limited and signal disturbances cannot be corrected by feedback loop
Solution Approach 1:
The patent implements a feedback loop that connects the output of the processing stage back to the input of the regulator. This feedback mechanism enables the system to detect signal disturbances and automatically correct them by adjusting the regulator's output, thereby resolving the limitation of the Zener diode approach where disturbances could not be corrected.
Solution Approach 2:
The patent separates the voltage regulation function from the signal processing function by placing the regulator outside the feedback loop of the processing stage. This segmentation allows the feedback loop to focus on signal accuracy while the regulator provides stable voltage, resolving the contradiction between voltage stability and signal correction capability.
2Device complexity
If a constant current source is used to power the measuring device, then the two-wire interface simplicity is maintained, but it is incompatible with the low impedance voltage power supply required by the processing stage
Solution Approach 1:
The patent introduces a regulator as an intermediary component between the constant current source and the processing stage. The regulator converts the constant current input into a stable low impedance voltage output, enabling the processing stage to receive compatible power while maintaining the simplicity of the two-wire interface. This intermediary resolves the incompatibility between constant current供电 and low impedance voltage requirements.
3Adaptability or versatility
If an auxiliary power supply circuit (regulator) is added to provide low impedance voltage, then the processing stage can be powered, but the device complexity increases
Solution Approach 1:
The patent designs the regulator to serve multiple functions: it provides voltage regulation for the processing stage, acts as part of the feedback loop for signal correction, and interfaces with the constant current source. By making the regulator multi-functional, the patent minimizes the increase in device complexity while achieving the required power supply capability.
Data Source
AI summary
The invention relates to an electronic device for measuring a specific quantity, the device having a two-wire interface having two connection terminals intended to be connected to a conductive pair supplying the measuring device and conveying in return an electrical quantity representative of the measured quantity. The device comprises a transducer providing a raw measurement of the determined quantity, a processing stage for conditioning the raw measurement, the processing stage including one input connected to the transducer and one output, a regulator electrically connected to the processing stage. The regulator includes an input port electrically connected to the two connection terminals of the two-wire interface and an output port supplying regulated voltage to the transducer and/or to the processing stage. The device also includes a feedback circuit electrically connected to the regulator input port and to the processing stage.