Physical Quantity Detection Circuit With Arm-Level Signal Balancing
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Solution Overview
Problem
Existing physical quantity detection devices face challenges in accurately measuring the vibration characteristics of individual detection arms due to potential generation of unnecessary signals, hindering appropriate balance tuning and overall performance improvement.
Innovation Solution
The device includes a physical quantity detection element with multiple detection arms and a circuit device featuring amplifier circuits that input specific detection signals from each arm to distinct input nodes, with wiring configurations that allow for grounding during inspection and operation, enabling separate measurement and improved signal balance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If detection signals from both positive and negative electrodes of detection arms are input to detection circuit without grounding, then detection sensitivity is improved, but it becomes impossible to individually measure vibration characteristics of each detection arm
Solution Approach 1:
The patent segments the detection arms into first detection arms and second detection arms, and segments the detection circuit into first amplifier circuits and second amplifier circuits. By grounding one electrode of each detection arm pair and connecting them to corresponding amplifier circuits, the system can individually measure vibration characteristics of each detection arm while maintaining high detection sensitivity through the segmented architecture.
2Ease of operation
If detection signals are coupled between detection electrodes of different arms, then signal input to amplifier circuits is enabled, but unnecessary signals are generated that prevent individual measurement of detection arms
Solution Approach 1:
The patent extracts and removes the grounding connection from one electrode of each detection arm pair (second detection electrode of first detection arm and fourth detection electrode of second detection arm). This extraction allows the remaining detection electrodes to be individually connected to amplifier circuits without generating unnecessary coupled signals, enabling clear identification and measurement of individual detection arm vibrations.
3Difficulty of detecting and measuring
If grounding is applied to detection electrodes, then individual measurement of detection arms is enabled, but detection sensitivity may be reduced
Solution Approach 1:
The patent applies grounding locally and selectively only to specific electrodes (second detection electrode of first detection arm and fourth detection electrode of second detection arm) while leaving other electrodes (first detection electrode and third detection electrode) ungrounded and connected to amplifier circuits. This local grounding approach enables individual measurement capability while preserving detection sensitivity in the active detection pathways.
Data Source
AI summary
A physical quantity detection device includes a physical quantity detection element, a support substrate, and a circuit device. The physical quantity detection element includes a first detection arm including a first detection electrode and a second detection electrode, and a second detection arm including a third detection electrode and a fourth detection electrode. A detection circuit of the circuit device includes a first amplifier circuit to which a first detection signal from the first detection electrode and a fourth detection signal from the fourth detection electrode are input, and a second amplifier circuit to which a third detection signal from the third detection electrode and a second detection signal from the second detection electrode are input. The support substrate includes first wiring, second wiring, third wiring, and fourth wiring coupled to the first detection electrode, the second detection electrode, the third detection electrode, and the fourth detection electrode, respectively. On the support substrate, the second wiring is coupled to ground during inspection and coupled to the third wiring during operation, and the fourth wiring is coupled to the ground during the inspection and coupled to the first wiring during the operation.