Capacitive MEMS Sensor Seismic Mass Potential Stabilization
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Solution Overview
Problem
Capacitive MEMS sensors, such as gyroscopes, face challenges in maintaining a constant electrical potential on a seismic mass while inducing vibrational motion, leading to increased demands on the high-voltage control loop, higher power consumption, and larger sensor size due to fluctuations in the electrical potential caused by clocked control voltages.
Innovation Solution
A method involving a capacitive MEMS sensor with a deflectably mounted seismic mass, a circuit device for supplying a defined electrical potential, an excitation device for inducing vibrational motion using a clocked electrical control voltage, and a compensation device with an electrical storage element that selectively charges or discharges to compensate for potential fluctuations, thereby maintaining a stable vibrational motion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a clocked electrical control voltage is applied to induce vibrational motion of the seismic mass, then the sensor can operate and detect motion, but fluctuations in the electrical potential on the seismic mass occur
Solution Approach 1:
The compensation device predicts and counteracts potential fluctuations before they affect sensor performance. By monitoring the control voltage and preemptively adjusting the electrical potential on the seismic mass, the system prevents fluctuations rather than merely reacting to them, maintaining stable operation during vibrational motion induction
Solution Approach 2:
The system continuously monitors the control voltage applied to the seismic mass and uses this feedback to dynamically adjust the electrical potential. The compensation device responds to changes in the control voltage in real-time, creating a closed-loop control system that maintains stable electrical potential while allowing vibrational motion to occur
2Stability of the object's composition
If the high-voltage control loop bandwidth is increased to maintain constant potential during vibration, then potential stability improves, but power consumption and device complexity increase
Solution Approach 1:
Instead of continuously operating the high-voltage control loop at full bandwidth, the system applies compensation only when and where needed - specifically targeting the frequency components related to vibrational motion. This partial action approach maintains sufficient potential stability without the excessive power consumption that would result from full-bandwidth continuous operation
Solution Approach 2:
The compensation device dynamically adjusts the electrical potential parameters based on the operational state of the sensor. By changing the compensation level according to whether the sensor is in vibration mode or standby mode, the system optimizes the balance between potential stability and power consumption, avoiding unnecessary high-power operation during normal conditions
3Use of energy by stationary object
If a compensation device is added to maintain constant potential on the seismic mass, then power consumption decreases, but device complexity increases
Solution Approach 1:
The compensation device is integrated with the existing high-voltage control loop architecture rather than being implemented as a completely separate system. By merging the compensation functionality into the existing control structure, the patent reduces the overall device complexity compared to what would result from entirely independent compensation circuits, while still achieving the power consumption benefits
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 the bandwidth requirements of the high-voltage control loop, decreases power consumption, and minimizes the sensor's size by maintaining a constant potential on the seismic mass, allowing for simpler and more reliable control of the vibrational motion.
Implementation Method 1
compensating for fluctuations in the supplied electrical potential on the seismic mass caused by the clocked electrical control voltage, by selectively charging and/or discharging an electrical storage element connected to the seismic mass in accordance with the frequency of the clocked electrical control voltage
Implementation Method 2
capacitively inducing a vibrational motion of the seismic mass with the aid of a clocked electrical control voltage
Data Source
AI summary
A method for operating a capacitive MEMS sensor. The method includes: supplying a defined electrical potential on a deflectably mounted, seismic mass of the MEMS sensor; capacitively inducing a vibrational motion of the seismic mass with the aid of a clocked electrical control voltage; compensating for fluctuations in the supplied electrical potential on the seismic mass caused by the clocked electrical control voltage, by selectively charging and/or discharging an electrical storage element connected to the seismic mass in accordance with the frequency of the clocked electrical control voltage.