Time-Multiplexed Signal Processing for MEMS Sensor Calibration
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Solution Overview
Problem
Current MEMS systems with multiple inertial measurement devices face inefficiencies due to redundant components and environmental drift issues, requiring a more efficient signal processing architecture and dynamic calibration method to address size, cost, power consumption, and noise reduction.
Innovation Solution
A time-domain multiplexed signal processing architecture that shares a common signal processing block among multiple MEMS devices, allowing for dynamic calibration of sensor error signals by deriving and applying calibration signals in a multiplexed manner to maintain sensors at optimal states despite environmental changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate analog signal processing blocks are used for each MEMS device, then each device can be processed independently, but the space, expense, and fabrication complexity increase due to multiple occurrences of identical components
Solution Approach 1:
The patent merges multiple separate analog signal processing blocks into a single shared processing block that serves multiple MEMS devices. This consolidation eliminates redundant components while maintaining the ability to independently process signals from each device through time-multiplexed switching architecture.
Solution Approach 2:
The shared signal processing block is designed to perform multiple functions by sequentially processing signals from different MEMS devices. The universal block can handle acceleration and rotation sensing for multiple devices through time-multiplexed operation, replacing the need for dedicated processing blocks for each sensor.
2Ease of manufacture
If a single factory calibration is performed, then the calibration process is simple, but the sensor outputs drift with changes in external conditions such as temperature, stress, and humidity during normal operation
Solution Approach 1:
The patent implements a feedback-based dynamic calibration system that continuously monitors sensor outputs and applies correction signals to compensate for drift caused by environmental changes. The system uses feedback loops to detect calibration errors and automatically adjusts sensor parameters to maintain accuracy during normal operation.
Solution Approach 2:
The calibration system transitions from a static factory calibration to a dynamic calibration process that adapts to changing environmental conditions. The calibration parameters are continuously updated based on real-time sensor performance, allowing the system to maintain accuracy despite temperature, stress, and humidity variations.
3Productivity
If multiple MEMS devices are processed simultaneously with separate processing blocks, then each device receives dedicated processing resources, but the power consumption and area requirements increase
Solution Approach 1:
The patent employs periodic time-multiplexed switching to sequentially process signals from multiple MEMS devices through a single processing block. Each device is processed in alternating time slots, creating a periodic operation pattern that maintains simultaneous processing capability while significantly reducing power consumption by activating only one processing path at a time.
Data Source
AI summary
A sense channel signal processing block is time-domain multiplexed among multiple MEMS devices and utilizes an anti-aliasing filter disposed after track-and-hold switches, to prevent the bandwidth of the sense channel from being limited by the anti-aliasing filter. A multiplexed signal processor architecture performs dynamic calibration of all sensor error signals in response to environmental changes.