MEMS Barometric Sensor with Dedicated Hardware Circuit
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Solution Overview
Problem
Existing portable electronic devices with barometric altimeter functions face power consumption issues due to microprocessors handling all signal processing, leading to delays and inefficiencies in altitude determination, and signal quality degradation from electromagnetic noise.
Innovation Solution
Integration of a MEMS pressure sensor and a dedicated hardware processing circuit within a single integrated circuit, including a temperature sensor, to autonomously perform altimeter and altimeter-setting operations, reducing computational burden on the microprocessor and minimizing signal noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the microprocessor handles all signal processing for altitude calculation, then the device can perform general operations and altimetric measurements, but power consumption increases and processing delays occur
Solution Approach 1:
The system is divided into two functional segments: a dedicated processing circuit for altimetric signal processing and a microprocessor for general operations. The processing circuit includes a pressure sensor, temperature sensor, and dedicated processing unit that autonomously handles barometric pressure measurements and altitude calculations, allowing the microprocessor to enter low-power standby mode while maintaining accurate altimetric functionality.
2Measurement precision
If the microprocessor processes barometric pressure signals, then altitude information can be determined, but processing priority is low causing delays
Solution Approach 1:
The processing circuit is designed to autonomously acquire barometric pressure measurements, compensate for temperature effects, calculate altitude information, and manage altimeter setting procedures without requiring microprocessor intervention. The circuit independently executes processing routines, prioritizing altimetric measurements and providing results to the microprocessor only when ready, thereby eliminating processing delays and ensuring timely altitude determination.
3Productivity
If dedicated microprocessors are used for altimetric detection, then processing efficiency improves, but device complexity and computational burden increase
Solution Approach 1:
The altimetric processing functions are extracted from the general-purpose microprocessor and implemented in a dedicated processing circuit using hardware logic and specialized analog-to-digital conversion. This extraction eliminates the computational burden from the microprocessor, allowing it to focus on general operations while the dedicated circuit handles all altimetric calculations with high efficiency and deterministic timing.
4Ease of manufacture
If barometric pressure signals are communicated over long distances within the device, then integration is easier, but signal quality degrades due to electromagnetic noise
Solution Approach 1:
The pressure sensor, temperature sensor, analog-to-digital converter, and processing logic are merged into a single integrated processing circuit that is closely coupled with the microprocessor. This physical merging minimizes the distance over which sensitive barometric pressure signals must travel, reducing exposure to electromagnetic interference and maintaining signal integrity while achieving full functional integration.
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 solution reduces power consumption, enhances processing efficiency, and improves signal quality by performing altimeter functions within the integrated circuit, allowing the microprocessor to conserve power and focus on other tasks while maintaining accurate altitude measurements.
Implementation Method 1
Piezoresistive elements 5, connected in a Wheatstone-bridge configuration, are diffused in a surface portion of the flexible membrane 4... the flexible membrane 4 is deformed as a function of the difference between the atmospheric pressure and the pressure present within the buried cavity 3, and this deformation causes unbalancing of the Wheatstone bridge formed by the piezoresistive elements 5
Data Source
AI summary
A barometric-pressure-sensor device for a portable electronic device, having a pressure sensor of a MEMS type designed to supply a barometric-pressure measurement, and with a processing circuit coupled to the pressure sensor that is designed to supply an altitude measurement as a function of the barometric-pressure measurement. The pressure sensor and the processing circuit are integrated in a single chip, and the processing circuit is a dedicated circuit of a purely hardware type. The processing circuit executes altimeter-setting operations through a plurality of reference registers containing respective pressure references.