Integrated Stress Sensor IC for Compact Torque Measurement
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing torque sensor systems are bulky and costly due to the use of external components like Hall-based magnetic systems, optical systems, and MEMS torque sensors, which require separate signal conditioning circuits and power supplies, and strain gauge systems are cumbersome with separate components mounted to the shaft.
Innovation Solution
An integrated circuit (IC) with strain-sensitive sensors, including piezoresistive sensors, is developed to measure torque by integrating the sensors directly on a semiconductor substrate, which includes a sense circuit to determine stress components like normal and shear forces, and incorporates temperature compensation to correct resistance variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If external components like Hall-based magnetic systems, optical systems, and MEMS torque sensors are used, then torque measurement capability is achieved, but system size becomes large and bulky
Solution Approach 1:
The patent combines the sensing element (piezoresistors) and signal conditioning circuitry into a single integrated circuit chip. This merging eliminates the need for separate external components and circuits, directly reducing system size while maintaining torque measurement capability through on-chip stress sensing and signal processing.
Solution Approach 2:
The patent replaces traditional mechanical torque sensing methods (Hall-based magnetic systems, optical systems, external MEMS sensors) with an integrated piezoresistive sensing system. The piezoresistors directly convert mechanical stress into electrical signals that are processed on-chip, substituting complex mechanical and external electronic systems with a compact integrated solution.
2Measurement precision
If external standalone readout and signal conditioning circuits are mounted to a printed circuit board, then signal processing capability is achieved, but system complexity and bulkiness increase
Solution Approach 1:
The patent integrates the signal conditioning circuitry (amplifiers, filters, analog-to-digital converters) directly onto the same semiconductor substrate as the piezoresistive sensors. This consolidation reduces the number of separate components and interconnections, simplifying the overall system architecture while maintaining full signal processing capability.
Solution Approach 2:
The integrated circuit chip performs multiple functions: it senses mechanical stress through piezoresistors, conditions the resulting electrical signals, and processes the data. This multi-functional integration eliminates the need for separate dedicated signal conditioning circuits, reducing system complexity while achieving comprehensive signal processing.
3Measurement precision
If strain gauges with separate components are mounted to the shaft, then torque measurement is achieved, but the system becomes cumbersome and requires multiple separate components
Solution Approach 1:
The patent merges the strain sensing elements (piezoresistors) and all associated signal processing circuitry into a single integrated circuit package. This eliminates the need to separately mount strain gauges, signal conditioning circuits, and power supplies to the shaft, simplifying installation to a single component mounting operation while maintaining measurement accuracy.
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
The IC-based torque sensor system is compact, efficient, and accurate in measuring torque by integrating strain-sensitive components directly on the substrate, reducing bulkiness and costs while providing precise force measurements.
Implementation Method 1
The strain-sensitive sensors may include circuit components or devices formed on or in the semiconductor substrate. Examples of strain-sensitive components are active and passive components including bipolar transistors, complementary metal oxide semiconductor (CMOS) transistors, metal lines, piezoresistors and the like.
Data Source
Figure 1A~1B
Figure 2A~3
Figure 4~6
AI summary
An integrated circuit (100) is described herein that includes a semiconductor substrate (102). First and second piezoresistive sensors (108, 112) are on or in the substrate (102) where each piezoresistive sensor (108, 112) has a respective sensing axis (110, 114) extending in first and second directions respectively parallel with a surface (104) of the substrate (102), where the second direction is perpendicular to the first direction. A third piezoresistive sensor (116) is on or in the substrate (102) and has a respective sensing axis (118) extending in a third direction parallel with the surface (104) of the substrate (102) that is neither parallel nor perpendicular to the first and second directions.