Physical Quantity Detection Device Arithmetic Resolution Memory Trade-off
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Solution Overview
Problem
Physical quantity detection devices, such as air flow sensors, face challenges in improving arithmetic resolution while maintaining memory capacity, as existing methods do not effectively address the variation in output characteristics due to insufficient resolution, particularly when dealing with low flow rates.
Innovation Solution
A physical quantity detection device with a 20-bit arithmetic unit and a 16-bit memory, where the arithmetic unit performs correction arithmetic operations using a correction amount stored in the memory, reducing the resolution difference by scaling conversion and gain term adjustments, allowing for improved arithmetic resolution without increasing memory capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the arithmetic resolution is increased from 16 bits to 20 bits, then the output characteristic variation is reduced and measurement precision is improved, but the memory capacity must be increased 16 times which increases cost
Solution Approach 1:
The patent divides the 20-bit correction data into two segments: a 16-bit main data portion stored in the memory, and a 4-bit differential portion calculated in real-time by the arithmetic unit. This segmentation allows the system to achieve 20-bit precision without requiring 20-bit memory storage, thereby resolving the contradiction between measurement precision and memory capacity.
Solution Approach 2:
The patent transitions from a single-dimension storage approach (storing all correction data in memory) to a two-dimension approach combining memory storage (16 bits) with real-time computational generation (4 bits differential data). This dimensional change in data handling enables high precision arithmetic without proportionally increasing memory capacity.
2Reliability
If a 20-bit memory is used to maintain arithmetic resolution, then the output characteristic variation is reduced, but the device complexity and cost increase due to requiring a highly functional memory
Solution Approach 1:
The patent applies local quality by using a standard 16-bit memory for the main correction data while generating the additional 4 bits of precision locally through real-time differential calculation in the arithmetic unit. This approach achieves high reliability without requiring a high-specification 20-bit memory, thereby reducing device complexity.
3Measurement precision
If the memory capacity is increased to provide sufficient resolution, then the detection precision is improved, but the cost increases
Solution Approach 1:
The patent performs preliminary action by pre-calculating and storing only the essential 16-bit correction data in memory, while the 4-bit differential precision is generated on-demand through real-time calculation. This approach achieves high detection precision without the cost of storing all precision data in memory.
Data Source
AI summary
A physical quantity detection device that can improve arithmetic resolution while preventing an increase in memory capacity is obtained. A physical quantity detection device 100 according to the present invention includes: a physical quantity detection sensor that detects a physical quantity of a measurement target gas; a storage unit that records a correction amount corresponding to a detection value of the physical quantity detection sensor; and an arithmetic unit 110 that performs output adjustment of the detection value using the detection value and the correction amount. Resolution of the storage unit 120 is lower than arithmetic resolution of the arithmetic unit 110.