Sensor Supply Circuit Compensation for Process Variations
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Solution Overview
Problem
Sensors for physical quantities face challenges in achieving reliability and accuracy due to variations such as temperature and process-related deviations, leading to unstable sensing conditions and increased manufacturing and implementation complexities.
Innovation Solution
A circuit and method that utilize a supply circuit with a closed-loop configuration to provide sensor arrangements and further sensor elements with supply signals, where the magnitude of the further supply current is proportional to the supply current, improving compensation for variations and simplifying manufacturing and implementation while maintaining stable sensing conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional sensor configurations are used, then manufacturing and implementation are simpler, but reliability and accuracy deteriorate due to temperature and process variations
Solution Approach 1:
The sensor system is divided into two independent but correlated parts: a sensor arrangement and a further sensor element. Both are sensitive to the same physical quantity but serve different purposes - the sensor arrangement provides the measurement while the further sensor element provides compensation information for variations. This segmentation allows independent optimization of each component while maintaining overall system reliability.
Solution Approach 2:
The supply current magnitude is changed as a control parameter to compensate for temperature and process variations. By adjusting the supply current based on the predetermined relationship with the further sensor element output, the system compensates for parameter drift without requiring complex circuitry. This parameter-based compensation improves reliability while keeping the circuit relatively simple.
2Manufacturing precision
If traditional sensor configurations are used, then device complexity is lower, but manufacturing precision and accuracy deteriorate due to unstable sensing conditions
Solution Approach 1:
The system uses feedback from the further sensor element to adjust the supply current to the sensor arrangement. The output of the further sensor element, which experiences the same environmental variations, is used to compensate for inaccuracies in the main sensor arrangement. This feedback mechanism improves manufacturing precision by compensating for post-manufacturing variations without requiring extremely precise initial manufacturing.
Solution Approach 2:
Both the sensor arrangement and the further sensor element are exposed to the same environmental conditions (temperature, process variations) and are supplied with correlated currents. This creates an equipotential situation where both elements experience identical variations, allowing the further element to accurately compensate for the main element's inaccuracies.
3Measurement precision
If supply current is increased to improve signal quality, then measurement accuracy improves, but energy consumption increases
Solution Approach 1:
The supply current is made dynamic rather than static. The magnitude of the supply current changes based on the output of the further sensor element, which reflects current environmental conditions. This dynamic adjustment allows the system to optimize measurement accuracy by increasing current only when needed while reducing current consumption during normal operation, resolving the trade-off between precision and energy use.
Data Source
AI summary
A circuit for obtaining information on a physical quantity according to an embodiment includes a sensor arrangement sensitive to the physical quantity, at least one further sensor element sensitive to the physical quantity and a supply circuit configured to provide the sensor arrangement with a supply signal comprising a supply voltage controlled by the supply circuit in a closed-loop configuration. The supply circuit is further configured to provide the at least one further sensor element with a further supply signal comprising a further supply current such that a magnitude of the further supply current fulfills a predetermined relationship with a magnitude of a supply current of the supply signal. As a consequence, it may be possible to improve a trade-off between an improved compensation of variations, simplifying an implementation, simplifying the manufacturing, simplifying the sensing and providing stable sensing conditions.