Bridge Sensor Compensation Circuit Topology
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Solution Overview
Problem
Sensors, particularly resistive sensors like Wheatstone bridges, face performance variations due to manufacturing inconsistencies, temperature effects, and environmental noise, leading to non-linear output and offset issues that existing technologies struggle to fully compensate for.
Innovation Solution
A circuit topology and method that separates the sensor input, compensation, and output bridge into non-interacting segments, using a transformation circuit to null-adjust and amplify sensor outputs, and a simulator circuit to provide a noise-filtered and temperature-compensated signal representative of an ideal sensor, independent of offset and noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If traditional Wheatstone bridge sensors are used, then the sensor structure is simple and easy to manufacture, but the output signal is affected by manufacturing variations, temperature effects, noise and drift
Solution Approach 1:
The patent divides the sensor system into two independent segments: the physical sensor that experiences environmental effects and the simulated bridge that generates the compensated output. The sensor segment (real Wheatstone bridge) remains simple to manufacture, while the simulation segment (operational amplifier circuitry) handles compensation, allowing each part to optimize its function without compromising the other.
Solution Approach 2:
The patent creates a simulated copy of the bridge sensor output using operational amplifiers that replicate the ideal bridge characteristics. This simulated bridge copy generates an output signal that mimics what a perfect sensor would produce, replacing the need for physically perfect sensor components while maintaining the simple sensor structure.
2Measurement precision
If compensation circuits are added to correct sensor performance variations, then measurement precision improves, but device complexity increases
Solution Approach 1:
The patent introduces an intermediary simulated bridge circuit that acts as a mediator between the simple physical sensor and the required precise output. This intermediate simulation stage translates the sensor's raw output into a compensated signal without requiring complex direct compensation of the sensor itself, simplifying the overall architecture while achieving high precision.
3Device complexity
If the sensor is directly connected to the output, then the device complexity is low, but the output is affected by offset voltage, temperature dependence and noise
Solution Approach 1:
The patent extracts the harmful effects (offset voltage, temperature dependence, noise) from the output signal by using the simulated bridge to generate a separate, clean reference signal. The simulation circuit takes out these detrimental factors by creating an idealized output that does not inherit the sensor's environmental sensitivities, effectively separating the measurement function from the error sources.
Data Source
AI summary
An apparatus includes a sensor excited by an input voltage adapted to provide a sensor output first voltage corresponding to a physical input excitation. A transformation circuit device provides the operational voltage to the sensor, detects the sensor output first voltage, nulls an amount of offset voltage in the sensor output first voltage, amplifies the nulled offset sensor output first voltage, and provide a noise filtered and temperature compensated output second voltage. A simulator circuit receives the compensated output second voltage and provides an output third voltage representative of a simulated bridge sensor, being absent of offset voltage, and being independent of temperature dependence and noise in the sensor.