Environmental Sensor Gain Switching for Low-Noise Measurement
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Solution Overview
Problem
Existing environmental sensors face challenges in reducing noise, increasing efficiency, and improving accuracy while managing amplifier saturation and non-linearities, especially with varying environmental magnitudes, and oversampling techniques increase power consumption.
Innovation Solution
The sensor employs a controller to manage gain and offset adjustments in analog circuitry, subdividing measurement ranges into multiple subranges with tailored gain and offset settings, and uses calibration to optimize these parameters for precise measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If different analog circuits are used for different magnitude ranges, then measurement accuracy is improved, but device complexity and component count increase
Solution Approach 1:
The patent implements a single analog circuit that can operate across multiple magnitude ranges by dynamically adjusting its gain through digital control. The controller selectively activates different gain stages based on the measured magnitude range, allowing one circuit to perform multiple measurement functions that would traditionally require separate dedicated circuits for each range.
2Measurement precision
If amplifier gain is increased to reduce noise, then measurement accuracy is improved, but amplifier saturation occurs reducing reliability
Solution Approach 1:
The patent employs dynamic gain adjustment where the amplifier gain is not fixed but changes based on the input signal magnitude. The controller monitors the measurement range and selectively activates different gain stages, allowing the system to use high gain for small signals (reducing noise) and low gain for large signals (preventing saturation), thus adapting to varying conditions in real-time.
3Measurement precision
If oversampling techniques are used to reduce noise, then measurement accuracy is improved, but power consumption increases
Solution Approach 1:
The patent changes the operational parameters of the amplifier by dynamically adjusting the gain level based on the measured magnitude range. Instead of using oversampling to reduce noise, the system achieves noise reduction through optimal gain selection - using higher gain for small signals to amplify them above the noise floor, and lower gain for large signals to avoid distortion, thereby reducing the need for extensive oversampling and associated power consumption.
Data Source
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AI summary
There is disclosed a controller (10) for an environmental sensor (200) providing digital environmental measurement values (13, 208) from analog environmental measurements (380, 480, 580) performed by analog circuitry (100, 400), the digital environmental measurement values (13, 208) lying in a global scale range (70). The controller (10) is configured to subject the global scale range (70) to a subdivision into a plurality of scale subranges (71', 72", 73"') which are proper subranges of the global scale range (70). The controller (10) is configured to: select (S71), among the plurality of scale subranges (71', 72", 73"'), one scale subrange (71') in which an analog environmental measurement is to be performed, select (S72) an offset information (11) and a gain information (14) which are associated with the selected scale subrange (71') and which are indicative of an offset (11) and a gain (14), respectively, to be applied by the analog circuitry (100, 400) to perform an analog environmental measurement in the selected scale subrange (71'); and provide (S73) the offset information (11) and the gain information (14) to the analog circuitry (100, 400).