Digital Gain Control for Analog Sensor Signal Accuracy
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Solution Overview
Problem
Existing techniques for amplifying and outputting analog sensor signals face challenges with offset errors and gain errors, particularly due to lifetime drifts and environmental changes, which can introduce additional errors and require additional circuitry.
Innovation Solution
A device and method utilizing a digital control circuit to determine and apply a digital control signal to an analog main signal path, allowing for a digitally-controllable output amplitude that reduces gain and offset errors, implemented through a split architecture that processes the analog signal in the analog domain with minimal digital assistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If analog control signals are used to control gain and offset, then the sensor signal can be adjusted, but additional errors are introduced and additional circuitry (DACs) is required
Solution Approach 1:
The patent replaces the analog control signal mechanism with a digital control signal mechanism. Instead of using analog DACs to control gain and offset, the invention uses digital control signals that are processed through a ratiometric calculation circuit, substituting the mechanical/analog control system with a digital one that avoids the inherent errors of analog conversion.
Solution Approach 2:
The patent introduces a ratiometric calculation circuit as an intermediary between the digital control signal and the analog sensor signal. This intermediary circuit performs ratiometric calculations to determine the appropriate gain and offset adjustments, avoiding direct analog control while maintaining signal adjustment capability.
2Measurement precision
If offset correction coefficients are used to adjust sensor signal, then offset errors can be corrected, but the correction is inaccurate and subject to lifetime drifts
Solution Approach 1:
The patent changes the fundamental parameter used for offset correction from fixed correction coefficients to dynamic ratiometric calculations. Instead of applying predetermined offset values that drift over time, the system continuously calculates offset corrections based on the ratio of reference signals, making the correction parameter adaptive and stable throughout the device lifetime.
Solution Approach 2:
The patent implements a feedback mechanism where the ratiometric calculation circuit continuously monitors the sensor signal and reference signals, automatically adjusting the offset correction in real-time. This closed-loop feedback ensures that offset corrections remain accurate and stable, compensating for any drift or environmental changes.
3Ease of operation
If additional circuitry (DACs) is added to control analog signals, then signal adjustment is enabled, but device complexity increases
Solution Approach 1:
The patent merges the signal control functionality directly into the existing analog signal path by using a ratiometric calculation circuit that processes digital control signals and outputs adjusted analog signals. This integration eliminates the need for separate DAC circuits while maintaining full signal control capability, reducing overall device complexity.
Data Source
AI summary
A device includes an analog main signal path and a digital control circuit. The digital control circuit determines and provides a digital control signal to the analog main signal path to reduce a gain error of the analog main signal path.