Sensor Amplifier Diode Feedback for High-Input-Impedance Signal Range
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing sensor amplifier arrangements face challenges in handling high input impedances and signal distortion, particularly for capacitive sensors like MEMS microphones, due to limitations in amplifying sensor signals without muting or significant distortion, especially for loud sounds and high amplitude signals.
Innovation Solution
The proposed sensor amplifier arrangement incorporates an anti-parallel diode circuit and a feedback path with an offset voltage source and voltage divider, which provides a feedback current to adjust the signal input impedance and attenuate high signal amplitudes, ensuring low noise and high input impedance while preventing signal muting and distortion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a conventional amplifier is used to amplify sensor signals, then the signal amplitude is increased, but signal distortion and muting occur for high amplitude signals
Solution Approach 1:
The patent implements a feedback path that couples the signal output back to the signal input through an anti-parallel diode circuit. The feedback current is derived from the amplified sensor signal and fed back to adjust the signal input impedance dynamically. This feedback mechanism prevents signal distortion and muting by compensating for amplifier saturation effects, allowing high amplitude signals to be amplified without distortion.
Solution Approach 2:
The patent makes the signal input impedance dynamic rather than fixed. The anti-parallel diode circuit in the feedback path causes the input impedance to vary with the signal amplitude. For low amplitude signals, the impedance remains high for low noise operation. For high amplitude signals, the impedance automatically adjusts to prevent distortion and muting, enabling the amplifier to handle a wider dynamic range without signal degradation.
2Object-affected harmful factors
If the input impedance is kept high for low noise operation, then noise is reduced, but the ability to handle high amplitude signals without distortion is limited
Solution Approach 1:
The patent transforms the static input impedance into a dynamic parameter that adapts to signal amplitude. The anti-parallel diode circuit ensures that for small signal amplitudes, the input impedance remains high (maintaining low noise operation), while for large signal amplitudes, the impedance automatically decreases to prevent distortion and muting. This dynamic adaptation allows the amplifier to handle the full dynamic range effectively.
Solution Approach 2:
The patent changes the input impedance parameter dynamically based on the signal amplitude. Through the feedback path with anti-parallel diodes, the input impedance transitions from a fixed high value to a variable value that decreases with increasing signal amplitude. This parameter change enables the amplifier to maintain low noise for weak signals while preventing distortion for strong signals, thereby expanding the usable dynamic range.
3Measurement precision
If the amplifier gain is increased to amplify weak signals, then sensitivity is improved, but distortion occurs for loud sounds
Solution Approach 1:
The patent implements dynamic input impedance control that automatically adjusts to signal amplitude. For weak sensor signals, the high input impedance enables high gain operation with low noise, improving sensitivity. For loud sounds, the input impedance automatically decreases through the anti-parallel diode feedback circuit, preventing distortion and muting. This dynamic adaptation allows high sensitivity for weak signals without sacrificing reliability for strong signals.
Solution Approach 2:
The feedback path with anti-parallel diodes provides automatic gain control through impedance modulation. The feedback current, derived from the amplified output signal, adjusts the input impedance in real-time. For weak signals, the feedback is minimal and impedance remains high for maximum sensitivity. For strong signals, the feedback increases and impedance decreases to prevent distortion, thereby maintaining measurement precision across the full dynamic range.
Data Source
AI summary
A sensor amplifier arrangement includes an amplifier having a signal input to receive a sensor signal and a signal output to provide an amplified sensor signal, and a feedback path that couples the signal output to the signal input and provides a feedback current that is an attenuated signal of the amplified sensor signal and is inverted with respect to the sensor signal.