Chopper Amplifier Compensation Circuit for Filter-Free Error Cancellation
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Solution Overview
Problem
Conventional chopper amplifiers suffer from increased resistance and capacitance due to filters, leading to larger chip area and signal distortion, which deteriorates amplification accuracy and signal quality.
Innovation Solution
An amplifier design incorporating a first and second signal polarity inversion circuit, a load capacitor, and a compensation circuit to extract and negatively feed back input error components, allowing for signal amplification without filters, thus removing input error components through discrete analog operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a filter is disposed in the signal path to enhance attenuation effect, then error component removal accuracy is improved, but resistance and capacitance increase leading to larger chip area
Solution Approach 1:
The patent extracts the error component removal function from the filter and implements it through a separate compensation circuit that operates in parallel with the signal path. The compensation circuit includes error amplifiers and feedback mechanisms that specifically target error components without requiring traditional filter elements, thereby removing the need for large resistance and capacitance values in the main signal path.
Solution Approach 2:
The patent segments the error removal function from the main signal amplification function. The compensation circuit is divided into independent error amplifiers (first and second error amplifiers) that process error components separately from the main signal path. This segmentation allows error removal to be achieved without requiring the entire signal path to include large filter components.
2Measurement precision
If a filter is disposed in the signal path to enhance attenuation effect, then error component removal accuracy is improved, but signal distortion increases leading to deteriorated amplification accuracy
Solution Approach 1:
The patent extracts the error removal function from the filter and implements it through a separate compensation circuit that operates in parallel with the signal path. The compensation circuit includes error amplifiers and feedback mechanisms that specifically target error components without requiring traditional filter elements, thereby removing the need for large resistance and capacitance values in the main signal path.
Solution Approach 2:
The patent employs feedback mechanisms in the compensation circuit where the output of the error amplifiers is fed back to adjust and cancel error components. The first and second error amplifiers use feedback loops to continuously monitor and correct error signals, achieving high error removal accuracy without introducing the signal distortion that would result from using large filter components in the main signal path.
3Measurement precision
If resistance and capacitance are increased to enhance filter attenuation effect, then error component removal is improved, but chip area increases
Solution Approach 1:
The patent extracts the error removal function from the filter and implements it through a separate compensation circuit that operates in parallel with the signal path. The compensation circuit includes error amplifiers and feedback mechanisms that specifically target error components without requiring traditional filter elements, thereby removing the need for large resistance and capacitance values in the main signal path.
Solution Approach 2:
The patent substitutes the traditional mechanical filter system (based on large resistance and capacitance values) with an electronic compensation system using operational amplifiers and feedback circuits. This substitution replaces the need for large physical filter components with active electronic circuits that achieve error removal through amplification and feedback rather than passive filtering, significantly reducing the required chip area.
Data Source
AI summary
An amplifier includes: a signal polarity inversion circuit; an amplifier circuit, connected with the signal polarity inversion circuit, generating a current based on a voltage, and outputting the current from output terminals; a signal polarity inversion circuit, having input terminals respectively connected with the output terminals, and outputting, in a non-inverted or inverted polarity, the current output from the amplifier circuit; a capacitor, obtaining a voltage based on the current output from the signal polarity inversion circuit; and a compensation circuit, wherein a node 12 and a node 10 are connected and a node 13 and a node 11 are connected, an input error component current comprising an input error component of the amplifier circuit is extracted from a voltage between terminals of the capacitor, and the input error component current that is extracted is supplied to the node 10 and the node 11.