Differential Amplifier Feedback Circuit for Offset Drift Reduction
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Solution Overview
Problem
Differential amplifier circuits face issues with offset voltage and drift voltage, which can lead to errors in output signals, and replacing the operational amplifier with a high-precision one may limit the circuit's performance in terms of gain bandwidth product and slew rate.
Innovation Solution
A differential amplifier circuit configuration that includes a basic differential amplifier and a high-precision operational amplifier, where the potential at the non-inverting input terminal of the basic amplifier is used as a reference signal for the high-precision amplifier to apply negative feedback, reducing the offset voltage or drift voltage while maintaining performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a high-precision operational amplifier is used to reduce offset voltage or drift voltage, then measurement precision is improved, but device complexity increases and performance parameters such as gain bandwidth product or slew rate may be limited
Solution Approach 1:
A second operational amplifier with lower offset voltage and drift voltage characteristics is introduced as an intermediary component. This second op-amp is connected to receive the output signal from the first op-amp and process it to reduce offset voltage and drift voltage effects, thereby improving measurement precision without completely replacing the original operational amplifier and maintaining performance parameters such as gain bandwidth product and slew rate
Solution Approach 2:
The circuit employs feedback mechanisms where the second operational amplifier processes the output signal from the first operational amplifier. By feeding back corrected signals and using the specific connection configuration described in the patent, the system reduces offset voltage and drift voltage while maintaining the performance characteristics of the original operational amplifier
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration effectively reduces the offset voltage or drift voltage of the operational amplifier, maintaining its performance by using negative feedback from the high-precision amplifier, thus improving signal accuracy without compromising the circuit's performance.
Implementation Method 1
negative feedback is applied from the inverting input terminal of the operational amplifier to the non-inverting input terminal of the operational amplifier via the high-precision operational amplifier, and thus the potential difference between the input terminals of the operational amplifier is reduced
Data Source
AI summary
A differential amplifier circuit includes a basic differential amplifier circuit including an operational amplifier configured to amplify a potential difference between output ends of a first input resistor and a second input resistor, a feedback resistor connected to the output end of the first input resistor, and a first resistance element connected to the output end of the second input resistor. Furthermore, the differential amplifier circuit includes a high-precision operational amplifier having an offset voltage or a drift voltage lower than that of the operational amplifier. The high-precision operational amplifier includes an inverting input terminal connected to the output end of the first input resistor and an output terminal connected to the output end of the second input resistor.