Programmable-Gain Amplifier Circuit for Large Single-Ended Inputs
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Solution Overview
Problem
Differential difference amplifier architecture experiences significant output signal distortion under large signal amplitudes, making it unsuitable for single-terminal input applications without additional circuit conversion.
Innovation Solution
A programmable-gain amplifier circuit with specifically designed resistances and capacitors forms non-inverting and inverting amplifier structures, maintaining signal integrity even with large single-terminal inputs, and includes capacitors for high-frequency noise filtering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If differential difference amplifier architecture is used with large signal amplitude, then the amplifier can handle large input signals, but output signal linearity deteriorates dramatically causing distortion
Solution Approach 1:
The amplifier circuit is divided into two separate input terminals: a first input terminal for small-signal inputs and a second input terminal for large-signal inputs. Each terminal has dedicated feedback resistors (first feedback resistor for small-signal path, second feedback resistor for large-signal path) that are optimized for their respective signal ranges. This segmentation allows each path to maintain optimal linearity within its designated signal amplitude range, resolving the contradiction between handling large signals and maintaining output linearity.
2Device complexity
If differential difference amplifier architecture is used for single-terminal input, then circuit simplicity is maintained, but signal distortion occurs without additional conversion circuits
Solution Approach 1:
The amplifier circuit is designed with dual input terminals that can independently accept either single-terminal or differential input signals. The first input terminal and its associated feedback network handle small-signal single-terminal inputs, while the second input terminal and its feedback network handle large-signal inputs. This multi-functional design allows the same amplifier circuit to maintain high signal fidelity across different input types and amplitude ranges without requiring additional single-terminal to double-terminal conversion circuits, thus preserving circuit simplicity while improving signal fidelity.
Data Source
AI summary
An amplifier circuit includes a programmable-gain amplifier, a first resistor, a second resistor and at least one third resistor. The programmable-gain amplifier has a first positive input terminal, a first negative input terminal, a second positive input terminal, a second negative input terminal, a positive output terminal and a negative output terminal. The first resistor is connected between the first negative input terminal and the positive output terminal. One terminal of the second resistor is connected to the first negative input terminal and the first resistor, and another terminal is connected to the second positive input terminal. The at least one third resistor is connected between the second positive input terminal and the negative output terminal. A sum of resistances of each of the first resistor and the second resistor is the same as a resistance of the at least one third resistor.