Multi-Stage Power Amplifier Feedback to Eliminate Output Inductors
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing power amplifiers with multistage configurations require an inductor, such as a coil, between the power amplifier and the load to prevent phase rotation, making it difficult to reduce the overall device size when multiple elements are arranged on the path from the power amplifier to the load.
Innovation Solution
A power amplifier configuration with a 3-stage amplifier setup, including a differential amplifier, an intermediate amplifier, and an output amplifier, where feedback signals from both the intermediate and output amplifiers are combined and fed back to the differential amplifier, eliminating the need for an inductor by reducing capacitive effects and allowing for a more compact design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an inductor is added between the power amplifier and the load to prevent phase rotation, then the phase stability is improved, but the device size increases
Solution Approach 1:
The patent implements a feedback circuit that feeds back a portion of the output signal to the input of the power amplifier. This feedback mechanism compensates for phase rotation effects without requiring additional inductors, thereby maintaining phase stability while avoiding increased device size.
Solution Approach 2:
The patent changes the electrical parameters within the existing amplifier stages, specifically adjusting the gain and frequency response characteristics through the feedback network. This allows the system to compensate for phase effects by modifying signal parameters rather than adding physical components.
2Adaptability or versatility
If multiple elements are arranged on the path from the power amplifier to the load, then the signal processing capability is improved, but the device complexity increases
Solution Approach 1:
The patent combines the feedback function with the existing amplifier stages, integrating phase compensation capabilities into the current signal path without adding separate processing elements. This merging approach maintains signal processing capability while reducing overall device complexity.
Solution Approach 2:
The feedback circuit serves multiple functions simultaneously: it provides phase compensation, stabilizes the output signal, and works across different operating conditions. This multi-functionality achieves versatile signal processing without requiring dedicated components for each function.
3Power
If a multistage configuration with differential input stage and multiple amplification stages is used, then the gain and output signal amplitude are improved, but the need for additional components like inductors increases
Solution Approach 1:
The feedback circuit compensates for phase effects that would otherwise require additional inductors, allowing the multistage amplifier to achieve high output signal amplitude without the need for extra components in the signal path.
Solution Approach 2:
The patent eliminates the need for inductors by using the feedback mechanism to recover and correct phase rotation effects, thereby discarding the requirement for additional magnetic components while maintaining the desired output power level.
Data Source
AI summary
A power amplifier includes a first amplifier configured to output a signal based on a difference between an input signal and a feedback signal; a second amplifier that amplifies the power of the signal output from the first amplifier and outputs the amplified signal; a first feedback circuit that feeds the signal output from the second amplifier back to the first amplifier; a third amplifier that amplifies the power of the signal output from the second amplifier and outputs the amplified signal; and a second feedback circuit that feeds the signal output from the third amplifier back to the first amplifier, in which the feedback signal is a signal obtained by combining an output signal of the first feedback circuit with an output signal of the second feedback circuit.