Hybrid Precision Amplifier Topology for Efficiency and Bandwidth
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Solution Overview
Problem
Existing precision amplifiers face challenges in achieving high efficiency while maintaining accuracy and handling complex loads, as they often require large inductors and capacitors, leading to limited slew rate and efficiency, especially with dynamic loads.
Innovation Solution
A high efficiency precision amplifier design combining a linear amplifier stage and a class D amplifier stage, where the linear amplifier supplies full load current and the class D amplifier stage provides a small inductor with large current ripple, allowing fast reaction to load changes, and a buffer capacitor supports load variations without saturating the linear amplifier.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a class D amplifier is used to achieve high efficiency, then power efficiency is improved, but bandwidth is reduced and output noise increases
Solution Approach 1:
The amplifier is divided into two independent stages: a class D amplifier stage for high-efficiency power amplification and a linear amplifier stage for accurate signal processing. Each stage operates in its optimal mode, with the class D stage handling the power-efficient amplification and the linear stage providing precision and bandwidth, thereby resolving the contradiction between efficiency and bandwidth.
2Measurement precision
If a linear amplifier is used to achieve high accuracy, then signal processing accuracy is improved, but power efficiency deteriorates
Solution Approach 1:
The amplifier is divided into two independent stages: a class D amplifier stage for high-efficiency power amplification and a linear amplifier stage for accurate signal processing. Each stage operates in its optimal mode, with the linear stage providing precision and the class D stage providing efficiency, thereby resolving the contradiction between accuracy and power efficiency.
3Loss of energy
If a large inductor is used in a class D amplifier, then efficiency is improved, but slew rate is limited
Solution Approach 1:
The amplifier is divided into two independent stages, allowing the class D stage to use a small inductor for fast response while the linear stage handles the precision amplification. This segmentation eliminates the need for a large inductor, thereby maintaining both efficiency and slew rate.
Solution Approach 2:
The invention changes the operating parameters of the class D amplifier by using a small inductor with large current ripple, which allows fast reaction to load changes and ensures high efficiency even with highly dynamic loads, thereby resolving the contradiction between efficiency and slew rate.
4Adaptability or versatility
If a class D amplifier handles complex loads, then versatility is improved, but accuracy and speed are compromised
Solution Approach 1:
The amplifier is divided into two independent stages: a class D amplifier stage for handling complex and dynamic loads with high efficiency and a linear amplifier stage for providing accurate and high-speed signal processing. The linear stage directly drives the load while the class D stage provides power-efficient voltage amplification, thereby resolving the contradiction between versatility and accuracy.
Data Source
AI summary
A high efficiency precision amplifier which comprises a linear amplifier stage, a class D amplifier stage and a set of switches is provided. Both amplifier stages receive the same input signal. The load is driven by the output of the linear amplifier stage. The set of switches connect the output of the class D amplifier stage to either of the positive and negative supply terminals of the linear amplifier stage and the other of the positive and negative supply terminals of the linear amplifier stage to a negative or positive supply, depending on the polarity of the signal being amplified.