A -106.3dB THD+N Feedback-After-LC Class-D Audio Amplifier Employing Current Feedback to Enable 530kHz LC-Filter Cut-Off Frequency

📋 论文概要

本论文提出了一种采用反馈-after-LC架构的Class-D音频放大器，通过电流反馈技术实现了530kHz的LC滤波器截止频率，同时达到-106.3dB的THD+N。该设计有效减小了LC滤波器的体积和成本，满足了汽车等应用对EMI的严格要求。

💡 主要创新点

• 提出反馈-after-LC架构，将反馈点置于LC滤波器之后，允许使用更高的LC滤波器截止频率（530kHz），从而大幅减小滤波器的体积和成本。
• 采用电流反馈技术代替传统的电压反馈，有效补偿LC滤波器的相位和增益误差，在宽带内保持低失真和高稳定性。
• 实现了-106.3dB的超低THD+N性能，同时确保对LC元件公差的鲁棒性，适用于实际量产。

🏷 关键词

📄 原文摘要

Goodix Technology, Nijmegen, The Netherlands 1 2 Class-D amplifiers (CDAs) are used in various audio applications thanks to their high power efficiency. However, they produce high-frequency switching energy that poses EMI challenges. For applications such as automotive, the stringent EMI requirement necessitates the use of an LC filter, which can add significant bulk and cost. To reduce these, not only the LC component values but also their linearity requirements should be reduced. Moreover, a certain LC tolerance should be allowed for practical usage. In [1], high LC filter cut-off frequency (fLC) (580kHz) is enabled, resulting in small LC component values. However, relatively expensive and bulky linear LC components are still required to achieve low THD+N due to a lack of LC nonlinearity suppression. Using a voltage feedback-after-LC architecture to suppress LC nonlinearity, the CDA in [2] enables the

👥 作者与机构

Huajun Zhang1, Haochun Fan1, Miao Zhang1, Marco Berkhout2, Qinwen Fan1

Delft University of Technology, Delft, The Netherlands