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JSSC 2020第12期Analog Circuits

A 28-W 1022-dB THDN Class-D Amplifier Using a Hybrid ΔΣM-PWM Scheme

一款用于汽车应用的28W高线性度D类放大器,采用混合ΔΣM-PWM方案。
28-W输出功率,91%效率,102.2 dB THD+N,4Ω负载,14.4V电源
D类放大器汽车电子高线性度ΔΣM-PWM低EMI
创新点1:混合多比特ΔΣM-PWM方案(方法创新) - 通过结合多比特ΔΣ调制和PWM技术,显著提高了放大器的线性度和动态范围,实现了-102.2 dB的超低THD+N性能,适用于高保真音频应用。
创新点2:高开关频率设计(电路创新) - 采用高开关频率设计,有效降低了AM波段EMI干扰,同时提升了系统的整体效率,在28W输出功率下实现了91%的高效率。
创新点3:小型低成本LC滤波器(系统创新) - 通过优化设计,仅需150 kHz截止频率的小型LC滤波器即可满足CISPR-25 EMI标准,显著降低了系统成本和体积。
创新点4:宽输出功率范围高线性度(性能创新) - 在宽输出功率范围内保持高线性度,适用于多种汽车音频应用场景,提升了系统的适用性和可靠性。
Abstract
This article presents a 28-W class-D amplifier for automotive applications. The combination of a high switching frequency and a hybrid multibit /Delta1/Sigma1M-PWM scheme results in high linearity over a wide range of output power, as well as low AM-band EMI. As a result, only a small (150-kHz cutoff frequency), and thus low-cost, LC filter is needed to meet the CISPR-25 EMI average limit (150 kHz–30 MHz) with 10-dB margin. At 28-W output power, the proposed amplifier achieves 91% efficiency while d