低失真、高PSRR的D类音频功率放大器  

Class D audio power amplifier with low THD and high PSRR

作　　者：应建华[1] 曾强[1] 谢金纯[1] 

机构地区：[1]华中科技大学电子科学与技术系,湖北武汉430074

出　　处：《华中科技大学学报（自然科学版）》2008年第8期52-55,共4页Journal of Huazhong University of Science and Technology(Natural Science Edition)

摘　　要：设计了一种低失真、高电源抑制比的D类音频功率放大器.该功率放大器采用幅值为1 V,频率为300kHz且斜边失真小于0.1%的双边三角波作为载波的PWM调制方式,大大降低了D类音频功率放大器的总谐波失真度,并提高了系统的电源抑制比.仿真测试结果表明:在5 V的电源电压下驱动4Ω负载,可提供2 W的额定输出功率,且典型总谐波失真小于0.08%,在频率为217 Hz时电源抑制比可达到77 dB.在保证D类音频功率放大器高效率输出的同时,也保证了输出信号较小的失真度和较强的抗电源干扰能力.A class D power amplifier with low total harmonic distortion （THD） and high power supply rejection rate （PSRR） was presented, in which pulse width modulation （PWM）, with double-sided sawtooth carrier of amplitude of 1 V, frequency of 300 kHz and nonlinearity of 0.1%, was used to decrease THD and improve PSRR. According to the simulation, it could supply an output power of 2 W at a supply voltage of 5 V with a 4 Ω load, the THD was less than 0.08% and PSRR was 77 dB at 217 Hz. The results indicated the high efficiency output with strong power supply rejection.

关 键 词：D类音频功率放大器 PWM调制 谐波失真 电源抑制比 

分 类 号：TN722.7[电子电信—电路与系统]