发明名称 Class D amplifier no low pass filter feedback with zero phase delay
摘要 A circuit for generating an accurate reproduction of the output of a Class D amplifier for error-correction purposes includes a reference signal amplifier circuit. The reference signal amplifier circuit includes an op-amp configured as a differential amplifier that combines the digital outputs of the internal output stage of the amplifier into a single reference signal. By reducing the bandwidth of the op-amp, switching noise is removed from the digital signals, without adding any phase shift to the generated reference signal. In addition, by using the digital signals directly from the output stage rather than the filtered analog outputs of the amplifier, distortion due to external speaker-induced back-EMF is prevented. The reference signal can then be compared to the original signal input to the amplifier for error-correcting purposes.
申请公布号 US5949282(A) 申请公布日期 1999.09.07
申请号 US19980030746 申请日期 1998.02.25
申请人 NATIONAL SEMICONDUCTOR CORPORATION 发明人 NGUYEN, HUEY;TAKAGISHI, HIDETO
分类号 H03F3/217;(IPC1-7):H03F3/38 主分类号 H03F3/217
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