公开(公告)号：US20190123694A1

公开(公告)日：2019-04-25

申请号：US16222281

申请日：2018-12-17

Applicant: STMicroelectronics (Shenzhen) R&D Co. Ltd

Inventor： Ru Feng DU ,  Qi Yu LIU

IPC: H03F1/32 ,  H03G3/34 ,  H03F1/30 ,  H03F3/45 ,  H04R3/00 ,  H03F3/183 ,  H03F3/217 ,  H03F1/02 ,  H03F3/185 ,  H03F3/187 ,  H03F3/21

CPC classification number: H03F1/3205 ,  H03F1/0205 ,  H03F1/305 ,  H03F3/183 ,  H03F3/185 ,  H03F3/187 ,  H03F3/211 ,  H03F3/2171 ,  H03F3/2173 ,  H03F3/45179 ,  H03F2200/03 ,  H03F2200/351 ,  H03F2203/21106 ,  H03F2203/45151 ,  H03F2203/45156 ,  H03G3/345 ,  H03G3/348 ,  H04R3/002

Abstract: A class D amplifier receives and amplifies a differential analog signal which is then differentially integrated. Two pulse width modulators generate pulse signals corresponding to the differentially integrated analog signal and two power units generate output pulse signals. The outputs the power units are coupled to input terminals of integrators via a resistor feedback network. An analog output unit converts the pulse signals to an output analog signal. The differential integration circuitry implements a soft transition between mute/un-mute. In mute, the integrator output is fixed. During the soft transition, the PWM outputs change slowly from a fixed 50% duty cycle to a final value to ensure that no pop noise is present in the output as a result of mode change.