Class-D type power audio amplifier's pop noise avoiding circuit i.e. zero-crossing anti pop noise system, for e.g. portable audio system, has digital weighing apparatus transmitting gain value on rising edge of input of apparatus

摘要

The circuit has a voltage comparator (1) i.e. zero crossing detector, comparing input differential voltage to zero v, and a digital counter (2) i.e. timer, counting time of gain change of a class-D type power audio amplifier, where the circuit includes a low silicon surface. A digital logic block (7) provides an output rising on a rising edge of a timer's output or on a comparator's rising/falling output. A digital weighing apparatus (3) transmits a gain value on a rising edge of input of the apparatus. An output of the apparatus is a gain value used for a control circuit (4) of the amplifier.