| 摘要 |
PROBLEM TO BE SOLVED: To suppress a popping sound (click noise) produced when a standby and a standby release are performed within a short term in an audio amplifier or a headphone amplifier, using a simple circuit. SOLUTION: With the provision of a resistance element between an output of the audio amplifier or the headphone amplifier and GND, a charge stored in a capacitor for cutting DC in an output portion is discharged at a sufficiently lower speed than a time constant corresponding to 20 Hz. Also, by providing a switch which conducts at the time of the standby between the output of the audio amplifier or the headphone amplifier and the input side of a buffer circuit outputting an analog reference voltage, the voltage of the capacitor for cutting DC is made to coincide with the initial voltage of an analog reference voltage generation circuit at the time of the standby. Thus, the popping sound (click noise) produced when the standby is released in a short term after the standby is suppressed. COPYRIGHT: (C)2006,JPO&NCIPI
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