Pop noise prevention circuit and pop sound prevention method

摘要

PPROBLEM TO BE SOLVED: To provide a click noise prevention circuit and click noise prevention method which prevent click noise caused by output offset of an audio amplifier without taking a time for power-on. PSOLUTION: When normally driving a speaker SP, the speaker SP is driven in an order of a series of offset calibration phase, dummy driving phase and normal driving phase. First, offset calibration processing is performed to minimize an amount of variation in DC voltage which is to be input to the speaker SP when the speaker SP is connected. Next, an amplifier and the speaker SP are not connected immediately but the speaker SP is driven in a dummy driving state and then driven in a normal state. PCOPYRIGHT: (C)2011,JPO&INPIT