| 摘要 |
PROBLEM TO BE SOLVED: To provide an acoustic device that suppress interruption of sound as much as possible at the time of excessive output, even when using a power source equipped with an overcurrent protection circuit having a fold-back type drooping characteristic. SOLUTION: When a current supplied to a power amplifier 13 from a first power source Vcc1 exceeds a second maximum current Ix which is lower than a first maximum current Imax by a margin current m, an overcurrent detecting circuit 11 turns off a power FET 12 to stop the supply of the first DC power source Vcc1 to the power amplifier 13. Even at the time of excessive output of the power amplifier 13, the overcurrent protection circuit of an AC adapter 2 does not operate, and a signal processing part 17 continues operation.After the end of the excessive output, the power amplifier 13 is supplied with the first DC power source Vcc1 quickly. Thus, interruption of sound can be prevented as much as possible even at the excessive output of the power amplifier 13. COPYRIGHT: (C)2010,JPO&INPIT |
