CPC H04R 27/00 (2013.01) [H04R 1/04 (2013.01)] | 7 Claims |
1. A public address device comprising:
a voltage transforming unit that performs voltage transformation of a direct-current power source input from a power source device;
a power amplifier that amplifies a sound signal using the direct-current power source after the voltage transformation to generate a driving signal that drives an electroacoustic transducer;
a power detection unit that detects input power from the power source device;
a threshold holding unit that holds a power determination threshold corresponding to upper-limit supply power of the power source device;
a voltage control unit that controls an output voltage of the voltage transforming unit on a basis of the input power and the power determination threshold; and
a charge accumulation unit that is connected between the voltage transforming unit and the power amplifier, and supplies a power source to the power amplifier when the output voltage of the voltage transforming unit drops.
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