US 12,170,872 B2
Public address system
Kazuma Asada, Hyogo (JP); and Ryosuke Ozaki, Hyogo (JP)
Assigned to TOA CORPORATION, Hyogo (JP)
Appl. No. 18/009,743
Filed by TOA Corporation, Hyogo (JP)
PCT Filed Jun. 30, 2020, PCT No. PCT/JP2020/025737
§ 371(c)(1), (2) Date Dec. 12, 2022,
PCT Pub. No. WO2022/003844, PCT Pub. Date Jan. 6, 2022.
Prior Publication US 2023/0247377 A1, Aug. 3, 2023
Int. Cl. H04B 3/00 (2006.01); H04R 1/04 (2006.01); H04R 27/00 (2006.01)
CPC H04R 27/00 (2013.01) [H04R 1/04 (2013.01)] 7 Claims
OG exemplary drawing
 
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.