公开(公告)号：US12170872B2

公开(公告)日：2024-12-17

申请号：US18009743

申请日：2020-06-30

Applicant: TOA Corporation

Inventor： Kazuma Asada ,  Ryosuke Ozaki

IPC: H04B3/00 ,  H04R1/04 ,  H04R27/00

Abstract: Provided is a public address device that facilitates recognizing a sound while performing power control so that input power does not exceed upper-limit supply power of a power source device. Included are a voltage transforming unit 204 that performs voltage transformation of a direct-current power source input from a power source device 10; a power amplifier 202 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 205 that detects input power from the power source device 10; a threshold holding unit 207 that holds a power determination threshold Pth corresponding to upper-limit supply power of the power source device 10; a voltage control unit 206 that controls an output voltage of the voltage transforming unit 204 on the basis of the input power Pi and the power determination threshold Pth; and a charge accumulation unit 208 that is connected between the voltage transforming unit 204 and the power amplifier 202, and supplies a power source to the power amplifier 202 when the output voltage of the voltage transforming unit 204 drops.