The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.

The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.

Date of Patent:
Jul. 27, 2010

Filed:

Oct. 24, 2005
Applicants:

Makoto Yamamoto, Mishima-gun, JP;

Keiichi Fujii, Kusatsu, JP;

Inventors:

Makoto Yamamoto, Mishima-gun, JP;

Keiichi Fujii, Kusatsu, JP;

Assignee:
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H04R 29/00 (2006.01);
U.S. Cl.
CPC ...
Abstract

The present invention detects whether the supply voltage applied to the power supply terminal () is used for the dynamic speaker or for the piezoelectric speaker by the power supply voltage detection circuit (), switches the gain of the amplifier circuit () in accordance with the detection result by the gain switching circuit () so that the same output power is produced for the same input signal in the respective speaker driving, and amplifies the input signal from the input terminal () by the amplifier circuit () having the gain to drive a speaker () that is connected to the output terminals ().


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