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.
Patent No.:
Date of Patent:
Dec. 25, 1990
Filed:
Oct. 13, 1989
Masao Noro, Hamamatsu, JP;
Daisuke Suzuki, Hamamatsu, JP;
Yamaha Corporation, Hamamatsu, JP;
Abstract
A driving apparatus for negative-impedance driving a speaker as a load, comprises a detection element, a positive feedback circuit, a temperature compensation circuit, a sensor element, a control circuit, and an input f characteristic control circuit. The resistor as the detection element connected in series with the load detects a current flowing through the load. The feedback circuit feeds back a detection output of the detection element to an input side of the driving apparatus. The temperature compensation circuit controls the negative-impedance driving state to compensate for an increase in load impedance upon an increase in temperature of the load. The sensor element detects that a temperature of the load reaches a predetermined value. The control circuit stops temperature compensation of the temperature compensation circuit or decreases a degree of temperature compensation in accordance with an output from the sensor element. The input f characteristic control circuit controls frequency characteristic of an input signal in accordance with an output from the control circuit.