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:
Apr. 17, 2012
Filed:
Jul. 21, 2009
Applicants:
Jwin-yen Guo, Chupei, TW;
Ching-hsiang Yang, Taoyuan, TW;
Inventors:
Jwin-Yen Guo, Chupei, TW;
Ching-Hsiang Yang, Taoyuan, TW;
Assignee:
Richtek Technology Corporaton, Hsin-Chu, TW;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H03G 3/00 (2006.01);
U.S. Cl.
CPC ...
Abstract
The present invention discloses a multi-voltage headphone driver circuit comprising: at least one operational amplifier having an output supplied to a headphone speaker, the operational amplifier receiving a first power supply as its high operation voltage; a charge pump receiving a second power supply to generate a negative voltage corresponding to the second power supply in magnitude; and an m-fold circuit multiplying the negative voltage by m and providing the result to the operational amplifier as a low operation voltage thereof, wherein m is a real number.