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:
Nov. 20, 2001
Filed:
Apr. 14, 1999
Abstract
A piezoelectric-transformer inverter includes a piezoelectric transformer for supplying a transformed voltage to a load connected to a secondary electrode thereof. A first coil and a first transistor are connected to one primary electrode of the piezoelectric transformer, and a second coil and a second transistor are connected to the other primary electrode of the piezoelectric transformer. The first and second transistors are alternately turned on and off such that the phase of the voltage applied between the primary electrodes is reversed cyclically. The operation frequency is controlled such that an AC current flowing through the load is maintained at a predetermined level. The piezoelectric transformer has a piezoelectric substrate. In a first half region of the piezoelectric substrate, a plurality of electrode films are layered in order to form the primary electrodes. The secondary electrode is formed on an end surface of the piezoelectric substrate opposite to the primary electrodes. The piezoelectric substrate is polarized in a first direction in the first half region where the primary electrodes exist and is polarized in a second direction different from the first direction in a second half region where the secondary electrode exists. The piezoelectric transformer operates in a half wavelength mode.