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:
Jul. 12, 1994
Filed:
Jul. 19, 1993
Toshiyuki Zaitsu, Tokyo, JP;
Nec Corporation, Tokyo, JP;
Abstract
In a piezoelectric transformer converter for power use that includes a switching circuit that generates alternating current, a power-use piezoelectric transformer, and a rectification-smoothing circuit, the alternating current output of the power-use piezoelectric transformer is directly phase-inverted and amplified by a phase inversion-amplification circuit, and by way of a driving circuit, produces self-excited oscillation. In addition, the output voltage of the rectification-smoothing circuit is compared with a reference voltage by means of an error amplifier, and based on the resulting amplified voltage difference, the output voltage is controlled by using PWM control or frequency modulation control without the need for an additional electrode for self-excited oscillation. In addition, when controlling the output voltage to be constant, stable control is enabled that is unaffected by variance in the frequency characteristics of the power-use piezoelectric transformer.