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:
Feb. 18, 2003
Filed:
Sep. 01, 2000
Masashi Nakayama, Shizuoka-ken, JP;
Yazaki Corporation, Tokyo, JP;
Abstract
A multi-voltage level power supply unit has a constant voltage source for providing a first voltage, a switching circuit connected to the constant voltage source and a DC/DC converter for reducing the first voltage so as to provide the second voltage. The first voltage may be 42-volts and the second voltage may be 14-volts, for example. The switching circuit is connected to the constant voltage source. And the switching circuit has a first relay designed to operate at the second voltage lower than the first voltage, a first semiconductor device and a control unit (CPU). Namely, the first semiconductor device has a first control electrode (base electrode), a first main electrode (emitter electrode) for receiving the first voltage, a second main electrode (collector electrode) connected to the first relay. And the CPU is connected to the first control electrode. The CPU provides a first control signal to the first control electrode so as to increase an interelectrode voltage between the first and second main electrodes, only during transition periods between open to closed states and closed to open states. Further the CPU provides second control signal to the first control electrode so as to decrease the interelectrode voltage during steady state periods of the first relay. The constant voltage source is constructed of an alternator and an AC/DC converter connected to the alternator.