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. 04, 1989
Filed:
Jul. 21, 1988
Yukio Maeba, Kyoto, JP;
Abstract
In a direct current power unit, a-c (alternating current) voltages outputted to secondary windings (28, 47) of transformers (26, 45) are rectified by rectifier diodes (30a, 30b), respectively, to output a positive d-c (direct current) voltage and a negative d-c voltage. The level of the positive d-c voltage is regulated by a first voltage regulator crcuit (34a) while the level of the negative d-c voltage is regulated by a second voltage regulator circuit (34b). A first switch (36a) and a first variable resistance (38a) as well as a second variable resistance (38b) and a second switch (36b) are connected in series to outputs of the first voltage regulator circuit and the second voltage regulator circuit, respectively. When the first switch is closed and the second switch is opened, the positive d-c voltage is outputted to an output terminal (44) from the first variable resistance through a backflow preventing diode (42a). On the other hand, when the first switch is opened and the second switch is closed, the negative d-c voltage is outputted to the output terminal from the second variable resistance through a backflow preventing diode (42b).