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:
Sep. 22, 1998
Filed:
Jul. 19, 1996
Hideo Nunokawa, Kawasaki, JP;
Fujitsu Limited, Kawasaki, JP;
Abstract
A voltage step-down circuit includes a first transistor having an input terminal supplied with a first power supply voltage, an output terminal and a control terminal. A step-down voltage derived from the first power supply voltage is output through the output terminal when a load circuit to be driven by the voltage step-down circuit is in an active mode. The first transistor is OFF when the load circuit is in a standby mode. A first voltage dividing circuit has an input terminal connected to the output terminal of the first transistor, and an output terminal. A first control circuit controls a voltage of the control terminal of the first transistor so that, when the load circuit is in the active mode, a feedback control is performed on the basis of a result of comparing a reference voltage with a voltage of the output terminal of the first voltage dividing circuit, and so that, when the load circuit is in the standby mode, the feedback control is stopped and the first transistor is OFF. A resistance element cooperates with the first voltage dividing circuit so that a second voltage dividing circuit is formed, so as to divide the first power supply voltage when the load circuit is in the standby mode and so that the step-down voltage is applied to the load circuit via the resistance element.