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. 04, 2003
Filed:
Feb. 09, 2001
Koichi Inoue, Kyoto, JP;
Hirokazu Oki, Kyoto, JP;
Rohm Co., Ltd., Kyoto, JP;
Abstract
A power supply device produces a predetermined voltage from a supply voltage through a voltage follower composed of a plurality of transistors. The voltage follower has a function of preventing backflow current. The voltage follower has one end connected to the supply voltage and another end connected to a capacitor. A constant voltage generating circuit produces a constant voltage from the voltage across the capacitor. A switch circuit is connected between the supply voltage and the control electrode of one of the transistors constituting the voltage follower other than the first-stage transistor thereof. A voltage drop detecting circuit detects a drop below a predetermined level in the voltage across the capacitor, and turns on the switch circuit on detecting such a drop.