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. 24, 2004
Filed:
Jan. 16, 2003
Fujitsu Limited, Kawasaki, JP;
Abstract
A DC—DC converter in which no operational instability occurs and ranges of input and output voltages are wide, an electric appliance using such DC—DC converter, and a duty-ratio setting circuit in which no operational instability occurs and ranges of input and output voltages of a converter circuit can be widen in controlling the converter circuit are provided. A DC—DC converter has a converter circuit , an output voltage detection circuit and a duty-ratio setting circuit . An error amplifier circuit compares Vref with Vd to output a control voltage Vfb. A pulse-width modulator circuit compares a triangular-wave voltage Vct with the control voltage Vfb to output a first pulse signal PWO. A second-pulse generator circuit outputs a second pulse signal PSO having a predetermined on-duty ratio. A selector circuit selects the first pulse signal PWO or the second pulse signal PSO according to the control voltage Vfb to output the selected signal to a transistor M as a rectangular-wave signal PS.