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:
Aug. 01, 1995
Filed:
Mar. 30, 1994
Shinko Electric Industries, Co., Ltd., Nagano, JP;
Fujitsu Limited, Kawasaki, JP;
Abstract
A PLL circuit comprising a phase comparator unit which forms a differentiation signal based upon both edges of an external signal, outputs an early pulse only during a period in which the differentiation signal is overlapped on a period from the leading edge to the trailing edge of a reference signal, and outputs a late pulse only during a period in which the differentiation signal is overlapped on a period from the trailing edge to the leading edge thereof, a charge pump unit which calculates and compares the amounts of integration of the early pulse and the late pulse, lowers the output voltage when the amount of the late pulse is larger than the amount of the early pulse and raises the output voltage when it is smaller, and a VCO which outputs a corrected reference signal of which the frequency decreases or increases accompanying the increase or decrease in the output voltage of the charge pump unit, wherein the VCO is controlled by the output voltage of the charge pump unit and by the early pulse and the late pulse, and works to raise the oscillation frequency when the late pulse is longer than the early pulse and to lower the oscillation frequency when it is shorter.