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.

Date of Patent:
Nov. 16, 1993

Filed:

Jul. 20, 1992
Applicant:
Inventors:

Yasuhiro Hashimoto, Kawasaki, JP;

Katsuya Ishikawa, Kawasaki, JP;

Chikara Tsuchiya, Kawasaki, JP;

Assignee:

Fujitsu Limited, Kanagawa, JP;

Attorney:
Primary Examiner:
Int. Cl.
CPC ...
H03B / ; H03B / ;
U.S. Cl.
CPC ...
331 45 ; 331 57 ; 331 60 ; 331 74 ; 3311 / ;
Abstract

A ring oscillator comprises a plurality of amplifiers connected in a multi-stage connection and each including a pair of output terminals from which first output signals are issued respectively; a pair of input terminals to which another pair of output terminals of a last stage amplifier are connected, respectively, and an amplifying circuit arranged between the output terminals and the input terminals. An oscillating signal can be generated by taking out the respectively corresponding second output signals from the amplifiers and combining these second output signals. The ring oscillator is constructed such that the second output signals are taken out from any middle output terminals in the amplifying circuit, other than the output terminals and the input terminals. Preferably, the amplifying circuit includes differential amplifying units each having a pair of differential transistors and a pair of emitter follower units having emitter follower transistors, respectively, and the second output signals are taken out from any portions among the output portions of the emitter follower units and all stage amplifying units other than the final stage differential amplifying unit.


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