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:
Oct. 01, 1996

Filed:

May. 16, 1995
Applicant:
Inventor:

Richard R Rasmussen, Fremont, CA (US);

Assignee:

National Semiconductor Corporation, Santo Clara, CA (US);

Attorneys:
Primary Examiner:
Int. Cl.
CPC ...
H03B / ; H03L / ;
U.S. Cl.
CPC ...
331 / ; 331 45 ; 331 52 ; 331 57 ; 3311 / ; 3311 / ; 3311 / ;
Abstract

A differential delay stage for a ring oscillator utilizes a resonant circuit formed by an inductor and a capacitor consisting of two varactor diodes connected back-to-back. A common cathode connection is connected to a variable voltage source to vary the capacitance of the diodes. Other forms of capacitors may replace the varactor diodes. Varying the capacitance value varies the resulting oscillation frequency of the ring oscillator. When several delay stages, each incorporating the resonant circuit, are connected together in a ring, the net effect is to allow only a signal at the resonant frequency of the resonant circuits to propagate around the ring. Other oscillator circuits employing a resonant circuit are disclosed.


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