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:
Nov. 18, 1986
Filed:
Oct. 18, 1985
Shouji Abou, Kawasaki, JP;
Keiko Chikaoka, Tokyo, JP;
Kabushiki Kaisha Toshiba, , JP;
Abstract
A voltage controlled oscillator includes an oscillator having at least one first capacitor. The oscillator receives first and second input voltages and charges the first capacitor with a first current corresponding to the first input voltage. The oscillator oscillates at a frequency corresponding to the first and second input voltages. To remove the adverse influence on the oscillating frequency by the change of process parameters caused in the stage of manufacturing the voltage controlled oscillators, a second capacitor is charged for a predetermined period by a current corresponding to the first voltage. After the charging of the second capacitor ends, a sample/hold circuit samples and holds the charged voltage across the second capacitor. An operational amplifier receives, at its positive input terminal, the output voltage of the sample/hold circuit, and, at its negative input terminal, the reference voltage. The operational amplifier controls the first voltage so that the output signal of the sample/hold circuit will be equal to the reference voltage. Repeating the sequence of the charging, sampling and comparing operations eliminates the influence upon the oscillating frequency by the change of the process parameters caused in the manufacturing stage.