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:
Jan. 27, 1998

Filed:

Feb. 22, 1996
Applicant:
Inventors:

Yoshikazu Shimada, Kyoto, JP;

Isoshi Takeda, Kyoto, JP;

Assignee:

Rohm Co. Ltd., Kyoto, JP;

Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H03B / ;
U.S. Cl.
CPC ...
3311 / ; 331 57 ; 3311 / ; 331135 ;
Abstract

An oscillation circuit is provided which is easily adjusted with a high degree of accuracy. The oscillation circuit including a filter having a time constant and an inverting amplifier which feeds back the output of the filter to the input side of the filter so that an oscillation condition is fulfilled. The filter includes a gm amplifier formed of a differential amplifier, and a capacitor. The constant current source of the differential amplifier is connected to a free running oscillation frequency adjusting circuit. The adjusting circuit includes a microcomputer, a decoder which decodes the output data of the microcomputer and a switching circuit driven by the output of the decoder and varying the current value according to the output of the decoder. A current in accordance with a current value depending on the setting of the switch flows through the constant current source.


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