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:
Feb. 12, 2002

Filed:

Dec. 22, 1999
Applicant:
Inventors:

Masami Aiura, Sendai, JP;

Yuichi Nakatani, Sendai, JP;

Takashi Kumazaki, Sendai, JP;

Assignee:

Motorola, Inc., Schaumburg, IL (US);

Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H03M 1/80 ;
U.S. Cl.
CPC ...
H03M 1/80 ;
Abstract

A digital-to-analog conversion circuit including a plurality of unit current output cells ( ) arranged in a matrix. Each of the current output cells ( ) includes a unit current source ( ) having a power supply input and a current output, and a selecting switch ( ) connected to the current output and having two switching output terminals. The circuit further includes at least one ½ and/or ¼ weighted current output cell ( ) disposed on a row in the matrix, and at least one ½ and/or ¼ supplementary current source ( ) disposed on a desired row so that the total current consumption of the unit, weighted and supplementary current sources on each row is substantially the same. A decoder responds to a digital signal to control the switching of the selecting switches one by one as the digital signal gradually increases.


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