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:
Jul. 19, 2011
Filed:
Sep. 22, 2010
Heiji Ikoma, Nara, JP;
Heiji Ikoma, Nara, JP;
Panasonic Corporation, Osaka, JP;
Abstract
In a current steering D/A converter, a 1LSB current sourceand a 2LSB current sourceare binary code current sources for outputting currents with current values weighted by ½, and a 4LSB current sourceis one of a large number of current sources designed as thermometer code current source with the same structure. In first circuits A, Aand Afor respectively determining constant current values of the current sourcesthrough, a plurality of MOS transistors with a channel length Land a channel width Ware cascode-connected to one another with gate terminals thereof shared. In second circuits B, Band Brespectively used for setting high output impedance of the current sourcesthrough, a plurality of MOS transistors with a channel length Land a channel width Ware cascode-connected to one another with gate terminals thereof shared. Accordingly, the current characteristics of the current sources can be made more uniform while reducing their circuit areas, resulting in improving the linearity of the D/A conversion characteristic.