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. 10, 2009
Filed:
Feb. 15, 2008
Osamu Uehara, Chiba, JP;
Osamu Uehara, Chiba, JP;
Seiko Instruments Inc., , JP;
Abstract
Provided is an adder in which all of circuits can be constituted by CMOS transistors, a process is simplified, and a chip size can be reduced as compared with a conventional art. The adder according to the present invention includes: a first VI converter and a second VI converter that allow a current corresponding to an input voltage to flow therein; and a current addition resistor having one end commonly connected to output terminals of the first VI converter and the second VI converter and another end grounded, which is adjustable in a resistance value. Each of the first VI converter and the second VI converter includes: a prestage VI converter that generates a reference current; a poststage VI converter that generates a current corresponding to the input voltage; a first current mirror circuit whose first terminal on a reference side is connected with the prestage VI converter and whose first output terminal in which a current corresponding to the first terminal flows is connected with the poststage VI converter; and a second current mirror circuit whose second terminal on the reference side is connected to the first output terminal, and which can adjust a current ratio from a second output terminal in correspondence with the current that flows in the second terminal. A voltage at the one end of the current addition resistor is output as an addition voltage.