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:
Aug. 18, 1998
Filed:
Oct. 30, 1996
Ken Tanabe, Yokohama, JP;
Tadashi Nukui, Yokohama, JP;
Kabushiki Kaisha Toshiba, Kawasaki, JP;
Abstract
An offset cancellation circuit of this invention includes operational amplifiers 11, 12 having fully differential outputs and common mode output, and comprises an adder 15 supplied with one Vo.sup.+ 1 of the fully-differential outputs of the operational amplifier 11 and one Vo.sup.+ 2 of the fully-differential outputs of the operational amplifier 12 to add them to output added result, an adder 16 supplied with the other Vo.sup.- 1 of the fully-differential outputs of the operational amplifier 11 and the other Vo.sup.- 2 of the fully-differential outputs of the operational amplifier 12 to add them to output added result, an adder 13 supplied with common mode output Vcm1 of the operational amplifier 11 and common mode output Vcm2 of the operational amplifier 12 to add them to output added result, and a multiplier 14 for multiplying an output of the adder 13 by 1/2 to output it. Thus, it is possible to eliminate influence of error resulting from offset quantities existing in respective common mode output potentials in plural operational amplifiers having fully-differential outputs.