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:
Jun. 23, 1992
Filed:
Mar. 04, 1991
Philip W McEntarfer, Gilbert, AZ (US);
Dejan Mijuskovic, Chandler, AZ (US);
Motorola, Inc., Schaumburg, IL (US);
Abstract
An amplifier circuit with internal offset cancellation receives a differential input signal and provides differentially related currents which flow through first and second conduction paths of a differential-to-signal-ended converter for providing an output signal. Although ideally the differentially related currents should be equal with a zero differential input signal, the inherent mismatches between the transistors of the amplifier produce error currents causing the offset error. During an auto-zero phase, the differential input signal is zeroed while first and second capacitors are connected to the first and second conduction paths of the differential-to-single-ended converter for storing a charge representative of the input offset voltage. During the operational phase, the capacitor voltages control first and second transistors operating in parallel with the first and second conduction path for removing any error current thereby providing compensation of the offset error for the differential input signal.