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:
Mar. 06, 1990
Filed:
Mar. 15, 1989
Rudolf Koch, Unterhaching, DE;
Siemens Aktiengesellschaft, Munich, DE;
Abstract
A circuit configuration includes a differential operational amplifier having differential input terminals and differential output terminals. A common mode feedback circuit sets a direct voltage operating point of the output terminals. A reference voltage terminal connected to the output terminals supplies a reference voltage. Two pairs of operating point transistors of complementary conductivity types have control terminals and have output circuits connected in series at a respective connection point for each pair. Each of the connection points is connected to a respective one of the output terminals. A reference current source controls the operating point transistors in parallel. First coupling capacitors are each connected between a respective one of the output terminals and a respective one of the control terminals of an associated operating point transistor of one conductivity type. The common mode feedback circuit includes second coupling capacitors and a remainder of the common mode feedback circuit. The second coupling capacitors are each connected between a respective one of the output terminals and a respective one of the control terminals of an associated operating point transistor of a conductivity type complementary to the one conductivity type, for decoupling the first coupling capacitors and the associated operating point transistors from the remainder of the common mode feedback circuit.