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:
Dec. 19, 1989
Filed:
Jun. 29, 1988
Joannes M Sevenhans, Brasschaat, BE;
Dirk H Rabaey, Wijnegem, BE;
Alcatel N.V., Amsterdam, NL;
Abstract
An amplifier includes two differential amplifiers which are connected to an output stage comprising two field effect transistors of opposite conductivity typed directly coupled in series between opposite poles of a DC voltage source. The junction between the two output transistors constitutes the output of the amplifier. A negative feedback loop connects the amplifier's output to the inputs of the differential amplifiers. A correction arrangement is provided to prevent excessive current consumption and cross-over distortion. Preferably, the correction arrangement uses a pair of current mirror circuits to generate respective measuring currents proportional to the current in each of the output transistors. Each such measuring current is compared with a reference current. Any difference between the measuring current and the reference current causes a change in the voltage on the control electrode of the other output transistor, which in turn results in a change in the output voltage and thus a change in the negative feedback applied to both differential amplifiers.