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:
Jan. 30, 1990
Filed:
Jul. 25, 1988
Anthony D Wang, Tucson, AZ (US);
R Mark Stitt, II, Tucson, AZ (US);
Burr-Brown Corporation, Tucson, AZ (US);
Abstract
A wideband integrated circuit amplifier includes a pair of current mirror circuits sensing emitter currents of NPN and PNP transistors in the amplifier output stage. A pair of current mirror circuits divide the emitter currents, respectively, by a factor of 20. The current mirror output currents are summed, current splitter directs approximately 1/20 of the summed mirror currents through a transistor, the collector of which is coupled to the gate electrode of a field effect input transistor of a bias control circuit, to produce a scaled down feedback current. A high impedance current source is connected to the collector of the transistor. The bias circuit adjusts the DC bias voltage applied between the base electrodes of the transistors to cause the scaled down feedback current to equal the constant current. A very small compensation capacitor produces a low frequency pole that prevents the bias circuit from interfering with high frequency performance characteristics of a wide band amplifier.