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. 28, 1982
Filed:
Mar. 26, 1980
Hiromi Kusakabe, Yokohama, JP;
Masahide Nagumo, Kawasaki, JP;
Abstract
A power-amplifying circuit embodying this invention includes a pre-amplifier stage which comprises two emitter-connected transitors, one of whose bases is supplied with an input signal and an output stage comprising complementary pair of a first transistor of a PNP type and an emitter-grounded second transistor of an NPN type which carry out a class-AB push-pull operation in accordance with the amplitude of a current from the pre-amplifier stage. The power-amplifier circuit of this invention further comprises third transistor for detecting an operating current of the first transistor of the output stage, a fourth transistor which is driven by the third transistor and whose base is connected to the base of the second transistor of the output stage, and fifth and sixth transistors which are connected in such a manner that a sum of the base-emitter voltages of the fifth and sixth transistors is made equal to a sum of the base-emitter voltages of the second and fourth transistors, and through which there flows a current corresponding to a product of the operating currents of the first and second transistors constituting the output stage. A current running through the fifth and sixth transistors is supplied to the pre-amplifier means through a negative feedback path so as to be regulated.