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:
Jul. 06, 1976
Filed:
Dec. 02, 1974
Masayuki Hongu, Komae, JA;
Tsutomu Niimura, Tokyo, JA;
Sony Corporation, Tokyo, JA;
Abstract
A signal to be controlled is applied to the base of an emitter-follower input transistor, the emitter of which is connected to an input terminal of a differential amplifier. This input terminal of the amplifier is connected by a diode to a controllable current source so that the base current of the differential amplifier input transistor is controlled. A constant current source is connected to the common emitter circuit of the differential amplifier, and the gain of the circuit is determined by the ratio of current in the latter source to current in the controllable source. A current conducting circuit, such as, an emitter load resistor, is connected to the emitter of the input transistor to hold the output impedance thereof at a substantially constant low value inspite of changes in the current of the controllable current source, Maximum gain of the circuit may be determined by separating the controllable current source into a controllable portion and a fixed portion in parallel so that the minimum current is at least as great as the current of the fixed portion. This limits the maximum circuit gain by limiting the maximum ratio of fixed current to controllable current. A fixed voltage source connected to the common circuit point between the controllable current source and the diode assures that the gain of the circuit will not fall below a selected minimum value.