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:
Oct. 06, 1998
Filed:
Jan. 28, 1997
Yoji Hirano, Tokyo, JP;
NEC Corporation, Tokyo, JP;
Abstract
In a differential amplifier formed with first and second transistors having emitters connected to each other via a resistor, an input signal is supplied to a base of the first transistor. On the other hand, to a base of the second transistor, an external constant voltage is supplied. In order to control the emitter current of the second transistor, a third transistor having a base supplied a control voltage is added. The emitter of the third transistor is commonly connected to the emitter of the second transistor in common, and a collector thereof is connected to a high power source voltage terminal. By varying at least one of the control voltage on the base of the third transistor and the constant voltage on the base of the second transistor, a gain of the circuit can be controlled. Also, the transistors are connected in single stage connection with respect to the power source, operation with the low power source voltage becomes possible.