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:
Nov. 28, 1995
Filed:
Jun. 01, 1993
Marc H Ryat, Santa Clara, CA (US);
SGS-Thomson Microelectronics, Inc., Carrollton, TX (US);
Abstract
A logarithmic amplifier has first and second mirror circuits, each having active transistors interconnected by a resistor. The current input is applied within one of the mirror circuits so that a logarithmic function thereof is generated for output by an output current mirror circuit. The mirror circuits are similarly constructed with an active transistor, a cascode transistor, and a base current compensating transistor. The cascode and active transistors are connected in series between an input node and a reference potential, or ground, with the base current compensating transistor connected between a supply voltage source and a base of the active transistor. The base of the base current compensating transistor is connected to the reference current input node. Through modification of the basic circuit by injection of an input current to the active transistor with respect to the reference potential, an exponential converter is presented.