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:
May. 25, 1993
Filed:
Mar. 26, 1992
Douglas R Curtis, Los Gatos, CA (US);
Other;
Abstract
An analog multiplier/divider circuit comprising in basic form four bipolar transistors with all collectors in common and a high gain differential input amplifier controlling an output transfer means. All input signals and the output signal are applied as currents to the emitters of the four transistors. The emitters, as opposed to the collectors, are monitored and sensed by the amplifier. The four transistors are arranged such that the base-emitter voltage of the third transistor, the value of which is proportional to the logarithm of a third input current applied to its emitter, is added to the base-emitter voltage of the fourth transistor, the value which is proportional to the logarithm of the output current applied to the fourth transistor's emitter. The sum of the two voltages is forced by the amplifier to be equal to the sum of the base-emitter voltage of the first transistor, the value which is proportional to the logarithm of a first input current applied to its emitter, and the base-emitter voltage of the second transistor, the value of which is proportional to a second input current applied to the second transistor's emitter. The amplifier forces the first sum equal to the second sum by comparing the two sums at its inputs and regulating the output current until the amplifier inputs are equal.