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. 30, 1997
Filed:
Apr. 05, 1996
William Eric Main, Mesa, AZ (US);
Motorola, Inc., Schaumburg, IL (US);
Abstract
A current mirror circuit (31) that includes an active loop which operates transistors of different conductivity type at equal base-emitter junction voltages to minimize error. A first resistor (38) couples to a base of a first transistor (32) of a first conductivity type in a voltage follower configuration. A reference current is coupled to the first resistor (38). The voltage across the first resistor (38) and base-emitter junction of the first transistor (32) is mirrored across the base-emitter junction of a second transistor (34) of a second conductivity type and a second resistor (39). A third transistor (35) of the second conductivity type in a diode configuration is coupled to receive current from the second transistor (34). The voltage across the third transistor (35) biases a fourth transistor (33) of a first conductivity type. The current from the fourth transistor (33) is provided to the first transistor such that the first and second transistors (32,34) operate at equal base-emitter voltages.