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. 02, 1999
Filed:
Dec. 17, 1997
Vladimir Koifman, Rishon Lezion, IL;
Yachin Afek, Kfar Saba, IL;
Motorola Inc., Schaumburg, IL (US);
Abstract
A circuit (200) comprises transistors (240, 250, 260), an operational amplifier (270) and serially coupled resistors (210, 220). The circuit (200) is coupled to reference lines (201, 202). An input voltage V.sub.X on an input terminal (203) is applied across the resistors (210, 220) and divided to an output voltage V.sub.Y on an output terminal (204). Output voltage V.sub.Y is measured (as V.sub.M) by the operational amplifier (270). The operational amplifier (270) controls a current I.sub.A in a first current path between the reference lines (201, 202). The current I.sub.A is mirrored to a current I.sub.S in a second current path through the resistors (210, 220). The current I.sub.S is generated by one of the transistors (260) and substantially proportional to the input voltage V.sub.X. Therefore, the resistors (210, 220) do not substantially load the input and the circuit (200) exhibits a high input impedance.