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:
Sep. 03, 1996
Filed:
Feb. 13, 1995
Applicant:
Inventor:
Geoffrey W Perkins, Chandler, AZ (US);
Assignee:
Motorola, Inc., Schaumburg, IL (US);
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G06G / ;
U.S. Cl.
CPC ...
327563 ; 330252 ;
Abstract
A controllable resistance circuit (16, 20) changes effective resistance value in response to an external control signal. The control circuit uses a simple current steering mechanism (32, 34, 38, 40, 42, 44, 46, 48) through a fixed resistor (62) to allow uni-directional or bi-directional operation. When configured as a bi-directional device, both ends of the effective resistance circuit (18, 24) are high impedance and therefore float with respect to any power supply. The effective resistance can be set with the control voltage and adjusted with changing conditions.