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:
Apr. 19, 2011
Filed:
Feb. 20, 2009
Lee D. Wallis, Murfreesboro, TN (US);
Lee D. Wallis, Murfreesboro, TN (US);
Square D Company, Palatine, IL (US);
Abstract
A voltage isolation circuit. The input voltage Vin is connected to a primary winding of a transformer Tthrough a current limiting resistor R. Ris preferably sized such that the current flow in the primary at nominal input voltage is approximately 1 milliamp. Transformer Tis wound as a current transformer with a fixed ratio between the primary and secondary windings. Thus, when 1 mA flows in the primary winding, 1 mA will also flow in the secondary winding. An inverting operational amplifier will continuously attempt to drive its inverting input to a zero potential through resistor R. The voltage at Vout produced by the op-amp is a faithful replica of the voltage at Vin, but scaled according to the values selected for Rand R