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:
Feb. 16, 1988
Filed:
Oct. 30, 1986
Thomas J Kenny, Pittsburgh, PA (US);
James F Sutherland, Plum Boro, PA (US);
Westinghouse Electric Corp., Pittsburgh, PA (US);
Abstract
A method and apparatus for controlling the magnitude of an analog current through a load to be proportional to the magnitude of an input voltage. A sensing resistor is connected in series with the load. A controllable voltage is applied across the series connection of the load and sensing resistor for driving a current therethrough. A pulse width modulator receives the input voltage and a feedback voltage corresponding to the voltage drop across the sensing resistors when current is conducted thereby and produces square wave pulses each having a pulse width which is adjusted in response to a difference between the magnitudes of the input voltage and the feedback voltage. The magnitude of the controllable voltage is adjusted as a function of the pulse width of the square wave pulses until the magnitude of the current flowing through the load and sensing resistor causes the magnitude of feedback voltage to correspond to the magnitude of the input voltage so that the current through the load is maintained proportional to the magnitude of the input voltage.