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:
Mar. 29, 2005
Filed:
Mar. 18, 2003
Robert H. Bohl, Fort Collins, CO (US);
Duane L. Harmon, Loveland, CO (US);
Kelly J. Reasoner, Fort Collins, CO (US);
Robert H. Bohl, Fort Collins, CO (US);
Duane L. Harmon, Loveland, CO (US);
Kelly J. Reasoner, Fort Collins, CO (US);
Hewlett-Packard Development Company, L.P., Houston, TX (US);
Abstract
A circuit for sensing the presence of an inductive load that is particularly applicable to sensing when a solenoid is being driven by a pulse width modulation (PWM) signal. The circuit includes a high side connected transistor having an output driving a load, with the transistor driven by a PWM signal. A circulating diode is coupled to the driving output of the transistor. The circuit further comprises an operational amplifier (op amp) circuit that is coupled to the circulating diode and operates as an inverting operational amplifier (op amp). The op amp circuit charges a first capacitor when the transistor releases driving an inductive load.