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:
May. 01, 2001
Filed:
Jun. 12, 2000
Scott C. Willis, Manassas, VA (US);
Mark J. Jones, Centreville, VA (US);
Lockheed Martin Corporation, Manassas, VA (US);
Abstract
A power transistor switched power supply connecting a power source to a capacitive load, including a circuit and method for limiting the inrush surge current through the power transistor. The control gate of a junction field effect transistor (JFET) is coupled between the conductive path of the power transistor and the load to sense voltage drop across the power transistor. The conductive controlled path of the JFET is connected to control the impedance of the power transistor. The JFET shunts some of the power transistor control terminal current during the on transition allowing the power transistor to only turn partially on for a period of time, thus limiting the current through the power transistor from the power source to the load. Because the inrush surge current is limited, the accompanying transient power source voltage drop is reduced with less impact to other circuits connected to the power source.