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. 16, 1997
Filed:
Feb. 17, 1995
Robert Allen Pease, San Francisco, CA (US);
National Semiconductor Corporation, Santa Clara, CA (US);
Abstract
A current regulator includes a regulation stage and a start-up stage. The regulation stage has a base bus and an output transistor having a base coupled to the base bus for generating a regulated current. The regulation stage also includes a current maintaining transistor coupled to the base bus for inducing and maintaining an operating current in the base bus in response to a start-up current first being induced in the base bus. The start-up stage includes a start-up transistor coupled to the base bus for inducing the start-up current in the base bus before the current maintaining transistor is turned on. The start-up transistor is turned off by the regulation stage after the current maintaining transistor is maintaining the operating current in the base bus. A method of starting-up a regulator circuit includes the steps of: establishing a base bus; inducing a start-up current in the base bus; inducing an operating current in the base bus; establishing a conduction path between an emitter of a current maintaining transistor and an emitter of a start-up transistor; and gradually increasing a current which flows through the conduction path in order to gradually decrease a current conducted by the start-up transistor in order to turn the start-up transistor off.