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:
Oct. 28, 2003
Filed:
Jun. 18, 2002
Control circuit employing preconditioned feedback amplifier for initializing vco operating frequency
James Edward Wells, Merrimack, NJ (US);
Vishal Gupta, Manchester, NH (US);
Texas Instruments Incorporated, Dallas, TX (US);
Abstract
A control circuit for a piezo transformer based power supply includes oscillator circuitry, drive circuitry, sense circuitry, and feedback circuitry collectively operating to regulate an operational parameter of the supply, such as the current supplied to a cold cathode fluorescent lamp (CCFL). The feedback circuitry includes initialization circuitry that establishes an initial value of an oscillator control signal corresponding to an initial operating frequency, and thereafter permits the feedback circuitry to gradually drive the oscillator control signal to a normal operating value such that the operating frequency is swept from the initial operating frequency to a normal operating frequency. When controlling the power supplied to a CCFL, the initial operating frequency is preferably a maximum frequency of the oscillator, and the operating frequency is swept downward so as to pass through the frequency at which the lamp “strikes”, or begins conduction, and thereafter into regulation.