Patent ID: 6392355
Filing Date: 2002-05-21
Classification: H01J

Abstract:
A closed-loop cold cathode current regulator circuit comprising:a cold cathode having an emitter and an electrode that cooperates to extract electrons from said emitter; a current limiting element in electrical communication with said emitter cathode that controls the flow of electrons to said cold cathode in response to a control signal; a current sensing element in electrical communication with said current limiting element that produces an output signal that is a function of the current flowing through said emitter; a current control element responsive to said current sensing element that based upon the output signal of said current sensing element and a reference level produces said control signal; an alternating-current (AC) circuit power supply in electrical communication with said emitter that provides power to said circuit at a voltage dependent on a voltage of said AC circuit power supply; and a non-inverting gain element in electrical communication with said current control element that produces said reference level, wherein the gain element allows for a set point current level of said circuit to vary at a rate different from the rate of variation of said AC circuit power supply voltage.