Startup circuit for electronic ballasts for instant-start lamps
AssigneeMagneTek Triad
InventorAntonio Marques
Life of this patent
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Abstract
A start-up delay circuit for an electronic ballast for "instant-start" type fluorescent lamps of the type having an electronic converter powered by an active electronic preregulator. The converter is an inductive-capacitive parallel-resonant push-pull circuit or other type of current-fed power-resonant circuit. The preregulator may be a boost-type. The start-up circuit may be either a resistor and zener diode or resistor, capacitor and diac network or programmable unijunction transistor circuit connected between the preregulator output and an oscillation-enabling input of the converter.
Claims8
In an electronic ballast of the type having an electronic converter powered by an active electronic preregulator that takes a predetermined start-up time to reach steady state operating conditions, the improvement in combination therewith comprising delay means connected between the preregulator and the converter for delaying the start-up of the converter for a predetermined delay time after electrical power is supplied to the ballast, the delay time being longer than the start-up time.
A method of starting an electronic ballast of the type having an active electronic preregulator that takes a predetermined start-up time to reach steady state operating condition supplying power to a self-resonant electronic converter, the method comprising the steps of applying power to a power input of the preregulator;
- and delaying oscillation of the electronic converter for a period longer than the start-up time, such that the preregulator achieves substantially steady-state output.
Dependencies are inferred from the claim text.