Patent ID: 6784626
Filing Date: 2004-08-31
Classification: H05B

Abstract:
An electronic ballast, comprising:a direct current power supply configured to provide a direct current voltage; a switching circuit, including first and second switching elements, connected in parallel with the direct current power supply, configured to convert the direct current voltage to a high-frequency alternating current; a load circuit, including a discharge lamp, a resonance inductor, and a resonance capacitor, being operated by the high-frequency alternating current; a driving circuit, arranged between the switching circuit and the load circuit, provided with feedback windings magnetically connected to a detecting winding of the current transformer, and configured to control a switching frequency of the first and second switching elements according to a detected current of the detecting winding; a magnetic energy control means, configured to control a magnetic energy of the current transformer; a current detecting means detecting an average current either an output current of the direct current power supply or a current of the switching circuit; and a current control means, configured to control the magnetic energy control means, and to fix the average current to a designated value.