Patent ID: 7394206

Claim:
An electronic ballast with life-ended protection comprising: a rectifier and filter circuit, a DC/AC inverter circuit and a resonant circuit, an input of the rectifier and filter circuit being connected to an outside power supply, an output of said rectifier and filter circuit being connected to an input of the DC/AC inverter circuit, an output of the DC/AC inverter circuit being connected to an input of a resonant circuit, and an output of the resonant circuit being connected to a lamp, a feedback driver circuit and a filament current loop connected to the lamp at an input of said feedback driver circuit, an input of the feedback driver circuit being connected to the filament current loop, an output of said feedback driver circuit being connected to a control terminal of the DC/AC inverter circuit, and a filament capacitor circuit having a filament capacitor loop connected to one end of the lamp at its input and to the input of the feedback driver circuit at its output, electrical signals of the filament current loop controlling the DC/AC inverter circuit to drive the resonant circuit through the feedback driver circuit.