A low-frequency cold cathode fluorescent lamp lighting system is proposed in this paper. The driving scheme adopts the full-bridge phase-shifting resonant inverter along with a three-winding step-up transformer such that the parasitic capacitance effect and the leakage loss are reduced while the lighting efficiency can be increased. The circuit starts with the high-frequency voltage to accelerate the ignition of the lamp.
This is followed by a frequency-scanning approach to reduce the frequency down to 1 kHz in order to ensure the luminance can be linearly increased and the time to stabilize the lighting is shortened. A prototype of the proposed circuit has been completed and analyzed. Test results help validate the advantages and feasibility of the proposed approach for the application investigated.