The CCFL tube, transformer secondary, and capacitor form a resonant circuit. The OZ965 utilizes the low energy loss resonate mode principle to deliver a very high efficiency inverter. The OZ965 drives the transformer primary with a variable pulse width voltage directly from the +5v supply. The resultant primary drive current is alternately reversing with zero-voltage-switching. Because of the transformer leakage inductance and the secondary resonant circuit, the secondary voltage and current are approximately sinusoidal. This sinusoid results in very little harmonic emi/rfi emissions.