High efficient power supply for a cold cathode fluorescence lamp

A switched-mode power supply, which converts a relative DC input voltage into an AC output voltage high enough to supply CCFL, for energizing a cold cathode fluorescence lamp (CCFL) includes: (1) a first semiconductor switch having a first main terminal, a second main terminal, and the control terminal; the main terminal is connected with the ground terminal of the circuit in this on-off type power supply; (2) a step-up transformer having the primary winding of primary inductor and a secondary winding; (3) a second semiconductor switch having a first main terminal, a second terminal, a control terminal, and a capacitor; (4) a control circuit having the first switch driving terminal connected with the control terminal of the first semiconductor switch, and the second switch driving terminal connected with the control terminal of the second semiconductor switch for delivering control signal to turn the first and second semiconductor switches on and off at a frequency that is higher than a resonant frequency of