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A switched-mode power supply for energizing a cold-cathode fluorescent lamp (“CCFL”) includes a first semiconductor switch connects in series with a primary winding of a step-up transformer. The primary winding and a secondary winding, having many more turns than the primary winding, are disposed ab

A switched-mode power supply for energizing a cold-cathode fluorescent lamp (“CCFL”) includes a first semiconductor switch connects in series with a primary winding of a step-up transformer. The primary winding and a secondary winding, having many more turns than the primary winding, are disposed about a transformer core which has a linear magnetic permeability. A series connected second semiconductor switch and capacitor connect in parallel with the transformer\s primary winding. A controller circuit transmits signals to turn the switches on and off. The controller circuit turns the first and second semiconductor switches on and off at a frequency that is higher than a resonant frequency of a parallel resonant circuit formed by the primary inductance of the transformer and capacitance of the capacitor. A decoupling capacitor connects in series to a first end of the transformer\s secondary winding. A second terminal of the decoupling capacitor and a second end of the secondary winding provide ac power output terminals for the switched-mode power supply across which a CCFL may be connected.

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A switched-mode power supply for energizing a cold-cathode fluorescent lamp (“CCFL”), the switched-mode power supply converting a comparatively low, direct current (“dc”) input voltage into high, alternating current (“ac”) output voltage that may be supplied to a CCFL, the switched-mode power supply

A switched-mode power supply for energizing a cold-cathode fluorescent lamp (“CCFL”), the switched-mode power supply converting a comparatively low, direct current (“dc”) input voltage into high, alternating current (“ac”) output voltage that may be supplied to a CCFL, the switched-mode power supply comprising: a first semiconductor switch having a first principal terminal, a second principal terminal, and a control terminal; the first principal terminal being coupled to a circuit ground of the switched-mode power supply; a step-up transformer having a primary winding that has a primary inductance, and a secondary winding; the primary winding and the secondary winding being disposed about a core; the secondary winding having a number of turns that is at least ten times greater than a number of turns of the primary winding; a first end of said primary winding connecting to the second principal terminal of said first semiconductor switch, whereby said transformer and said first semiconductor switch connect in series, and the primary winding having a second end that is coupled to a power source terminal for the switched-mode power supply; a second semiconductor switch having a first principal terminal, a second principal terminal, and a control terminal; and a capacitor having a capacitance and a first terminal that connects to one of the principal terminals of said second semiconductor switch, whereby said second semiconductor switch and said capacitor connect in series; the other principal terminal of said second semiconductor switch and a second terminal of said capacitor connecting respectively to the second principal terminal of said first semiconductor switch and to the second end of the primary winding of said transformer, whereby said series connected second semiconductor switch and capacitor connect in parallel with the primary winding of said transformer; the combined primary inductance of said transformer and capacitance of said capacitor having a resonant frequency; a controller circuit having a first switch-driving output-terminal that connects to the control terminal of said first semiconductor switch, and having a second switch-driving output-terminal that connects to the control terminal of said second semiconductor switch, said controller circuit transmitting signals to said first semiconductor switch and to said second semiconductor switch for turning said first semiconductor switch first on and then off while concurrently turning said second semiconductor switch first off and then on thereby establishing duty cycles respectively for said first and second semiconductor switches; whereby periodically a current flows through the primary winding of said transformer and through said first semiconductor switch while said first semiconductor switch is turned-on and said second semiconductor switch is turned-off, and whereby a current flows through the primary winding and through said series connected second semiconductor switch and capacitor while said second semiconductor switch is turned-on and said first semiconductor switch is turned-off; said controller circuit turning said first and second semiconductor switches on and off at a frequency that is higher than the resonant frequency of the combined primary inductance of said transformer and capacitance of said capacitor; and a decoupling capacitor having a first terminal that connects to a first end of the secondary winding of said transformer, whereby the decoupling capacitor and the secondary winding are connected in series; said decoupling capacitor having a second terminal and the secondary winding having a second end that provide ac power output terminals of the switched-mode power supply across which a CCFL may be connected.