| 摘要 |
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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