| 摘要 |
PURPOSE: A device and a method for controlling an LCD on a portable computer using starting voltage and operating voltage are provided to enhance a transformation efficiency of a transformer and prevent start failure of a light emitting device by differently applying the starting voltage and the operating voltage to the light emitting device with a multi-tap transformer. CONSTITUTION: The transformer(532) has a dual tap structure. A CCFL(Cold Cathode Fluorescence Lamp)(190) is connected to a secondary side of the transformer. A switch(535) switches a turn ratio to a high or low transformation ratio by being installed to a primary side of the transformer. A switching circuit(531) changes the turn ratio to the high transformation ratio for the start of the CCFL by switching the switch to one side, and changes the turn ratio to the low transformation ratio after the start by switching the switch to another side.
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