| 摘要 |
PURPOSE: To reduce a cost and to lighten a device by making output signals of inverters as high frequency current supply sources respectively provided corresponding to plural fluorescent tubes of surface light source arranged on a rear surface of a liquid crystal panel the same common-mode. CONSTITUTION: Inverter circuits IV1-IV3 for lighting the fluorescent tubes RL1-RL3 are connected in parallel, and they share the base winding wire Lb1 of the inverter IV1 and a resistor R1. Then, whenever the voltage polarity of the base winding wire Lb1 when power source is turned on and by a resonance voltage, respective one side bipolar transistors Q1, Q3, Q5 of the inverters IV1-IV3 are turned on/off simultaneously always, and the other side bipolar transistors Q2, Q4, Q6 are turned on/off simultaneously always also. Then, these secondary side outputs become the common-mode, and a maximum voltage difference generated in the circuits becomes that between a secondary side maximum output voltage and ground of the circuits. Thus, an insulation breakdown strength of an insulation material is designed with by the amplitude of the output voltage. |
