| 摘要 |
PURPOSE: To provide an inverter circuit capable of achieving the high efficiency in the operation after starting while obtaining the voltage by which starting of lighting of a cold cathode-ray tube in starting of a circuit. CONSTITUTION: The space between the center tap of a primary coil N1 of a transistor T and a coil end are further divided, a releasing switch S2 is connected to the center tap, a bypass switch S3 is connected to the divided point between a coil N11-a and a coil N11-b, and a bypassing switch S4 is connected to the divided point between a coil 12-c and a coil N12-d, so as to constitute a turn ratio changing circuit 4. A lighting detecting circuit 3 is provided in a secondary side circuit to which a cold cathode-ray tube 2 is to be connected, the releasing switch S2 of the turn ratio changing circuit 4 and the bypassing switches S3, S4 are interlocked with each other by the output of the lighting detecting circuit 3, so as to be operated. Accordingly, the loss to be generated on the transistor is decreased by the decrease of the exciting current of the transistor in the operation after starting, and the efficiency is improved. |
