| 摘要 |
PURPOSE: A neon sign transformer is provided to lengthen useful life of semiconductor device by preventing high voltages from entering the neon sign transformer circuit, while improving configuration of over voltage protection circuit. CONSTITUTION: A neon sign transformer comprises a rectifier unit(300) for receiving an AC power and rectifying the received AC power; a first FET(326a) serving as a first switching element which is turned on when a voltage higher than a predetermined voltage level is input to a control voltage input terminal from the rectifier unit; a second FET(326b) serving as a second switching element which is turned on alternately with the first switching element; a transformer(330) for lighting a neon tube by generating an oscillation frequency signal having a predetermined size from a secondary coil coupled with a primary coil, through the alternate switching operation of the first switching element and the second switching element; and an over voltage protection unit(310) coupled to the rectifier unit and control voltage input terminals of first and second switching elements, and which stops switching operations of first and second switching elements and suppresses generation of the oscillation frequency signal from the secondary coil of the transformer, when the output voltage of the rectifier unit is larger than a preset voltage value.
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