| 摘要 |
PURPOSE: A circuit for restraining a high voltage increase in a monitor is provided to limit an output high voltage of a flyback transformer when a high voltage applied to a CRT of a monitor becomes higher than a maximal limit value. CONSTITUTION: An MCU(23) compares a voltage fed back from a flyback transformer(20) with a reference voltage in order to restrain an increase of a high voltage, and outputs a control signal to restrain the increase of the high voltage according to the comparison result. A high voltage restraining section(24) includes a transistor(Q1) and a corrector resistor(R3) of the transistor(Q1). When a high level signal of the MCU(23) is applied to a base of the transistor(Q1), the transistor(Q1) is turned on. The corrector resistor(R3) of the transistor(Q1) is connected to a voltage dividing resistor(R2) with parallel. The corrector resistor(R3) of the transistor(Q1) drops a reference voltage of a comparator(21) when the transistor(Q1) is turned on.
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