| 摘要 |
A high-voltage generator includes a high-voltage transformer having a primary coil, a secondary coil, and an auxiliary coil, and a PNP bipolar junction transistor. Based on the self-oscillation theory of a LC oscillator, an oscillating voltage is generated across the primary coil. The oscillating voltage is amplified to a high-level AC voltage through the secondary coil. One end of the auxiliary coil and an emitter of the transistor are coupled to an input DC voltage, and the other end of the auxiliary coil is connected to the base of the transistor through a RC circuit. One end of the primary coil is connected to the collector of the transistor, and the other end of the primary coil is connected to ground. Therefore, the primary coil can generate a voltage detection signal indicative of the voltage of the secondary output of the high-voltage generator by itself without using one extra voltage detection winding, so that a comparing unit can generate a control signal based on the comparison of the voltage detection signal and a reference signal to control the base current of the transistor to change the oscillating amplitude of the oscillating voltage, thereby controlling the voltage of the secondary output.
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