Murata Manufacturing Co., Ltd.

Masaru Omura

Hisashi Takiguchi

Nobuaki Imamura

Haruo Takahashi

Yasuhiko Toda

Yasunobu Saida

Tadao Nagai

Kenji Naito

Masahiko Kitamoto

Tsuyoshi Umemoto

The number of layers of a secondary winding of a flyback transformer for use in a PWM controlled high-tension voltage generator is increased to six or higher. The distributed capacitance of the flyback transformer is thus decreased, the frequency of ringing is increased, and the pulse width of a flyback pulse is narrowed. The timing of the on-operation of a control FET is expedited, and the input current to the flyback transformer is lowered. A compact and power-saving flyback transformer thus results.

Flyback transformer

A high-voltage generating circuit includes a high-voltage production circuit, a high-voltage detecting circuit, and a control circuit. The high-voltage detecting circuit has a high-voltage circuit section to which a voltage of 1 kV to several tens of kilovolts is applied and a low-voltage circuit section to which a voltage of several tens of volts is applied. In the high-voltage circuit section, a parallel circuit formed of a first voltage-dividing resistor and a part of a second voltage-dividing resistor and a speed-up capacitor, and another parallel circuit formed of the remaining part of the second voltage-dividing resistor and a third voltage-dividing resistor and another speed-up capacitor are connected in series to form a two-stage parallel circuit.

High-voltage generating circuit

A high-voltage generating circuit includes a high-voltage production circuit, a high-voltage detecting circuit and a control circuit. The high-voltage production circuit includes clamping diodes to provide a good response for stabilizing a high voltage. The control circuit applies pulse-width control to a power source voltage. The high-voltage detecting circuit has a high-voltage circuit section to which a voltage of 1 kV to several tens of kilovolts is applied and a low-voltage circuit section to which a voltage of several tens of volts is applied. The high-voltage circuit section comprises a parallel circuit including voltage-dividing resistors and a speed-up capacitor. The speed-up capacitor is set to 1000 pF or less.

High voltage generating circuit including high voltage circuit section

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Moriyama, Japan

Masaru Omura