Murata Manufacturing Co., Ltd.

Masahiko Kitamoto

Tadao Nagai

Hisashi Takiguchi

Kenji Naito

Tsuyoshi Umemoto

Nobuaki Imamura

Masaru Omura

An igniter transformer includes a secondary coil and a primary coil which are closely coupled. A plurality of round single-core wires disposed substantially parallel to one another in a common plane are bonded side by side to form a flat multicore wire that is substantially rectangular in cross-section. The secondary coil includes the flat multicore wire which is edgewise wound such that the larger surfaces of the flat multicore wire face each other in the turns while standing upright. The primary coil includes a wide thin metal sheet wound substantially perpendicularly to an axis of the secondary coil.

Igniter transformer

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 generation circuit including a transformer, the transformer having a primary winding having a primary inductance; a power supply for supplying a voltage to the primary winding of the transformer; a switching element for controlling current flowing through the primary winding of the transformer from the power supply; and a resonance capacitor which resonates with the primary winding of the transformer when the switching element is off, so that a flyback pulse is generated. The circuit has a distributed inductance and a resonance capacitance. The switching element is controlled so as to be switched on nearly at the bottom of a quiescent ringing pulse which is produced by a resonance of the primary inductance of the transformer with a capacitance included in a circuit connected to the primary winding of the transformer, after the flyback pulse is generated.

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Rittou, Japan

Masahiko Kitamoto