Murata Manufacturing Co., Ltd.

Tsuyoshi Umemoto

Tadao Nagai

Hisashi Takiguchi

Kenji Naito

Masahiko Kitamoto

Takafumi Toda

Masaru Omura

A discharge lamp lighting apparatus includes an inverter circuit supplying an AC voltage to a discharge lamp and a resonant circuit that increases a supply voltage supplied to the discharge lamp. The inverter circuit is driven using a first frequency including a resonant frequency of the resonant circuit during a first period in which breakdown and a glow discharge are generated, driven using a second frequency including a resonant frequency of the resonant circuit, lower than the first frequency, during a second period in which an arc discharge is generated, and driven using a third frequency lower than the second frequency, during a third period. Further, a dead time is set in which both of a high-side switching device and a low-side switching device are turned off so that the dead time is longer in the second period than in the first period and the third period.

Discharge lamp lighting apparatus

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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Nagaokakyo, Japan

Tsuyoshi Umemoto