Other

Denso Corporation

Yasushi Noyori

Hiroaki Okuchi

Tomoyuki Funayama

Noboru Yamamoto

Hiromi Hiramatsu

Yasutoshi Horii

Goichi Oda

Kenji Yoneima

Masamichi Ishikawa

Yuji Kajita

Yukinobu Hiranaka

Tomoyuki Ichikawa

In a discharge lamp apparatus for a vehicle, it is determined that a grounded condition is present when a lamp voltage is less than a predetermined voltage and a lamp current is less than a predetermined current. Electric power supply to the lamp is stopped temporarily in response to the determination of the grounded condition, and then the lighting operation is restarted again. If the grounded condition is determined again, the above operation is repeated. If this repetition continues for a predetermined period, the lighting operation is disabled continuously. In controlling the lamp, a voltage of a battery is boosted by a voltage booster transformer, which is turned on and off by a MOS transistor so that electric power supplied to the lamp is duty-controlled. An upper limit is set to the duty ratio, and the upper limit is increased as the lamp current decreases, so that the lighting characteristics of the lamp is improved. A starter transformer has a closed magnetic circuit core, and is encased within a ballast casing, which is disposed under the lamp.

Discharge lamp apparatus

A hybrid IC of electronic circuit for a discharge lamp is disposed on the bottom of a metal case. A transformer, an inductor, a transformer, and a capacitor are disposed in a resin case. The resin case is contained in a metal case. In this instance, the transformer, the inductor, the transformer, and the capacitor are located outside the outer periphery of the IC so that the IC does not overlap on the transformer and other components. The transformer for a starter circuit has a secondary winding the inductance of which is 2.5 mH or larger, and a capacitance of a smoothing capacitor of a DC&mdash;DC converter is 0.5 &mgr;F or smaller. The switching frequency f of a MOS transistor is selected so that L2&times;C1 is equal to or larger than 1&times;10 &times;f .

High voltage discharge lamp apparatus for vehicles

Growing community of inventors

Shimizu, Japan

Yasushi Noyori