Denso Corporation

Nippondenso Co., Ltd.

Kenji Aida

Koichi Toyama

Koichi Kato

Hiroaki Okuchi

Masamichi Ishikawa

Kouichi Katou

A discharge lamp unit with noise shields includes a discharge lamp, a discharge lamp control circuit, a filter circuit, the first and the second shield cases, and a power supply. The first shield case shields a discharge lamp control circuit and a filter circuit. The second shield case exclusively shields the filter circuit. Further, a ground wire of the filter circuit and the first shield case are electrically connected. Still further, a ground wire of the control circuit and the second shield case are electrically connected.

Discharge lamp unit with noise shields and noise control method for discharge lamp unit

A mounting structure for mounting a discharge lamp lighting device is arranged to directly connect a discharge lamp provided in a headlight unit to a connector provided in the discharge lamp lighting device. The headlight unit includes a reflector, and the mounting structure comprises a holder for holding the discharge lamp, wherein the holder includes a holder securing portion directly connected to the reflector and is secured to the reflector via the holder securing portion. The discharge lamp is secured to the reflector via the holder. The mounting structure further comprises a securing member directly connected to the reflector for securing the discharge lamp lighting device to the reflector. The holder and the securing member are separated from each other and the discharge lamp lighting device is secured to the reflector via the securing member.

Mounting structure for a discharge lamp lighting device

A lighting device for a discharge lamp includes a power supplying circuit for supplying electric power to the discharge lamp. A current sensing circuit is operative for sensing a lamp current which flows through the discharge lamp. A control circuit is operative for enabling the power supplying circuit to supply one of a direct-current electric power and a low-frequency electric power to the discharge lamp during a time interval in start of the discharge lamp. The control circuit is also operative for adjusting a duration time of supply of a one-polarity electric power to the discharge lamp in accordance with a magnitude of the lamp current sensed by the current sensing circuit. Further, the control circuit is operative for enabling the power supplying circuit to supply an alternating-current electric power to the discharge lamp after the time interval elapses.

Discharge lamp lighting device

When a discharge lamp repeatedly flickers out after illuminating for a long period of time because the same discharge lamp is nearing the end of its usage lifetime, a stored voltage of a capacitor rises gradually every time the discharge lamp flickers out. When the stored voltage of the same capacitor becomes no less than a predetermined voltage, a comparator generates a high level voltage which actuates a transistor. The transistor then terminates the operations of a PWM circuit to deactuate the discharge lamp.

Device for accurately detecting end of usage lifetime of a discharge lamp

DC/DC converter 31 boosts an output voltage of a battery 1 having a negative terminal grounded to a vehicle body, and supplies a boosted voltage to a discharge lamp 4 interposed between a positive output terminal and a negative output terminal of battery 1. A lamp current detecting resistance 35, connected in series with discharge lamp 4, detects a lamp current flowing through discharge lamp 4. Lamp voltage detecting resistances 33 and 34 detect a lamp voltage applied to discharge lamp 4. An electric power of DC/DC converter 31 is controlled by lamp power calculating circuit 36 and DC/DC converter drive circuit 37 based on the lamp current detected by lamp current detecting resistance 35 and the lamp voltage detected by lamp voltage detecting resistances 33 and 34. Discharge lamp 4 and lamp current detecting resistance 35 are connected at a connecting point 'a' which is grounded. An excessive current flowing through lamp current detecting resistance 35 is detected to stop electric power supply to discharge lamp 4. Detection of the excessive current is inhibited until a predetermined period of time has elapsed after starting a lighting operation of discharge lamp 4.

Control apparatus for a lighting system of a discharge lamp used in

A discharge lamp unit which does not require enlargement of the discharge lamp and can still prevent application of a high voltage to a cap holder when the lamp is not connected includes a core of a high-voltage transformer inside a cap of the discharge lamp. Both a primary coil and a secondary coil of the high-voltage transformer are provided around a cap holder of the discharge lamp power supply. The cap of discharge lamp is inserted into the cap holder of the discharge lamp power supply to provide an electromagnetic link between the primary coil and the secondary coil of the high-voltage transformer.

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Kariya, Japan

Kenji Aida