Nippondenso Co., Ltd.

Denso Corporation

Fujitsu Ten Limited

Toyoda Boshoku Corporation

Koichi Toyama

Kenji Aida

Koichi Kato

Ko Narita

Toshihito Nonaka

Hironao Yamaguchi

Takeshi Matsui

Hiroshi Haraguchi

Noboru Yamamoto

Toshiharu Iwata

Tomoatsu Makino

Koji Sakakibara

Kiyosei Shibata

Yuichi Nakajima

Koichi Kamabora

Yasushi Sugiura

Kiyoshi Ootani

Naoki Fujikawa

Kouichi Katou

Youichi Mikami

Munekazu Yanagida

Hiranao Yamaguchi

An object is to enhance workability in attachment in a sound generating apparatus that generates sound by vibrating a vibration plate with a vibrator while ensuring acoustic performance as good as that achieved by fastening with fine screw threads. Workability in attaching operation is improved while ensuring acoustic performance as good as that provided by fastening with fine screw threads, by providing first fixing portion that brings engagement portions into screw engagement with each other by rotation by a predetermined angle that can be attained by a user without taking his/her hand that holds a coupler off it and second fixing portion for fixing the coupler to a bracket so as to prevent the coupler from rotating relative to said bracket in a direction to loosen the engagement achieved by said first fixing portion.

Attachment structure for a sound generating apparatus

A discharge lamp ballast circuit has a snubber circuit to perform a soft switching when the MOS transistor is turned off. The snubber circuit has, for example, a capacitor that resonates with a reactance of the fly-back transformer and enables a zero voltage switching. Before a breakdown of a discharge lamp, a control circuit drives the MOS transistor in a non-zero voltage switching manner by turning on the MOS transistor just after a peak voltage. The non-zero voltage switching increases an output voltage of the fly-back transformer. After the breakdown of the discharge lamp, the control circuit turns on the MOS transistor in the zero voltage switching manner to perform the soft switching. As a result, it is possible to reduce switching loss during a lighting of the discharge lamp and to supply sufficient voltage in the lighting preparation period.

Discharge lamp ballast circuit having snubber circuit

In a discharge lamp apparatus, a casing of an electronic controller unit for a discharge lamp is comprised of a resin casing and a metal casing and accommodates therein circuit components for generating a voltage supplied to the discharge lamp. The resin casing couples with and contacts with the connector part of the discharge lamp. A power MOS transistor is attached to the metal casing through a plate member made of an insulating material. With this arrangement, heat generated by the discharge lamp is less likely to transfer from the resin casing to the metal casing, and heat generated by the power MOS transistor is efficiently radiated from the metal casing to the outside.

Discharge lamp apparatus having directly coupled lamp and electronic controller

A discharge lamp driver circuit is provided which features a field canceller. The driver circuit includes a power supply circuit which turns on and off a switching element to step up a dc voltage and provide it for turning on a discharge lamp. The power supply circuit includes an electrical path through which an interrupted current arising from the on-off operation of the switching element flows. The field canceller includes an electric line through which the interrupted current having passed through the electrical path flows in an opposite direction, thereby producing a field canceling a field caused by flow of the interrupted current through the electrical path.

Discharge lamp driver circuit designed to minimize radiation or noise

In a headlamp for a vehicle, a lighting control circuit unit is provided in a lamp housing. The lighting control circuit unit is fixed to a holder with screws and the holder is fixed to a rear surface of a reflector with screws. A discharge lamp bulb is held on the reflector. The discharge lamp bulb is directly connected to the lighting control circuit unit. The lighting control circuit unit is removable through an opening of the lamp housing in a state that the discharge lamp bulb is held on the reflector. Also, the discharge lamp bulb is exchangeable through the opening.

Vehicle headlamp having removable lighting control unit

An AC power generating apparatus for lighting a discharge lamp has a smoothing circuit with an electrolytic capacitor therein for smoothing ripples included in a DC voltage supplied from a power source. The apparatus further has a switching device and a transformer for transforming a smoothed voltage by turning on and off application of the smoothed voltage to the transformer thereby to supply AC electric power for activating a discharge lamp. A capacitor is connected in parallel with the electrolytic capacitor. This parallel capacitor is located inside an area surrounded by the transformer, the switching device and the electrolytic capacitor to reduce a circuit area where electromagnetic radiation noise is generated.

AC power generating apparatus having electrolytic capacitor and ceramic capacitor

Providing a discharge lamp device to reduce noise radiation and to reduce a surge pulse current resulting from a shield sheath involves providing a ballast, including a DC/DC conversion circuit for boosting a direct current voltage from a battery, an inverter circuit for converting the voltage boosted by the DC/DC conversion circuit into an alternating current voltage, a starting circuit having a second transformer for boosting to such a voltage that causes a breakdown between electrodes of a lamp in starting up the lamp, and a metal case for accommodating the DC/DC conversion circuit, the inverter circuit, and the starting circuit. A secondary winding of the second transformer of the starting circuit is connected between the lamp and the inverter circuit connected to the lamp. An electrode member is interposed between the second transformer and the metal case.

Discharge lamp device for reducing noise radiation and surge pulse current

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

A discharge lamp driver is configured so that it can be operationally tested using a substitute impedance instead of a discharge lamp. The time required to functionally test the driver circuit with such a substituted non-discharge lamp load is considerably less than if an actual discharge lamp is used for such testing.

Method and apparatus for reduced discharge lamp driver test time

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

In a discharge bulb control, a time constant circuit comprised of a capacitor and a resistor is used to determine an electric power to be supplied to a discharge bulb. During a warm-up period of the discharge bulb, the capacitor is charged to produce a voltage which varies, toward a predetermined voltage, with an electric current flowing thereto so that the electric power is increased gradually. After the warm-up control, the time constant for charging the capacitor is reduced to maintain the capacitor voltage at the predetermined voltage. Even with the current leakage occurring in the capacitor after the warm-up control, the electric power is controlled by the predetermined voltage which is not influenced by the current leakage. Thus, the electric power applied to the discharge bulb after the warm-up control can advantageously be maintained at the required level.

High voltage discharge bulb control

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.

Discharge lamp unit having separable high-voltage transformer safeguard

A knocking vibration detecting unit (1) and a knock deciding unit (c) are integrated, and the communications of a knock intensity between the knock deciding unit (c) and an engine controlling microcomputer (7) are carried out in combination of a change from the previous value of a signal line level. In the engine controlling microcomputer (7), the ignition timing is controlled by a predetermined retard angle in case of combination of no change of the present read signal line level from the previous signal line level. Thus, an internal combustion engine is prevented from any damage by relieving a failure without fail when a signal line (10) is troubled, while minimizing the influences of noises and reducing the space and size of an ECU.

Knock control system for internal combustion engine

An ignition detecting device for use in an internal combustion engine. An ignition surge current detector detects an ignition surge current due to capacitive discharge of the ignition coil. A comparator compares an output voltage detected by the ignition surge current detector with a predetermined reference voltage to detect accurately occurrence or non-occurrence of ignition spark.

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Kariya, Japan

Koichi Toyama