Abstract: A vehicle light apparatus 1 includes a discharge lamp 7 as a dipped (low)-beam light source and a high-beam light source or a light source of an auxiliary light (incandescent lamp) 3 as a substitutional light source of the discharge lamp. If the apparatus detects an input voltage from a power supply becoming equal to or greater than a threshold value in a state that only the discharge lamp is lit, the incandescent lamp is automatically lit on. To use the high-beam light source in place of the discharge lamp, light extinction lighting is performed or the light application direction is directed downward from the horizontal direction.

Abstract: In a discharge lamp lighting apparatus 1, power is supplied from a DC power supply 2 through a switch control circuit 3 to a lighting circuit 4 and a discharge lamp 5. Power is supplied to the lighting circuit through a semiconductor switch element 11 placed in a switch control circuit 8 and a part of the current flowing into a semiconductor switch element 12 is detected and is compared with reference values in comparators 21 and 22, thereby detecting an anomaly in the lighting circuit or the discharge lamp.

Abstract: In a discharge lamp lighting apparatus 1, power is supplied from a DC power supply 2 through a switch control circuit 3 to a lighting circuit 4 and a discharge lamp 5. Power is supplied to the lighting circuit through a semiconductor switch element 11 placed in a switch control circuit 8 and a part of the current flowing into a semiconductor switch element 12 is detected and is compared with reference values in comparators 21 and 22, thereby detecting an anomaly in the lighting circuit or the discharge lamp.

Abstract: A vehicle light apparatus 1 includes a discharge lamp 7 as a dipped (low)-beam light source and a high-beam light source or a light source of an auxiliary light (incandescent lamp) 3 as a substitutional light source of the discharge lamp. If the apparatus detects an input voltage from a power supply becoming equal to or greater than a threshold value in a state that only the discharge lamp is lit, the incandescent lamp is automatically lit on. To use the high-beam light source in place of the discharge lamp, light extinction lighting is performed or the light application direction is directed downward from the horizontal direction.

Abstract: 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—DC converter is 0.5 &mgr;F or smaller. The switching frequency f of a MOS transistor is selected so that L2×C1 is equal to or larger than 1×10−1×f−1.68.

Abstract: 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.

Abstract: A discharge lamp lighting device for turning on a discharge lamp, including: a power system which generates a high voltage, the power system having a grounding line; a control system having an analog circuit which has a grounding line, and a digital circuit which has a ground wire, the control system for controlling the power system; and a power source system for generating voltages to drive the power system and the control system, wherein the grounding line of the power system, the grounding line of the analog circuit in the control system and the grounding line of the digital circuit in the control system are provided independently of each other.

Abstract: A lighting circuit for a discharge lamp comprises abnormality detection means for detecting an input voltage and/or an input current to be input to a lighting circuit from a power supply and stopping power supply to a discharge lamp when detecting an abnormality in the value of the input voltage and/or the value of the input current. First and second reference values or reference ranges for comparison (the first reference value or reference range is smaller than the second reference value or reference range) are set for the input voltage and/or the input current. When the state where the value of the input voltage and/or the value of the input current is equal to or smaller than the first reference value or the first reference range continues for a predetermined time or longer, the abnormality detection means stops power supply to the discharge lamp.

Abstract: A lighting circuit for a discharge lamp comprises detection means for detecting a voltage and/or a current to be applied to a discharge lamp or a voltage and/or a current equivalent thereto, input voltage/current detection means for detecting an input voltage and/or an input current to the lighting circuit, and abnormality detection means for stopping power supply to the discharge lamp when detecting an abnormality in the discharge lamp or a circuit abnormality based on those detection signals. In the abnormality detection means, a plurality of reference values for comparison or a plurality of reference ranges are set for the detection signals, and determination times are set in association with the reference values or reference ranges.

Abstract: In a lighting circuit, a battery voltage is sent via a DC power supply section to a DC-AC converter to be converted to a square-wave AC voltage which is in turn supplied to a discharge lamp. The lighting circuit comprises an auxiliary power supply section for producing a predetermined voltage based on the input voltage from a battery and supplying this predetermined voltage to the individual sections of the lighting circuit and an abnormality detection circuit for detecting an abnormality in the discharge lamp, the circuit status, the battery voltage and so forth. In accordance with a signal from the abnormality detection circuit, a switch section, which is provided on a current line whose current is smaller than a current flowing on a power supply line to the discharge lamp, is switched on or off to enable or disable the auxiliary power supply section, thereby permitting or inhibiting power supply to the discharge lamp.

Abstract: A lighting circuit converts the output voltage of a DC booster circuit to an AC voltage which is in turn supplied to a discharge lamp connected between AC output terminals. The lighting circuit comprises a short-circuit detector for detecting a change of a DC voltage from the DC booster circuit to a square-wave voltage when short-circuiting between one of the AC output terminals and ground occurs, and sends a detection signal via a hold circuit to a power cutoff relay circuit. As a result, a relay contact in the power cutoff relay circuit is opened to inhibit the operation of the lighting circuit.

Abstract: A lighting circuit converts the output voltage of a DC booster circuit to an AC voltage which is in turn supplied to a discharge lamp. The lighting circuit comprises a current/voltage detector for detecting signals equivalent to the current and voltage of the discharge lamp and a control circuit for controlling the output voltage of the DC booster circuit in accordance with detection signals from the current/voltage detector.

Abstract: A lighting circuit, which is lit with a voltage with a square wave, has a DC booster circuit, a bridge type DC-AC converter and an inductor provided at the subsequent stage of the DC-AC converter. A metal halide lamp is connected in series to the inductor. Another inductor and a capacitor are provided between the DC booster circuit and the DC-AC converter. A series circuit of a resistor and a diode is connected in parallel to the second inductor. This structure generates a resonance voltage having a high peak value to compensate for a re-ignition voltage of a discharge lamp which is produced when the polarity of the square-wave voltage is switched, thereby preventing the lighting failure of the discharge lamp immediately after the lighting starts.

Abstract: Disclosed is a lighting circuit for a discharge lamp, which employs a rectangular-wave based lighting system and is designed to prevent lighting failure from frequently occurring in the discharge lamp immediately after the lighting of the discharge lamp starts or at the end of the lamp's life. In the lighting circuit, a battery voltage is boosted by a DC booster circuit and is then converted to a rectangular-wave voltage by a DC/AC converter. This rectangular-wave voltage is then applied via an inductor of an igniter circuit to a metal halide lamp. The DC booster circuit has a chopper type structure and has a smoothing capacitor at the output stage. A resonance controller comprising a diode and a resonance capacitor is located between the DC booster circuit and the DC/AC converter. The DC/AC converter has a bridge structure having field effect transistors (FETs). The two pairs of FETs are reciprocally switched from one pair to the other by a drive controller.

Abstract: Disclosed is a lighting circuit for a vehicular discharge lamp which controls current limitation in accordance with the status of the discharge lamp to thereby suppress an increase in consumption current when a source voltage drops. In the lighting circuit, when a lighting switch 5 is set on, a battery voltage is boosted in a DC booster circuit and is converted into an AC voltage by a DC/AC converter before it is applied to a metal halide lamp. The DC booster circuit has a chopper structure having an inductor and a field effect transistor (FET). A control signal from a control circuit is sent to the FET. The control circuit has a V (voltage)-I (current) controller for controlling the lighting and a PWM (Pulse Width Modulation) controller. The lighting circuit further has a current compensator to prevent an excessive current from flowing through the FET at the beginning of the lighting or when the battery voltage drops.

Abstract: A cord connection structure for connecting a ballast circuit and a starter circuit in which an output cord from a starter circuit unit mounted on a lamp body is connected to a discharge bulb inserted into a bulb insertion hole, and an output cord from a ballast circuit unit disposed in the vicinity of a starter circuit unit is removably connected through a connector to a connector connection part (receptacle) provided in the starter circuit unit, characterized in that a connector slip-off preventing protector covering the connector coupled into the connector connection part is provided around the connector connection part (receptacle). Such a construction makes it difficult for a general user to connect and disconnect the connector of high voltage to and from the connector connection part.

Abstract: A lighting circuit for a vehicular discharge lamp comprises a DC-to-AC converter, a lamp voltage detector, a lamp current detector, a voltage-current controller, and a power change reducing means. The DC-to-AC converter converts a DC voltage into an AC voltage and supplies it to the discharge lamp. The lamp voltage detector acquires a detection signal concerning a lamp voltage of the discharge lamp. The lamp current detector acquires a detection signal concerning a lamp current of the discharge lamp. The voltage-current controller produces a lamp current controller instruction signal generated with respect to the lamp voltage upon reception of the detection signal from the lamp voltage detector, and supplies a control signal to the DC-to-AC converter so as to minimize differences between the instruction signal and the detection signal from the lamp current detector, thereby controlling the output voltage of the DC-to-AC converter.

Abstract: An electric discharge lamp assembly including a lamp bulb having two lead wires, and a lamp base supporting two lead support members with respective tip ends thereof being connected respectively to the lead wires of the lamp bulb. One of the lead support members is formed to have an elongated length and is covered by an insulating tubular member substantially. The rear end portion of the insulating tubular member is fitted on and secured to a tubular portion of the lamp base which portion is integrally formed with the lamp base. Whereby the electric discharge between the two support members is prevented effectively, and the insulating tubular member is secured to the lamp base reliably.

Abstract: A lighting circuit for a vehicular discharge lamp for lighting a discharge lamp using a DC power supply, comprises an OFF state detector, a DC input voltage detector and a power cutoff means. The OFF state detector detects an OFF status of a discharge lamp. The DC input voltage detector detects if a DC input voltage is within a predetermined range. The power cutoff means inhibits power supply to the discharge lamp when the OFF status of the discharge lamp is detected by the OFF state detector and the DC input voltage lying off the predetermined range is detected by the DC input voltage detector, and permits power supply to the discharge lamp upon reception of a signal indicating that the DC input voltage has returned within that range.

Abstract: A lighting circuit for high-pressure discharge lamp or high-pressure discharge lamp for vehicular use including a DC voltage booster circuit, a voltage detector, a current detector, an a control circuit. The booster circuit boosts the input voltage from a DC voltage input terminal to provide an output voltage that is converted into an AC voltage to be applied to a high-pressure discharge lamp. The voltage detector detects the output voltage of the booster circuit. The current detector detects an output current of the booster circuit. The control circuit applies a control signal corresponding to signals from the voltage detector and the current detector to control the output voltage of the booster circuit. The control circuit, the voltage detector and the current detector constitute a feedback system for the booster circuit.