摘要:
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.
摘要:
In a discharge lamp device, the electric power supplied to a discharge lamp is controlled in order of first to fourth control regions from the start of lighting of the discharge lamp. In the first control region, the lamp current is held constant until the lamp voltage reaches a first voltage value. In the second control region, the lamp current is reduced so as to have a correlation with a first time constant curve for a constant time after the lamp voltage reaches the first voltage value. In the third control region, the lamp current is reduced so as to have a correlation with a second time constant curve after a lapse of the constant time. The second time constant curve differs from the first time constant curve. In the fourth control region, a control value of the electric power supplied to the discharge lamp is free of a function of a lapse of time from the start of lighting of the discharge lamp, but is a function of at least the lamp voltage and the lamp current, and the electric power supplied to the discharge lamp is controlled by that control value. Through such a control, luminous flux is built up in a short time from the start of the lighting and an occurrence of overshoot or undershoot is minimized to a possible extent.
摘要:
In a discharge lamp lighting apparatus for a discharge lamp, each circuit component including a starter transformer is assembled to a bus bar casing, and a high voltage terminal of the starter transformer is connected to one end of a connecting terminal. The bus bar casing is adhesive-cemented to a metal base to which a HIC is attached. Then, a sealing resin fills the bus bar casing to seal the starter transformer and the HIC with the sealing resin. After the sealing resin solidifies, the other end of the connecting terminal and an output cable are connected, and subsequently a resin cover is assembled to the metal base. A shielding sheath covering the output cable is fixed to the bus bar casing by a clip. A ground connection part of the bus bar connectable to the ground side of an electric power source is shaped to protrude from the bus bar casing. The cover, the clip, the ground connection part and the base are ground-connected by a thread.
摘要:
A lamp current i.sub.L flows through a first resistor. Electric current I, which is the output current of a voltage-current converter which converts a lamp voltage V.sub.L to a lamp current I, flows through a second resistor. Feedback control is executed to make V.sub.-, which is the voltage of one terminal of the second resistor, equal a reference voltage V.sub.ref. The power applied to the lamp during start-up is controlled to be the same as the power applied to the lamp during its stable lighting for a predetermined lamp voltage range. Using the following two linear equations, the electric current I is set as I=aV.sub.L +b (where a and b are positive constants) when the lamp voltage V.sub.L is lower than a first predetermined voltage V.sub.a which is less than the lamp voltage during the normal stable lighting period of the lamp, and as I=cV.sub.L +d (where c and d are positive constants with c b), when the lamp voltage V.sub.L is greater than or equal to the first predetermined value V.sub.a.
摘要:
A semiconductor switching element is connected to the first winding of a transformer. A smoothing capacitor is connected to the second winding of the transformer through a rectifier diode. The charging voltage Va of this smoothing capacitor serves as the applied voltage of a discharge lamp. When the discharge lamp is lighting, the second winding serves as a power source for supplying power to the discharge lamp. A capacitor is connected to the third winding of the transformer through a rectifier diode. The charging voltage of this capacitor serves as the applied voltage of a discharge tube. When the discharge tube discharges, a high-voltage starting pulse is provided to the secondary winding of a high-voltage coil, thereby rendering the discharge lamp ready for lighting. Therefore, when the discharge lamp is starting, the third winding serves as a power source for supplying starting power to the discharge lamp.
摘要:
A discharge lamp control circuit for a vehicular lamp uses a starting circuit capacitor that is charged by the same high voltage generator used later as the lamp's power source after it is turned on. As a result, no separate dedicted starting transformer is necessary. Further, a thyristor and diode are used in the starting circuit in place of a spark-gap for initially activating the discharge lamp.
摘要:
In a discharge lamp control circuit for a discharge lamp mounted on a vehicle, a capacitor in a starting circuit is charged by a high voltage generated by a transformer used in a direct current power source circuit. A transformer necessary for the starting circuit and the transformer necessary for the direct current power source circuit can commonly be used for cost reduction. Further, a thyristor is used in the starting circuit in place of a gap for activating the discharge lamp.
摘要:
In a discharge lamp control circuit for a discharge lamp mounted on a vehicle, a capacitor in a starting circuit is charged by a high voltage generated by a transformer used in a direct current power source circuit. A transformer necessary for the starting circuit and the transformer necessary for the direct current power source circuit can commonly be used for cost reduction. Further, a thyristor is used in the starting circuit in place of a gap for activating the discharge lamp.
摘要:
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.
摘要:
An electric discharge lamp device has a lighting start voltage storage circuit for storing a lamp voltage immediately after the start of lighting of a lamp, and a change detection circuit for detecting a change in the lamp voltage by subtracting the lamp voltage immediately after the start of lighting of the lamp from the lamp voltage detected currently. The electric power supplied to the lamp is controlled based upon the change in the lamp voltage.