Abstract: A vehicular lamp used for a vehicle, includes a semiconductor light emitting element for generating light to be emitted by the vehicular lamp and a current controlling unit for changing a current supplied to the semiconductor light emitting element based on the speed of the vehicle. The current controlling unit may reduce the current, if the speed of the vehicle is lower than a predetermined speed. The current controlling unit may reduce the current, if the vehicle is stopped.

Abstract: Switching elements S1, S2 connected in series are provided on the secondary side of a pulse transformer T to which an input voltage is supplied from a DC power supply E. On the primary side of the pulse transformer T, switching element S3, S4 are provided, and a regenerating unit RG including a current limiting inductor L1 and a regenerating inductor L2 is connected to the DC power supply E and the primary side of the pulse transformer T. A current is limited by the inductor L1 during an on time of the element S3 or S4, whilst a current is regeneratively supplied to the DC power supply E by using the inductor L2 during the off time of the elements S3, S4.

Abstract: A discharge lamp lighting circuit has a structure of a voltage resonance type including a transformer and a switching element to be provided on a primary side thereof as a DC—DC converting circuit for converting a DC input voltage into a desirable DC voltage. The lighting circuit further includes a control circuit serving to ON/OFF control the switching element, thereby controlling an output voltage Vout of the DC—DC converting circuit, and has a function of a current limitation related to the switching element. In the lighting circuit, if the output voltage Vout is raised, a current flowing to the switching element is limited to be decreased. Consequently, a voltage applied to the switching element can be suppressed, and furthermore, the winding ratio of the transformer does not need to be increased. Accordingly, it is possible to prevent an electrical efficiency from being deteriorated.

Abstract: When the level at an input terminal goes low upon the reception of a signal to dim an LED, a PNP transistor is rendered on and a voltage at the positive input terminal of an operational amplifier is raised, in accordance with a time constant that is defined by a resistor and a capacitor. In accordance with the increase in this voltage, a source current is supplied from the operational amplifier to a current detection terminal, and as the value of the source current is gradually increased, a current flowing across the shunt resistor of the switching regulator is gradually reduced. Further, the light emission level of the LED is gradually lowered from the fully lighted state to the 70% lighted state, and there is, for the LED, a light quantity change of about 30% in ten seconds.

Abstract: A vehicular lamp used for a vehicle, includes a semiconductor light emitting element for generating light to be emitted by the vehicular lamp and a current controlling unit for changing a current supplied to the semiconductor light emitting element based on the speed of the vehicle. The current controlling unit may reduce the current, if the speed of the vehicle is lower than a predetermined speed. The current controlling unit may reduce the current, if the vehicle is stopped.

Abstract: A lighting control apparatus of a vehicle-purpose lighting device can contribute power saving effect, and prevention of a deterioration of a semiconductor light source, and also, can maintain driving safety characteristics. When an input terminal becomes a low level while a vehicle is stopped, a PNP transistor is turned ON, so that a source current I1 flows through a current detecting terminal; a switching regulator lights an LED under beam attenuating operation of 70% in accordance with a light emitting degree capable of satisfying a luminous intensity distribution defined in a law; when an upper beam is lighted, the input terminal becomes a low level; a PNP transistor is turned ON; a source current I2 flows through the current detecting terminal, so that the light emitting degree of the LED is further decreased, and thus, the switching regulator lights the LED under beam attenuating operation of 50%.

Abstract: To control individually a plurality of loads to be turned on by combining a switching regulator with a charge pump circuit using some of the components of the switching regulator. An LED is controlled to be turned on by a switching regulator having an NMOS transistor connected to a transformer and a control circuit for generating an on/off signal. An LED is controlled to be turned on by a charge pump circuit that shares the NMOS transistor and the control circuit with the switching regulator to charge a condenser with an electric charge during an operation for turning on the NMOS transistor and discharge the electric charge accumulated in the condenser during an operation for turning off the NMOS transistor. Thus, circuit structure is simplified.

Abstract: When a forward direction voltage of any of several LEDs 14 to 20 is lowered, a drain voltage of an NMOS transistor 70 employed in any of series regulators 24 to 30 becomes higher than a defined voltage. A zener diode ZD1, which is connected to the LED where the abnormal condition occurs, becomes conductive. A voltage, which is increased from the defined voltage, is applied to a negative input terminal of a comparing amplifier 72, and an output voltage of the comparing amplifier 72 is lowered by this increased voltage portion so that a gate voltage of the NMOS transistor 70 is lowered. A current flowing through the NMOS transistor 70 is decreased. Even if an abnormal condition caused by a voltage drop occurs in any of the LEDs 14 to 20, then the LEDs 14 to 20 can be protected.

Abstract: A vehicular lamp, including: a plurality of semiconductor light emitting devices connected in parallel; a plurality of current limiting units provided corresponding to the plurality of semiconductor light emitting devices, wherein the plurality of current limiting units connect with the corresponding semiconductor light emitting devices respectively in series, and limit electric current flowing through the corresponding semiconductor light emitting devices respectively; and a current control unit for changing electric current to be supplied to at least one of the plurality of semiconductor light emitting devices.

Abstract: There is provided a vehicular lamp that can prevent excess current from flowing between an anode and a cathode at the lighting-up start to prevent a damage and life shortening of a cold cathode fluorescent lamp at low cost. The vehicular lamp includes: a cold cathode fluorescent lamp having a cathode, a gate, and an anode; and a lighting controlling unit operable to pre-discharge electricity from the cathode to the gate prior to lighting of the cold cathode fluorescent lamp, in which the lighting controlling unit applies a voltage between the cathode and the anode after once lowering a voltage between the cathode and the gate and then again applies an extraction voltage between the cathode and the gate in order to begin to discharge electricity from the cathode to the anode. The lighting controlling unit may pre-discharge electricity from the cathode to the gate until the temperature of the cathode is substantially equal to that of lighting-up time.

Abstract: Electric current supplied to light source rows of a vehicular lamp is controlled appropriately. The vehicular lamp includes: a plurality of semiconductor light emitting devices connected in parallel; a wire breakage detecting unit detecting wire breakage of each of the plurality of semiconductor light emitting devices; and an electric current supplying unit supplying a predetermined electric current to the plurality of semiconductor light emitting devices. The electric current supplying unit decreases the electric current to be supplied to the plurality of semiconductor light emitting devices when the wire breakage detecting unit detects wire breakage of at least one of the plurality of semiconductor light emitting devices.

Abstract: A lighting device for a vehicle comprises: a plurality of light source sections connected in parallel with each other; and a transformer for supplying an electric power to the plurality of light source sections. The transformer includes a primary coil and a plurality of secondary coils provided corresponding to the plurality of light source sections, for respectively supplying electric power to the corresponding light source sections. One end of each light source section is grounded and a semiconductor light emitting element is provided between one end and the other end of the light source section. The lighting device further comprises: a voltage detecting section for detecting voltages at the other ends of the plurality of light sources; and an output control section for controlling an electric current outputted from the transformer according to the voltage detected by the voltage detecting section.

Abstract: A DC/AC converter 3 performs AC conversion and a boosting function upon the reception of a DC voltage. A control unit 6 controls the DC/AC converter 3 to perform the lighting control of a discharge lamp. The DC/AC converter includes an AC conversion transformer 7, switching devices 5H, 5L and a resonance capacitor 8, and drives the switching devices to produce series resonance in the capacitor 8 and an inductance component for the transformer 7 or the inductance device 9. Before the discharge lamp 9 is turned on, the drive frequency for the switching devices gradually nears a resonance frequency f1 to increase an unloaded output, and a start signal is supplied to the discharge lamp. After the lighting of the discharge lamp has been initiated, the drive frequency is defined that is higher, by a predetermined frequency displacement value ?F, than the drive frequency immediately before the discharge lamp is turned on.

Abstract: A light emitting apparatus includes a semiconductor light emitting element mounted on a circuit board; a lighting circuit part mounted on the circuit board; and a cover which covers the semiconductor light emitting element and the lighting circuit part. The lighting circuit part converts a voltage inputted from a power source into electromagnetic energy and propagates the converted electromagnetic energy to the semiconductor light emitting element as light emitting energy, and the cover transmits light from the semiconductor light emitting element.

Abstract: In a process where the energy accumulated in the transformer while a transistor is turned ON is emitted to an output circuit and an LED is illuminated with the emitted energy, a voltage generated across a resistor is monitored by a control circuit. When the current flowing through the transistor has reached a limit current value, the ON operation of the transistor is limited. When the output voltage of the output circuit has exceeded a first set voltage, the limit current value is lowered and the ON operation of the transistor is further limited. When the output voltage of the output circuit has exceeded a second set voltage, the ON operation of the transistor is forcibly stopped.

Abstract: Relative comparison is made between a voltage applied to the whole of the first through eighth LEDs and a voltage applied to the first LED by a comparator. When the voltage applied to the whole of the LEDs has relatively dropped with respect to the voltage applied to part of the LEDs, the comparator outputs a Low Level signal, assumes an abnormality that accompanies a short-circuit fault in any one of the LEDs and causes a ninth LED to illuminate. Meanwhile, relative comparison is made between a voltage applied to the whole of the first through eighth LEDs and a voltage applied to the first LED by another comparator. When the voltage applied to the whole of the LEDs has relatively dropped with respect to the voltage applied to part of the LEDs, the comparator outputs a Low Level signal, assumes an abnormality that accompanies a short-circuit fault in the first LED and causes a ninth LED to illuminate.

Abstract: There is provided a vehicular lamp that can flow an electric current having a predetermined variation ratio into each of a plurality of semiconductor light-emitting element units and can individually illuminate each of the plurality of semiconductor light-emitting element units.

Abstract: A discharge lamp lighting circuit 1 has: a DC-AC converter circuit 3 which receives a DC input, and which conducts AC conversion and a boosting operation; and a starting circuit 4 which supplies a starting signal to a discharge lamp 10. The lighting circuit has a structure in which the primary and secondary circuits of an AC conversion transformer 7 constituting the DC-AC converter circuit 3 are electrically insulated from each other. An input terminal of the starting circuit 4 is connected to the secondary winding 7s of the AC conversion transformer 7 to obtain an input voltage for the starting circuit, and a starting signal which is boosted by the AC conversion transformer 7 is superimposed on the AC-converted output to be supplied to the discharge lamp 10.

Abstract: A lighting circuit for lighting a vehicular lamp including a plurality of light-emitting diodes, includes: a selection unit for selecting the number of light-emitting diodes to be connected in series in the vehicular lamp based on an instruction from the outside; a switching regulator for applying an output voltage based on a power-supply voltage output by an external DC power supply to the selected number of light-emitting diodes to be connected in series, so as to supply a supply current to the selected number of light-emitting diodes; and an output controlling unit for controlling the output voltage of the switching regulator based on the supply current.

Abstract: A discharge lamp illumination circuit 1 has a DC-AC conversion circuit 3 which effects AC conversion and boosting upon receipt of a DC input, and a starter circuit 4 for supplying a start-up signal to a discharge lamp. Power output from the DC-AC conversion circuit 3 is controlled by control means 6, thereby controlling illumination of a discharge lamp 10. An AC transformer 7 constituting the DC-AC conversion circuit 3 is provided, and a primary circuit and a secondary circuit, both forming part of the AC transformer 7, are insulated from each other. The start-up signal boosted by the AC transformer 7 is superposed on the AC-converted output, and the resultant signal is supplied to the discharge lamp 10. Thus, the need for a starter transformer specifically designed for startup can be obviated.