Abstract: In a process in which a control signal having a low level is output from an ON/OFF control circuit to series regulators connected to LEDs serving as lighting targets to turn ON the LEDs in accordance with digital communication information, the ON/OFF control circuit calculates a specified current value to be supplied to the LEDs serving as the lighting targets and compares the specified current value with a detected current value which is detected by a current detecting circuit, and outputs a stop signal to a control circuit on the assumption that a current flows without the series regulators with grounding generated on a cathode side of any of LEDs when the detected current value is greater than the specified current value. When the control circuit turns OFF an NMOS transistor in response to the stop signal, an operation of a switching regulator is stopped.

Abstract: A discharge lamp lighting unit and vehicle headlamp are provided. The discharge lamp lighting unit includes a case body comprising a fitting portion and a projection portion, the fitting portion and the projection portion arranged in an L-shaped configuration, the discharge lamp being connected to the discharge lamp lighting unit at the fitting portion of the case body, and the projection portion projecting in the emergent light direction alongside of the discharge lamp; and a plurality of lighting circuit components, at least one of which is arranged in the projection portion. The vehicle headlamp includes a lamp unit which includes a discharge lamp which emits light, a reflector which reflects the light from the discharge lamp in an emergent light direction, and a holding projection which is provided at an end of the reflector at which the discharge lamp is mounted; and the discharge lamp lighting unit.

Abstract: A thermoplastic resin foam which has both high reflectance and superior shape-retention properties, suitable for use in backlights and illumination boxes for illumination signboards, lighting fixtures, displays and the like. The thermoplastic resin foam is manufactured by a manufacturing method including a procedure for holding a resin sheet composed of thermoplastic resin (A) and thermoplastic resin (B), which has a functional group having an affinyty with thermoplastic resin (A), within a pressurized inert gas atmosphere to enable the resin sheet to contain inert gas, and a procedure for foaming by heating the resin sheet containing inert gas at a temperature higher than the softening temperature of thermoplastic resin, under normal pressure.

Abstract: A vehicular lamp used in an automobile includes: semiconductor light emitting elements for emitting light; a time measurement unit for measuring time in which the semiconductor light emitting elements continues to emit light; and a current supplying unit for supplying a supply current that increases as the time measured by the time measurement unit increases, to the semiconductor light emitting elements.

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: A discharge lamp lighting circuit includes an emission acceleration controller for detecting a voltage for a discharge lamp and for supplying power exceeding a rated value when the discharge lamp is initially lighted, and thereafter gradually reducing the power to shift the discharge lamp to a steady state. While the value of the power supplied when the lighting of the discharge lamp is started is employed as the maximum, the power supplied to the discharge lamp is controlled. Thus, the speed at which the power is reduced during a period of transition to the steady state is increased in consonance with an increase in the discharge lamp voltage.

Abstract: In conduction of light emitting diodes LEDs 1 to 4, a switching signal 101 is converted into a voltage V2 or 0V through a signal converter 26 in accordance with a logic level thereof The voltage obtained by the conversion is compared with a voltage V1 on both ends of a resistor R1 through an operational amplifier 20 to open/close an output loop by an NMOS transistor 22, a current If of the light emitting diodes LEDs 1 to 4 is limited to a current If1 so as not to exceed a maximum current, and a current defined with an ON duty of the switching signal 101 is caused to flow as a mean current to the light emitting diodes LEDs 1 to 4 to inhibit an overshoot current from flowing to the light emitting diodes LEDs 1 to 4 while the output loop is closed.

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 device includes multiple light units each of which includes a semiconductor light source, and a current supply control means for controlling supply of current to the semiconductor light source. A control unit includes a control signal generation means for generating and providing a control signal. The light emitting device also includes switching means for controlling feeding from a DC power source to a corresponding one of the light units in response to the control signal. Each of the switching means is coupled to a corresponding one of the light units through a feed line.

Abstract: A higher voltage out of a battery voltage applied to an ignition voltage terminal or a control voltage applied to a control voltage terminal is supplied to a switching regulator via a diode. Then, a supply of current to an LED in the switching regulator is controlled in compliance with the control voltage while using an input voltage as energy. When a PWM signal is input into a control voltage terminal as the control voltage, transistors are turned off and on, whereby an instruction to turn on the LED in a dimmed lighting mode is issued to the switching regulator. Then, a current that is smaller than that supplied in a full lighting mode is supplied to the LED.

Abstract: A control unit for generating control signals in response to a communication signal fed from a vehicle, and a plurality of supply units for controlling a supply F of current to respective LEDs in compliance with the control signals generated by the control unit are provided. The control unit changes contents of the control signals in answer to the contents of the communication signal, i.e., to meet to changes of specifications when contents of the communication signal are different every type of a car or every vehicle, whereby standardization of circuit configurations can be achieved.

Abstract: A light emitting device drive circuit includes: a power conversion unit for receiving an input electric power and performing an electric power conversion on the input electric power in accordance with a control signal so as to generate the predetermined output current; a current detection unit for detecting an output current IL of the power conversion unit; a temperature detection unit for detecting a case internal temperature TD, which is an interior temperature of a case for accommodating the light emitting device drive circuit; a regulation unit being operable to a) detect whether a temperature TL of the light emitting device has reached a first predetermined temperature TLmax based on TD, IL, and a temperature rise coefficient a relative to IL, the temperature rise coefficient a being set in advance so that TL satisfies a relationship of TL=TD+?·IL, and b) generate a regulation signal for reducing a predetermined output current IL0 so that TL does not exceed TLmax in the event that a result of the detecti

Abstract: A power supply device includes: a regulator transformer; a primary switch for selectively supplying a current to the regulator transformer; a control circuit for reducing to 0, following each election made at the primary switch, the minimum value of a current output by the secondary side of the regulator transformer; and a coupling transformer for magnetically coupling routes along which a plurality of loads are connected in parallel to the secondary side of the regulator translator in a direction in which magnetic flux along each of the routes is offset by a current change. In this case, the control circuit increases the maximum value of the output current on the secondary side larger than twice of the target value of the current supplied to the loads.

Abstract: A lighting controller for a lighting device for a vehicle includes a semiconductor light source; a power source for supplying electric power; and control circuitry for receiving the electric power from the power source and controlling a current supplied to the semiconductor light source. The control circuitry determines an amount of time the semiconductor light source is in a turned on state and an amount of time the semiconductor light source is in a turned off state. The control circuitry controls a value of the current supplied to the semiconductor light source based on both the determined amount of time the semiconductor light source is in a turned on state and the determined amount of time the semiconductor light source is in a turned off state.

Abstract: A lighting controller for a lighting device for a vehicle includes a semiconductor light source; a power source for supplying electric power; and control circuitry for controlling a supply of a current to the semiconductor light source. The control circuitry selectively supplies the current to the semiconductor light source through a resistance element or through a bypass circuit for bypassing the resistance element based on a determination of a state of the current. A method for controlling a lighting device for a vehicle includes receiving electric power from a power source; supplying a current to a semiconductor light source; determining a state of the current supplied to the semiconductor light source; and selectively supplying the current to the semiconductor light source through a resistance element or through a bypass circuit for bypassing the resistance element based on the determination of the state of the current.

Abstract: In a lighting circuit for a discharge lamp, the discharge lamp is kept lit without fail when a DC input voltage becomes low, while avoiding a complicated circuit configuration and control method. A DC-AC converter circuit receives a DC input voltage and converts it to an AC voltage and boosts the AC voltage. The DC-AC converter circuit is controlled by a control means having a circuit for detecting the DC input voltage “+B” to perform a lighting control of the discharge lamp. The lighting circuit comprises a transformer for AC conversion, switching elements, and resonance capacitor. The switching elements are driven to cause a series resonance of the resonance capacitor and an inductance component of the transformer for AC conversion or an inductance element.

Abstract: A PMOS transistor is inserted in a circuit connecting a power supply terminal of a power supply circuit and a battery terminal. When a control signal input terminal goes to a low level, it is decided that a PWM signal or an H control signal is input into the control signal input terminal. Then, transistors are turned on, and then the PMOS transistor is turned on to apply a battery voltage to the power supply circuit via a power supply terminal, whereby a supply of current to an LED is controlled by the control signal. When the control signal input terminal goes to a high level, it is decided that an L control signal is input as the control signal. Then, the transistors are turned off, and then the PMOS transistor is turned off to cut off a power supply to the power supply circuit from a battery, whereby a dark current can be prevented from flowing through the power supply circuit when the LED is turned off.

Abstract: A power supply unit comprises: a voltage output section for supplying a voltage to a plurality of loads connected in parallel with each other; and a plurality of output side coils provided respectively corresponding to the plurality of loads, the plurality of output side coils being trans-connected with each other, the plurality of output side coils being connected with the corresponding loads in series. An electric current to be supplied from the voltage output section to the corresponding load flow in each output side coil.

Abstract: The supply of a predetermined current to LEDs is controlled by using series regulators. In accordance with the controlled states of the series regulators, a switching regulator adjusts an output voltage relative to the LEDs to the maximum voltage. When a ground fault occurs at the anode of one of the LEDs, and when a short circuit occurs at the output terminal of the switching regulator and the output voltage drops abnormally, the operation of the switching regulator is halted. When the gate voltage of an NMOS transistor is raised due to the disconnection of one of the LEDs, or when the drain voltage of the transistor is raised due to a short circuit at one of the LEDs, a Zener diode becomes conductive and an NPN transistor and a PNP transistor are rendered on. Then, a current flows through a diode, and as the gate voltage has been lowered, the operation of the NMOS transistor is halted, so that the remaining, normal LEDs are protected when an abnormality occurs.