Abstract: An ON/OFF-operation of a main switch SW and auxiliary switches SW1 to SW5 is controlled by a microcomputer 28. Electromagnetic energy in a transformer T is accumulated in an ON operation of the main switch SW and discharged in the transformer T sequentially to output blocks 14 to 22 on the secondary side in an OFF operation of the main switch SW. The electromagnetic energy is discharged twice separately to the output blocks 14, 18 connected to semiconductor light sources A, C having a heavy load, respectively, in one control period T, whereas the electromagnetic energy is discharged only once to the output blocks 16, 20, 22 connected to remaining semiconductor light sources B, D, E, respectively. Therefore, the peak value of the primary current I1 flowing through the primary winding L of the transformer T can be reduced.

Abstract: This disclosure relates to protecting a switching regulator by sensing immediately a change in an input voltage when the input voltage of the switching regulator is changed suddenly. When an input voltage of a switching regulator 12 is changed suddenly and an interrupt request signal IRQ is provided from an input voltage sensing circuit 16 while electromagnetic energy accumulated in the switching regulator 12 is discharged to an output block 14 by turning ON/OFF a switch SW1 in accordance with a switching signal generated by a microcomputer 18, to control a lighting of an LED1, the microcomputer 18 reduces an ON duty of the switching signal provided to the switch SW1 in response to the interrupt request signal IRQ and limits an increase of a peak value of a current flowing through a primary side of the switching regulator 12.

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.

Abstract: A discharge lamp illumination circuit 1 has a DC-AC conversion circuit 3 which effects DC-AC conversion and boosting upon receipt of a DC input, and a starter circuit 4. The DC-AC conversion circuit 3 has an AC transformer 7, a plurality of switching elements 5H and 5L, and a resonance capacitor 8. The switching elements are activated by control means 6, thereby inducing series resonance between the resonance capacitor 8 and an inductance component of the AC transformer 7, or between the resonance capacitor 8 and an inductance element connected to the resonance capacitor 8. In connection with the operating frequency of the switching elements, a first frequency value is a frequency value of a period when outputs are open before the discharge lamp 10 is illuminated, and a second frequency value is a frequency value of a period from illumination of the discharge lamp by the starter circuit until elapse of a predetermined time period or a time period which is specified in accordance with an illumination state.

Abstract: An LED is connected to a power supply circuit, and a Zener diode is reverse-connected to the LED and then packaged in an LED package. When a load of the power supply circuit is lightened due to disconnection in the LED package, an output voltage of the power supply circuit shows a rising tendency. However, the power supply circuit limits the maximum voltage applied to the LED within a specified range between a forward voltage of the LED and a forward voltage+a Zener voltage of the Zener diode to prevent that a current flows through the Zener diode. As a result, no current flows through a resistor R1, then an NPN transistor is turned on, and then the LED acting as a disconnection sensing indicator lamp is turned on.

Abstract: When an H signal of H/L binary signals is input into a control signal input terminal, a PWM signal is output from a multivibrator. When this PWM signal is input into a power supply circuit via a voltage converter circuit, such a control is repeated that a rated current flows through an LED at an ON time of the PWM signal and a supply of current to the LED is stopped at an OFF time of the PWM signal. An average current flowing through the LED is lowered and thus an emission of light is weakened, nevertheless an emitted light of the LED can be kept white because the rated current is supplied to the LED while the LED emits the light.

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 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: 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 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 discharge lamp illumination circuit 1 has a DC-AC conversion circuit 3, which effects DC-AC conversion and boosting upon receipt of a DC input, and a starter circuit 4. Power output from the DC-AC conversion circuit 3 is controlled by means of control means 6. The DC-AC conversion circuit 3 has an AC conversion transformer 7; a plurality of switching elements 5H and 5L; and a resonance capacitor 8. The switching elements are activated by the control means 6, thereby causing serial resonance between the resonance capacitor 8 and a leakage inductance component of the AC conversion transformer 7, or between the resonance capacitor 8 and an inductance component 9 connected to the resonance capacitor 8.

Abstract: A vehicular lamp used in a vehicle, includes: a light source for emitting light in accordance with power given thereto; a lamp body for accommodating the light source and protecting the light source from water; a first resistor provided in the outside of the lamp body and connected in series with the light source; and a current limiting circuit, provided in the inside of the lamp body, for preventing an excess current supplied to the light source in a case where dump surge occurs in a supplied voltage or current to be supplied to the light source.

Abstract: A discharge lamp lighting circuit includes an emission acceleration controller for detecting a lamp voltage for the discharge lamp, and supplying power greater than a rated value when the discharge lamp is initially lighted, and for gradually reducing the power supplied thereafter so as to shift the discharge lamp to a steady state. Power control is provided so that the power supplied to the discharge lamp is reduced in accordance with a rise in the voltage of a capacitor, and a charge current is supplied to the capacitor by current sources that provide a current that depends on the time elapsed since the lighting of the discharge lamp started and a second current that depends on a lamp voltage.

Abstract: There is provided a vehicular lamp at low cost. A power source apparatus includes: an output controlling switch operable to intermittently carry an electric current; an output coil operable to accumulate energy according to the current flowing into the output controlling switch and to output an electric power based on the accumulated energy when the output controlling switch is turned off; an end detecting unit operable to detect that the output coil ends the output of the power; and an output controlling unit, in which the output controlling unit includes: a time memorizing unit that memorizes OFF time for which the output controlling switch should be kept off; a switch controlling unit that switches the output controlling switch on and off based on the OFF time memorized in the time memorizing unit; and a time changing unit that changes the OFF time memorized in the time memorizing unit.

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: There is provided a vehicular lamp that can reduce a high-frequency noise occurring between a primary side and a secondary side of an anode voltage applying coil at low cost. The vehicular lamp includes a cold cathode fluorescent lamp having a cathode, a gate, and an anode, and an anode voltage applying coil operable to apply an acceleration voltage between the cathode and the anode of the cold cathode fluorescent lamp, in which one end of a secondary side of the anode voltage applying coil is connected to a reference potential of a primary side. Moreover, the vehicular lamp further includes an anode current detecting unit operable to detect an electric current flowing between a connecting point to the reference potential in the secondary side of the anode voltage applying coil and the cold cathode fluorescent lamp.

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: A vehicular lamp used for a vehicle includes a semiconductor light emitting element for emitting light, a resistor for current detection for causing a current detection voltage in response to a current flowing through the semiconductor light emitting element, the resistor being coupled in series to the semiconductor light emitting element, a serial diode being coupled in series to the resistor for current detection and the semiconductor light emitting element in a forward direction, and an open circuit detecting unit for detecting an open circuit of the semiconductor light emitting element based on a sum voltage, which is a sum of a forward voltage of the serial diode and the current detection voltage.

Abstract: A vehicular head lamp includes a first light source module having a plurality of semiconductor light emitting elements and a second light source module connected in series to the first light source module, having semiconductor light emitting elements the number of which is smaller than that of the first light source module and generating the light of brightness higher than that of the first light source module when an electric current substantially equal to that of the first light source module is supplied.