Abstract: A lighting control apparatus and a method of lighting control for a vehicle lighting device includes a semiconductor light source including a semiconductor light emitting element; and a current supply controller coupled between a power supply and the semiconductor light source. Supply of a current from the power supply to the semiconductor light source is restricted by the current supply controller during a current restriction period to a value smaller than a prescribed current. A microcomputer compares a forward voltage generated from the semiconductor light source during the current restriction period with an abnormality determination value to determine whether or not an abnormality occurs due to a change of the forward voltage of the semiconductor light source.

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 vehicle lighting apparatus includes a plurality of semiconductor light sources that are connected with each other in series, a switching regulator for supplying an electric power from a power source to each of said plurality of semiconductor light sources, forward voltage detection circuitry for detecting a forward voltage of each of said plurality of semiconductor light sources, and failure detection circuitry for detecting the failure of each of said semiconductor light sources based on the detected value of said forward voltage detection means. A semiconductor light source having a lower forward voltage is connected closer to a reference potential side of said power source among said plurality of semiconductor light sources.

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 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 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: 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: A lighting control apparatus and a method of lighting control for a vehicle lighting device includes a semiconductor light source including a semiconductor light emitting element; and a current supply controller coupled between a power supply and the semiconductor light source. Supply of a current from the power supply to the semiconductor light source is restricted by the current supply controller during a current restriction period to a value smaller than a prescribed current. A microcomputer compares a forward voltage generated from the semiconductor light source during the current restriction period with an abnormality determination value to determine whether or not an abnormality occurs due to a change of the forward voltage of the semiconductor light source.

Abstract: A vehicle lighting apparatus includes a plurality of semiconductor light sources that are connected with each other in series, a switching regulator for supplying an electric power from a power source to each of said plurality of semiconductor light sources, forward voltage detection circuitry for detecting a forward voltage of each of said plurality of semiconductor light sources, and failure detection circuitry for detecting the failure of each of said semiconductor light sources based on the detected value of said forward voltage detection means. A semiconductor light source having a lower forward voltage is connected closer to a reference potential side of said power source among said plurality of semiconductor light sources.

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: 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: 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: 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: 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 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.