Koito Manufacturing Company, Ltd.

Takayoshi Kitagawa

Masayasu Ito

Yasushi Noyori

Kentarou Murakami

Toru Nakayama

Kotaro Matsui

Takao Sugiyama

Yasunobu Ohmura

Noriyuki Nakamura

A DC-DC converter includes a plurality of converter portions, each of which includes a switching circuit portion and a control circuit portion, the switching circuit portion being configured to obtain an output voltage by stepping up or stepping down an input voltage with a switching converter circuit including a switch element, a wound element, and a rectifier element, and the control circuit portion being configured to control the output voltage by controlling the switch element of the switching circuit portion. The plurality of converter portions are arranged on a single circuit board such that the switching circuit portion of each of the converter portions is not adjacent to the control circuit portion of each of a rest of the converter portions.

DC-DC converter and vehicular lamp

A lighting circuit for lighting a semiconductor light source includes: a DC/DC converter configured to receive a DC first voltage and a DC second voltage and generate a DC third voltage; a first connector including a first terminal, wherein the third voltage is applied to the first terminal, wherein the first connector connects the first terminal and one end of the semiconductor light source; and a control circuit that controls the DC/DC converter. The control circuit selects only the first voltage as a voltage applied to the other end of the semiconductor light source, when a voltage for emitting the semiconductor light source is less than an absolute value of a difference between the first and second voltages. The control circuit selects the first voltage or the second voltage as the voltage applied to the other end thereof, when the voltage is not less than the absolute value.

Semiconductor light source lighting circuit

A vehicle lamp includes: an infrared light semiconductor light source which emits infrared light; a white light semiconductor light source which emits white light; and a control unit including: a current supply circuit which supplies a light source driving current to each of the infrared light semiconductor light source and the white light semiconductor light source; and a light source abnormality detecting unit which detects abnormality of the white light semiconductor light source and stops a driving operation of the infrared light semiconductor light source when the abnormality is detected.

Vehicle lamp

A vehicle lighting control device includes a switching unit to perform ON/OFF control of a driving current supplied to a semiconductor light source depending on a light control signal; and a constant-current control unit to perform constant-current control on the driving current. The constant-current control unit includes a switch unit to perform ON/OFF control of the switching unit; and a signal-maintaining unit to provide a voltage signal corresponding to the driving current to the switch unit when the switching unit performs ON control, and to provide continuously the voltage signal to the switch unit when the switching unit performs OFF control.

Vehicle lighting control device

A lighting controller of a lighting device for a vehicle includes M (M is an integer of one or more) switching regulators for supplying driving currents to first to Nth (N is an integer of one or more) semiconductor light sources; first to Nth current driving portions; a temperature detector; and a control circuit. The first to Nth current driving portions include first to Nth current detecting portions connected to the semiconductor light sources and serving to detect the driving currents respectively; and first to Nth switching portions connected to the semiconductor light sources respectively. The first to Nth current driving portions operates the switching portions corresponding to magnitudes of the driving currents detected by the current detecting portions respectively. The temperature detector detects a temperature and sends a temperature detecting signal when the detected temperature is equal to or higher than a pre-specified temperature. The control circuit controls the current driving means in order to decrease the driving currents to be supplied to the semiconductor light sources upon receipt of the temperature detecting signal. The control circuit sets a priority of each of the semiconductor light sources for decreasing the driving current and decreases the driving current in order from the semiconductor light source having a highest priority.

Lighting controller of lighting device for vehicle

A lighting controller has current driving means which include a shunt resistor connected in series to each of multiple LEDs to detect an LED driving current, a PMOS transistor connected to the positive electrode side of each of the LEDs, and an amplifier for sending an output according to the result of comparison between the respectively detected driving current values and a reference value, and which subject each of the PMOS transistors to ON/OFF operation. Control means includes a Zener diode ZDand a Zener diode ZDfor detecting an abnormality occurring in the current driving means and for sending the abnormality detection result. The control means controls the PMOS transistor to be turned OFF after elapse of a predetermined time upon receipt of the abnormality detection result.

Lighting controller for a vehicle lamp

A vehicle headlight device includes a lower beam unit for illuminating a lower beam, an upper beam/infrared ray switching unit for switching between illuminating an upper beam and an infrared ray, a low-beam abnormality detecting circuit for detecting an abnormality of the lower beam unit, a power-supply abnormality detecting circuit for detecting an abnormality of a power supply of the vehicle headlight, and a control circuit that inhibits the upper beam/infrared ray switching unit from illuminating the infrared ray when an abnormality is detected by either the low-beam abnormality detecting circuit or the power-supply abnormality detecting circuit.

Vehicle headlight device

A lighting controller of a lighting device for a vehicle includes a switching regulator for supplying a driving current to first to Nth (N is an integer of one or more) semiconductor light sources; first to Nth current driving portions; and a control portion. The first to Nth current driving portions include first to Nth current detecting portions connected in series to the semiconductor light sources and serving to detect the driving current respectively, first to Nth switching portions connected to positive electrode sides of the semiconductor light sources respectively, and first to Nth comparing portions for transmitting a comparing output corresponding to a result of a comparison, which is obtained by comparing values of the driving currents detected by the current detecting portions with a predetermined threshold respectively. The first to Nth current driving portions serve to carry out operations of the switching portions corresponding to the comparing output respectively. The control portion includes first to Nth first voltage drop detecting portions for detecting voltages on output sides of the comparing portions and transmitting first to Nth first detection results, and first to Nth second voltage drop detecting portions for detecting voltages on positive electrode sides of the semiconductor light sources and transmitting first to Nth second detection results respectively. The control portion controls the first to Nth current driving portions corresponding to the first to Nth first detection results and the first to Nth second detection results respectively.

A lighting control device for a vehicle lighting device is arranged so that loads applied to switching regulators are about equal when driving multiple semiconductor light sources (e.g., LEDs) as multifunctional lamps through the switching regulators. The LEDs are divided into two groups. The LEDs belonging to the first group are driven to be turned ON through a first switching regulator and the LEDs belonging to the second group are driven to be turned ON through a second switching regulator. Maximum values of power to be supplied to the LEDs are set to be about equal to each other, and loads to be applied to the switching regulators are about equal to each other.

Lighting control for vehicle lighting device

A lighting controlling device of vehicle lighting equipment includes switching regulators for supplying a current to a plurality of semiconductor light sources respectively; a plurality of current driving portions, having switching elements connected to the semiconductor light sources for controlling ON/OFF of the semiconductor light sources, for current-driving the semiconductor light sources at a maximum current value or a current value smaller than the maximum current value in response to respective operating states of the switching elements; current setting portion for setting a maximum current value applied in current-driving the current driving portion or a maximum current value of currents fed from the switching regulators to the semiconductor light sources separately in plural stages in response to respective assignments; and a controlling portion for controlling the current driving portion and the current setting portion in response to a plurality of lighting modes based on communication information from an external device. The controlling portion assigns the maximum current value corresponding to each lighting mode to the current setting portion for every lighting mode, and assigns ON/OFF periods of the switching elements to the current driving portion for every lighting mode.

Lighting controlling device of vehicle lighting equipment

A vehicular lamp includes a semiconductor light source and a switching means arranged to switch between a first lighting mode, in which the semiconductor light source stays on, and a second lighting mode, in which the semiconductor light source repeatedly turns on and off. The lamp is arranged so that a peak current flowing through the semiconductor light source in the second lighting mode is smaller than that in the first lighting mode. The arrangement can help suppress overshooting and undershooting in the light source current.

Vehicular lamp

In conduction of light emitting diodes LEDsto, a switching signalis converted into a voltage Vor 0V through a signal converterin accordance with a logic level thereof. The voltage obtained by the conversion is compared with a voltage Von both ends of a resistor Rthrough an operational amplifierto open/close an output loop by an NMOS transistor, a current If of the light emitting diodes LEDstois limited to a current Ifso as not to exceed a maximum current, and a current defined with an ON duty of the switching signalis caused to flow as a mean current to the light emitting diodes LEDstoto inhibit an overshoot current from flowing to the light emitting diodes LEDstowhile the output loop is closed.

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Shizuoka, Japan

Takayoshi Kitagawa