Koito Manufacturing Company, Ltd.

Kotaro Matsui

Takao Sugiyama

Tomoyuki Ichikawa

Yasushi Noyori

Shinji Ohta

Takayoshi Kitagawa

Soichi Yagi

Susumu Ogo

A light emission drive device includes a current supply unit, which supplies driving current to a light emitting element, which performs light emission of a first function and light emission of a second function, a controller, which controls the driving current so as to have a current value depending on a dimming voltage, and a dimming voltage generator, which generates the dimming voltage. The dimming voltage generator applies a voltage, obtained according to the resistance value of a connected external resistor, to a voltage buffer, and controls the output voltage of the voltage buffer according to whether to perform light emission of any one of the first function and the second function so as to generate the dimming voltage.

Light emission drive device and vehicle lamp

Provided is a lighting circuit that drives a first light source and a second light source connected in series with each other. A bypass switch is provided in parallel with the second light source. A constant current circuit is connected in parallel with one of the first light source and the second light source. A drive circuit supplies a drive current to a serially-connected circuit of the first light source and the second light source.

Lighting circuit and vehicular lamp

A lighting circuit which lights a semiconductor light source, the lighting circuit includes a drive circuit configured to receive a PWM signal from a controller, to generate a drive current to the semiconductor light source, and to switch the drive current according to the PWM signal. When a non-input state of the PWM signal exceeds a predetermined time, the lighting circuit is configured to assert an abnormality detection signal and to output the abnormality detection signal to the controller.

Lighting circuit and vehicle lamp

A drive circuit supplies a drive current to a second light source. A dummy load circuit is connected to a control line to which a lighting control signal, which instructs the second light sourceto be turned on and off, is input, and the dummy load circuit sinks a dummy load current Iwhich decreases as a temperature increases.

A lighting circuit is configured to supply a driving current to a first light source and a second light source. The light circuit includes a conversion unit which receives a first voltage for the first light source and a second voltage for the second light source via a common input terminal, performs voltage conversion on the first voltage or the second voltage and supplies the driving current, a control unit which controls a current value of the driving current output from the conversion unit, a first switch which selects whether to supply the driving current to the first light source by a first signal based on the first voltage, a signal generation unit which receives the first voltage and the second voltage and generates a second signal, and a second switch which selects whether to supply the driving current to the second light source by the second signal.

Lighting circuit

A semiconductor light source lighting circuit includes a transistor and a current detection resistor provided in series in a semiconductor light source current supply path, a control circuit for controlling the transistor so as to decrease any difference between the voltage occurring at the current detection resistor and a reference voltage, and a bypass resistor to establish a bypass path for the current supplied to the semiconductor light source, where a first end of the bypass path is located at a connection node between the transistor and the semiconductor light source.

Semiconductor light source lighting circuit and control method

A lighting circuit includes: a countercurrent prevention unit including a first control terminal and a second control terminal, the countercurrent prevention unit transmitting a first current or a second current; and a current controller including: a common terminal connected to the first control terminal and the second control terminal; and a switching terminal connected to the first control terminal, the current controller providing a first driving current or a second driving current from the common terminal to the light source. The countercurrent prevention unit further includes: a first rectifier, wherein voltage at the first control terminal is provided to the switching terminal through the first rectifier; a first P-FET provided between the first control terminal and the common terminal; a second P-FET provided between the second control terminal and the common terminal; and a second rectifier provided between the second P-PET and the common terminal.

Light source lighting circuit and lamp system for vehicle

A vehicle lamp lighting control device includes: a current control unit which is of a non-insulation type and supplies a supply current to a semiconductor light source; an abnormality detecting unit which detects abnormality of a positive-electrode-side output based on at least one of a power supply voltage or a supply voltage supplied to the semiconductor light source, and outputs signal indicating the abnormality; and a bypass unit which bypasses the supply current supplied from the current control unit in accordance with the signal indicating the abnormality.

Vehicle lamp lighting control device

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 discharge lamp lighting circuitincludes a direct current-alternating current converting circuit, a starting circuit, controlling meansfor controlling power, switching elementsH,L driven by the controlling meansand a series LC resonance circuit (). A frequency modulating circuit is provided for restraining acoustic resonance by modulating a frequency of driving the switching element. When a basic frequency related to the drive frequency is equal to or higher than 1 MHz, a modulation width is set to be equal to or higher than 20 kHz.

Discharge lamp lighting circuit

A discharge lamp lighting circuitincludes an electric power supply part and a control part. The control part generates a control signal (Sc) for controlling the magnitude of electric power based on a lamp voltage (VL) of a discharge lamp. The electric power supply part supplies the electric power based on the control signal (Sc) from the control part to the discharge lamp. The control part has a differential computation part for differentiating a lamp voltage corresponding signal (VS) with respect to time and generating a first differential signal Sd(=dVS/dt), and an integral computation part for integrating a second differential signal (Sd) which monotonously increases and decreases as the first differential signal (Sd) increases and decreases with respect to time and generating a first integral signal (Si), and generates the control signal (Sc) so that the electric power decreases with an increase in the first integral signal (Si).

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Shizuoka, Japan

Kotaro Matsui