Matsushita Electric Works, Ltd.

Panasonic Corporation

Panasonic Intellectual Property Management Co., Ltd.

Takashi Kambara

Toshiaki Nakamura

Toshifumi Tanaka

Hirofumi Konishi

Haruo Nagase

Miki Kotani

Masanobu Murakami

Toshiya Moriwaki

Tetsuya Hamana

Yoshitaka Taga

Masahiko Koizeki

Shojiro Kido

A lighting apparatus includes a control circuit configured to control a power supply circuit such that a measurement value of an output current measured by a current measuring device approaches a target value. The control circuit is configured to execute a control mode alternatively selected from the plurality of control modes to control the power supply circuit. The plurality of control modes of the control circuit includes at least a first control mode and a second control mode. The first control mode is a control mode of adjusting the target value in accordance with a first direct-current voltage. The second control mode is a control mode which includes adjusting the target value regardless of the first direct-current voltage.

Lighting apparatus, luminaire, movable object, control method, and non-transitory recording medium

A lighting device includes a current outputter, a load characteristic obtainer and a controller. The current outputter is configured to supply a current to a light source of at least one light source unit. The load characteristic obtainer is configured to obtain load information from a corresponding load information outputter of the at least one light source unit, by supplying the electric power to the load information outputter. The controller is configured to control the current of the current outputter, which is supplied to the light source, based on the load information. The load characteristic obtainer is configured to supply the electric power to the corresponding load information outputter only during a time period of obtaining the load information, but stop supply of the electric power to the corresponding load information outputter during a time period other than the time period of obtaining the load information.

Lighting device, luminaire, vehicle with same, and lighting method

A lighting device includes: a power conversion unit which converts a direct current (DC) power into a power required by a load; an output current detection unit which detects an output current of the power conversion unit; and a source voltage detection unit which detects a source voltage. Further, the lighting device includes an operation unit which calculates an output current command value so as not to exceed an upper limit of the output current command value set according to a resistance value of an externally connected resistor; and a control unit which controls the power conversion unit such that the output current thereof the power conversion unit becomes the output current command value.

Lighting device, headlamp lighting device, and headlamp unit and vehicle having same

An LED driver circuit is provided for protecting one (or more) LEDs connected in series from over-current damages which may result from a short circuit condition. The driver circuit includes a current control circuit for receiving an input signal from a power source and providing a current output for powering the LED. A voltage sensor detects a voltage across the LED. An LED current restriction circuit such as a switching element restricts a current flow into the LED. A short circuit response circuit controls the LED current restriction circuit dependent on a comparison between the voltage detected by the voltage sensor and a predetermined threshold value. When the detected voltage is less than or equal to the threshold value, the response circuit determines a short circuit, and a signal is sent to the current restriction circuit to restrict current flow into the one or more LEDs.

LED driver circuit with over-current protection during a short circuit condition

A DC-DC converter reduces a surge voltage developed across a switching element () in making the voltage conversion with the use of a transformer () inherently having considerable leakage. A snubber circuit is included to absorb the surge energy and transferring it to a load, or output end of the converter, reducing the surge voltage across the switching element (). A snubber capacitor () is provided to absorb the surge energy developed by the transformer () when the switching element () is off. Thus absorbed energy is collected in a storage capacitor () through a reactor () while the switching element () is on and off, and is then transferred from the storage capacitor () to the load, i.e., the output side of the converter, leaving only a minimum voltage being applied across the switching element ().

DC-DC converter with reduced surge voltage and an electronic ballast including the converter for a discharge lamp

An electronic ballast for a discharge lamp has a controller that increase luminous flux of the lamp to a stabilized level in a constant time irrespective of possible variations in lamp characteristic. The controller utilizes a reference lamp power table and a reference lamp voltage table respectively defining a reference lamp power and a reference voltage varying with time. The controller includes a voltage deviation detector that gives a voltage correction index indicating a voltage deviation between the reference voltage and a monitored lamp voltage. The voltage correction index is processed at an offset provider that gives an offset power. A target power generator is included to correct the reference lamp power in view of the offset power, thereby generating a target lamp power which is constantly updated and is supplied to the lamp.

Electronic ballast for a discharge lamp

An improved ballast for a discharge lamp includes a DC&#x2014;DC converter which receives an input DC voltage from a voltage source to provide a pre-starting voltage to make the lamp ready for being ignited or started. The DC&#x2014;DC converter has a switching element which is driven to turn on and off for generating the pre-starting voltage. A start-accelerating means in included in the ballast in order to vary at least one of the switching frequency and the on-period of the switching element based upon the monitored input DC voltage in a direction of accelerating the increase of the output DC voltage to the pre-starting voltage until the output DC voltage reaches the pre-starting voltage.

Discharge lamp ballast with DC-DC converter

A ballast for a discharge lamp includes a DC-DC converter which provides a regulated DC output so as to start and keep operating the lamp. A controller is included to give a closed-loop control for regulating the DC output based upon a monitored DC output. The controller also provides an open-loop control which interrupts the closed-loop control for a limited period immediately after the initiation of the lamp discharge in order to supplement a sufficient lamp current which would not expected with the closed-loop control, thereby successfully complementing the lamp start and proceeding to the stable lamp operation.

Ballast for a discharge lamp

A power source device includes a voltage converting means to input side of which a DC voltage source is connected and to output side of which a capacitance element and a load circuit are connected, while a control circuit is connected to the voltage converting means and the load circuit, the latter circuit having a load impedance made lower upon starting of a load in the load circuit than that in stable lighting of the load, wherein such control constant as oscillation frequency and duty are made to be substantially constant at the time of the starting and stable lighting of the load, and a switching means in the voltage converting means is turned OFF when the capacitance element has a voltage below a predetermined value.

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Osaka, Japan

Takashi Kambara