Panasonic Intellectual Property Management Co., Ltd.

Katsuyuki Doi

Takeshi Kamoi

Daisuke Yamahara

Keisuke Seki

Masafumi Yamamoto

Hiroyuki Asano

Masato Himeda

Hideaki Abe

Teruhito Takeda

Kei Mitsuyasu

Hiromichi Goto

Kiyoshi Ogasawara

Takafumi Fujino

Satohiko Hosomi

In a lighting device, a voltage detector outputs a detection voltage with a magnitude corresponding to a magnitude of a DC voltage outputted from a power supply circuit, a state determiner makes determination of whether a light source is in a turned-on state or in a turned-off state, a power controller is configured to control a DC power supplied from the power supply circuit based on a result of the determination by the state determiner, and the state determiner determines, when a value obtained by subtracting the detection voltage from a first reference voltage is equal to or larger than a first threshold value, that the light source is in the turned-off state.

Lighting device and luminaire capable of determining a turned-off state of a load connected thereto when power supply is off

A lighting device includes a rectifier circuit, a conversion circuit, a constant current circuit and a control circuit. The conversion circuit includes a first series circuit, a second series circuit and a third series circuit. The conversion circuit is configured to output a DC current by on/off of a switching element being controlled by the control circuit. A high potential-side terminal of the third capacitor is electrically connected to an output terminal. The low potential-side terminal of the third capacitor is electrically connected to an output terminal, via the constant current circuit.

Lighting device and lighting fixture using same

A lighting device includes a rectifier circuit, a conversion circuit and a control circuit. A first inductor of a first series circuit and a second inductor of a second series circuit have inductances by which a time period, during which a diode is electrically conducted, is made shorter than a half period of a resonance period of a closed loop circuit. The closed loop circuit includes a first capacitor, the first inductor, a second capacitor and a third capacitor. The control circuit is configured to control a switching element in such a manner that the switching element is turned on at fixed periods.

In a power supply device, a primary winding of a transformer is connected in series to a main switching element, and is connected in parallel to a series circuit of a resonance capacitor and a sub switching element. A secondary winding of the transformer is connected in series to a series circuit of a rectifying element and a resonance inductor. The capacitance of the resonance capacitor and the inductance of the resonance inductor are each set such that, when the sub switching element is in an on state, the waveform of the voltage that is generated between the first main terminal and the second main terminal of the main switching element takes a protruding curve shape, the voltage being generated due to a resonance phenomenon of at least the resonance capacitor and the resonance inductor.

Power supply device and lighting apparatus using the same

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Osaka, Japan

Katsuyuki Doi