Matsushita Electric Works, Ltd.

Shingo Masumoto

Hiroshi Kido

Shinji Makimura

Akira Nakajo

Yuji Kumagai

Electrodeless discharge lamp lighting device. Start circuitsweeps operating frequency of resonance circuitfrom start frequency to end frequency of resonance frequency side through drive circuitand DC/AC conversion circuit, and starts electrodeless discharge lamp. Control circuitincreases or decreases variable power into circuitso that detection current comes to equal prescribed current for shifting the operating frequency to middle range frequency between the start frequency and the end frequency. The prescribed current is set so that the detection voltage in case of the middle range frequency becomes lower than that in case of the end frequency. Capacitorconstituting integration circuit starts suppression of operation of circuitwhen lampis started, and holds the suppression during at least start mode. Accordingly, it is possible to stably start lampand control stress on circuit(s) after lampis successfully started.

Electrodeless discharge lamp lighting device and luminaire

A ballast for an electrodeless discharge lamp includes a high frequency power supply that supplies a high frequency electric power to an induction coil for operating the lamp. A dimmer controller generates a control signal in response to a dimmer command designating a varying dimming ratio. The control signal defines a first period Ton in which the power supply is controlled to apply a coil voltage of a first level Vto the induction coil for operating the lamp. The first period is followed by a second period Toff in which the power supply is controlled to apply the coil voltage of a second level Vthat is lower than the first level and fails to sustain the lamp. The control signal defines, between the second period and the first period, a starting period Tst in which the coil voltage increases continuously for smooth transition from an off-condition to an on-condition of the lamp.

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Hirakata, Japan

Shingo Masumoto