Lamp driving device
AssigneeTaiyo Yuden Co., Ltd.
InventorsHirofumi Honda, Shinichi Ishida, Tatsuya Sakurai
Life of this patent
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Abstract
In one aspect, an impedance component which exhibits a high impedance in a high frequency region is arranged on a high pressure line formed on a secondary side of a transformer. The potential difference generated at both ends of the impedance component is used to detect an abnormal electrical discharge generated in the high pressure line. When the abnormal electrical discharge is detected, a switching operation is stopped by a controlling circuit whereby a protection operation is performed.
Claims5
A lamp driving device having an AC power supply connected to a primary side of a transformer, a secondary closed-loop formed on a secondary side of the transformer, and a lamp arranged on the closed-loop in series configuration, comprising:
- an impedance component arranged in the closed-loop in a high impedance region, wherein the impedance component has a frequency dependent impedance value with a peak corresponding to a frequency higher than a frequency of an electrical current supplied from the AC power supply to the lamp, so that an abnormal electrical discharge of the lamp is detected using the high impedance region of the impedance component.
A lamp driving device having a secondary closed-loop formed on a secondary side of a transformer, and a lamp arranged on the closed-loop in series configuration, comprising:
- a plurality of frequency dependent impedance components having peak impedance in frequency ranges different from each other, the impedance components being arranged in the closed-loop to detect an abnormal electrical discharge of the lamp using high impedance regions of the respective impedance components.
A method of detecting abnormal electrical discharge in a lamp driving device, said method comprising selectively detecting current in a pre-defined frequency range on a secondary side of a transformer in said lamp driving circuit.
Dependencies are inferred from the claim text.