Discharge lamp operation device and illumination device

Abstract

In order to enhance stability of a discharge lamp at the time of dimming lighting even in the case where a light output is lowered, a direct current superimposing circuit 1 superimposes a direct current voltage on an alternating current voltage applied to a fluorescent lamp FL, and a dimming signal correction circuit K1 receives a detection value of a direct current voltage detection circuit 2 and a dimming signal Vs1 that is from an outside, outputs a dimming signal Vs0 higher in level than the dimming signal Vs1 in the case where the detection value of the direct current voltage detection circuit 2 exceeds a first threshold value Vth1, and decreases the level of the outputted dimming signal Vs0 to the level of the inputted dimming signal Vs1 in the case where the detection value of the direct current voltage detection circuit 2 falls down below a second threshold value Vth2 that is equal to or less than the first threshold value Vth1. Then, an amount of alternating current power supplied to the fluorescent lamp FL by an inverter circuit INV is increased and decreased in response to fluctuations of the level of the dimming signal Vs0 outputted by the dimming signal correction circuit K1, whereby the fluorescent lamp FL is dimmed.

Description

technical field [0001] The present invention relates to a discharge lamp lighting device and a lighting device. Background technique [0002] As a discharge lamp lighting device for lighting a discharge lamp typified by a fluorescent lamp, generally an electronic stabilizer that converts a commercial AC voltage into a DC voltage and converts the DC voltage into a high-frequency voltage using The inverter circuit lights the discharge lamp with high frequency. Such an electronic stabilizer has a dimming function, that is, it can change the brightness of the discharge lamp by increasing or decreasing the power supplied to the discharge lamp according to the increase or decrease of the dimming signal input from the outside. The electronic stabilizer with dimming function generally has the purpose of energy saving and performance. Such a discharge lamp lighting device with a dimming function requires stable dimming that does not cause fluctuations in light output and unstable p...

AI Technical Summary

Problems solved by technology

Therefore, for example, in a low-beam dimming region where the dimming ratio is 10% or less of the rated light output, the detection values ​​of the lamp current and the lamp power become minute values, and the accuracy of the feedback control deteriorates.

Therefore, especially when the ambient temperature of the discharge lamp is low, not only the light output of the discharge lamp is lowered and flickering is likely to occur, but also there is a problem that it is difficult to maintain the lighting state and interruption occurs.

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