Lighting circuit for discharge lamp

A technology for lighting circuits and discharge lamps, which is applied in the use of discharge lamps, circuits, and gas discharge lamps to achieve good reproducibility and suppress individual differences.

Inactive Publication Date: 2007-12-05
KOITO MFG CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Therefore, in the discharge lamp device described in Patent Document 1, it is difficult to control the supplied power with good reproducibility.

Method used

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  • Lighting circuit for discharge lamp
  • Lighting circuit for discharge lamp
  • Lighting circuit for discharge lamp

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Experimental program
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Effect test

no. 1 approach

[0041] Fig. 1 is a block diagram showing the configuration of a first embodiment of a discharge lamp lighting circuit according to the present invention. The discharge lamp lighting circuit 1 shown in FIG. 1 is a circuit that supplies power for lighting the discharge lamp L to the discharge lamp L, and converts a DC voltage from a DC power supply B into an AC voltage and supplies it to the discharge lamp L. . The discharge lamp lighting circuit 1 is mainly used for lamps such as headlights for vehicles, in particular. Furthermore, as the discharge lamp L, for example, a mercury-free metal halide lamp is preferably used, but a discharge lamp having another structure may also be used.

[0042] The discharge lamp lighting circuit 1 includes: a power supply unit 2 that receives power supply from a DC power supply B and supplies AC power to a discharge lamp L; L provides power to the size control unit 10a.

[0043] The power supply unit 2 supplies the discharge lamp L with power...

no. 2 approach

[0101] Next, another mode of the control unit will be described as a second embodiment of the discharge lamp lighting circuit of the present invention. FIG. 12 is a block diagram showing the configuration of the control unit 10b of this embodiment. The control unit 10b of the present embodiment includes a power calculation unit 31 instead of the power calculation unit 11 of the first embodiment. The power calculation unit 31 has input terminals 31a and 31b, and an output terminal 31c. The input terminal 31 a is connected to the center tap of the secondary coil 7 b (see FIG. 1 ) via the peak hold circuit 21 . The input terminal 31 b is connected to one end of a resistor element 4 (see FIG. 1 ) provided for detecting a lamp current IS of the discharge lamp L via a peak hold circuit 22 and a buffer 23 . The output terminal 31c is connected to the input terminal 12a of the error amplifier 12 .

[0102] The power calculation unit 31 has a differential calculation unit 15 , a fir...

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Abstract

The present invention provides a discharge lamp lighting circuit capable of controlling supplied power with good reproducibility while suppressing the influence of variation in inter-electrode voltage due to individual differences in discharge lamps or temporal changes. A discharge lamp lighting circuit (1) has a power supply unit (2) and a control unit (10a). The control unit generates a control signal Sc for controlling the magnitude of the power according to the lamp voltage VL. A power supply unit (2) supplies power based on a control signal Sc from a control unit (10a) to a discharge lamp (L). The control unit has: a differential calculation unit (15) that time-differentiates the lamp voltage equivalent signal VS to generate a first differential signal Sd1 (=dVS / dt); An integral operation unit (16) that time-integrates the second differential signal Sd2 of the second differential signal Sd2 to generate the first integrated signal Si1, and generates a control signal Sc so that the power decreases corresponding to the increase of the first integrated signal Si1.

Description

technical field [0001] The present invention relates to a lighting circuit for a discharge lamp. Background technique [0002] Discharge lamps such as metal halide lamps used in vehicle headlights and the like are generally turned on as follows. That is, a high-voltage pulse (several tens of kV) is first applied to promote dielectric breakdown between the electrodes, thereby generating a discharge arc between the electrodes, and conducting between the electrodes. Next, a large power is supplied in order to increase the luminous intensity as soon as possible. Then, the inter-electrode voltage (lamp voltage) of the discharge lamp increases as the luminous efficiency increases due to evaporation of the metal enclosed in the tube, and the supplied power is gradually reduced in accordance with the increase in the lamp voltage. In this way, overshooting is prevented while the luminous intensity of the discharge lamp converges to a prescribed intensity as quickly as possible. ...

Claims

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Application Information

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Patent Type & AuthorityApplications(China)
IPC IPC(8): H05B41/288H05B41/38
CPCH05B41/2887Y02B20/202Y10S315/07Y02B20/00H05B41/288H05B41/14H05B41/24
Inventor松井浩太郎市川知幸
OwnerKOITO MFG CO LTD