JPS63310596A - Lighting device for high brightness discharge lamp - Google Patents

Abstract

PURPOSE:To start discharge at a low voltage and eliminate bad effects to a computer by applying a voltage of a high frequency generation circuit including semiconductor switching elements while a voltage for main discharge is applied to a discharge lamp. CONSTITUTION:If a discharge starting switch 50 is put on, a bias necessary for keeping generation is given from a power source 56 to a generating transistor 51 through a bias resistance 53 and a tertially winding of a generation transformer 43. For this generation output, a voltage is increased by serial resonance circuit 41, and supplied to a discharge lamp 34, where discharge is started. If the switch 50 is put off in this condition, current from a source 33 for main discharge starts stationary discharge. By forming a discharge starting voltage generating circuit 35 by a noncontact circuit including the transistor 51, and starting discharge by a high frequency current produced by the circuit 35, production of spark is restricted, and bad effects to a computer are eliminated.

Description

DETAILED DESCRIPTION OF THE INVENTION TECHNICAL FIELD The present invention relates to a lighting device for a high-intensity discharge lamp, which is preferably implemented in a metal halide lamp or the like.

Prior Art FIG. 2 is a diagram showing the electrical configuration of a typical prior art lighting device 1. The main discharge power supply circuit 3 converts the power from the commercial power supply 2 into the rated voltage of the discharge lamp 4, and discharges it! 41
11! It is applied to the discharge lamp 4 via the fins 6 and 7 in the starting high pressure generating circuit 5. A secondary winding m9 of a secondary high-voltage pulse generating transformer 8 is interposed in the line 6, and a primary winding 10 of the secondary high-voltage pulse generating transformer 8 is connected to a pulses are applied.

In other words, Ho 1! When the start switch 22 is turned on, the DC? DC voltage from four sources 11 is applied to a primary high voltage generation capacitor 13 via a current limiting resistor 12. As a result, the -th order high voltage generation capacitor 13 starts charging, and when the charging voltage exceeds the breakover voltage of the Cybook 14, the -th order high voltage generation capacitor 13 is charged with vM.
The electric power thus obtained is applied all at once to the primary winding 16 of the primary high-voltage pulse generating transformer 15. As a result, the voltage induced in the secondary winding 17 of the -order high voltage pulse generating transformer n15 is:
Secondary pulse generation capacitor 19 via rectifier Jj18
is applied to When the charging voltage of the secondary pulse generating capacitor 19 exceeds the breakover voltage of the spark gap 20, the primary winding 411 of the secondary high voltage pulse generating transformer 8
A discharge current momentarily flows through the secondary winding 9.
A pulsed high voltage of approximately 10 WLKV is generated. The high-voltage pulse for starting discharge thus generated flows in the order of discharge lamp 4 - line 7 - bypass capacitor 21 - line 6, discharge lamp 4 starts discharging, and when the discharge start switch 22 is shut off in this state, A transition is made to steady lighting using the power applied by the main discharge power supply circuit 3.

Problems to be Solved by the Invention In such prior art, since the discharge of the discharge lamp 4 is started by a high voltage pulse, the circuit for starting the discharge needs to have a high withstand voltage, and the circuit configuration is complicated. become. Also, due to the noise generated from the spark gap 20,
Electronic equipment such as computers installed nearby may malfunction.

Furthermore, in order to stabilize the discharge state of the discharge lamp 4, high-frequency power of, for example, about 250 KHz is generated from the main discharge power supply circuit 3, and if the configuration is such that so-called high-frequency lighting is performed, such For high-frequency oscillation, semiconductor devices such as field-effect transistors and MO8 type integrated circuits are often used (these devices are sensitive to the high-voltage pulse at the beginning of the discharge mentioned above, and , which makes circuit configuration difficult.

The purpose of the present invention is to provide a lighting device for a high-intensity discharge lamp that starts lighting the discharge lamp without using high voltage and suppressing the generation of sparks.

Means for Solving the Problems The present invention provides a lighting device for lighting a high-intensity discharge lamp such as a metal halide lamp, characterized in that lighting of the discharge lamp is started by a high-frequency oscillation circuit including a semiconductor switching element. This is a lighting device for a brightness discharge lamp.

Function According to the present invention, while a voltage for main discharge is being applied to the discharge lamp, a voltage from a high frequency oscillation circuit having a semiconductor switching element is applied to the discharge lamp.

This prevents the ions in the discharge lamp from repeating excitation and annihilation (the ions are constantly excited and discharge starts at a relatively low voltage. Therefore, the ions inside the discharge lamp are not repeatedly excited and extinguished, and the discharge starts at a relatively low voltage. Therefore, the ions in the discharge lamp are not repeatedly excited and extinguished. In addition, if the discharge lamp is configured to be lit steadily using high frequency waves using semiconductor elements, there will be no adverse effect on these semiconductor elements.

Embodiment FIG. 1 is a diagram showing the electrical configuration of a lighting device fi31 according to an embodiment of the present invention. The main discharge power supply circuit 33 converts the power from the commercial power supply 32 into direct current or commercial frequency power having the rated voltage of the discharge lamp 34, or high frequency power of about 250 KHz, and converts the power from the commercial power supply 32 into the line 3G in the discharge starting voltage generation circuit 35. , 37 to the discharge lamp 34. line 36
A secondary winding 1139 of the output transformer 38 is interposed, and a resonant capacitor 40 is connected in parallel with this secondary winding fi39.
is connected. Thus the secondary winding 39 of the output transformer 38
and the resonant capacitor 40 form N# parallel resonant circuits 41. The output from the secondary winding 44 of the oscillation transformer 43 is applied to the primary 8 wire 42 of the output transformer 38.
The secondary winding 44 of the oscillation transformer 43 includes a high frequency oscillation circuit 4.
The output from 5 is given.

The high frequency oscillation circuit 45 includes an oscillation transistor 51 which is a semiconductor switching element, an oscillation transformer 43, a resonant capacitor 52, bias resistors 53 and 54, and a bypass capacitor 55. When the discharge start switch 50 is turned on, the oscillation transistor 51 has the following effects:
Power from the DC current 'a56 is applied via the bias resistor 53 and the tertiary 8m47 of the oscillation transformer 43 as a base bias necessary for sustaining oscillation, and in this embodiment, the oscillation frequency is selected to be 13 MHzI. The oscillation output thus obtained is boosted by the parallel resonant circuit 41 and given to the discharge lamp 34, and the ions in the discharge lamp 34 do not repeat excitation and extinction, but remain excited and start discharging. When the discharge start switch 50 is shut off in this state, a transition is made to steady discharge using the power from the main discharge power supply circuit 33.

In this way, in this Pt-embodiment, the oscillation transistor 5
High voltage generation circuit 3 starts releasing Ml by a non-contact circuit including 1
5 and 61, and discharge of the discharge lamp 34 is started by the high frequency power generated by the circuit 35, so that the spark gap 20 as described in the prior art section is
Therefore, there is no generation of noise that has an adverse effect on computers installed nearby, and by starting the discharge with high-frequency power in this way, it is possible to avoid the generation of sparks as shown in the prior art. Discharge can be started with a relatively low voltage instead of a pulse-like high voltage, and therefore a semiconductor element is used in the main discharge power supply circuit 35 to power the discharge lamp 3 with high frequency.
Even if the light source 4 is configured to be lit constantly, there will be no adverse effect on these semiconductor elements.

Effects As described above, according to the present invention, the discharge of the discharge lamp is started by a high-frequency oscillation circuit constituted by a non-contact circuit including a semiconductor switching element, so that generation of sparks is suppressed, and for example, it is possible to suppress the generation of sparks. There is no negative effect on electronic equipment. In addition, since the discharge can be started at a relatively low voltage instead of the pulse-like high voltage shown in the conventional technology, there is no need to increase the voltage resistance of the circuit configuration unnecessarily, and furthermore, it is possible to use a semiconductor terminal. Even if the discharge lamp is configured to be constantly lit using high frequency waves, these semiconductor elements will not be adversely affected.

[Brief explanation of the drawing]

il1 is a diagram showing the electrical configuration of the lighting device 'a31 according to an embodiment of the present invention, and FIG. 2 is a diagram showing the electrical configuration of the lighting device 1 of the prior art.

Claims (1)

[Claims] A lighting device for lighting a high-intensity discharge lamp such as a metal halide lamp, characterized in that lighting of the discharge lamp is started by a high-frequency oscillation circuit including a semiconductor switching element.