JPH0590896U - Discharge lamp lighting device - Google Patents

Abstract

(57) [Abstract] [Purpose] A sufficient voltage for lighting the discharge lamp is obtained, the discharge lamp is not adversely affected, the safety is improved, and the transformer is small-sized and economical. [Structure] A series circuit of a diode 6 and a resistor 7 is connected in parallel to a discharge lamp 1 connected to a power supply circuit 4 via a phase advancing capacitor 2 to connect the phase advancing capacitor 2 to a diode 6
The discharge lamp 1 is turned on by charging through the discharge resistor 8 and the switching resistor 11 of the phase advancing capacitor 2.
Equipped with. The switcher 11 connects the series circuit in parallel with the discharge lamp 1 for a predetermined time required to start lighting of the discharge lamp 1 after connecting the power supply circuit 4 to the power supply, and thereafter advances the discharge resistor 8. It operates so as to intervenely connect to the discharge circuit of the phase capacitor 2.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a lighting device for a discharge lamp.

[0002]

[Prior Art]

 Conventionally, a circuit as shown in FIG. 2 is known as a lighting device for a discharge lamp. In the figure, the discharge lamp a is connected to a power supply circuit e having a transformer d through a phase advancing capacitor b and a current waveform improving choke coil c, and is connected in parallel with the discharge lamp a to a diode f. A series circuit of a resistor g is connected, and a discharge resistor h is connected in parallel with the phase advancing capacitor b.

[0003]

[Problems to be solved by the device]

According to the above circuit configuration, the peak voltage Vp ₁ applied between the points A and B, that is, both ends of the discharge lamp a is, as shown in FIG. 3, the secondary voltage V ₂ (r It has a value close to 2√2 times m.s). To start the lighting of the discharge lamp a, a peak voltage value of 2√2V ₂ is required, but the above-mentioned is caused by the relationship between the resistance value R ₁ of the discharge resistor h and the resistance value R ₂ of the resistor g. As a result, the value becomes lower than 2√2V ₂ . If the resistance value R ₂ of the resistor g is made considerably smaller than the resistance value R ₁ of the discharging resistor h, V p ₂ = 2√2V ₂ as shown in FIG. 4, but the discharge lamp a is turned on. Since the discharge lamp current later becomes a half-wave and approaches a half-wave discharge, which adversely affects the discharge lamp a, there is a limit to reducing the resistance value R ₂ by itself. Further, when the discharge lamp a cannot be discharged due to the service life of the discharge lamp a or is in a no-load state in which the discharge lamp a is not attached, a high voltage of the peak voltage V p ₁ is applied between points A and B. Therefore, it is not preferable from a safety point of view. To solve this problem, the transformer d may be an insulated type, or an interlock mechanism may be provided to turn off the power when replacing the discharge lamp a. , Not economical. Also, if the discharging resistor h is removed, Vp ₂ = 2√2V ₂ , but the DC voltage Vd remains in the phase advancing capacitor b for many hours even when the power is turned off. The above safety measures are very dangerous.

An object of the present invention is to eliminate the inconvenience of the conventional lighting device for a discharge lamp.

[0005]

[Means for Solving the Problems]

 In order to achieve the above-mentioned object, the present invention connects a series circuit of a diode and a resistor in parallel to a discharge lamp connected to a power supply circuit via a phase advancing capacitor to connect the phase advancing capacitor to the diode. In a lighting device for a discharge lamp that lights a discharge lamp by charging via a discharge lamp, the discharge resistor of the phase advancing capacitor and the power supply circuit are connected to a power source before the discharge lamp starts lighting. And a switch for connecting the capacitor discharging resistor to the discharge circuit of the phase advancing capacitor after connecting the series circuit in parallel with the discharge lamp for a required predetermined time.

[0006]

[Action]

A voltage is applied to the power supply circuit, the phase-advancing capacitor is charged through the diode, and a peak voltage of 2√2 of the output voltage V ₂ (r · m · s) of the power supply circuit is applied to the discharge lamp for a predetermined time. After the lapse of time, when the discharge lamp starts lighting, the switching device operates, the series circuit of the diode and the resistor is disconnected from the lighting circuit, and the capacitor discharge resistor is interveningly connected to the discharge circuit of the phase advance capacitor. .. Thus, after the discharge lamp discharges, or even when the discharge lamp does not discharge due to life etc., after a predetermined time has passed since the voltage was applied to the power supply circuit, the voltage across the discharge lamp is equal to the output voltage V ₂ ( The peak voltage becomes √2 of r · m · s), and the voltage drops.

[0007]

【Example】

 Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a circuit diagram of an embodiment of the present invention.

In the figure, reference numeral 1 denotes a discharge lamp such as a metal halide lamp, which is connected to a transformer 5 of a power supply circuit 4 via a phase advancing capacitor 2 and a choke coil 3 for improving a current waveform. The diode 6 and the capacitor discharging resistor 7 are connected to the terminal A at one end of the discharge lamp 1, and the other end of the resistor 7 and the other end of the resistor 8 connected in series with the diode 6 are connected. The fixed contacts a and b of the changeover switch 9 are connected to each other, and the changeover contact c is connected to the terminal B at the other end of the discharge lamp 1. Although not shown, 10 is connected to the power supply circuit 4, starts operating when a voltage is applied to the power supply circuit, and changes the switching contact c to a fixed contact a for a time (for example, 30 seconds) required for the discharge lamp 1 to start discharging. The timer 10 and the changeover switch 9 constitute a changeover device 11 after connecting to the fixed contact b.

Thus, when a voltage is applied to the power supply input terminal 12 of the power supply circuit 4, the voltage V ₂ (r · m · s) is output to the secondary terminal of the transformer 5. During the half-cycle of the voltage V ₂ at which the point B becomes positive during the predetermined time when the diode 6 and the resistor 8 are connected to the points A and B, the phase advance capacitor 2 causes the peak value V ₂ of the voltage V ₂ to rise. Since it is charged to 2V ₂ , the voltage of Vp ₂ = 2√2V ₂ (r · m · s) as shown in FIG. 4 is applied to the discharge lamp 1 in the next half cycle. Thus, when the discharge lamp 1 is turned on and a predetermined time elapses, the capacitor discharging resistor 7 is connected to the points A and B by the switcher 11, and as a result, the DC voltage charged in the phase advancing capacitor 2 becomes Vd. Is discharged through point A, resistor 7, point B, transformer 5 and choke coil 3. Therefore, the discharge lamp 1 does not perform half-wave discharge, and the voltage when the discharge lamp 1 does not discharge is only √2V ₂ (r · m · s).

[0010]

[Effect of the device]

 As described above, the present invention provides a series circuit of a diode and a resistor for discharging a phase advancing capacitor and a predetermined time required to start lighting a discharge lamp after connecting a power circuit to a power source. Is connected in parallel with the discharge lamp, and a switching device interveningly connecting the capacitor discharging resistor to the discharge circuit of the phase advancing capacitor is provided, so that a voltage sufficient to light the discharge lamp can be obtained. At the same time, the life of the discharge lamp is not adversely affected, the safety is improved, and it is not necessary to use an insulation type, so that the transformer has a small size and is economical.

[Brief description of drawings]

FIG. 1 is a circuit diagram of an embodiment of the present invention.

FIG. 2 is a circuit diagram of a conventional lighting device.

FIG. 3 is an operation explanatory view of a conventional lighting device.

FIG. 4 is an explanatory view of the operation of the present invention and the conventional lighting device.

[Explanation of symbols]

1 Discharge Lamp 2 Capacitor for Phase Advance 2 4 Power Circuit 5 Transformer 6 Diode 7 Resistor 8 Resistor 9 Changeover Switch 10 Timer 11 Changer

Claims (1)

[Scope of utility model registration request] 1. A discharge lamp connected to a power supply circuit via a phase advancing capacitor is connected in parallel with a series circuit of a diode and a resistor, and the phase advancing capacitor is charged through the diode to discharge the discharge lamp. In a discharge lamp lighting device for lighting an electric lamp, the series circuit is discharged for a predetermined time necessary to start lighting the discharge resistor of the phase advancing capacitor and the power supply circuit after the power supply circuit is connected to a power source. A lighting device for a discharge lamp, comprising: a switch for connecting the capacitor discharging resistor to the discharge circuit of the phase advancing capacitor after connecting in parallel with the electric lamp.