JPS60202693A - Device for firing discharge lamp - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] Industrial applications The present invention relates to a lighting device for a discharge lamp.

Conventional configuration and its problems When a discharge lamp is operated with alternating current, the direction of the discharge current is alternately reversed, which causes flickering at the tube end of the discharge lamp. In order to prevent this flicker, a lighting device is used that lights a discharge lamp using a power source whose output voltage has a constant polarity.

A conventional discharge lamp lighting device will be described below.

Figure 1 shows the circuit configuration of a conventional discharge lamp lighting device, in which 1 is a DC power supply with a current limiting function, 2 is an AC power supply,
3 is a full-wave rectifier, 4 is a capacitor, 6 is a step-down chopper circuit, 6 is a capacitor, γ is a diode, 8 is a discharge lamp,
9 is a starting DC voltage generator, 10 is a capacitor, and 11 is a diode.

An AC power source 2 is connected to the input end of the full-wave rectifier 3, and a capacitor 4 is connected to the output end. A step-down chopper circuit 6 is connected to the output end of the capacitor 4 so that the charge stored in the capacitor 6 flows through a diode 7 to a discharge lamp 8. The starting DC voltage generator 9 is a step-up chopper circuit connected to input the DC current from the capacitor 4 and store the DC voltage in the capacitor 10 via the diode 11, and the capacitor 10 is connected to the discharge lamp. 8 in parallel to match the polarity of the output voltage of the power source 1.

The operation of the conventional discharge lamp lighting device configured as described above will be described below.

Charge is accumulated in the capacitor 4 by the AC power supply 2 via the full-wave rectifier 3, and a smoothed DC voltage is obtained. The DC current flowing from the capacitor 4 is controlled intermittently by the transistor Q in the step-down chopper circuit 6 to limit the current, and the voltage of the capacitor 6 is set to a predetermined voltage. Furthermore, capacitor 4
The current flowing from is input to the starting DC voltage generator 9, which is a step-up chopper circuit, and is applied to the capacitor 1o via the diode 11 to obtain a DC voltage higher than the voltage of the capacitor 4 and sufficient to start the discharge lamp 8. . Instead, the discharge lamp 8 starts and lights up. During lighting, the lighting is maintained by the current flowing from the step-down chopper circuit 5 through the diode 7.

However, in the above configuration, in order to obtain a high DC voltage for starting, capacitor 1Q and diode 7 are used.
．． 11 had the disadvantage of requiring components with high voltage resistance.

Furthermore, since current is caused to flow from the capacitor 4 to the starting DC voltage generating section 9, there is a disadvantage that there is a large amount of wiring, making the wiring and wiring complicated.

OBJECT OF THE INVENTION The present invention solves the above-mentioned conventional problems.It is an object of the present invention to provide a unidirectional discharge lamp which does not require the use of many high-voltage components for starting, and which simplifies the wiring of the starting circuit. An object of the present invention is to provide a discharge lamp lighting device that lights with a current of .

Structure of the Invention In order to achieve the above object, the present invention has a current limiting function and at least one
A power supply having a diode connected to one output terminal, a discharge lamp connected to the output terminal of the power supply, and a pulse voltage of the same polarity to the output terminal of the power supply by inputting the current from the power supply. The discharge lamp lighting device is equipped with a pulse generation circuit that outputs a pulse, and a diode connected to the output terminal of the power supply prevents the pulse output from the pulse generation circuit from inputting to the power supply, and By directly applying a pulse to start, the only components with high voltage resistance are the diodes connected to the output terminal of the power supply, other than the pulse generation circuit itself, and the input/output terminals of the pulse generation circuit are connected to the output terminal of the power supply. By using two terminals connected to each other, wiring can be easily routed.

DESCRIPTION OF EMBODIMENTS FIG. 2 shows the circuit configuration of a discharge lamp lighting device according to a first embodiment of the present invention, in which 1 has a current limiting function and is connected to at least one output terminal of at least A. 12 is a pulse generation circuit, 13 is a resistor, 1
4 is a step-up transformer with a center tap; 16 is a one-way groove reverse blocking two-terminal thyristor (hereinafter referred to as thyristor) which is a voltage sensitive switch; and 16 is a capacitor. Power supply 1
The configuration is the same as that of the conventional example shown in FIG. 1, and the same symbols are attached.

In the pulse generating circuit 12, the step-up transformer 14 and the thyristor 15 located between the intermediate taps are connected in series, and the end of the power supply 1 whose polarity is positive is connected to the step-up transformer 14 via a resistor 13, and the capacitor One end of the capacitor 16 is connected to the intermediate tap of the step-up transformer 14, the other end of the capacitor 16 is connected to the end of the thyristor 16 that is not connected to the step-up transformer 14, and the connection point between the capacitor 16 and the thyristor 15 is connected to the center tap of the step-up transformer 14. Connected to the end with negative polarity.

The operation of the discharge lamp lighting device of this embodiment configured as described above will be described below.

In the embodiment of FIG. 2, from the AC power supply 2 to the full-wave rectifier 3
, a DC voltage is obtained via the capacitor 4, and the transistor Q in the step-down chopper circuit 6 performs current-limiting control intermittently to set the voltage of the capacitor 6 to a predetermined voltage, and the discharge lamp 8 is started and lit. The rest is a step-down chopper circuit 5
The lighting is maintained by the current flowing from the lamp through the diode 7, which is the same as the conventional example shown in FIG.

The operation of the pulse generating circuit 12 will be explained below.

In the embodiment of FIG. 2, the polarity of the power supply 1 starts from the positive end,
A current flows to the capacitor 16 via the resistor 13 and a part of the step-up transformer 14, and charges are accumulated therein. capacitor 16
When the voltage across the capacitor 16 reaches the breakover voltage of the thyristor 16, the thyristor 15 becomes conductive and the capacitor 16,
Current flows in the direction of the intermediate tap of the step-up transformer 14 - the connection point between the step-up transformer 14 and the thyristor 15 - the thyristor 16 -> the capacitor 16 . No way, step-up transformer 1
A high voltage pulse is generated at both ends of the thyristor 4 such that the end to which the thyristor 15 is not connected is positive. Therefore, the polarity of the output pulse of the pulse generation circuit 12 outputted from the step-up transformer 12 via the resistor 13 is the same as the polarity of the power supply 1. Therefore, the output pulse of the pulse generating circuit 12 is blocked by the diode 7 and is not input to the power supply 1, but is applied to the discharge lamp 8 and starts the discharge lamp 8. After the discharge lamp 8 is started, the power supply 1 keeps it lit.

As described above, according to this embodiment, it has a current limiting function and at least one
a power supply 1 having a diode connected to one output end;
A discharge lamp 8 connected to the output end of the power source 1; and a pulse generation circuit 12 that receives current from the power source 1 and outputs a pulse voltage of the same polarity to the output end of the power source 1. , a diode 7 connected to the output terminal of the power supply 1
By preventing the pulses output from the pulse generating circuit 12 from being input to the power source 1, and starting the discharge lamp 8 by applying a pulse directly to the discharge lamp 8, components with high voltage resistance are connected to the power source 1, except for the pulse generating circuit itself. By using only the diode 7 connected to the output end of the power source 1 and by connecting the input/output terminals of the pulse generating circuit to the output end of the power source 1 and having two terminals, wiring can be easily routed.

In the embodiment shown in FIG. 2, the resistor 13 is connected to the positive polarity end of the power source 1, but the same effect can be obtained by connecting it to the negative polarity end of the power source 1.

Furthermore, it is not impossible to obtain the same effect even if the input and output terminals of the pulse generation circuit 120 are connected in reverse.

In the embodiment shown in FIG. 2, a one-way conductive reverse-blocking two-terminal thyristor is used as the voltage sensitive switch, but the switch is not limited to this, and any switch that conducts at a predetermined voltage may be used.
Needless to say, it may be a terminal thyristor, a three-terminal thyristor with a control terminal, a transistor, or the like.

If the breakover voltage of the voltage sensitive switch is set between the output voltage of the power supply 1 before and after the discharge lamp 8 is started, the pulse ordering circuit 12 will send a pulse when starting the discharge lamp 8. However, it goes without saying that the pulses can be prevented from being generated after the discharge lamp 8 is started and lit.

Furthermore, the power supply may be a DC power supply with a constant current control function,
It may be a DC power supply with a current limiting circuit added to it, or it may be of any other type as long as it has a current limiting function and has a diomide at the output end to output a unidirectional voltage. .

As is clear from the description of the embodiments above, the present invention does not require the use of many high-pressure components required for starting, and it is possible to simplify the wiring of the starting circuit. It can be done.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram of a conventional discharge lamp lighting device, and FIG. 2 is a circuit diagram of a discharge lamp lighting device in an embodiment of the present invention. 1...Power supply, 7...Diode, 8.
...Discharge lamp, 12...Pulse generation circuit, 1
3... Resistor, 14... Step-up transformer with intermediate tap, 16... Thyristor, 16...
...Capacitor. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
figure\

Claims (2)

[Claims] (1) a power source having a current limiting function and having a diode connected to at least one output end so as to be in the forward direction with respect to the output voltage; a discharge lamp connected to the output end of the power source; and a pulse generation circuit that inputs current from a power source and outputs a pulse voltage of the same polarity to an output end of the power source, and the pulse generation circuit outputs a voltage from a diode connected to the output end of the power source. A discharge lamp lighting device characterized in that the discharge lamp is started by preventing pulses from being input to a power source and applying a pulse voltage between electrodes of the discharge lamp. (2) The pulse generation circuit includes a series circuit of a step-up transformer with an intermediate tap and a voltage sensitive switch, a resistor connected in series with the series circuit, and one end connected to the intermediate tap of the step-up transformer and the other end. comprises a capacitor connected to an end not connected to a step-up transformer of a voltage sensitive switch, and both ends of the series circuit of the series circuit and the resistor are input/output terminals. The discharge lamp lighting device according to item 1.