JPS5912599A - 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 The present invention relates to an improvement in a lighting device for a discharge lamp with a preheating electrode, and particularly to an electrode preheating circuit for starting this type of lamp.

A discharge lamp with a preheating electrode, such as a fluorescent lamp, is started by first passing an electrode preheating current when starting the lamp, and then applying a high voltage necessary for starting the lamp. Conventionally, a glow starter is used to start a lamp, which preheats the lamp electrodes and generates a starting pulse voltage. However, it is known that when two lamps are lit in series, it is not possible to preheat all the electrodes and stably start the lamp using a glow starter. Therefore, in this case, a rabbit or tostart type lamp is used, and a preheating transformer or the like is used to flow a preheating current from the time of starting to the entire time the lamp is lit.

Other lamp electrode preheating methods include a semiconductor starter using a semiconductor switch circuit and a restriking lighting circuit every cycle in which the switching circuit continues to operate even during lighting as shown in FIG. In order to form a lamp electrode preheating circuit, the semiconductor starter described above requires at least as many switch elements as the number of lamps, or has a specially devised circuit configuration. Moreover, these elements are often expensive because they do not break down due to the high voltage required to start the lamp, and are therefore often disadvantageous in terms of cost.

Next, the conventional every-half-cycle restriking lighting circuit shown in FIG. 5 will be described. In the figure, 1 is an AC power supply, 2 is a choke coil, 3 is a rung, 4 is a switching circuit, 7 is a power switch, 8 is a full-wave rectifier, and 9 is a switching transistor driven by a control circuit 10. Figure 4 shows the operating waveforms during lighting. In operation, at time t when the lamp current equal to the input current iI becomes 0 during the off period of the switching circuit 4, the transistor 9 is turned on by a signal from the control circuit 10, and the switching circuit 4 is turned on. Besides, the input current is 11
flows through the choke coil 2, both electrodes of the lamp 3, and the switching circuit 4, and no lamp current flows. and,
The input current 11 gradually increases, and electromagnetic energy e is applied to the choke coil 2. Then, a predetermined current value Jcut
When this happens, the drive current from the control circuit 10 becomes 0, and the transistor 9 turns off. Then, a high voltage pulse is generated across the choke coil 20, which is applied as a pulse voltage V across the lamp 3, and the lamp 3 is re-lit.

Thereafter, the energy stored in the choke coil 2 is superimposed on the energy from the power supply 1, and the input current iI flows through the lamp 3 between times t and t3, and the lamp is lit during this period. After time t3, the same operation is repeated to maintain the lighting state.

In this lighting method, preheating at startup is performed by extending the period during which the switching circuit 4 is on; however, with the same lighting method, it may be necessary to connect the switching circuit 4 to the middle tap of the choke coil 2. However, with such a connection, it is not possible to form a preheating circuit.

Therefore, an object of the present invention is to short-circuit the non-power supply side terminals of the lamp electrodes to allow a preheating current to flow;
Furthermore, in a discharge lamp lighting device that can generate a lamp starting voltage with the above terminals open, a constant It is an object of the present invention to provide a discharge lamp lighting device which allows a time electrode preheating current to flow and then, after stopping the preheating current, the starting voltage is applied to enable reliable lamp starting.

Therefore, in the present invention, in order to flow the electrode preheating current when starting the lamp, a circuit is configured to short-circuit the non-power supply side terminals of the lamp electrodes, and an electromagnetic relay is used to short-circuit the terminals. The electromagnetic relay is characterized in that a control switch circuit is connected in series with the excitation winding of the electromagnetic relay in order to open the terminals after the preheating current is applied.

An embodiment of the present invention will be explained below with reference to FIG. 1st
The figure shows the connection end of the switching circuit 4 of the lighting circuit shown in FIG. 5 connected between the center tap of the choke coil 2 and the other end of the power supply 1.

In this case, it is clearly impossible to form a double electrode preheating circuit for the lamp 3 through the switching circuit 4. Therefore, in the present invention, the normally open circuit contact 501 and the excitation winding 502
Preheating is performed using an electromagnetic relay 5 having a switch circuit 6 which is turned on for about one second after the power switch 70 is turned on. Accordingly, an excitation current is applied to the electromagnetic relay 5, the contact 501 is closed, and the choke coil 2,
A preheating current is passed through both electrodes of the lamp 3.

The switching circuit 4 continues to operate immediately after the power switch 7 is turned on, and from the next half cycle when the contact 501 is opened after preheating the electrodes of the lamp 3, high voltage pulses generated by the operation of the switching circuit 4 are generated. V, lamp 3 starts immediately. Thereafter, the lighting is maintained by the operation described in the explanation of FIGS. 5 and 6. In the configuration shown in FIG. 1, a high-voltage pulse voltage Vp for starting the lamp is applied to both ends of the lamp 3, so constructing a preheating circuit using semiconductor elements is often expensive. Therefore, using an electromagnetic relay as shown in Figure 1 has a
This is advantageous in terms of current capacity.

FIG. 2 shows another embodiment of the invention. When using an electromagnetic relay, a large number of lamps 301 to 304 are used as shown in FIG.
Many contacts 503 to 506 of one electromagnetic relay
It is most advantageous to preheat using In the lighting circuit shown in FIG. 2, two lamps 3 shown in FIG. 1 are connected in series, and the two lighting circuits are simultaneously operated by one power switch 7.

For example, in a semiconductor switch circuit, contacts 503 to 50
If you want to configure 6 switches, you will need to configure at least 4 separate circuits, and it will be more advantageous to configure the preheating circuit with 1 electromagnetic relay as shown in Figure 2. do not have.

60 circuits surrounded by dotted lines show an example of an electromagnetic relay control circuit. 11 is a full wave rectifier, 12 is 5CR113, 15,
Reference numeral 14 denotes a resistor and a constant voltage element for triggering the gate of the 5CR12.

20. 19 is a time constant circuit that determines the length of time that the excitation current is passed through the excitation winding IWI502, and 17 is a time constant circuit such as SBS.
A voltage sensitive switching element 16.21 which turns on when a voltage of about V is applied is a diode for reverse blocking. The constant voltage element of 14 is lower than the turn-on voltage of SBS 17, and the voltage of 5BS17 is also lower than that of SBS 17. It is selected to be higher than the sum of the forward voltages of the diodes 16 and 5BS17 in the on state.

The operation of the control circuit 6 shown in FIG. 2 is such that when the power switch 7 is turned on, an excitation winding 502 is connected to both ends of the 5CR
, the voltage of the power supply l is applied through the full-wave rectifier 11.

This voltage is applied to 5C through the resistor 13 and constant voltage element 14.
The gate trigger current of R12 flows and the SC switch 12 is turned on.

As a result, the excitation current of excitation winding #51502 flows, and contacts 503, 504, 505, and 506 are turned on. 5CRI2 repeats on-off operation every half cycle, but since the excitation current of the excitation winding 502 has a delayed phase, immediately after the half cycle of excitation current finishes flowing,
The voltage developed across 808120 when 80R12 turns off is large enough that 5CFL12 turns on again instantly, so contacts 503-506 do not open.

On the other hand, the capacitor 19 is charged with electric charge through the diode 21 and the resistor 20 immediately after the power switch 7 is turned on.
The voltage is approximately 100 volts (for example, approximately 1
seconds), the turn-on voltage of 5BS17 is reached, and 5BS1
7 turns on.

After that, the voltage of 8CR14 is diode 16.8BS1
Since the voltage is higher than that of voltage 7, SC 12 does not turn on.
Current flows through resistor 13 → diode 16 → 5BS17, or diode 21 → resistor 20 → resistor 18 → 8BS17, and 5BS17 remains on. Therefore, the lamps 301 to 304 are connected to the switching circuit 401,
The lamps 301 to 304 are started by the pulse voltage Vp generated by the operation of 402, and since no excitation current flows through the excitation winding 502 after that, the lamps 301 to 304 maintain their lighting state. When the power switch 7 is opened and the light is turned off, the charge on the capacitor 19 is transferred from the capacitor 19 with a short time constant to the resistor 18 → 5B.
The SBS 17 is discharged in the circuit of S17, and the SBS 17 instantly returns to the OFF state and is reset.

Therefore, even if the power switch 7 is turned on immediately after the light is turned off, the light can be reliably turned on again.

FIG. 3 shows the upper half of the circuit shown in FIG. 2 with a slightly different configuration. The secondary coil 202 in FIG. 2 is placed between the two lamps 301 and 302, and the secondary coil 2
It was set as 05. With such a configuration, the switching current flowing through the switching circuit 401 is diverted from the lamp 3 during lighting.
01 and 302 to preheat the electrodes. In this way, the breaking current Jc of the switching circuit 401
When dimming lighting is performed with a small value ut, the degree of cooling of the electrode is small and stable lighting is possible. The excitation current control circuit simplifies the gate circuit of SC'R12. When the power switch 7 is turned on, the diode 22 → capacitor 2
3, 80R12 is turned on and excitation winding 502
An excitation current flows, and an electrode preheating current for the lamps 301 and 302 flows. This operation is similar to that shown in Fig. 2, and after about 1 second, the capacitor 23 is charged to the peak value of the 1-source voltage.
5CR12 becomes unable to turn on. Capacitor 23・
Since the discharge time constant of the resistor 25 is sufficiently large, the 5CRI 2 is not gate-triggered and turned on during lighting.

FIG. 4 shows still another embodiment of the present invention, in which the preheating circuit is applied to a phase advance type two-stroke series lighting circuit. in this case,
The lamps 301 to 304 are of the rapid start type, and the starting voltage is obtained from the no-load output voltage. In the same figure, 261
, 262 are cage transformers, and 271 and 272 are phase advance capacitors. In this case as well, four lamps 301~
304 electrode preheating is performed by one electromagnetic relay.

It is clear that the number of lamps to be preheated by one electromagnetic relay can be arbitrarily selected depending on the number of contacts of the electromagnetic relay. Further, in this case, since the preheating current during lighting is 0, the power consumption is reduced by about 10% compared to the conventional method.

Furthermore, the preheating method of the present invention can generate a lamp starting voltage with the lamp end open using the high frequency lighting method shown in FIG. It is clear that the present invention can be applied to any discharge lamp lighting device in which a preheating current can be passed by short-circuiting the ends.

In FIG. 7, 100 indicates a high frequency inverter.

As described above, according to the present invention, the lamp starting voltage can be generated when the lamp end is open, and furthermore, the electrode preheating current can be caused to flow by short-circuiting the non-power supply side end of the lamp electrode. In such a discharge lamp lighting circuit, contacts of an electromagnetic relay are used to short-circuit the non-power supply side of the lamp electrode for preheating and to open the lighting reservoir.

A switch circuit is connected in series to the excitation winding of the electromagnetic relay to allow an excitation current to flow only during a period necessary for preheating, and is connected in parallel to a power source.

This method is economical because a large number of lamps can be preheated with one relay. In particular, when a switching circuit is connected to the intermediate tap to interrupt the current in the every-half-cycle restriking method, the starting pulse voltage is sufficient, so the electromagnetic relay preheating method of the present invention can be used easily and with high reliability. Circuit configuration is possible. Furthermore, in the case of multiple lights, it becomes possible to create a lighting device that is highly economical. Furthermore, when applied to a rabbit start lamp lighting circuit, power savings can be expected.

[Brief explanation of the drawing]

1v1, FIG. 1, FIG. 3, FIG. 4, and FIG. 7 are circuit configuration diagrams of different embodiments of the lighting device according to the present invention, and FIG.
The figure shows the configuration of a conventional half-cycle restriking lighting circuit.
FIG. 6 is an operational waveform diagram of the circuit of FIG. 5. 1... AC power supply, 2,210... choke coil,
201.203...Primary coil, 202,204゜2
05...Secondary coil, 3,301,302,303°304...Discharge lamp with preheating electrode, 4,401°40
2... Switching circuit, 5... Electromagnetic relay, 50
2... Excitation coil, 501, 502, 503° 504
．． 505.506... Contact, 6... Control circuit, 7... Power switch, 8.11... Full wave rectifier,
9...Transistor, 10...Drive circuit, 12
...SCR, 16, 21, 22... Diode, 1
4... Constant voltage diode, 13, 15, 18, 20° 24.25... Resistor, 17... Voltage sensitive switch,
19.23,271,272...capacitor, 261
゜262・Leakage transformer, 100...High frequency inverter. fJ 5 Figure 4 Figure 6

Claims (1)

[Claims] 1. Discharge lamp lighting consisting of an AC power source, a discharge lamp with a preheating electrode, and a lighting circuit for the discharge lamp, wherein the output voltage of the lighting circuit during no-load is at least a value necessary for starting discharge of the discharge lamp. In the device, a normally open electromagnetic relay is connected between the non-power side terminals of the discharge lamp preheating electrode,
A switch circuit that remains on for the time required to preheat the discharge lamp is connected in series with one end of the excitation winding of the electromagnetic relay, and the other end of the excitation winding of the electromagnetic relay is connected to the AC power source. A discharge lamp lighting device characterized by: