JPS62241295A - Discharge lamp lighting apparatus - 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 application field] 1゜ The present invention uses an inductive element and a valley without using a transformer.

The point where a discharge lamp is lit by series resonance of a quantum element.

Related to lighting equipment, especially the current generated when the power is turned on.

A low price discharge lamp suitable for reducing energy consumption and extending the life of discharge lamps.

Regarding measuring instruments. 15 [
BACKGROUND ART A conventional device is disclosed in, for example, Japanese Patent Application Laid-Open No. 58-2 (1989) No. 9895.

The switching element is turned on and off at the top of the board.

The oscillation frequency of the drive circuit is always the specified frequency.

There are many things that are fixed. For this reason, power supply 1. .

It is difficult to pay careful attention to the Lashier current after turning on and the operation of the secondary voltage applied to the discharge lamp, and a new type of drive circuit has been desired. Also, on the one hand, the power supply voltage.

There are also devices that manipulate the oscillation frequency according to fluctuations and try to light the discharge lamp stably and steadily. However, as mentioned above, there is still insufficient improvement in the details of the lighting process. There are many things that have not been done.

[One point to be solved by the invention] 11 (Now, Figures 2 and 6 show examples of a discharge lamp lighting device that lights a discharge lamp by utilizing the series resonance of an inductive element, a capacitive element, and a child. This will be explained with the help of diagrams. Figure 2 shows the basic circuit configuration of the discharge lamp lighting device. 1 is the power supply, 2 and 3 are resonance capacitors 1, 56 is the discharge lamp, and 4 and 5 are the Make the electric light 6 series resonance.

It consists of an inductive element and a capacitive element for lighting.

This is a choke and a capacitor. 7. .

Half-bridge circuit with 8 series resonant circuits in between.

This is the switching element 25 that makes up the circuit.

This is a drive circuit for the switching cables 7 and 8. child.

The discharge lamp lighting device configured as shown above can start discharging the discharge lamp 6 with the voltage obtained by series resonance. In addition, at this time, a discharge lamp.

4. Choke during the period until the discharge of 6 starts.・Condens'+j5. How many times is the load including discharge lamp 6.

The path can be represented as shown in FIG.

Here, the resonant frequency of the load (a series resonant circuit including a choke 4, a capacitor 5°, and a discharge lamp 6) is ・fo, and the end tube voltage of the discharge lamp 1l16 that starts the discharge of the discharge lamp 6 (the terminal voltage of the capacitor 5 ) The oscillator station of the switching cables 7, 8 to obtain 9to.

If the wave number is F, the end tube voltage h? 0 and oscillation frequency.

The relationship between y is shown in FIG. Namely.

In Figure 4, the horizontal axis represents the oscillation frequency F, and the vertical axis represents the end tube voltage.

This shows the rooting frequency of the conventional device.

Since the number F is always fixed, turn on power 1.

Then, the end tube voltage 2fgo is immediately applied to the discharge lamp 6.

is applied, and the discharge of the discharge lamp begins.

Become. However, the fact that the rated end tube voltage of 2° is applied at the same time as the power is turned on causes the discharge lamp 6 to fail.

Since discharge may start in a state close to the initial start, it becomes difficult to extend the life of the discharge lamp 6.

SUMMARY OF THE INVENTION An object of the present invention is to provide a discharge lamp lighting device that can prevent the discharge lamp 6 from starting cold and extend the life of the discharge lamp.

[Means for solving problems]

The object of the present invention is to supply an appropriate direct end tube voltage to an IC discharge lamp by utilizing the movement of the series resonance point.

This is achieved by

[Effect]

That is, the present invention skillfully utilizes the characteristics of the series resonance of the load to start the discharge lamp at an oscillation frequency of 1° away from the series resonance point of the load, and as the starting progresses.

As the oscillation frequency moves toward the resonance point,

According to the present invention, a discharge lamp is preheated to obtain a high end tube voltage for starting discharge.

Discharging can be started after sufficient 2°, 6
.

Ru.

〔Example〕

An embodiment of the present invention will be described below with reference to FIG.

In this embodiment, as already explained in FIG. 2, a series resonant load is basically driven by a bar bridge circuit. In other words, it is a control IC that obtains the PWM signal that forms the core of the drive circuit for controlling the 10 switching elements 7 and 8.
494 etc. are used. In this control work C10,
A sawtooth oscillator whose oscillation frequency can be set arbitrarily, various comparators, error amplifiers, and constant voltage power supplies.

It is designed to invert the output of the internal transistor 1 and the transistor at a frequency determined by the time constant circuit connected to terminals A and B (individual internal transistors have a frequency determined by the time constant 4).

It consists of

Continuing the explanation further, 9 is a switching element.

5.1 is the pulse transformer that drives the children 7 and 8.
4.

The input side is connected to the internal transformer of the control IC, and the output side is connected to the respective base circuits of switching elements 7 and 8. The series circuit is a constant voltage power supply circuit for obtaining power for driving the control/utility C10, and the series circuit of capacitor 14 and resistor 13, and the resistor connected in parallel with this circuit, are as follows:
This is for changing the oscillation frequency of the control IC 1o, and the diode 1 connected to one end of the capacitor 14
5 is for discharging the charge of the capacitor 14 when the light is turned off, and is Il+.

Now, before moving on to the explanation of the operation, let's use an example.

How to set the oscillation frequency f of the control ICI Q.

explain about. To the A terminal of this control device C10.

is a resistor (hereinafter referred to as RT), and the B terminal, 5
Each has a capacitor (hereinafter referred to as G).

A capacitor connected to the B terminal of and.

CT is determined by the value of the resistor RT connected to the A terminal.

The battery is charged with a constant current determined by stop.

So, is the control equipment C10 a condenser fc? When the charging voltage reaches a predetermined voltage, this charge is discharged and the 1° cycle is completed. At this time, the control equipment (oscillation frequency of 10.
teeth.

/ #1 / RT and CT, but the actual oscillation frequency F of the switching elements 7 and 8 is Fζt/2 since these are putnoble operations.

In this example, such characteristics are utilized 1 (.
Is the current flowing through resistor RT when power supply 1 is turned on?

(isometrically, it is the same as increasing the resistance of resistor RT) to change the oscillation frequency.

It is something that makes you change your mind.

Next, the operation of the embodiment configured as described above will be explained. First, when power 1 is turned on.

The potential of the capacitor 14 is determined by a resistor connected in series with the capacitor 14.

It gradually increases due to the time constant with resistor 13. Therefore,
The current flowing through the resistor 13 will gradually decrease. For this reason, the resistor R seen from the A terminal of the control circuit C10
The change in the oscillation frequency F corresponding to the time change in T is as shown in FIG. In other words.

The oscillation frequency F of the control mechanism C10 starts from the start-up frequency F1 and changes toward the start-up completion frequency F2.

, and settles at the starting completion frequency Fy.
#j/RT, CT F2 1/RT, CT However, at the initial stage of startup, the charging current of the capacitor 14.

flows, so the resistance of resistor RT is equal to resistance 12.

This is the value of 13 combined resistances. 'Also. When starting is completed, the charging current of the capacitor 14 decreases, so the resistor R
The directivity of T is equal to the value of resistor 12.・Changes in the end tube voltage vro of the discharge lamp 6 at this time are shown in FIGS. 6 and 7. In this embodiment, when the power supply 1 is turned on, the oscillation of the control C10 is sufficiently far away from the series resonance frequency 10 of the load 1 (both series).

(sufficiently higher than the oscillation frequency fo) start-up starting frequency F+.

, and gradually lower the oscillation frequency F.

At the starting completion frequency F2 which is higher than the resonant frequency IO.

The constants for each circuit are selected to ensure peace of mind. 2゜・
7 - In this embodiment, the starting completion frequency F? Sufficient consideration is given to the setting of 5 constants so that the value does not become too close to the resonance frequency of 10. This is because if the load is operated at the series resonance point, the load current/current may rise beyond the rated value. Adding a slight explanation to Fig. 7, since the starting frequency F+ is far away from the series resonance frequency IO, the end tube voltage of discharge lamp 6 at this time is as small as 1 oscillation frequency F.
・As the series resonant frequency approaches 711, the end tube voltage becomes
1. .

It rises at pea-7. During this process, discharge lamp 6 is removed.

The preheating of the second lamp is sufficient and the discharge lamp 6 is turned off.

Discharge starts when the tube voltage reaches 1 pto.

It becomes. After the discharge lamp 6 starts discharging, this end tube voltage decreases to the discharge voltage. 1. When the discharge lamp 6 is turned on and the power source 1° is disconnected, the charge on the capacitor 14 becomes diode.

- It is discharged through the power cord 15, and preparations are made for the next start.

It will be called.

Next, the embodiment shown in FIG. 8 will be described. This 2°, 8
.

In the embodiment, a current transformer 19 is installed in the load circuit,
The aim is to obtain an appropriate oscillation frequency F in accordance with the load current and in accordance with each process of the starting state (operating state). That is, in this embodiment, the load starting completion frequency F
2 is set to an oscillation frequency F that is even lower than the series resonant frequency ``IO.'' This is explained in Fig. 9 as follows: ・Start completion frequency Fy (Series resonant frequency 10 ・〈Start start frequency 1・There is a relationship. 11)
Now, the current signal taken out by the current transformer 19 is full wave rectified by the diode bridge 20.

It is divided into a series circuit consisting of resistor 22 and resistor 23.

be pressured. A transistor 21 whose base is connected to the aforementioned voltage dividing circuit is connected to the A terminal of the control circuit C10. This transistor 21 has a lamp current ratio of 1.

It is introduced only during the preheating period of the discharge lamp 6 where the flow is relatively large.

The resistors 22, 25 . and.

Circuit constants such as the resistor 24 are selected.

The operation of such an embodiment will be explained below. .

On the flow side as well, the control I (1Q
The oscillation frequency F gradually decreases from the starting frequency F+. At the same time, huh.

Due to the increase in pump current (preheating current), transistor 21
conducts, and the apparent resistance value of the A terminal of the control IC 1o decreases in accordance with the lamp current. - Therefore, the oscillation frequency F of the control mechanism C10 is - separated from the series resonance frequency io of the load, starts from a starting start frequency F1 higher than this, and gradually approaches the series resonance frequency IO. However, as the load current increases as it approaches the series resonance point, the transistor

Since the resistance value of the oscillation frequency F decreases, the decrease in the oscillation frequency F slows down and is temporarily balanced at a frequency F'2, for example, which is closer to the series resonance frequency /II than the starting frequency F1. In this state, preheating of the discharge lamp 6 is completed and discharged.

When the shift starts, a transition occurs due to the decrease in load current.

The star 21 becomes non-conductive. Then, from the A terminal.

The apparent resistance value will increase significantly.

Therefore, the oscillation frequency F of the control mechanism C10 is as follows.

When the local wave number fo is exceeded, F suddenly becomes low, and the start is completed and the frequency settles down to Fz.

In this way, in the embodiment, the current transformer 19
By providing the transistor 21, the circuit 5 can continue to operate at an oscillation frequency F that is safe for the operation of the circuit 5 during preheating of the discharge lamp 6 and even after completion of preheating.

Now, with reference to FIGS. 10 to 12, the explanation regarding the selection of circuit constants for this embodiment will be continued. Implementation/Example:
For those that drive a load using the series resonance of an inductive element and a capacitive element, operation.

When the frequency matches the resonant frequency, excessive current flows.

This may cause damage to the circuit or load.

Ru. Therefore, consider variations in each circuit component.

Taking this into account, sufficient care must be taken when setting the oscillation frequency. In addition, the ambient temperature increases and electricity increases.

Continues safe operation even in the event of a drop in power supply voltage.

It must be something that can be done. First, Figure 10.

Looking at the temperature characteristics of C10 for control 5, as the temperature rises from room temperature, the oscillation frequency decreases.

, 116. That is, if the starting completion frequency Fl is selected to be lower than the series resonance frequency 11.

If the ambient temperature increases, its oscillation frequency F will become further apart from the series resonant frequency fa.

The heat generation of the circuit itself is suppressed, and at the same time, destruction of the circuit can be prevented. Next, used in the example.

The weld control work C10 is a conte connected to the B terminal.

The sensor CT is charged with a constant current, and the charging voltage is within.

This charging occurs when the voltage reaches a certain value.

The charge is discharged and a triangular wave is generated at this B terminal, which is the reference voltage that is the basis of this constant current charging.

As shown in FIG. 11, the voltage decreases as the power supply voltage Vcc decreases. Therefore, when the power supply voltage Vcc decreases, the charging time of the capacitor CT increases, and as a result, the control IC
The oscillation frequency F of 10 decreases. -1, that's a big deal. That is, if the starting completion frequency Fy is selected to be lower than the series resonance frequency IO, the discharge lamp 6 can continue to be lit safely even when the power supply voltage drops. In either case, if the oscillation conditions of the example are satisfied, series resonance and
It is possible to avoid operation at the 12φ point and safely light the discharge lamp 6.

Next, another embodiment shown in FIG. 13 will be described.

In this embodiment, the starting frequency F1 is shown in FIG.

As shown, five positions sufficiently distant from the series resonance frequency fO are selected, and the discharge lamp 6 is lit by increasing the starting completion frequency F7 to a position closer to the series resonance frequency. That is, a capacitor 14 is connected between the A terminal of the control ICIQ and the power supply, and when the power is turned on, the apparent resistance value of the A terminal is 10, which gradually decreases from a high value as shown in Figure 15. Let's go. Accordingly, the oscillation frequency F of the control IC 1o increases from the startup start frequency F1 to the startup completion frequency Pp, and the discharge lamp 6 is preheated and lit.・The diogorado 25 connected in series with the capacitor 14 is used to prevent discharge of the capacitor 14, and the resistor 26 connected in parallel with the capacitor 14 is used to prevent discharge of the capacitor 14.

When the power supply is disconnected, the charge in the capacitor 14 is discharged,
This is to prepare for the restart.

Also in this embodiment, starting completion frequency F? If b2゜ is selected to be lower than the series resonant frequency 7o within the range that ensures safe operation, the actual Safe operation is ensured even in the face of fluctuations.

Of course, in the above embodiments as well, the discharge lamp 6 starts lighting after the discharge lamp 6 has been sufficiently preheated.
It is possible to continue lighting stably and gradually without shortening the service life of the lamp. Also, turn on the power.

At startup, operation begins at a frequency of 1°, which is sufficiently far away from the load's series resonance point, so the rack is in the initial stage of startup.

It is also possible to prevent the occurrence of double current. According to experiments conducted by the inventors, it is important to select circuit constants so that the preheating time from turning on the power to turning on the lamp is about 0.8 to 1 second.゜It turned out to be preferable.

〔Effect of the invention〕

As explained above, the present invention provides a lighting device that lights a discharge lamp by using series resonance between an inductive element and a capacitive element, and the oscillation frequency of the lighting device is increased during the period from power-on until the discharge lamp is lit. .

Perform sufficient preheating by changing the number.

The discharge lamp is then turned on. According to the invention, therefore, the discharge lamp is in ideal conditions.

Can be lit, which is advantageous for the lifespan of discharge lamps.

This is the result.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 illustrates one embodiment of the present invention. Figure 2 is a circuit diagram of a conventional lighting device. Figure 3 shows the equivalent circuit with a load of 1° for the discharge lamp in Figure 2 to start discharging, and Figure 4 shows the circuit for the discharge lamp in Figure 3. Shows the relationship between local wave number and secondary voltage (end tube voltage). Figures 5, 6, and 7 are diagrams for explaining the operation of the embodiment shown in Figure 1, respectively; Figure 1 is a circuit diagram showing another embodiment of the present invention; , Figure 59, Figure 10,
11 and 12 are diagrams for explaining the operation of the embodiment shown in FIG. 8, FIG. 13 is a circuit diagram showing still another embodiment of the present invention, and FIGS. 14 and 15. 16 are diagrams for explaining the operation of the embodiment shown in FIG. 16, respectively. ,?・ 15・ 1... Power supply 4... Inductive element 5...
・Capacitive element 6...Discharge lamp F...Oscillation frequency.

Claims (1)

[Claims] A lighting device for lighting a discharge lamp using series resonance of an inductive element and a capacitive element, characterized in that the oscillation frequency of the lighting device is changed during a period from when the power is turned on until the discharge lamp is lit. discharge lamp lighting device.