JPS6210000B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is designed to turn off the discharge lamp when it enters the half-wave discharge state at the end of its life, thereby preventing any inconvenience caused by the continuation of the main-wave discharge state. The present invention relates to a discharge lamp lighting device.

The present applicant has proposed that in a device in which a discharge lamp is first energized by the output of an inverter, when the discharge lamp enters a half-wave discharge state, an abnormal voltage based on this half-wave discharge state is detected and the inverter is activated. An application was filed for suspension (Japanese Patent Application No. 1984-94884). Since this can reliably prevent the discharge lamp from continuing half-wave discharge, it can ultimately prevent abnormal heat generation of circuit components and damage to the discharge lamp tube wall.

The present invention was developed in consideration of the fact that in the above-mentioned device, the state changes and the detection signals vary until the discharge lamp stably lights up when the power is turned on. It is an object of the present invention to provide a discharge lamp lighting device that does not stop power supply to a discharge lamp even when abnormal voltage is detected, and does not cause the discharge lamp to undesirably go out. It is something.

The present invention provides a method for stopping the energization of a discharge lamp by an abnormal voltage based on the half-wave discharge state when the discharge lamp temporarily enters a half-wave discharge state before stable lighting at the time of startup. This is characterized by the provision of a timer.

Hereinafter, one embodiment of the present invention will be described with reference to FIGS. 1 and 2.

Reference numeral 1 denotes a power source, which includes, for example, a commercial AC power source 2 and a rectifier 3 for rectifying the output of this power source 2. However, this power source 1 can be a battery. Reference numeral 4 denotes a high frequency generator, such as a transistor inverter, which is connected to the power source 1. In this embodiment, for example, a push-pull type inverter is used, including a pair of transistors 5 and 6, an inverter transformer 7,
It is mainly composed of a resonance capacitor 8, and is provided with a constant current inductor 9 on the input side, and outputs a high frequency AC voltage of, for example, 20 to 40 KHz. one pole of the power supply 1 and the transistor 5,
Resistors 10, 11, 12 and a diode 13 are provided between the base of the motor and the base of the motor 6 for supplying base current at the time of starting. Further, the inverter transformer 7 is provided with a base winding 14, which is connected to the bases of the transistors 5 and 6, respectively. Further, the inverter transformer 7 is provided with a feedback winding 15, and the output of the feedback winding 15 is passed through a rectifying/smoothing circuit 16 to the transistors 5,
6. I try to supply it to each base.
That is, the transistor inverter in this embodiment is supplied with base current through the resistors 10, 11, 12 and diode 13 at the time of starting, and is supplied with base current mainly by the output of the feedback winding 15 after starting. It is. Reference numeral 17 denotes a load such as a discharge lamp connected to the secondary winding 18 of the inverter transformer 7, and is energized by the high frequency alternating current power of the high frequency generator 4, which is the transistor inverter, to turn on. 19 and 20 are windings provided in the inverter transformer 7 for heating the electrodes of the discharge lamp. In this embodiment, the inverter transformer 7 has a leakage inductance between the primary winding 21 and the secondary winding 18, and this leakage inductance is used for the stabilization device of the discharge lamp, which is the load 14. There is.

22 is a detection device. This detection device 22 detects an abnormal voltage based on the half-wave discharge state when the discharge lamp 17 enters the half-wave discharge state. For example, the inverter transformer 7 includes a detection winding 23, and the output of the detection winding 23 is inputted to an input terminal of a rectifier 26 via a capacitor 24 and an inductor 25. An impedance element 27 is provided between the output terminals of the rectifier 26, and a detection signal is output from both ends of the impedance element 27.

Next, 28 is a control device, and the detection device 22
The energization of the discharge lamp 17 is substantially stopped by the detection signal from the discharge lamp 17, and the discharge lamp 17 is turned off. In this embodiment, a three-terminal thyristor 29 is provided between the output terminals of the rectifier/smoothing circuit 16 provided in the feedback winding 15, and a capacitor 30 and a resistor 31 are provided between the gate and cathode of this thyristor 29. , a transistor 32 whose emitter is connected to the output terminal of the detection device 22 and whose collector is connected to the gate of the thyristor 29, and a resistor 33 provided between the base of this transistor 32 and the base resistor 10.
It consists of. Such a control device 28
In this case, if a predetermined time has elapsed after the power source 1 is turned on, the voltage across the capacitor 30 increases in accordance with the magnitude of the detection signal from the detection device 22, and the three-terminal thyristor 29 This is what turns on the . By turning on the thyristor 29, the base current supply path between the output terminals of the rectifying/smoothing circuit 16 of the feedback winding 15 and the base resistors 11 and 12 via the base resistor 10 is short-circuited, and the transistor inverter is substantially As a result, the discharge lamp 17 becomes inoperable and cannot be energized.

34 is the timer. This timer 34
The control device 28 is made inactive for a predetermined period of time after the power source 1 is turned on at the time of starting. In this embodiment, a time constant circuit 35 provided between the output terminals of the power supply 1 via the inductor 9;
a resistor 36 and a transistor 37 provided between the base of the transistor 32 of the control device 28 and the negative electrode of the power supply 1; a Zener diode 38 provided between the base of the transistor 37 and the voltage dividing point of the time constant circuit 35; It consists of The transistor 37 is not turned on until the potential at the voltage dividing point of the specific circuit 35 reaches the conduction voltage of the Zener diode 38, and therefore,
Since the transistor 32 of the control device 28 is never turned on, the control device 28 can be made inactive for a predetermined period of time until the potential at the voltage dividing point rises.

Next, the effect will be explained. Now, when the power source 1 is turned on using a switch (not shown), the transistor inverter as the high frequency generator 4 is activated, outputting a high frequency AC voltage of 20 to 40 KHz to preheat the electrodes of the discharge lamp 17 and to heat the secondary winding. 18 output voltages are applied. In the initial stage of startup, that is, in the no-load state, the oscillation frequency of the transistor inverter is determined by the relationship between the primary winding of the inverter transformer 7 and the resonance capacitor 8, and is set relatively low compared to the time of lighting, which will be described later. Then, the output voltage of the detection winding 23 is as shown in FIG. 2a. One cycle of the high frequency AC voltage shown in FIG. 2a is shown in FIG. 3a. At this time, the output voltage of the detection winding 23 is considerably large corresponding to the no-load voltage, but the capacitor 2 connected in series with the detection winding
4 has a relatively large impedance value with respect to the frequency under no load, and the detection output by the detection device 22 does not reach a value that can operate the control device 28. Next, due to its characteristics, the discharge lamp 17 goes through a half-wave discharge state and stably lights up. At this time, the output voltage of the detection winding 23 in the half-wave discharge state becomes that of FIG. 2b, which is an enlarged diagram of one cycle. is shown in Figure 3b. That is, when the discharge lamp 17 enters a half-wave discharge state, the oscillation frequency of the inverter is determined by the relationship between the resonance capacitor 8, the secondary winding 18 of the inverter transformer 7, and the leakage inductance, and This is set relatively high. Further, as is clear from FIG. 3b, the inverter transformer 7 is subjected to biased magnetization due to the half-wave discharge state of the discharge lamp 17, and a peak voltage is generated. Therefore, the detection device 2
2, the capacitor 24 has a relatively small impedance value, and the output detection signal becomes large. Therefore, the control device 28 attempts to turn on the three-terminal thyristor 29.

Here, in the timer 34, when the power supply 1 is turned on, the time constant circuit 35 starts charging, and the voltage at the voltage dividing point gradually increases. The transistor 37 is off before the potential at the voltage dividing point reaches the conduction voltage of the Zener diode 38. Therefore, during this period, the three-terminal thyristor 29 of the control device 28 is never turned on no matter what detection signal is input from the detection device 22.
That is, if the time required for the Zener diode 38 to turn on is set longer than the time required for the discharge lamp 17 to transition to stable lighting after passing through a half-wave discharge state at startup, the control device 28 can control the discharge lamp 17. It does not operate depending on the half-wave discharge state at the time of startup. In reality, for example, the time it takes for a 40W fluorescent lamp to turn on stably at startup is
Since this is about 0.1 to 1 second (at an ambient temperature of 25° C.), it is sufficient to set the time of the timer 34 to be slightly longer than this. When the discharge lamp 17 shifts to stable lighting,
The output voltage of the detection winding 23 is as shown in FIG. 2c and FIG. 3c, which are relatively small voltage values and do not operate the control device 28. When the discharge lamp 17 reaches the end of its life and enters a half-wave discharge state, as shown in FIG. 2b,
Since the voltage shown in FIG. 3b is detected and the transistor 37 of the timer 34 is on at this time, the control device is actuated by the detection signal and deactivates the transistor inverter. Note that when there is no load, such as when the discharge lamp 17 is removed, the detection signal of the detection device 22 cannot reach the value that activates the control device 28, as described above, and the control device 2
8 does not work. However, depending on the setting of constants, it is also possible to operate the control device 28 even when there is no load, and the present invention also includes this.

In this embodiment, since the power supply 1 outputs a pulsating DC voltage, the three-terminal thyristor 29 is turned off every half cycle. Therefore, although the discharge lamp 17 is supplied with power at the beginning of each half cycle, the peak voltage due to the half-wave discharge is detected and the lamp is immediately extinguished, so that the discharge lamp 17 cannot substantially continue the half-wave discharge state. Moreover, there is no problem even if there is a momentary half-wave discharge in the initial stage.
Further, it is also possible to easily maintain the control function of the control device 28 if necessary. That is, by providing appropriate capacitors at both ends of the three-terminal thyristor 29, it is possible to keep the thyristor 29 turned on. However, in view of the fact that when a discharge lamp in a half-wave discharge state is converted into a normal discharge lamp, the power must be turned off once, the above-mentioned embodiment is preferable.

FIG. 4 shows another embodiment of the invention. FIG. 4 shows only the parts that are different from FIG. 1, and other parts are omitted. In this embodiment, discharge lamps 40 and 41 are lit in parallel via a balancer 42. Therefore, inverter transformer 4
3 has a filament transformer 44 added thereto. Further, the detection winding 45 is provided in the inverter transformer 43 as in FIG. The other configurations and operations are the same as those of the first illustrated embodiment, so their explanations will be omitted. In addition, in the embodiment, the detection winding 4
5 may be magnetically coupled to the balancer 42.

FIG. 5 shows still another embodiment of the present invention. In this embodiment, the same parts as in FIG. 1 are given the same reference numerals, and their explanation will be omitted. In this embodiment, the timing device 50 is provided on the output side of the detection device 22. That is, it consists of a time constant circuit of a resistor 51 and a capacitor 52 provided between the output terminals of a detection device 22 constructed similarly to that of the first illustrated embodiment. On the other hand, the control device 53 in this embodiment is a three-terminal thyristor 5 provided between the output terminals of the rectifying/smoothing circuit 16 of the feedback winding 15.
4, a resistor 55 and a transistor 56 provided between the anode and gate of the thyristor 54, a resistor 57 provided between the gate and cathode of the thyristor 54, the base of the transistor 56, and one of the capacitors 52 of the timer 50. A resistor 58 is provided between the terminals of the resistor 58.
In this embodiment, even if the discharge lamp 17 enters the starting half-wave discharge state and the detection device 22 outputs a detection signal based on half-wave discharge, the timing device 50 prevents this detection signal from continuing for a predetermined period of time. Otherwise, the control device 53 will not be activated, so by appropriately setting the constant of the timer 50, the control device 53 can be prevented from being activated depending on the half-wave discharge state at the time of starting. The other functions are the same as those of the first illustrated embodiment, so their explanation will be omitted. However, in this embodiment, when the discharge lamp 17 enters a half-wave discharge state during lighting, even if the detection device 22 detects this, the time until the control device 53 operates is longer than that shown in the first figure. It is longer than other things.

Note that the present invention is not limited to the above embodiments. For example, high frequency generators are
Anything such as a thyristor inverter will do. Further, the detection device may be of any type as long as it can detect abnormal voltage during half-wave discharge of the discharge lamp, and its configuration can be modified in various ways. Furthermore, the control device may have other switching elements instead of the three-terminal thyristor. The configuration can be modified in various ways depending on the relationship with the detection device or the timer. Furthermore, the timer may be any device that can deactivate the control device for a predetermined period of time after power is turned on.

As detailed above, the present invention provides a detection device that detects abnormal voltage associated with the half-wave discharge state when the discharge lamp enters the half-wave discharge state, and a detection signal from the detection device that stops the energization of the discharge lamp. In a device equipped with a control device that causes
The control device does not operate in the half-wave discharge state that occurs before the discharge lamp shifts to stable lighting at startup, and the discharge lamp can be started reliably.

[Brief explanation of the drawing]

Figure 1 is a circuit diagram showing one embodiment of the present invention, Figure 2 is a circuit diagram showing an embodiment of the present invention.
3 and 3 are voltage waveform diagrams for explaining the operation, and FIGS. 4 and 5 are circuit diagrams showing other embodiments of the present invention. 1...Power supply, 4...High frequency generator, 17,40,
41... Discharge lamp, 22... Detection device, 28, 53... Control device, 34, 50... Time limit device.

Claims (1)

[Claims] 1. A power source, a high-frequency generator supplied with power from the power source, a discharge lamp energized by the output of the high-frequency generator, and detecting abnormal voltage during half-wave discharge of the discharge lamp. a control device that substantially stops energization of the discharge lamp by the high-frequency generator based on a detection signal from the detection device; and a control device that makes the control device inactive for a predetermined period of time from when the power is turned on. A discharge lamp device characterized by comprising a timer device. 2. The discharge lamp lighting device according to claim 1, wherein the high frequency generator is a transistor inverter. 3. The discharge lamp lighting device according to claim 2, wherein the control device limits the base current of the transistor inverter. 4. The discharge lamp lighting device according to any one of claims 1 to 3, wherein the timer is provided in the control device and is activated when the power is turned on. 5. Any one of claims 1 to 3, wherein the timer is provided at an output end of the detection device and outputs the detection signal when the detection signal of the detection device continues for a predetermined period of time. The discharge lamp lighting device according to (1) above.