JPS61240595A - 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 [Technical field to which the invention pertains] The present invention relates to a discharge lamp lighting device that lights a discharge lamp at high frequency using an inverter.

[Prior art and its problems]

FIG. 1 shows an example of a conventional high frequency lighting circuit. In this system, a rectifier circuit 2 is connected to an AC power supply 1 to obtain a pulsating output by full-wave rectification of AC, which is converted into a smoothed DC output via a smoothing circuit 3. Thereafter, the current is applied to the primary winding of the transformer 7 via the constant current inductor 4 and the push-pull connected transistor 5.6. By connecting the feedback winding 8 to the base @ wires of the transistors 5 and 6, the transistors 5 and 6 are alternately turned on and off, and a high frequency voltage is generated in the secondary winding of the transformer 7, causing radiation. Electric light 9 lights up. 10 in the figure. ! 1 is the base resistance, 12
is a capacitor.

However, in such a lighting device, even when the discharge lamp 9 malfunctions or when the discharge lamp is not connected to the secondary side of the transformer 7, the high frequency oscillation operation continues, and the secondary side of the transformer 7 A high frequency and high voltage is continuously generated on the side. For this reason, it is dangerous to the human body and sometimes causes dielectric breakdown of the secondary wiring. Further, in this type of discharge lamp lighting device, a half-wave discharge may occur due to a decrease in rectification that occurs as a prelude to a malfunction at the end of the life of the discharge lamp 9. In such a state, the input power of the discharge lamp lighting device increases, which is not preferable from the viewpoint of reliability.

[Purpose of the invention]

The present invention solves the above-mentioned drawbacks, and when the discharge lamp is in an unloaded state where it is not connected due to a malfunction or when the discharge lamp current abnormally decreases at the end of its life, the high-frequency oscillation operation is stopped and the user is notified of the malfunction of the discharge lamp. It is an object of the present invention to provide a discharge lamp lighting device having a function of notifying the state.

[Structure and operation of the invention]

An embodiment of the present invention will be described below with reference to FIG. The difference from FIG. 1 is that a transistor 13 is connected on the main circuit. In this conductive state of the I transistor, the circuit operation of FIG. 2 is basically the same as the circuit shown in FIG. 1, and a high frequency voltage is applied to the discharge lamp 9. On the other hand, when the transistor 13 is in the cutoff state, the transistors 5 and 6 are also in the cutoff state, the oscillation operation is stopped, and high frequency voltage is not applied to the discharge lamp.

Now, when the AC power supply 1 is turned on, the capacitor 14 is gradually charged through the resistors 15 and 16.

Therefore, the base current of the transistor 13 flowing through the resistor 17 also gradually increases. As the base current increases, the voltage between the collector and emitter of the transistor 13 also gradually decreases from the output voltage of the rectifier circuit 2, and finally reaches its saturation voltage value. Furthermore, while the base current of the transistor 13 gradually increases and reaches a certain value, the voltage between the positive electrode side of the output of the rectifier circuit and the collector of the transistor 13 gradually increases, and the voltage generated in the primary winding of the transformer 7 also increases. Gradually increases from O. The voltage applied to the discharge lamp 9 connected to the secondary side of the transformer 7 can also be gradually increased. Therefore, during the time until the secondary voltage of the transformer 7 reaches the starting voltage of the discharge lamp 9, a preheat current is passed through the preheat windings 18 and 19 to the discharge lamp 9, thereby preventing a cold start.

Next, when the discharge lamp 9 starts, a voltage corresponding to the magnitude of the discharge lamp current is induced in the secondary winding of the current transformer 20 provided in a part of the secondary winding of the transformer 7. .

This voltage is rectified by diode 21 and charges capacitor 22. If the lighting state of the discharge lamp 9 is normal,
The silicon bidirectional switch (hereinafter referred to as SBS) 23 breaks over due to the voltage of the capacitor 22 and becomes conductive, and a base current flows through the transistor 25, making it conductive. Then, the base current and collector current of the transistor 25 flow as the base current of the transistor 26, and the transistor 26 becomes conductive. At this time, the transistor 26 is designed to operate in saturation with only the base current of the transistor 25. transistor 2
6 operates in saturation, the voltage between its collector and emitter is lower than the on-voltage of the light emitting diode 27, so the current flowing from the output of the rectifier circuit 2 through the resistor 2 is:
flows into the collector of transistor 26.

Therefore, the light emitting diode does not emit light.

On the other hand, when the discharge lamp is malfunctioning or abnormally lit with a decrease in current, the voltage of the capacitor 22 does not reach the voltage that causes the 5BS23 to break over, and the SB323 remains in the cut-off state. In such a case, the transistor 25 is in a cut-off state, and the transistor 26 is also in a cut-off state without being supplied with base current. Therefore, the current flowing from the output of the rectifier circuit 2 through the resistor 28 flows through the light emitting diode 2.
7 and the light emitting diode 27 emits light.

That is, the light emitting diode 27 does not emit light when the discharge lamp 9 is normally lit, but emits light when it is malfunctioning or abnormally lit with a decrease in current.

Next, the capacitor 29 is gradually charged by flowing through the resistor 30 at the same time as the AC power supply 1 is turned on, and eventually the 5BS31 breaks over and becomes conductive, and from then on, the AC type +1!
The conductive state is maintained until 1 is turned off. 5BS31
The current flowing through the resistor 32 flows into the diode 33 or the collector of the transistor 25. Now 5B
If the lamp is normally lit at the moment S31 breaks over, transistors 25 and 26 are conductive. Since diodes 33 and 34 are connected in series to the base of transistor 35, the current flowing through 5BS31 flows toward the collector of transistor 25, and since transistor 26 is conductive, light emitting diode 27 does not emit light. Furthermore, since no base current flows through the transistor 35, the transistor 1 is in the cut-off state.
A base current is supplied to the discharge lamp 9 to maintain the conductive state, and a high frequency voltage is applied to the discharge lamp 9 to continue lighting it.

On the other hand, at the moment when the 5BS 31 breaks over after the AC power supply 1 is turned on, the transistor 25 is in a cut-off state when the discharge lamp 9 malfunctions or is abnormally lit with a decrease in current.

The current flowing through 5BS31 flows to the base of transistor 35 through diodes 33 and 34, and the current flows to the base of transistor 35.
5 is in a conductive state. When transistor 35 becomes conductive, transistor 1
The current flowing to the base of transistor 3 flows to the collector of transistor 35, and transistor 13 becomes cut off. Then, the high frequency oscillation operation stops, and no high frequency voltage is applied to the discharge lamp 9.

After the transistor 13 is cut off, the discharge lamp 9
Although high frequency voltage is no longer applied to transistor 25,
．． 26 is the light emitting diode 2 to maintain the cutoff state.
The lamp 7 continues to emit light until the AC power source 1 is turned off, and continues to notify the abnormality of the discharge lamp.

The explanation so far is that after AC power supply 1 is turned on, 5B
The operation during the time until S31 reaches breakover has been described. Next, until 5BS31 breaks over after the electric harp is cast, the discharge lamp 9 lights up normally and 5B
After the breakover in S31, the discharge lamp 9 is malfunctioning or
A case where an abnormal lighting state occurs with a decrease in current will be explained. In such a case, 5BS31 has already broken over and the discharge lamp 9 has been in a normal lighting state until then, so 5BS23 is in a conductive state and transistors 25.
26 is also in a conductive state. Therefore, the light emitting diode 27 is not emitting light. Now, if the discharge lamp 9 malfunctions or becomes abnormally lit due to a decrease in current for some reason, the voltage induced in the secondary winding of the current transformer 20 decreases, and the current flowing through the 5BS 23 becomes less than the holding current. 5BS
23 is in a cutoff state.

Then, 5BS31. Transistor 2 through resistor 32
The current flowing into the collector of diode 33
．． The light flows through 34 to the base of transistor 35, and at the same time transistor 35 becomes conductive, light emitting diode 27 emits light. No base current flows through the transistor 13, the transistor 13 is cut off, the high frequency oscillation operation is stopped, and no high frequency voltage is applied to the discharge lamp 9.

In this case as well, the light emitting diode 27 continues to emit light until the AC power supply 1 is turned off, and continues to notify the abnormality of the discharge lamp.

As mentioned above, if the time required for the SBS 31 to break over after turning on the AC power supply 1 is set to a time sufficient for the discharge lamp to pass through the preheating stage and then start (for example, 1 second), the discharge lamp can be started. without cold start,
In addition, in the event of a malfunction or abnormal lighting accompanied by a decrease in current, the application of high frequency voltage to the discharge lamp 9 can be immediately stopped, and an abnormality can be notified. Furthermore, even if the voltage value of the AC power supply 1 drops in a short period of time due to some reason, if the capacitance of the capacitor 22 is appropriately selected, the 5BS23 will maintain its conductive state even during the voltage drop period, and the light will turn on. The device continues to operate normally.

In the embodiment shown in FIG. 2, the present invention is applied to lighting a discharge lamp that requires filament preheat, but it can also be applied to a discharge lamp that does not require filament preheat, such as the HID light source of the present invention. be. FIG. 3 shows an embodiment in which the present invention is applied to lighting an 1110 light source. The difference from Figure 2 is a capacitor 14 and a resistor 1 for preheating time setting.
7 and the residual heat winding 18°19 provided in a part of the secondary winding of the transformer 7 are unnecessary.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to stop the discharge lamp in any case where it is malfunctioning or in abnormal lighting accompanied by a decrease in current, and to notify the user of the abnormality. As a result, insulation breakdown of the power distribution line and danger to the human body are reduced, and the life of the lighting device itself is extended.In addition, the abnormality alarm function allows the user to quickly learn of any abnormality in the discharge lamp.

Further, the present invention is effective not only for lighting discharge lamps for general lighting but also for lighting germicidal lamps that sterilize food, water, etc. using ultraviolet rays emitted from discharge lamps. When lighting this type of discharge lamp, the discharge lamp is covered with a shielding material such as metal for the purpose of increasing sterilization efficiency and protecting the human body, and its lighting condition can be checked with the naked eye like a discharge lamp for general lighting. It is difficult to confirm.

Further, in this type of discharge lamp, it is necessary to notify or restore the lamp while it is still in an abnormal lighting state with a malfunction or current reduction, but the above-mentioned problems can be solved by the present invention.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram showing an example of a conventional high-frequency lighting device, and FIG. 2 is a circuit diagram showing an embodiment of a discharge lamp lighting device according to the present invention. FIG. 3 is a circuit diagram showing another embodiment of the present invention.

Claims (1)

[Scope of Claims] 1. A discharge lamp lighting device comprising a rectifier circuit inputting an AC power source, an inverter circuit converting the DC output to a high frequency, and a discharge lamp energized by the output of the inverter circuit, the above-mentioned When the discharge lamp is malfunctioning or is lit abnormally with a decrease in current, a switch provided on the main circuit connecting the output of the rectifier circuit and the inverter is cut off, thereby applying high-frequency voltage to the discharge lamp. A discharge lamp lighting device characterized by having a function of stopping the discharge lamp and notifying a user of an abnormal state of the discharge lamp. 2. Claim 1, wherein the switch provided on the main circuit is substantially in a conductive state for at least one second after the AC power is turned on, regardless of the lighting state of the discharge lamp. The discharge lamp lighting device described. 3. If the discharge lamp is an electrode preheating type, after turning on the power,
Claim 1 or Claim 1 characterized in that the device has a function of preheating the electrodes of the discharge lamp by weakening the oscillation output of the inverter by controlling the voltage applied to the switch provided on the main circuit. The discharge lamp lighting device according to item 2.