JPH05283186A - Discharge lamp lighting device and lighting system using it - Google Patents

Abstract

(57) [Summary] [Purpose] To prevent over-output of the chopper circuit when the load is light, such as before lighting the discharge lamp. [Configuration] A chopper circuit 3 for outputting a predetermined constant voltage is provided to an inverter circuit 4 for lighting a discharge lamp 16,
The detection means 13 or 15 for detecting the output voltage or the input current of the chopper circuit 3 is provided, and the detection means 13 or 1 is provided.
The chopper circuit 3 according to the detection value detected by
In a discharge lamp lighting device provided with a chopper control circuit 9 for controlling the operation of the above, the start of regulating the constant voltage output by the chopper circuit 3 at the time of starting the discharge lamp 16 to a constant value lower than the predetermined constant voltage value. The hour output regulation means 23 is provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a discharge lamp lighting device having a chopper circuit called a pre-regulator or the like in front of an inverter circuit for lighting a discharge lamp, and a lighting device using the same.

[0002]

2. Description of the Related Art In recent years, in this type of discharge lamp lighting device, there has been a demand for the development of a low distortion input inverter as a measure against the harmonic regulation. As one example, an input circuit and an inverter circuit by a preregulator are provided. A combination of is attracting attention. Particularly, as the pre-regulator configuration, the boost chopper method is mainly used. Such a pre-regulator is an active smoothing method, that is,
The input current waveform becomes a sine wave that is macroscopically similar to the line voltage waveform by using the fact that the input current waveform becomes the average value of each cycle of the high-speed switching current by switching the full-wave rectified voltage after rectification at high speed. It is based on the correction method. The pre-regulator also has a voltage regulation function that keeps the input voltage to the subsequent inverter circuit constant regardless of the load.

Considering a discharge lamp lighting device equipped with a step-up chopper type pre-regulator, a chopper control circuit for high-speed switching control of the pre-regulator is provided in addition to the inverter control circuit for controlling the operation of the inverter circuit. I need.

In the conventional operation of such a chopper circuit, there is one that outputs a predetermined constant voltage when the power is turned on, and secondly, the lighting of a discharge lamp is detected. After that, there is a device that outputs a predetermined constant voltage.

In this type of equipment, a surge voltage may be generated, but in the prior art, when the generation of a surge voltage is detected, the oscillation operation of the inverter circuit is stopped and the chopper circuit is stopped. There is one configured like this.

Further, as a starting method for such a chopper circuit, a dedicated starting trigger circuit is provided.

[0007]

However, in a device which outputs a predetermined constant voltage when the power is turned on, when the oscillation operation is not started in the inverter circuit or the discharge lamp is not started, that is, In a so-called light load, the chopper output voltage becomes unnecessarily high and the switching element and the like are stressed.

In this respect, according to the one in which a constant voltage is output from the chopper circuit after detection of discharge lamp lighting, there is no such inconvenience, but if there is no chopper circuit output, the filament of the discharge lamp is preheated and the secondary starting At the time of voltage generation, the inverter oscillation frequency may become too low, leading to phase-advancing oscillation and destroying the inverter circuit.

Further, according to the conventional measures against the surge voltage, since the inverter oscillation is stopped, the lamp goes out when the surge voltage occurs, which is unsightly. Also,
The circuit configuration is complicated and the cost is high, and the reaction is delayed due to the complicated configuration.

Further, according to the conventional chopper circuit starting method, since the starting trigger circuit required only at the time of starting is exclusively provided, this contributes to the cost increase.

[0011]

According to a first aspect of the present invention, a chopper circuit that outputs a predetermined constant voltage is provided to an inverter circuit that lights a discharge lamp, and an output voltage or an input current of the chopper circuit is detected. A detection means for
In a discharge lamp lighting device provided with a chopper control circuit for controlling the operation of the chopper circuit according to a detection value detected by the detection means, a constant voltage output by the chopper circuit when the discharge lamp is started is set to the predetermined value. The output regulation means at the time of starting for regulating to a constant value lower than the constant voltage value of is provided.

According to another aspect of the present invention, a chopper circuit that outputs a predetermined constant voltage is provided to the inverter circuit that lights the discharge lamp, and a detection unit that detects the output voltage or the input current of the chopper circuit is provided. In a discharge lamp lighting device provided with a chopper control circuit for controlling the operation of the chopper circuit according to the detection value detected by the detection means, a surge voltage detection means is provided for the detection means,
A surge output regulation means is provided for regulating the constant voltage output by the chopper circuit to a constant value lower than the predetermined constant voltage value when a surge is detected.

According to another aspect of the present invention, a chopper circuit that outputs a predetermined constant voltage is provided to the inverter circuit that lights the discharge lamp, and a detection unit that detects the output voltage or the input current of the chopper circuit is provided. A chopper control circuit for controlling the operation of the chopper circuit according to the detection value detected by the detecting means is provided, and an inverter control circuit for giving a gate signal to the switching element in the inverter circuit to control the oscillation operation is provided. In the discharge lamp lighting device, the chopper starting means for inputting the gate signal from the inverter control circuit to the chopper control circuit as a start trigger signal when the chopper circuit is started up is provided.

According to a fourth aspect of the invention, in the third aspect of the invention, a delay circuit or a voltage detection circuit is provided in which the application of the gate signal to the switching element in the inverter circuit is started after the chopper circuit is activated.

According to a fifth aspect of the present invention, there is provided an instrument main body, a discharge lamp mounted on the instrument main body, and the discharge lamp lighting device according to any one of the first, second, third and fourth aspects for lighting the discharge lamp. Configured as a lighting device.

[0016]

According to the first aspect of the present invention, normally, a predetermined constant voltage is output from the chopper circuit to the inverter circuit side. By setting to output as a constant value lower than such a predetermined constant voltage, it is possible to prevent over-output from the chopper circuit and reduce stress on the switching element and the like.

Further, according to the second aspect of the present invention, when the surge voltage is detected, the output voltage of the chopper circuit is output as a constant value lower than a predetermined constant voltage at the normal time. The oscillation operation is not stopped, and therefore, the switching element can be protected while preventing the lamp from extinguishing. Moreover, since the output detection level of the chopper circuit may be switched, a simple configuration is sufficient and the reaction delay is small.

Further, according to the present invention, the gate signal for oscillating the switching element in the inverter circuit is used as the trigger signal to activate the chopper circuit. Therefore, the oscillation of the inverter circuit is performed. It is not necessary to separately provide a starting circuit dedicated to the chopper circuit without impairing the operation, and the cost can be reduced.

By using such a discharge lamp lighting device to construct a lighting device according to the invention of a fifth aspect, it is possible to provide a device with good startability without giving stress to the switching element.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the invention described in claim 1 will be described with reference to FIGS. First, a step-up chopper circuit 3 is connected to an AC power supply 1 via a full-wave rectifier circuit 2, and an inverter circuit 4 is connected to the output side of this chopper circuit 3. The chopper circuit 3 is a chopper control transformer (inductor) connected to the full-wave rectification output line.
5 and an output line connected to each other to perform a switching operation, an FET 6, a rectifying diode 7, and a smoothing output electrolytic capacitor 8. The chopper circuit 3 is provided with a chopper control circuit 9 for controlling the switching operation of the FET 6 (on-duty control) to maintain the output voltage generated across the electrolytic capacitor 8 at a predetermined constant voltage. There is. As such a chopper control circuit 9, for example, a commercially available power factor improvement dedicated IC, SG3561 manufactured by Silicon General Company, is used. Further, a detecting means 13 composed of resistors 10, 11, 12 connected in series is connected to both ends of the electrolytic capacitor 8, and a voltage divided by the resistors 10 and 11 and 12 is passed through a diode 14 for preventing backflow. The output voltage V _DC ′ of the chopper circuit 3 is input to the chopper control circuit 9 to control the chopper output voltage. A detection winding 15 magnetically coupled to the inductor 5 is provided, and the input current I _IN detected by the detection winding 15 is also input to the chopper control circuit 9 to control the chopper operation. Is configured.

The inverter circuit 4 includes an electrolytic capacitor 8
Is connected to both ends of the oscillating unit and oscillates to light the discharge lamp 16. For example, it is composed of two switching transistors such as FETs 17 and 18, a ballast 21 and a preheating capacitor 22. Has been done. A high-frequency pulsed gate signal is applied to the gates of the FETs 17 and 18 from an inverter control circuit (not shown) to alternately oscillate.

However, in this embodiment, after the power is turned on and before the discharge lamp 16 is turned on, the chopper circuit 3 is
Output regulation means 2 for starting and regulating the value of the output voltage output from the switch to a constant value lower than the normal constant voltage
3 is added. The start-time output regulating means 23 is connected to the discharge lamp 16 and detects a start of the lamp lighting detection circuit 24, and is connected in parallel to the resistor 11 so as to turn on / off according to the output of the lamp lighting detection circuit 24. Is controlled by the short-circuiting transistor 25.

In such a structure, after the power is turned on and before the discharge lamp 16 is turned on, the transistor 25 is in the off state, and the smoothed voltage generated across the electrolytic capacitor 8 is the resistance 10 and the resistances 11 and 12. The voltage is _divided by and detected as a higher output voltage V _DC1 ′, which is applied to the chopper control circuit 9. Therefore, the chopper control circuit 9 suppresses the boosting operation of the chopper circuit 3, and as a result,
The output voltage obtained from the chopper circuit 3 is controlled to a constant value lower than a predetermined constant voltage normally required.
Then, as shown in FIG. 2, when the lamp voltage V _L changes and the lamp lighting detection circuit 24 detects the start of lamp startup, the transistor 25 is turned on to short-circuit the resistor 12. As a result, the smoothed voltage generated across the electrolytic capacitor 8 is detected as a lower output voltage V _DC2 ′ by being _divided by the resistors 10 and 11, and is _supplied to the chopper control circuit 9. Therefore, the chopper control circuit 9 causes the chopper circuit 3 to perform a boosting operation, and as a result, controls the output voltage obtained from the chopper circuit 3 to a predetermined constant voltage that is normally required.

As described above, in this embodiment, the output voltage value of the chopper circuit 3 is changed before the lighting by switching the detection level of the chopper output voltage V _DC before and after the discharge lamp 16 is turned on. By suppressing the value to a lower constant value, it is possible to prevent a high output at a light load and reduce stress on the FET 6 and the like.

Next, a second embodiment of the invention according to claim 1 will be described with reference to FIGS. 3 and 4. The same parts as those shown in the above-mentioned embodiment are designated by the same reference numerals. In this embodiment, the lamp lighting detection circuit 24 is provided with a start-time output regulation means 23.
As a result, by directly inputting the detected output to the chopper control circuit 9, the output voltage of the chopper circuit 3 becomes a low constant value and a predetermined constant value for normal time before and after the discharge lamp 16 is lit. It is configured to be switch-controlled.

Further, a third embodiment of the invention according to claim 1 will be described with reference to FIG. In this embodiment, a timer circuit 26 is provided in place of the lamp lighting detection circuit 24, and a starting output regulation means 27 is constituted by the transistor 25. That is, in the first embodiment, the lamp lighting detection circuit 24 detects whether the discharge lamp 16 is before lighting or after lighting, and controls the switching of the output voltage level. During the fixed time set in the circuit 26, the discharge lamp 16 is considered to be in a state before lighting,
The same output voltage level switching control is performed.

Next, an embodiment of the invention described in claim 2 will be described with reference to FIG. In this embodiment, first, a series circuit of a Zener diode 28 serving as a surge voltage detecting means and a resistor 29 is provided in parallel at both ends of the resistors 11 and 12. Further, when the surge voltage detecting means detects the occurrence of a surge voltage, a surge is generated to regulate the value of the output voltage output from the chopper circuit 3 to a constant value lower than the normal constant voltage. A transistor 30, which serves as a time output regulating means, is connected in parallel with the resistor 12.

In such a configuration, the zener diode 28 is normally off and the transistor 30 is on, and the output voltage V _DC divided by the resistors 10 and 11 is applied to the chopper control circuit 9 to operate normally. Chopper control is performed. Then, when a surge voltage occurs, the Zener diode 28 becomes conductive and turns on, and the transistor 3
When 0 is turned off, the output voltage V _DC ′ divided by the resistance 10 and the resistances 11 and 12 is given as the output voltage of the electrolytic capacitor 8, so that the chopper circuit 3 is output as in the above-described embodiment. Output voltage is controlled to be a constant value lower than a predetermined constant voltage for normal time. Here, the output voltage is set to be higher than the output level when the chopper circuit 3 is stopped, although the output voltage is low. Therefore, even if a surge voltage occurs, the output voltage of the chopper circuit 3 can be suppressed to a low level,
Since the oscillating operation of the inverter circuit 4 is not stopped, the lamp does not extinguish and is not unsightly. Moreover, since the output voltage is suppressed to a low level, protection of the FETs 17, 18 and the like can be secured. Further, since the output voltage of the chopper circuit 3 may be controlled to be switched to a lower level in this way, a simple circuit configuration is required, cost can be reduced, and there is no delay in reaction. Further, when the output voltage V _DC is kept low, even in the mode in which the oscillation frequency is closest to the resonance point, the output voltage V _DC is kept at a constant value that does not drop below the resonance point, and the delayed oscillation operation is maintained.

Next, one embodiment of the invention described in claims 3 and 4 will be described with reference to FIGS. 7 and 8. In this embodiment, the starting method of the chopper circuit 3 is devised. That is,
An inverter control circuit 31 for controlling the oscillation operation of the inverter circuit 4 is connected to the chopper control circuit 9 via an output switching circuit 32 serving as a chopper starting means. The output switching circuit 32 is for activating the chopper circuit 3 using a gate signal, and first, a diode 35 having the cathode side as the chopper control circuit 3 side is provided. Further, there is provided a start-up detection section which is a voltage detection circuit formed by a resistor 36 and an electrolytic capacitor 37 connected between the output terminals of the chopper circuit 3, and is determined by an RC time constant of the resistor 36 and the electrolytic capacitor 37. Transistor 38 that turns on and turns on after a time
Together with the resistor 39, is connected between the gate of the FET 34 and the gate signal output terminal of the inverter control circuit 31. A diode 40 is connected between the collector and emitter of the transistor 38.

In such a configuration, when the power is turned on, the inverter control circuit 31 outputs a continuous pulse gate signal as shown by V _C in FIG. Such a gate signal V _C is given to the chopper control circuit 9 as a trigger signal V _A through the diode 35. As a result, the chopper circuit 3 is triggered and activated. At this point, the transistor 38 is not turned on and the FET
The gate signal V
_B is not given. After that, the chopper circuit 3 is activated,
The voltage for the chopper control circuit 9 is the voltage V _{A in} FIG.
When the input current I _IN detected by the detection coil 15 causes the output level to become higher than the trigger output level, the diode 35 stops inputting the gate signal V _{C to} the chopper control circuit 9, as shown in FIG. On the other hand, after a lapse of time determined by the RC time constant of the resistor 36 and the electrolytic capacitor 37, the transistor 38 is turned on and the inverter circuit 4 becomes ready to receive the gate signal V _C from the inverter control circuit 31 as the gate signal V _B. The inverter circuit 4 starts the oscillation operation.

As described above, according to this embodiment, since the gate signal V _C generated by the inverter control circuit 31 is used as the trigger signal V _A for activating the chopper circuit 3, a dedicated activation trigger circuit is separately provided. It is inexpensive and does not require. Further, the trigger signal is not required after the chopper is started, and the gate signal V _C is used only as the original gate signal V _B , so that the oscillation operation of the inverter circuit 4 can be surely performed.

When the inverter circuit 4 is oscillated while the chopper circuit 3 is activated, the output switching circuit 3 in which the transistor 36 is omitted as shown in FIG.
You can set it to 2.

The discharge lamp lighting devices as shown in these embodiments are actually, for example, as shown in FIG.
Instrument body 41 and discharge lamp 1 attached to the instrument body 41
6 (here, it is assumed that there are two lights), and the lighting device is configured (the invention according to claim 5).

[0034]

According to the first aspect of the present invention, there is provided a start-time output regulating means for regulating the constant voltage output by the chopper circuit at the time of starting the discharge lamp to a constant value lower than the predetermined constant voltage value. , Normally, a predetermined constant voltage is output from the chopper circuit to the inverter circuit side, but at the time of starting with a light load immediately after turning on the power and before starting the discharge lamp, a constant value lower than such a predetermined constant voltage is set. Since the output of the chopper circuit is switched by switching the detection level so as to output the output, it is possible to prevent over-output from the chopper circuit at the time of light load and reduce stress on the switching elements and the like.

According to a second aspect of the present invention, a surge occurrence output regulating means is provided for regulating the constant voltage output by the chopper circuit to a constant value lower than the predetermined constant voltage value when a surge occurs, When a surge voltage is detected, the output voltage of the chopper circuit is set to be output as a constant value lower than the predetermined constant voltage at the normal time, so that the oscillation operation of the inverter circuit is not stopped, and therefore, The switching element can be protected while preventing the lamp from extinguishing, and for this purpose, the output detection level of the chopper circuit can be switched. Therefore, a simple configuration is sufficient and the delay of the reaction is small.

Further, according to the present invention, the chopper starting means for inputting the gate signal from the inverter control circuit as a trigger signal to the chopper control circuit at the time of starting the chopper circuit is provided, and the inverter is provided. Since the chopper circuit is configured to start by using the gate signal for oscillating the switching element in the circuit as a trigger signal, it is necessary to separately provide a starting circuit dedicated to the chopper circuit without impairing the oscillation operation of the inverter circuit. Therefore, the cost can be reduced.

By using such a discharge lamp lighting device to construct a lighting device as in the fifth aspect of the present invention, it is possible to provide a device with good startability that does not stress the switching element.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing a first embodiment of the invention according to claim 1.

FIG. 2 is a timing chart for explaining the operation.

FIG. 3 is a circuit diagram showing a second embodiment of the invention according to claim 1.

FIG. 4 is a timing chart for explaining the operation.

FIG. 5 is a circuit diagram showing a third embodiment of the invention according to claim 1.

FIG. 6 is a circuit diagram showing an embodiment of the invention described in claim 2.

FIG. 7 is a circuit diagram showing an embodiment of the invention described in claims 3 and 4.

FIG. 8 is a timing chart for explaining the operation.

FIG. 9 is a circuit diagram showing a modified example.

FIG. 10 is a perspective view showing an example of the invention according to claim 5;

[Explanation of symbols]

 3 Chopper circuit 4 Inverter circuit 9 Chopper control circuit 13, 15 Detecting means 16 Discharge lamp 23, 27 Starting output regulating means 28, 29 Surge voltage detecting means 30 Surge occurrence output regulating means 31 Inverter control circuit 32 Chopper starting means 33, 34 Switching Element 41 Instrument Main Body

Claims (5)

[Claims] 1. A chopper circuit for outputting a predetermined constant voltage is provided to an inverter circuit for lighting a discharge lamp, and a detecting means for detecting an output voltage or an input current of the chopper circuit is provided, which is detected by the detecting means. In a discharge lamp lighting device provided with a chopper control circuit for controlling the operation of the chopper circuit according to the detected value, the constant voltage output by the chopper circuit at the time of starting the discharge lamp is lower than the predetermined constant voltage value. A discharge lamp lighting device, characterized in that start-time output regulating means for regulating to a constant value is provided. 2. A chopper circuit for outputting a predetermined constant voltage is provided to an inverter circuit for lighting a discharge lamp, and a detecting means for detecting an output voltage or an input current of the chopper circuit is provided, which is detected by the detecting means. In a discharge lamp lighting device provided with a chopper control circuit for controlling the operation of the chopper circuit according to the detected value, surge voltage detecting means is provided for the detecting means, and a constant voltage output by the chopper circuit at the time of surge detection. A discharge lamp lighting device, characterized in that output control means at surge occurrence is provided to regulate a voltage to a constant value lower than the predetermined constant voltage value. 3. A chopper circuit that outputs a predetermined constant voltage is provided to an inverter circuit that lights a discharge lamp, and a detection unit that detects an output voltage or an input current of the chopper circuit is provided. In a discharge lamp lighting device provided with a chopper control circuit for controlling the operation of the chopper circuit according to the detected value and an inverter control circuit for giving a gate signal to a switching element in the inverter circuit to control an oscillation operation. A discharge lamp lighting device, further comprising chopper starting means for inputting a gate signal from the inverter control circuit to the chopper control circuit as a start trigger signal when the chopper circuit is started. 4. The discharge lamp lighting device according to claim 3, further comprising a delay circuit or a voltage detection circuit for starting the application of the gate signal to the switching element in the inverter circuit after the chopper circuit is activated. 5. An apparatus main body, a discharge lamp mounted on the apparatus main body, and the discharge lamp lighting device according to claim 1, 2, 3 or 4 for lighting the discharge lamp. Lighting equipment.