JPH02297896A - Discharge lamp lighting device and illumination fixture - Google Patents

Abstract

PURPOSE:To provide controllability for the output of a discharge lamp by furnishing a saturable current transformer for alternate operation of two switching elements with the output of the secondary winding, varying the saturation time of this current current transformer, and thereby changing the output of an inverter circuit. CONSTITUTION:Output of a self-energizing inverter circuit 14 is changed by varying the saturation time of a saturable current transformer 6, which is provided for feedback control and operates two switching elements 4, 5 alternately with the output of the secondary winding. With saturation of this current transformer 6 the switching elements 4, 5 of the inverter circuit 14 are operated alternately so as to perform inversion, and thus a discharge lamp 16 is lit up. At this time, the saturation time of the current transformer 6 is varied by an output-variable circuitry to shift the timing at which the switching elements 4, 5 are actuated. Thus the output of a discharge lamp 16 lighting device can be varied.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a discharge lamp lighting device and a lighting fixture using an inverter circuit.

(Prior Art) Conventionally, there have been known discharge lamp lighting devices and lighting fixtures that rectify the power of a commercial AC power source and then reversely convert the power using an inverter circuit to light the discharge lamp.

(Problem to be Solved by the Invention) However, in the conventional discharge lamp lighting device or lighting equipment described above, when the power supply voltage changes by 10%, the current supplied to the discharge lamp changes by about 15%, and the input voltage changes. Output changes significantly in response to fluctuations.

Furthermore, when adding a soft start function, it is necessary to use a large-capacitance resistor or complicate the circuit, making it difficult to provide the soft start function at a low cost.

Furthermore, if an attempt is made to light the discharge lamp while the output of the inverter circuit is reduced, there is a problem in that the discharge lamp may not be completely lit.

The present invention has been made in view of the above problems, and the object of claim 1 is to provide a discharge lamp lighting device that can control the output, and claim 2 is directed to an inexpensive discharge lamp lighting device having a soft start function. The object of the present invention is to provide an electric lamp lighting device, and claim 3 aims to provide a discharge lamp lighting device that can keep the output constant even when the power supply voltage fluctuates, and can keep the light output of the discharge lamp constant. The object of the present invention is to provide a discharge lamp lighting device that can control the output and ensure the lighting of the discharge lamp when the discharge lamp is lit. It is an object of the present invention to provide a lighting fixture equipped with the discharge lamp lighting device according to any one of claims 1 to 4.

[Structure of the invention]

(Means for Solving the Problems) A discharge lamp lighting device according to claim 1 has a saturable current transformer for feedback control, and two switching modes are provided at the output of the secondary winding of the saturable current transformer. A self-excited inverter circuit that operates elements alternately, a discharge lamp that is energized by the inverter circuit, and an output of the inverter circuit that changes the saturation time of the saturable current transformer of the inverter circuit. It is equipped with a variable output circuit that changes the output.

The discharge lamp lighting device according to claim 2 is a self-excited type having a saturable current transformer for feedback control, and in which two switching elements are alternately operated by the output of the secondary winding of the saturable current transformer. an inverter circuit, a discharge lamp energized by the inverter circuit, and software that changes the saturation time of the saturable current transformer of the inverter circuit for a predetermined time at startup to reduce the output of the inverter circuit. It is equipped with a start circuit.

The discharge lamp lighting device of claim 3 has a saturable current transformer for feedback control, the input end of which is connected to the power source, and two outputs at the output of the secondary winding of the saturable current transformer. A self-excited inverter circuit that alternately operates switching elements, a discharge lamp that is energized by the inverter circuit, and a discharge lamp that changes the saturation time of the saturable current transformer of the inverter circuit in accordance with the power supply voltage. It is equipped with a constant output circuit that keeps the output of the inverter circuit constant.

The discharge lamp lighting device according to claim 4 has a saturable current transformer for feedback control, and is a self-excited type in which two switching elements are alternately operated by the output of the secondary winding of the saturable current transformer. an inverter circuit, a discharge lamp energized by the inverter circuit, and a variable output circuit that changes the output power of the inverter circuit by changing the saturation time of the saturable current transformer of the inverter circuit; a dimming switching circuit that changes the output of the output variable circuit; and a full-light start circuit that causes the inverter circuit to output an unreduced output regardless of the dimming switching circuit when starting the discharge lamp. It is equipped with

The lighting fixture C↓ according to claim 5 has the discharge lamp lighting device according to claims 1 to 4.

(Function) The discharge lamp lighting device of claim 1 operates the two switching elements of the self-excited inverter circuit alternately to perform reverse conversion by saturation of the saturable current transformer for feedback control. Turn on the lights. At this time, the output variable circuit changes the saturation time of the saturable current transformer to change the timing at which the switching element is operated, thereby changing the output of the discharge lamp lighting device.

A discharge lamp lighting device according to a second aspect of the present invention operates two switching elements of a self-excited inverter circuit alternately by saturation of a saturable current transformer for feedback control to perform reverse conversion and light the discharge lamp. . When starting the discharge lamp, the frequency is increased by changing the saturation time of the saturable current transformer using a soft start circuit, and the output is lowered for a predetermined time at the time of starting to perform soft start.

In the discharge lamp lighting device of claim 3, the saturation of the saturable current transformer for feedback control alternately operates two switching elements of a self-excited inverter circuit to perform reverse conversion and light the discharge lamp. . At this time, the constant output circuit changes the saturation time of the saturable current transformer according to the power supply voltage to keep the output of the inverter circuit constant.

A discharge lamp lighting device according to a fourth aspect of the present invention operates two switching elements of a self-excited inverter circuit alternately by saturation of a saturable current transformer for feedback control to perform reverse conversion and light the discharge lamp. . At this time, the saturation time of the saturable current transformer is changed by the output variable circuit using the dimming switching circuit to change the timing at which the switching element is operated, thereby changing the output of the discharge lamp lighting device. Further, when starting the discharge lamp, regardless of the dimming switching circuit, the full-light start circuit supplies power to the discharge lamp in a state where the output of the inverter circuit is not reduced to ensure that the lamp is characterized. The lighting fixture lights a discharge lamp using the discharge lamp lighting device according to any one of claims 1 to 4.

(Example) Hereinafter, an example of the discharge lamp lighting device of the present invention will be described with reference to the drawings.

In FIG. 1, 1 is a commercial AC power supply, and this commercial AC power supply 1 is connected to the AC input terminal of a rectifier circuit 2, and a smoothing electrolytic capacitor 3 is connected between the DC output terminals of this rectifier circuit 2. ing. In parallel to the electrolytic capacitor 3, a power MO3 type field effect transistor 4.5 is connected as a switching element whose drain and source are connected in series. Further, the source of the field effect transistor 4 and the drain of the field effect transistor 5 are connected to the primary winding 7 of the saturable current transformer 6 for feedback control, and this secondary winding 7 connects the saturable iron core 8 to a common magnetic field. It is magnetically coupled to the first secondary winding 9, the second secondary winding 1G, and the control winding 11 as a wire. One end of the first secondary winding 9 is connected to a connection point between the source of the field effect transistor 4 and the drain of the field effect transistor 5, and the other end is connected to the gate of the field effect transistor 4 via a resistor 12. , one end of the second secondary winding 10 is connected to the source of the field effect transistor 5, and the other end is connected to the resistor 13.
It is connected to the gate of the field effect transistor 5 via. In this way, the two field effect transistors 4.5, the saturable current transformer 6, etc. form a self-excited half-bridge type inverter circuit I4. The other end of the primary winding 7 of the saturable current transformer 6 is connected to one filament 17 of a discharge lamp 16 via a reactor 15, and the other filament 18 is connected via a capacitor 19 or a capacitor 20, respectively. , are connected to the DC output terminals of the rectifier circuit 2, respectively. Furthermore, a starting capacitor 21 is connected between both filaments 17 and 18. Further, a voltage dividing resistor 22 and a resistor 23 connected in series are connected in parallel to the capacitors 19 and 20, and an electrolytic capacitor 24 for charging is connected in parallel to the resistor 23. Further, an impedance circuit 2G serving as a soft start circuit is connected to a connection point between the resistor 22 and the resistor 23 via a Zener diode 25. In this impedance circuit 26, the base of a transistor 27 is connected to the anode of a Zener diode 25, the collector is connected to a resistor 28, the emitter is connected to the negative output terminal of the rectifier circuit 2, and a resistor 29 is connected between the emitter and the base. has been configured. And, at both ends of the resistor 28 and the resistor 29 which are the output ends of the impedance circuit 26,
A resistor 30 and a capacitor 31 connected in series are connected, and a DC output end of a rectifier circuit 32 is connected,
A control winding 11 is connected to the AC input terminal.

Next, the operation of the above embodiment will be explained.

Commercial AC from a commercial AC power source 1 is rectified and smoothed by a rectifier circuit 2 and an electrolytic capacitor 3. Then, current is supplied to the primary winding 7 of the saturable current transformer 6, and when the saturable iron core 8 is saturated, the current is reversed, and as the saturable iron core 8 is saturated, the current is repeatedly reversed. 4 and the field effect transistor 5 are turned on alternately to convert direct current to alternating current and light the discharge lamp 16.

On the other hand, for approximately 0.5 to 1 second until the electrolytic capacitor 24 is charged during startup, the potential at the connection point between the resistors 22 and 23 is lower than the Zener voltage of the Zener diode 25, so the base of the transistor 27 No base current is supplied to the transistor 27, and the transistor 27 maintains an off state. Therefore, the current flowing through the resistor 29 is not bypassed, and the impedance of the closed circuit connected to the DC output end of the rectifier circuit 32 increases, and as this impedance increases, the saturation time of the saturable iron core 8 becomes shorter. Then, the output frequency becomes high, and the output is lowered for a predetermined period of 0.5 to 1 second at startup to perform a soft start.

Thereafter, when the electrolytic capacitor 24 is charged, the resistor 22
The potential at the connection point between the zener diode 25 and the resistor 23
The base current is supplied to the base of the transistor 27, bypassing the 2 current of the resistor 29 to the transistor 27. Therefore, the rectifier circuit 32
The impedance of the closed circuit connected to the DC output end of the second
As shown in the figure, the output frequency decreases, the output increases, and the discharge lamps 16 are fully lit.

In other words, the circuit that becomes the load constitutes an LC resonant circuit with the primary winding 7 of the saturable current transformer 6, the reactor 15, the capacitor 19, and the capacitor 20, so as shown in Fig. 3, the impedance is increased. For example, if the frequency is increased, such as f2, the output decreases and becomes a dimming state, and conversely, by decreasing the impedance, for example f
When the frequency is decreased like l, the output increases and becomes an all-optical state.

Next, a discharge lamp lighting device according to another embodiment will be explained with reference to FIG.

The discharge lamp lighting device shown in FIG. 4 is the discharge lamp lighting device shown in FIG. 1 provided with a regulation improvement circuit 41 having functions as a variable output circuit and a constant output circuit.

This regulation improvement circuit 41 is connected to a resistor 2 from the positive output side of the rectifier circuit 2 via a resistor 42 and a variable resistor 43.
9 and the collector of the transistor 27, and the connection point between the resistor 42 and the variable resistor 43 is connected to the positive output side of the DC output end of the rectifier circuit 32 via a resistor 44. Further, the collector of a transistor 45 is connected to the connection point between the resistor 44 and the DC output end of the rectifier circuit 32, the base of this transistor 45 is connected to the variable terminal of the variable resistor 43, and the emitter is connected to the base of the transistor 46. It is connected. The collector of this transistor 46 is connected to the positive side DC output terminal of the rectifier circuit 32, the emitter is connected to the negative side DC output terminal of the rectifier circuit 32 via a resistor 47, and the emitter is connected to the negative side DC output terminal of the rectifier circuit 2. Connected to the DC output end.

Further, the positive DC output end of the rectifier circuit 32 is connected via a diode 48 and a Zener diode 49 to a connection point between the resistor 29 and the emitter of the transistor 27 .

Next, the operation of the discharge lamp lighting circuit according to the embodiment shown in FIG. 4 will be explained.

Similar to the discharge lamp lighting circuit shown in FIG. 1, the discharge lamp lighting circuit shown in FIG. 4 also converts direct current into alternating current using a self-excited half-bridge type inverter circuit 14. At this time, the output of the inverter circuit 14 changes the base current of the transistor 45 and the transistor 4G by changing the resistance value of the variable resistor 43, changes the saturation time of the saturable iron core 8, and changes the frequency. to change the output. At startup, the transistor 27 remains off for a predetermined period of time until the electrolytic capacitor 24 is charged, so that the closed circuit impedance on the output side of the rectifier circuit 32 becomes high, and the frequency of the inverter circuit 14 becomes high. , preheat the discharge lamp 16 at low output. Thereafter, when the electrolytic capacitor 24 is charged and the transistor 27 is turned on, the impedance of the closed circuit on the DC output side of the rectifier circuit 32 decreases, the frequency becomes low, and the discharge lamp 16 is started and lit with the normal output. Furthermore, when the voltage input to the inverter circuit 14 increases, the base current supplied to the transistor 46 decreases, the impedance of the closed circuit between the DC output terminals of the rectifier circuit 32 becomes high (the saturation time of the saturable iron core 8 becomes faster, the frequency of the inverter circuit 14 becomes higher, and even if the input voltage increases, the inverter circuit 14
The output from will not increase. On the contrary, the inverter circuit 14
When the voltage input to the saturable iron core 8 decreases, the base current supplied to the transistor 46 increases, the impedance of the closed circuit between the DC output terminals of the rectifier circuit 32 decreases, and the saturable iron core 8
The saturation time of the inverter circuit 14 becomes slower and the frequency of the inverter circuit 14 becomes lower, so that even if the input voltage decreases, the output from the inverter circuit 14 does not decrease. In this way, even if the voltage input to the inverter circuit 14 fluctuates, the inverter circuit 1
4 does not vary, the current supplied to the discharge lamp 16 does not change, and the discharge lamp 16 maintains a constant brightness.

Further, another embodiment will be described with reference to FIG.

A varistor 52 is connected to both ends of the commercial AC power supply 1 via a fuse 51, and one end of the first winding 54 of a noise prevention transformer 53 is connected to one end of the varistor 52.
One end of the second winding 55 of the noise prevention transformer 53 is connected to the other end, and a capacitor 56 is connected between the other end of the first winding 54 and the other end of the second winding 55. ing.

From one end of this capacitor 56, a rectifier circuit 2 consisting of two diodes 57 and 58 connected in opposite directions is connected.
A resistor 59 and a capacitor 60 are connected to the cathode of the diode 57 and the anode of the diode 58, and the drain and source of the power MO8 type field effect transistor 4 and the power M
The drain and source of the O8 type field effect transistor 5 are connected in series. In addition, the field effect transistor 4
A capacitor 61 is connected between the drain and source of
A diode 62 and a resistor 6 are connected between the connection point between the source of the field effect transistor 4 and the drain of the field effect transistor 5 and the connection point between the resistor 59 and the capacitor 6G.
3 is connected. A resistor 12 and a first secondary winding 9 of a saturable current transformer 6 for feedback control are connected between the drain and source of the field effect transistor 4, and a resistor is connected between the drain and source of the field effect transistor 5. 13 and a second secondary winding lO are connected, and further, a 5SS64 is connected between the gate of the field effect transistor 5 and the connection point between the resistor 59 and the capacitor 60.

Further, a connection point between the source of the field effect transistor 4 and the drain of the field effect transistor 5 is connected to one filament 17 of the discharge lamp 16 via the primary winding 7 of the saturable current transformer 6 and the reactor 15, The other filament 18 is connected to the noise prevention transformer 5 via a heat-sensitive switch 65.
3 and connected to the second winding 54 of both filaments 17.3.
A capacitor 21 is connected between the terminals 18 and 18. Note that the heat-sensitive switch 65 is thermally coupled to the reactor 15, and when an abnormal overcurrent flows in the circuit, the heat-sensitive switch 65 is activated.
5 is turned off, and the inverter circuit 14 is disconnected from the commercial AC power supply 1. Further, an electrolytic capacitor 66 and a resistor 67 are connected in parallel to the field effect transistor 4, and an electrolytic capacitor 68 is connected in parallel to the field effect transistor 5. Further, a resistor 69 connected in series and a resistor 23 of the soft start circuit 26 are connected in parallel to this electrolytic capacitor 68, and an electrolytic capacitor 24 for charging is connected in parallel to the resistor 23. . The connection point between the resistor 69 and the electrolytic capacitor 24 is connected to the base of the transistor 27 via the Zener diode 25, the resistor 29 is connected between the emitter and collector of the transistor 27, and the emitter of the transistor 27 is connected to the diode 5B.
A resistor 70 is connected to the collector. Further, a resistor 71 and a capacitor 72 are connected in series between the cathode of the diode 57 and the anode of the diode 58.
A regulation improvement circuit 41 is connected to the connection point 2.

The connection point of this resistor 71 and capacitor 72 is the resistor 4
2 and a resistor 70 via a variable resistor 43. Further, the resistor 71 and the capacitor 72 are connected to the emitter of the transistor 45 and the collector of the transistor 46 via the resistor 44, the base of the transistor 45 is connected to the variable terminal of the variable resistor 43, and the collector is connected to the base of the transistor 46. . The emitter of the transistor 46 is connected to a resistor 47, and the emitter of the transistor 46 is connected to a resistor 47.
A diode forming a bridge with a resistor 30 and an electrolytic capacitor 31 connected in series in parallel with the resistor 6 and the resistor 47? 3.74.75°76 is connected to the rectifier circuit 32, and the connection point between the diode 73 and the diode 75 of this rectifier circuit 32 and the diode 7
4 and the connection point of the diode 76.
is connected. Further, a diode 48 and a Zener diode 49 are connected in series between the connection point of the resistor 44 and the emitter of the transistor 45 and the anode of the diode 58.

Next, the operation of the embodiment shown in FIG. 5 will be explained.

AC from a commercial AC power supply 1 is rectified by a rectifier circuit 2, and then converted into two field effect transistors 4.5 by a first secondary winding 9 and a second secondary winding 10 of a saturable current transformer 6. Voltages are applied alternately to operate the field effect transistors 4 and 5 alternately. During the predetermined time until the electrolytic capacitor 24 is charged at the time of starting, the transistor 2
7 is not turned on, the impedance of the closed circuit on the output side of the rectifier circuit 32 increases, the output frequency of the inverter circuit 14 increases, the output of the inverter circuit 14 decreases, and the discharge lamp 16 is soft-started. During normal operation after the electrolytic capacitor 24 is charged, the transistor 27 is turned on and the current flowing through the resistor 29 is bypassed to the transistor 27, thereby reducing the impedance of the DC output circuit of the rectifier circuit 32. The output of the inverter circuit 14 increases, and the discharge lamp 16 performs normal lighting.

Note that at this time, by changing the resistance value of the transistor 45 connected to the variable resistor 43, the saturable iron core 8
By changing the saturation time of the inverter circuit 14, the output of the inverter circuit 14 can be changed.

Furthermore, when the power supply voltage increases, the equivalent resistance value between the collector and emitter of the transistor 46 increases, and the impedance of the closed circuit at the DC output end of the rectifier circuit 32 increases.
Reinverter circuit 14 with short saturation time of saturable iron core 8
frequency increases, and the output of the inverter circuit 14 decreases. On the other hand, when the power supply voltage decreases, the equivalent resistance value between the collector and emitter of the transistor 46 decreases, the impedance of the closed circuit at the DC output end of the rectifier circuit 32 decreases, and the saturation time of the saturable iron core 8 increases. As a result, the frequency of the inverter circuit 14 becomes lower, and the output of the inverter circuit 14 increases. In this way, even if the power supply voltage fluctuates, by keeping the output of the inverter circuit 14 constant, the current to the discharge lamp 16 can be kept constant, and the discharge lamp! Keep the brightness of 6 constant.

Further, a discharge lamp lighting device according to another embodiment will be explained with reference to FIG.

The lighting device shown in FIG. 6 is the same as the lighting device shown in FIG. 5 except that it includes a dimming switching circuit 81 and a full-light start circuit 82.

This dimming switching circuit 81 has a transistor 83 connected to the base and emitter of the transistor 27 of the soft start circuit 26.
The collector and emitter of the transistor 83 are connected to each other, and a Zener diode 84 and a switch 85 are connected in series to the base of the transistor 83.

In addition, in the all-optical start circuit 82, an electrolytic capacitor 88 is connected to the connection point between the electrolytic capacitor 66 and the electrolytic capacitor 67 via a resistor 86, and a switch 85 connects the electrolytic capacitor 88 to the connection point between the resistor 86 and the electrolytic capacitor 87. The other end of 87 is connected to the emitter of transistor 83. Furthermore, in parallel to the electrolytic capacitor 87,
The resistor 88 and the collector and emitter of a transistor 89 are connected, and the collector and emitter of a transistor 90 is connected between the base and emitter of the transistor 89, and the anode of a Zener diode 91 is connected to the base of the transistor 90. It is connected. A resistor 92 is connected between the cathode of the Zener diode 91 and the collector of the transistor 90, and a resistor is connected between the connection point of the resistor 92 and the Zener diode 91 and the connection point of the electrolytic capacitor 66 and the electrolytic capacitor 68. A resistor 94 is connected between the connection point of the resistor 92 and the cathode of the Zener diode 91 and the emitter of the transistor 90 .

Similar to the discharge lamp lighting circuit shown in FIG. 5, the discharge lamp lighting circuit shown in FIG. 6 also converts direct current into alternating current using a self-excited half-bridge type inverter circuit 14. When the switch 85 is turned off, no current is supplied to the base of the transistor 83 and the transistor 83 is turned off, and the base current is supplied to the transistor 27.
turns on, the current of the resistor 29 is bypassed to the transistor 27, the impedance of the impedance circuit 41 decreases, the frequency becomes low, and the discharge lamp! 6 lights up completely. Conversely, when the switch 85 is turned on, current is supplied to the base of the transistor 83, turning on the transistor 83 and bypassing the base current of the transistor 27.
Since the transistor 27 is turned off and current flows through the resistor 29, the impedance of the impedance circuit 41 increases, the frequency increases, and the output of the discharge lamp 16 decreases. In this way, by turning on and off the switch 85,
Two-step dimming is possible.

Furthermore, when starting the discharge lamp 16, a soft start is performed, and since the electrolytic capacitor 87 is not charged, even if the switch 85 is on, the voltage of the electrolytic capacitor 87 is changed to the Zener voltage of the Zener diode 84. The transistor 83 will not turn on until the
Full-light starting must be performed for about 2 seconds as shown in Figure 7 of cylinder after starting.

According to the above embodiment, even if the discharge lamp 16 is lit in the dimming state with the switch 85 turned on, it always starts in the full light state, so the secondary voltage decreases as shown in FIG. Since this does not occur, starting performance can be improved.

Furthermore, a discharge lamp lighting device according to another embodiment will be described with reference to FIG. 9.

A varistor 52 is connected to both ends of the commercial AC power supply via a fuse 51, and one end of a first winding 54 of a noise prevention transformer 53 is connected to one end of the varistor 52.
At the other end of 2 is a second winding 55 of a noise prevention transformer 53.
One end of the first winding 54 and the other end of the second winding 55 are connected to a capacitor 56 and an AC input end of the rectifier circuit 2 . Further, the drain and source of the field effect transistor 4 and the drain and source of the field effect transistor 5 are connected between the DC output terminals,
A capacitor 101 is connected between the drain and source of the field effect transistor 5, and a capacitor 102 is connected between the drain and source of the field effect transistor 5.

Further, a first secondary winding 9 and a resistor 12 are connected in series between the source and gate of the field effect transistor 4.
This resistor 12 has a diode 1 connected in series.
03 and a resistor 104 are connected in parallel, and a second secondary winding 1 is connected between the source and gate of the field effect transistor 5.
G and a resistor 13 are connected in series, and this resistor 13 has a diode 105 and a resistor 106 connected in series.
is connected.

The connection point between the source of the field effect transistor 4 and the drain of the field effect transistor 5 is connected to one filament 17 of the discharge lamp 16 via the primary winding 7 of the saturable current transformer 6 for feedback control and the reactor 15. The other filament 18 is connected to the DC output end of the rectifier circuit 2 via a capacitor 19 or 20, respectively, and a capacitor 21 is connected between both filaments 17 and 18.
is connected.

Further, a resistor 60 and a capacitor 59 connected in series are connected between the DC output terminals of the rectifier circuit 2.
A resistor 63 and a diode 62 are connected between the connection point between the resistor 60 and the capacitor 59 and the connection point between the source of the field effect transistor 4 and the drain of the field effect transistor 5, and the connection point between the resistor 60 and the capacitor 59 and the field effect A 5SS64 is connected between the gate of the transistor 5 and the gate of the transistor 5. Furthermore, two electrolytic capacitors 66 and 68 are connected in series between the DC output terminals of the rectifier circuit 2, and a resistor 67 is connected in parallel with the electrolytic capacitor 66.

Further, a resistor 69 connected in series and a resistor 23 of the soft start circuit 26 are connected in parallel with the electrolytic capacitor 68, and this resistor 23 is connected to the electrolytic capacitor 24 for charging.
is connected. The base of the transistor 27 is connected to the connection point between the resistor 69 and the resistor 23 via the Zener diode 25, and the emitter of the transistor 27 is connected to the negative side DC output terminal of the rectifier circuit 2, and between the emitter and collector. A resistor 29 is connected to the resistor 29, and a resistor 28 is connected to the collector.

Further, a resistor 30 and a capacitor 31 are connected in series to the resistor 28 and the resistor 29, and diodes 73 and 74 are connected in series.
The rectifier circuit 32 in which a bridge is formed is connected at 75 and 76, and further between the connection point between the cathode of the diode 73 and the anode of the diode 75 and the connection point between the cathode of the diode 74 and the anode of the diode 76. is connected to the control winding 11 of the saturable current transformer 6.

Next, the operation of the embodiment shown in FIG. 9 will be explained.

AC from a commercial AC power supply 1 is rectified by a rectifier circuit 2, and is alternately connected to a field effect transistor 4 and a field effect transistor 5.
and convert it into alternating current.

Since the transistor 27 is turned off until the electrolytic capacitor 24 is charged during startup, the impedance of the closed circuit between the DC output terminals of the rectifier circuit 32 is high, so that the saturable iron core saturates quickly. , the frequency increases, the output of the inverter circuit 14 is suppressed low, and the discharge lamp 1
6 is a soft start. After that, the electrolytic capacitor 24
When charged, the transistor 27 turns on and the rectifier circuit 3
The impedance of the closed circuit between the two DC output ends is reduced, saturation of the saturable iron core 8 is delayed, the frequency is lowered, the inverter circuit 14 has a normal output, and the discharge lamp 16 has a predetermined brightness.

Further, a discharge lamp lighting device according to another embodiment will be explained with reference to FIG. 10.

The discharge lamp lighting device shown in FIG. 10 includes a plurality of discharge lamps 16 in addition to the discharge lamp lighting device shown in FIG. 9, and a resistor 71. A regulation improvement circuit 41 is provided via a resistor 103, a resistor 28, and a resistor 29.

This discharge lamp lighting device performs a soft start similarly to the discharge lamp lighting device shown in FIG.

Further, by varying the base current of the transistor 45 with a variable resistor 43 connected to the transistor 45, the saturation time of the saturable iron core 8 is varied, and the frequency of the inverter circuit 14 is varied. The output of circuit I4 can be varied. Furthermore, when the voltage input to the inverter circuit I4 increases, the base current supplied to the transistor 46 decreases, the impedance of the closed circuit between the DC output terminals of the rectifier circuit 32 increases, and the saturable iron core 8 saturates quickly. Inverter circuit 1
Even if the frequency of inverter circuit 4 becomes higher and the input voltage rises, the output from inverter circuit 14 does not rise. Conversely, when the voltage input to the inverter circuit 14 decreases, the base current supplied to the transistor 46 increases, the impedance of the closed circuit between the DC output terminals of the rectifier circuit 32 decreases, and the saturation of the saturable iron core 8 decreases. Inverter circuit 1 becomes slow
Even if the frequency of the inverter circuit 14 becomes lower and the input voltage decreases, the output from the inverter circuit 14 does not decrease, and even if the input voltage fluctuates greatly, the fluctuation in the output voltage can be reduced.

Moreover, any of the above circuits can be built into a lighting fixture.

According to experiments, when the input voltage fluctuates by 10%, the lamp current fluctuates by about 5%, and the lamp current fluctuation can be suppressed to about 173% compared to the conventional method.

〔Effect of the invention〕

According to the discharge lamp lighting device of claim 1, in the output variable circuit,
By changing the saturation time of the saturable current transformer for feedback control, the output of the self-excited inverter circuit can be changed, so the output can be changed.

According to the discharge lamp lighting device of claim 2, the soft start circuit changes the saturation time of the saturable current transformer of the inverter circuit for a predetermined time at startup, so that the output of the inverter circuit is controlled for a predetermined time at startup. Since it can be kept low, a soft start function can be provided at low cost.

According to the discharge lamp lighting device of claim 3, by changing the saturation time of the saturable current transformer of the inverter circuit in the constant output circuit according to the output voltage of the power supply to make the output of the inverter circuit constant, the power supply voltage can be adjusted. Since the output can be kept constant even when there are fluctuations in the discharge lamp, the light output of the discharge lamp can be kept constant.

According to the discharge lamp lighting device of claim 4, the dimming switching device can perform dimming of the discharge lamp, and the full-light start circuit can perform full-light start regardless of the state set by the dimming switching device. This makes it possible to ensure the starting of the discharge lamp.

According to the lighting fixture of claim 5, claims 1 to 3
It can have any of the following effects.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing a discharge lamp lighting device according to an embodiment of the present invention, FIG. 2 is a graph showing the soft start operation of the same as above, and FIG. 3 is a graph showing the relationship between the frequency and output of the inverter circuit. FIG. 4 is a circuit diagram showing a discharge lamp lighting device according to another embodiment, FIG. 5 is a circuit diagram showing a discharge lamp lighting device according to still another embodiment, and FIG. 6 is a circuit diagram showing a discharge lamp lighting device according to still another embodiment. A circuit diagram showing the electric lamp lighting device, Fig. 7 is a graph showing the soft start operation by full-light dimming, Fig. 8 is a relation between voltage and current of the discharge lamp, and Fig. 9 is a diagram of another embodiment. FIG. 10 is a circuit diagram showing a discharge lamp lighting device according to another embodiment. 6. Saturable current transformer, 14. Inverter circuit, 16.
- Discharge lamp, 2G... Soft start circuit, 41... Variable output circuit, regulation improvement circuit as a constant output circuit, 81... Dimming switching circuit, 82... All-light start circuit.

Claims (5)

[Claims] (1) A self-excited inverter circuit that has a saturable current transformer for feedback control and alternately operates two switching elements with the output of the secondary winding of this saturable current transformer; A discharge lamp comprising: a discharge lamp energized by a circuit; and a variable output circuit that changes the saturation time of the saturable current transformer of the inverter circuit to change the output of the inverter circuit. lighting device. (2) A self-excited inverter circuit that has a saturable current transformer for feedback control and alternately operates two switching elements with the output of the secondary winding of the saturable current transformer; A discharge lamp energized by a circuit, and a soft start circuit that changes the saturation time of the saturable current transformer of the inverter circuit for a predetermined time at startup to reduce the output of the inverter circuit. Characteristic discharge lamp lighting device. (3) The input terminal is connected to the power supply and has a saturable current transformer for feedback control, and the output of the secondary winding of this saturable current transformer is 2
a self-excited inverter circuit that alternately operates two switching elements, a discharge lamp that is energized by the inverter circuit, and a saturation time of the saturable current transformer of the inverter circuit that changes in accordance with the power supply voltage. A discharge lamp lighting device comprising: a constant output circuit that keeps the output of the inverter circuit constant. (4) A self-excited inverter circuit that has a saturable current transformer for feedback control and operates two switching elements alternately with the output of the secondary winding of the saturable current transformer; a discharge lamp energized by a circuit; a variable output circuit that changes the saturation time of the saturable current transformer of the inverter circuit to change the output of the inverter circuit; and a variable output circuit that changes the output of the variable output circuit. A discharge lamp comprising: a dimming switching circuit; and a full-light start circuit that causes the inverter circuit to output an unreduced output regardless of the dimming switching circuit when starting the discharge lamp. lighting device. (5) A lighting fixture comprising any one of the discharge lamp lighting devices according to claims 1 to 4.