JP3922394B2 - Discharge lamp lighting device and lighting device - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a discharge lamp lighting device that operates a discharge lamp such as a low-pressure mercury vapor discharge lamp safely.
[Prior art]
Conventionally, a discharge lamp lighting device provided with means for detecting a half-wave discharge at the end of the life of a discharge lamp has a direct current voltage from a direct current power supply device composed of an alternating current power source A and a diode bridge B as shown in FIG. Is applied to one end of the primary winding D1 of the starting resistor C and the transformer D, and the other end of the primary winding D1 is connected to the collector of the switching transistor E. The emitter of the switching transistor E is connected to the negative reference potential point side of the DC voltage source device, and a series circuit including a diode F and a resistor G is connected between the base and emitter. The base of the switching transistor E is connected to the other end of the starting resistor C described above.
[0002]
One end of the secondary winding D2 of the transformer D is connected to one filament of the discharge lamp H, and the other end is the primary winding of the current transformer K through a series connection of a first capacitor I and a second capacitor J. Connected to line K1. The primary winding K1 of the current transformer K is connected to the other filament of the discharge lamp H. A resistor L is connected in parallel to the series circuit of the second capacitor J and the primary winding K1 of the current transformer K.
[0003]
A series circuit of a voltage adjusting diode M is connected in parallel to the secondary winding K2 of the current transformer K. One of the connection points is connected to the emitter of the switching transistor E via the capacitor N, and the other The connection point is connected to the base of the switching element E.
[0004]
The safety circuit O is configured to detect the voltage across the first capacitor I and prevent destruction of the inverter due to half-wave discharge at the end of the discharge lamp.
[0005]
A resonance capacitor P is connected in parallel to the primary winding D1 of the transformer D, and a resonance capacitor Q is also connected to the discharge lamp H.
[0006]
That is, the discharge lamp lighting device includes a discharge lamp H that is lit by a transistor inverter, and a current transformer K that is provided in a current path for the lamp current of the discharge lamp and that self-oscillates the switching transistor E of the transistor inverter by an output. And first and second series capacitors I and J, which are provided in series with the primary winding K1 of the current transformer K and block DC current from flowing into the input winding, respectively. 2 is provided with a direct current bypass resistor L connected in parallel to the capacitor J and the current transformer K. Here, the capacity of the first capacitor I is set larger than the capacity of the second capacitor J.
[0007]
And the safety circuit O which stops or reduces the output of a transistor inverter when the both-ends voltage of this 1st capacitor | condenser I is detected and a detection output rises is provided.
[0008]
According to this, a half-wave discharge at the end of the life of the discharge lamp causes a direct current to flow through the current path of the lamp current of the discharge lamp, but this current is blocked by the first and second capacitors. Inflow of direct current to the current transformer can be prevented, and abnormal oscillation of the inverter can be prevented. In addition, since the first capacitor has a larger capacity than the second capacitor, the DC voltage is blocked and the voltage is sufficiently high. By detecting the voltage across this capacitor, the operation of the safety circuit is started reliably. Can be made.
[Problems to be solved by the invention]
However, according to this conventional discharge lamp lighting device, since all the current bypassed by the resistor is accumulated and charged in the first capacitor where the voltage at both ends is detected, the capacitor is likely to become an abnormally high voltage. Met.
[0009]
Further, when the capacitor is discharged, the high voltage may be directly applied to the discharge lamp, and as a result, the surge voltage may be applied to the switching element of the inverter and the element may be destroyed.
[0010]
SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a discharge lamp lighting device and a lighting device capable of detecting the potential of a detection circuit without inducing generation of a high voltage.
[Means for Solving the Problems]
The invention described in claim 1 is a discharge lamp; a DC power supply device that converts an AC power source into a DC power source; an inverter that converts the DC power source into an alternating current by switching with a switching element and applies the AC to the discharge lamp through an inverter transformer; Feedback means for feeding back the lamp current of the discharge lamp to the switching element of the inverter; a capacitor connected in series to the feedback means; a resistor connected in parallel to the series body of the feedback means and the capacitor; A half-wave discharge detection circuit for detecting a potential corresponding to a voltage in a half-wave discharge state by the discharge lamp through a capacitor; a voltage dividing capacitor connected in parallel to the discharge lamp and a lamp voltage taken out from the voltage dividing capacitor; it has a capacitor for accumulating rectified by a diode, a lamp electric for detecting a lamp voltage of the discharge lamp Detection circuit and; lamp voltage detection circuit through the photocoupler an instruction signal protection operation when based rather half-wave discharge detection voltage and when the lamp shorted obtained from the detected lamp voltage the half-wave discharge detection circuit by the output And a control circuit for sending a control signal for controlling the inverter to the switching element in response to an instruction signal output from the safety circuit.
[0011]
The invention described in claim 2 is characterized in that the discharge lamp lighting device according to claim 1 is incorporated in the fixture body to light the discharge lamp.
[0012]
In addition, as an illuminating device, the discharge lamp etc. which comprised integrally the ballast called a bulb-type fluorescent lamp, etc. are included.
[Action]
According to the first aspect of the present invention, when the discharge lamp is normally lit, the discharge current is shunted by the capacitor connected in series with the feedback means and the resistor connected in parallel thereto, and the lamp is stably lit.
[0013]
At this time, the detection circuit detects a potential corresponding to the voltage across the resistor or capacitor. When the discharge lamp reaches the end of its life, half-wave discharge occurs, the lamp current includes a direct current component, and electric charge is accumulated in the capacitor, the voltage across the capacitor rises. At the same time, the capacitor blocks direct current, so that the potential of the resistor connected in parallel rises.
[0014]
Further, when the discharge lamp as a load becomes short-circuited, a large current is shunted and flows to the resistor and the capacitor, so that their potentials increase as described above. As described above, when the discharge lamp is in an abnormal state, the potential of the resistor or the capacitor greatly fluctuates.
[0015]
Further, since the safety circuit outputs an instruction signal so as to protect the inverter based on the potential detected by the detection circuit, the output of the inverter is reduced or stopped when the discharge lamp becomes abnormal. In addition, since the current flowing in the capacitor connected in series with the feedback means is shunted by the resistor, the charging voltage of the capacitor does not become high voltage, and it is connected in parallel even when the charging charge is discharged. Since the closed circuit is formed with the resistor, the charging voltage is not directly applied to the discharge lamp, and the surge voltage can be prevented from being applied to the switching element of the inverter.
[0016]
In addition to the detection circuit, a lamp voltage detection circuit for detecting the lamp voltage of the discharge lamp is provided, and the safety circuit outputs a control signal for the protective operation based on the potential and the lamp voltage detected by the detection circuit. In addition to the above operations, processing such as accurately detecting an abnormal state of the discharge lamp and reducing the inverter output can be performed.
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a configuration diagram of a discharge lamp lighting device according to an embodiment of the present invention. That is, for the discharge lamp 1, the alternating current from the alternating current power source 2 is rectified by the diode bridge 3, and the rectified output is smoothed by the smoothing capacitor 4 to obtain a direct current power source. It is supplied as a high frequency. A resonance capacitor 5 is connected in parallel to the primary winding of the inverter transformer 7, and a collector of a transistor 6 that is a switching element is connected to the capacitor 5.
[0017]
The primary winding of the current transformer 10 is connected to the secondary winding side of the transformer 7 via a DC cut capacitor 9 and further connected to the filament of the discharge lamp 1. The other filament of the discharge lamp 1 is connected to the secondary winding of the transformer 7.
[0018]
A starting capacitor 11 is connected to the discharge lamp 1 in parallel. The secondary side winding of the current transformer 10 constituting feedback means for feeding back the lamp current of the discharge lamp is connected to the base of the transistor 6, and an output limiting coil is provided between this winding and the emitter of the transistor 6. A capacitor 18 and a circuit in which a capacitor 19 and an FET 20 are connected in series are connected in parallel. In this circuit, when a voltage is generated in the transformer 7, the secondary winding of the transformer 10 and the capacitor 5 resonate and a resonance current flows through the current transformer 10. At this time, the transistor 6 is in the on state, but continues to be in the on state in response to the resonance current. The current in the secondary winding of the current transformer 10 works to charge the capacitor 18, and when the capacitor 18 is filled with electric charge, the charging current does not flow, the current transformer 10 is magnetically saturated, and the transistor 6 is turned off. . At this time, the transformer 7 is in resonance with the capacitors 5 and 11, and a current flows through the current transformer 10 in the opposite direction. Thereby, the transistor 6 is reverse-biased. During this time, the electric charge of the capacitor 18 is discharged through a discharge path (not shown), the transistor 6 is turned on again by the next resonance inversion, the same operation is repeated, and the filament of the discharge lamp 1 is preheated. To the discharge lamp.
[0019]
In the discharge lamp lighting device according to this embodiment, a half-wave discharge detection circuit 22 is provided which takes in a voltage corresponding to the lamp current of the discharge lamp 1 via the damper resistor 8 on the primary side of the current transformer 10. The potential detected by the half-wave discharge detection circuit 22 is output to the safety circuit 21.
[0020]
The safety circuit 21 obtains the output of the lamp voltage detection circuit 14 together with the output of the half-wave discharge detection circuit 22, and detects the abnormality of the discharge lamp load based on the relationship between these voltages. When the safety circuit 21 detects an abnormality, an instruction signal is sent to the control circuit 23 that is a control means via the photocoupler 16, and the control circuit 23 controls the gate signal to the FET 20, whereby the transistor 6 that is a switching element is controlled. Change the switching cycle to throttle or stop the inverter output. In other words, the control circuit 23 is configured to control the inverter, which is an electronic stabilization unit, in accordance with the output of the half-wave discharge detection unit 22 to perform a protective operation.
[0021]
A more detailed configuration example of the discharge lamp lighting device according to the above configuration is shown in FIG.
[0022]
In the following embodiments as well as in the present embodiment, the dot-dash line A portion in FIG. In this embodiment, a capacitor 31, diodes 32 and 33, a capacitor 34, and a resistor 35 are used as the half-wave discharge detection circuit 22. That is, as described above, the voltage at the connection point between the damper resistor 8 and the capacitor 9 serving as the DC cut means, in other words, the potential corresponding to the voltage across the capacitor 9 is taken out via the capacitor 31, and the diodes 32, 33 are extracted. The voltage is rectified and stored in the capacitor 34 and supplied as Vdet to the emitter of the transistor 40 and the collector of the Zener diode 41 constituting the safety circuit.
[0023]
More specifically, in the above circuit, when the discharge lamp is normally lit, the discharge current is generated by the capacitor 9 connected in series to the primary side of the current transformer 10 and the damper connected in parallel to the capacitor 9. The current is shunted by the resistor 8 and lighted stably. When the discharge lamp 1 reaches the end of its life, half-wave discharge occurs, the lamp current includes a direct current component, and when charge is accumulated in the capacitor 9 as the direct current cut means, both ends of the capacitor 9 The voltage between the capacitors rises, and the capacitor 9 blocks the direct current, so that the potential of the resistor 8 connected in parallel rises. Therefore, the voltage taken out via the capacitor 31 is supplied to the emitter of the transistor 40 and the collector of the Zener diode 41 as Vdet. Here, since the current flowing through the capacitor 9 connected in series to the current transformer 10 is shunted by the damper resistor 8, the charging voltage of the capacitor 9 does not become a high voltage. Even when the charged charge is discharged, a closed circuit is formed with the damper resistor 8 connected in parallel, so that the charging voltage is not directly applied to the discharge lamp, and the surge voltage is electronically stabilized. It can be prevented in advance from being applied to a switching element of an inverter as a means. The lamp voltage detection circuit 14 for determining whether or not the discharge lamp is performing half-wave discharge according to the voltage drop of the damper resistor 8 which is a resistance means includes diodes 36 and 37, a capacitor 38, and a resistor 39. ing. The ramp voltage taken out by the voltage dividing capacitors of the capacitors 12 and 13 is rectified by the diodes 36 and 37, stored in the capacitor 38, and supplied to the base of the transistor 40 as VL. A light emitting diode 42 of the photocoupler 16 is connected between the connection point between the collector of the transistor and the Zener diode 41 and the reference voltage.
[0024]
In the above configuration, the detected lamp voltage VL and the voltage Vdet corresponding to the lamp current IL, and the on / off state of the transistor 40 and the Zener diode 41 are shown.
[0025]
When normally lit VL> Vdet, 40 and 41 are both off.
[0026]
During half-wave discharge, VL> Vdet, but Vdet exceeds the zener voltage and only 41 is turned on.
[0027]
VL <Vdet, 40 on when the lamp is short-circuited.
[0028]
Oscillation is impossible without a resonance path without a lamp.
[0029]
Therefore, at the time of half-wave discharge and lamp short, a current flows through the light emitting diode 42, an instruction signal is given to the control circuit 23, and the output of the inverter is throttled or stopped.
[0030]
FIG. 3 shows an embodiment in which a configuration for controlling the switching according to the power source of the inverter is added to the embodiment of FIG. In this embodiment, the OP power source 56 is energized by the auxiliary power source 50 through the capacitor 52, and the voltage of the DC power source of the inverter is taken out by the resistors 51, 53, and 54 for application to the OP amplifier 56. A reference voltage is applied to the non-inverting side input terminal of the OP amplifier 56, the reference voltage 55 is compared with the voltage obtained by the voltage dividing resistor, and a voltage corresponding to the difference is output. This output is accumulated in the capacitor 59 through the diode 58 and is given to the gate of the FET 20 that performs the class A amplification operation. Thereby, if the output of the inverter is excessive, the switching cycle is controlled so as to decrease it. Conversely, if the output of the inverter is too small, the switching cycle is controlled so as to increase the switching cycle. On the other hand, the instruction signal relating to the output of the safety circuit 21 arrives at the phototransistor 60. As a result, the output of the OP amplifier 56 is stopped, and the switching cycle is controlled so that the output of the inverter is reduced.
[0031]
FIG. 4 shows another embodiment according to the present invention. In the embodiment shown in the figure, the anode of the diode 32 of the half-wave discharge detection circuit 22 is connected to the resistor 8 side from the filament of the discharge lamp 1 so as to extract the potential between both ends of the resistor 8 purely. . According to such a configuration, in addition to the advantages of the above-described embodiments, the potential to be taken out is not related to the impedance of the filament of the discharge lamp 1, and thus there is an advantage that an accurate half-wave discharge state can be detected stably. is there.
[0032]
FIG. 5 shows still another embodiment. In this embodiment, a DC cut capacitor 9 is connected between the filament of the discharge lamp 1 and the current and one end of the transformer 10, and the potential generated between the capacitors 9 is taken out to detect a half-wave discharge state. It is constituted as follows. According to this embodiment, the same effects as those of the embodiments of FIGS. 2 and 4 can be expected.
[0033]
Further, FIG. 6 shows another embodiment of the present invention. In this embodiment, a voltage dividing capacitor composed of two capacitors 62 and 53 connected in series is connected between the end of the current transformer 10 on the side to which the capacitor 9 is not connected and the filament of the discharge lamp 1, The reference potential of the voltage is taken out from the point, and the potential for detecting the half-wave discharge state is taken out from the connection point between the capacitor 62 and the resistor 8. The extracted potential is rectified by the diodes 64a and 64, accumulated in the capacitor 65, and a voltage related to half-wave discharge is detected. According to this embodiment, the same effect as in FIGS. 2 and 4 can be expected. The lamp voltage is taken out in the same manner as in the above embodiments.
[0034]
FIG. 7 shows still another embodiment. In this embodiment, the detection reference point of the half-wave discharge detection circuit 22 and the detection reference point of the lamp voltage detection circuit 14 are taken as a connection point between the secondary winding of the transformer 7 and the damper resistor 8, and the half-wave discharge detection circuit is used. 22, the potential between both ends of the resistor 8 is detected. As a result, the half-wave discharge state can be detected without being affected by the impedance of the filament of the discharge lamp 1, the lamp voltage can be detected by the secondary side voltage of the transformer 7, and the accuracy of the half-wave discharge state can be detected. Detection is possible.
[0035]
Furthermore, FIG. 8 shows another embodiment. This embodiment has substantially the same configuration as that of FIG. 2, but the configuration of the safety circuit 21 is different. That is, in a normal lighting state, a configuration is adopted in which the lamp voltage is used as a power source and a light is supplied to the light emitting diode 42 via the resistor 84 to turn on the lamp. Then, the Zener diode 65 detects that the lamp voltage has risen abnormally. At this time, a current due to the lamp voltage flows through the resistor 66, and the light emitting diode 42 stops emitting light. Furthermore, half-wave discharge detection is performed in two modes. That is, the transistor 81 is provided in response to the voltage Vdet appearing on the capacitor 34 due to the half-wave discharge being “0”. When the transistor 81 is turned on, the transistor 82 is turned on to turn on the transistor 82 and emit light. The diode 42 is turned off. Further, when the voltage Vdet appearing on the capacitor 34 due to the half-wave discharge is a voltage of a predetermined magnitude, a Zener diode 41 is provided, which is turned on to give an H level to the base of the transistor 82. In the same manner as described above, the light emitting diode 42 is turned off.
[0036]
Will be described with reference to FIGS. 9-12 the reason for half-wave discharge detection of the by two modes. FIG. 9 and FIG. 11 are diagrams showing portions related to half-wave discharge in the discharge lamp lighting device. During half-wave discharge, direct current is superimposed on the lamp current, the alternating current flows through the current transformer 10, and the direct current flows through the resistor 8. Assume that a direct current ILDC flows in the direction indicated by the arrow in FIG . Then, the current ILDC charges the capacitor 34 via the diode 33, and the potential Vdet appearing at the capacitor 34 has a certain potential as shown in FIG . In this case, detection by the Zener diode 41 is performed. In contrast, it is assumed that a direct current ILDC flows in the direction indicated by the arrow in FIG . Then, the current ILDC is blocked by the diode 33 and cannot charge the capacitor 34, and the potential Vdet appearing in the capacitor 34 has a potential “0” as shown in FIG . In this case, detection by the transistor 81 is performed. Thus, in this embodiment, accurate detection is possible regardless of the direction of the half-wave discharge current.
[0037]
In the above-described embodiments, the electronic stabilization means is described in which the present invention is applied to an apparatus using a one-stone inverter. However, the present invention is not limited to this, for example, a half-bridge type An electronic stabilizing means such as an inverter, push-pull type, full bridge type, or the like may be used.
【The invention's effect】
As described above, according to the present invention, since the current flowing through the capacitor connected in series with the feedback means is shunted by the resistor, the charging voltage of the capacitor does not become a high voltage. Furthermore, even when the charge is discharged, a closed circuit is formed with the resistors connected in parallel, so that the charge voltage is not directly applied to the discharge lamp, and the surge voltage is applied to the switching element of the inverter. Can be prevented in advance.
[0038]
In addition to the detection circuit, a lamp voltage detection circuit for detecting the lamp voltage of the discharge lamp is provided. Based on the potential and the lamp voltage detected by the detection circuit , a safety circuit is provided during half-wave discharge and lamp short- circuit. Outputs a control signal for the protective operation, so that in addition to the above-described operation, processing such as accurately detecting an abnormal state of the discharge lamp and reducing the inverter output can be performed.
[0039]
Moreover, according to invention of Claim 2, the illuminating device which has the same effect as said invention can be provided.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of a discharge lamp lighting device according to an embodiment of the present invention.
FIG. 2 is a main part configuration diagram of a discharge lamp lighting device according to an embodiment of the present invention.
FIG. 3 is a configuration diagram of a discharge lamp lighting device according to another embodiment of the present invention.
FIG. 4 is a configuration diagram of a main part of a discharge lamp lighting device according to another embodiment of the present invention.
FIG. 5 is a configuration diagram of a main part of a discharge lamp lighting device according to another embodiment of the present invention.
FIG. 6 is a configuration diagram of a main part of a discharge lamp lighting device according to another embodiment of the present invention.
FIG. 7 is a main part configuration diagram of a discharge lamp lighting device according to another embodiment of the present invention.
FIG. 8 is a configuration diagram of a main part of a discharge lamp lighting device according to another embodiment of the present invention.
FIG. 9 is a diagram for explaining half-wave discharge.
10 shows the voltage according to FIG.
FIG. 11 is a diagram for explaining half-wave discharge.
12 shows the voltage according to FIG.
FIG. 13 is a conventional configuration diagram.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Discharge lamp 2 ... AC power supply 3 ... Diode bridge 4, 5, 9, 11, 12, 13, 18, 19 ... Capacitor 6 ... Transistor 7 ... Transformer 8 ...・ Resistance 10 ... Current transformer (feedback means)
14 ... Lamp voltage detection circuit 16 ... Photocoupler 20 ... FET
21 ... Safety circuit 22 ... Half-wave discharge detection circuit 23 ... Control circuit

Claims (2)

With a discharge lamp;
A DC power supply device that converts AC power into DC power;
An inverter that converts a DC power source into AC by switching with a switching element and applies the AC to the discharge lamp through an inverter transformer;
Feedback means for feeding back the lamp current of the discharge lamp to the switching element of the inverter;
A capacitor connected in series with the feedback means;
A resistor connected in parallel with a series of feedback means and a capacitor;
A half-wave discharge detection circuit for detecting a potential corresponding to a voltage in a half-wave discharge state by the discharge lamp via a resistor or the capacitor;
A voltage dividing capacitor connected in parallel to the discharge lamp and a capacitor for rectifying and accumulating the lamp voltage extracted from the voltage dividing capacitor with a diode, and detecting a lamp voltage of the discharge lamp;
A safety circuit that outputs via the photocoupler an instruction signal protection operation when based rather half-wave discharge during lamp short obtained from the lamp voltage detected by the lamp voltage detection circuit and the detection voltage of the half-wave discharge detection circuit ;
A control circuit for sending a control signal for controlling the inverter to the switching element in response to an instruction signal output from a safety circuit;
A discharge lamp lighting device comprising: A lighting device characterized in that the discharge lamp lighting device according to claim 1 is built in a fixture body, and the discharge lamp is turned on.

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