JP2003347088A - Lighting device for discharge lamp - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lighting device for a discharge lamp capable of mounting at least one of multiple kinds of discharge lamps having substantially equal rated current and different rated output power. <P>SOLUTION: This lighting device is provided with an inverter circuit having a pair of switching elements 2 and 3 for converting DC supplied from a power source 1 into high frequency current, a discharge lamp load circuit L100 constituted of a choke coil 5, the discharge lamps 6 and 10 and a capacitor 7 connected to a series circuit of a coupling capacitor 8 and the discharge lamps 6 and 10 in parallel, connectable terminal boards a-h by changing kinds and the number of connections of the discharge lamps 6 and 10, secondary windings 5S1 and 5S2 provided on the choke coil 5 to output voltage for driving the pair of switching elements 2 and 3, an f-V conversion circuit 100 performing DC voltage conversion corresponding to an oscillation frequency from output voltage of the secondary windings 5S1 and 5S2, and a control means 101 for controlling current of the discharge lamps 6 and 10 based on an output of the f-V conversion circuit 100. <P>COPYRIGHT: (C)2004,JPO

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 for lighting a discharge lamp with high-frequency power from a self-excited inverter circuit, wherein one lighting device has substantially the same rated current and different rated output power. The present invention relates to a lighting device in which a plurality of types of discharge lamps can be mounted in different combinations of the number of connections.

[0002]

2. Description of the Related Art FIG. 18 shows a circuit diagram of a conventional discharge lamp device. In the figure, 1 is a DC power source obtained from a commercial power source,
Reference numerals 2 and 3 denote switching elements made of MOSFETs constituting an inverter circuit, 5 denotes a choke coil, 6 denotes a discharge lamp, 7 denotes a capacitor connected in parallel to the discharge lamp 6, 8
Are coupling capacitors, which constitute a discharge lamp load circuit L100. L110 has the same configuration as the discharge lamp load circuit L100, and is a discharge lamp load circuit connected in parallel to the discharge lamp load circuit L100.
It comprises a discharge lamp 10, a capacitor 11, and a coupling capacitor 12.

A current transformer (hereinafter referred to as CT) 4 is connected between a connection point of the two switching elements 2 and 3 and a connection point of the parallel circuit of the discharge lamp load circuits L100 and L110.
The secondary winding is connected between the polarity connection points shown
At T, the secondary windings 4S1 and 4S2 are connected to the gates of the switching elements 2 and 3 via the resistors 13 and 14 so that the switching elements 2 and 3 are alternately turned ON / OFF with the polarity shown in the drawing. Connected between sources (CT
4 to indicate the coupling between the primary and secondary windings). In addition, the equivalent diode built in parallel between the drain and source of the switching elements 2 and 3 is omitted in the drawing. A starting circuit for starting the inverter is not shown.

FIG. 19 shows an example of the configuration of a DC power supply 1 for obtaining DC power from a commercial power supply. As shown in the figure,
The AC power output from the commercial power supply 1a is configured to be full-wave rectified by the diode bridge 1b, smoothed by the smoothing capacitor 1c, and output as a DC power to the load circuit.

The operation of the conventional circuit shown in FIG. 18 will be described below. In the figure, when a DC power supply 1 is turned on, switching elements 2 and 3 are alternately driven at a high frequency by a starting circuit (not shown), and the discharge lamp is turned on.

FIG. 4 (a) is a diagram for explaining the operation when the two discharge lamps 6 and 10 are replaced with a model A having the same or almost the same rated current and a model B having a lower rated voltage. ). Here, the type A discharge lamp is, for example, FH
In T42EX, the rated discharge lamp current is 0.320 A, the rated discharge lamp voltage is 135 V, and the rated discharge lamp power is 42 W. The type B discharge lamp is, for example, FHT32EX, the rated discharge lamp current is 0.320 A, the rated discharge lamp voltage is 100 V, and the rated discharge lamp power is 32 W. By replacing the discharge lamps 6 and 10 from the model A to the model B as shown in FIG.
The voltage across the discharge lamp decreases, and with this decrease, the current flowing through the choke coil 5 and the choke coil 9 increases, and the current of CT4, through which the combined current of the two choke coils flows, also increases.

[0007]

However, in the conventional discharge lamp device, when the current flowing through the CT4 increases, the secondary winding voltage increases, and the discharge current becomes smaller than when the discharge lamp of type A is mounted. The lamp is lit at a low oscillation frequency, and the power of the discharge lamp increases from the rated power. That is, when a discharge lamp of type A having a high rated voltage of the discharge lamp is mounted on the lighting device and the rated power is set to be optimal in that state, the rated currents of the discharge lamps are almost equal, and the rated voltage is When a lower type B discharge lamp is replaced and mounted, the discharge lamp current increases, and there is a problem that the operation state exceeds the rated power of the type B discharge lamp. In addition, when one of the discharge lamps 6 and 10 is removed in addition to the replacement mounting of the discharge lamp, C
Since the current flowing through T4 decreases, there is a problem that the frequency increases and the output power of the remaining discharge lamp also decreases as compared with the case where all two lamps are mounted. Further, there is a problem that a CT for driving the switching element is required, and the lighting device is expensive and large.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems. A first object of the present invention is to mount a plurality of discharge lamps, one or more, and to have a rated current of approximately one. It is an object of the present invention to provide a lighting device to which a plurality of types of discharge lamps having different rated output powers can be mounted.

A second object of the present invention is to provide a discharge lamp lighting apparatus in which at least one discharge lamp is left and at least one discharge lamp is removed from a plurality of discharge lamp lighting devices. Correspondingly, an object of the present invention is to provide a lighting device capable of lighting with substantially the same output power as when all the lamps are mounted.

A third object of the present invention is to connect a plurality of discharge lamps having the same or substantially the same rated current to one discharge lamp load circuit in series for a discharge lamp of a low rated voltage type. Another object of the present invention is to provide a lighting device to which one of the discharge lamps having a high rated voltage can be connected.

A fourth object of the present invention is to provide a lighting device capable of reducing the number of electric wires from the discharge lamp to the lighting device when connecting a plurality of discharge lamps.

[0012]

SUMMARY OF THE INVENTION A discharge lamp lighting device according to the present invention is an inverter circuit comprising a DC power supply and a half-bridge circuit having a pair of switching elements for converting DC supplied from the DC power supply into a high-frequency current. And a discharge lamp load comprising a choke coil, at least one discharge lamp lit by high-frequency current from the inverter circuit, a series circuit in which coupling capacitors are respectively connected in series, and a capacitor connected in parallel to the discharge lamp. Circuit, connection means provided in the load circuit, which can be connected by changing the type and the number of connections of the discharge lamp, and a voltage which is provided in the choke coil of the discharge lamp load circuit and drives the pair of switching elements. A secondary winding to be output, and f-converting an output voltage of the secondary winding into a DC voltage corresponding to the oscillation frequency. A conversion circuit, and control means for controlling the current of the discharge lamp based on the output of the fV conversion circuit, wherein the connection means have substantially the same rated current, but different rated voltage and rated discharge lamp power. When the discharge lamp is connected, the discharge lamp is lit at an output power corresponding to each rated output power of the discharge lamp regardless of the number of connected discharge lamps.

Also, an inverter circuit including a DC power supply, a half-bridge circuit having a pair of switching elements for converting DC supplied from the DC power supply into a high-frequency current, a choke coil, and a high-frequency current from the inverter circuit. A discharge lamp, a series circuit in which coupling capacitors are respectively connected in series, and a plurality of discharge lamp load circuits connected in parallel comprising a capacitor connected in parallel to the discharge lamp; and the discharge lamp provided in the load circuit. A connection means that can be connected by changing the type and the number of connections, and a voltage output to drive the pair of switching elements, each being provided in the choke coil of the discharge lamp load circuit.
A secondary winding, an fV conversion circuit for converting the output voltage of the secondary winding into a DC voltage corresponding to the oscillation frequency thereof,
Control means for controlling the current of the discharge lamp based on the output of the -V conversion circuit, wherein the connection means connects the discharge lamps having substantially the same rated current, different rated voltage and different rated discharge lamp power. Sometimes, in each of the load circuits, the connection is made such that the sum of the rated voltages of the discharge lamps of each of the load circuits is substantially equal, regardless of the number of connected discharge lamps,
The discharge lamp is lit at an output power corresponding to the rated output power of each of the discharge lamps.

Further, an inverter circuit including a DC power supply, a half-bridge circuit having a pair of switching elements for converting DC supplied from the DC power supply into a high-frequency current, a choke coil, and a high-frequency current from the inverter circuit. A discharge lamp, a series circuit in which coupling capacitors are respectively connected in series, and a plurality of discharge lamp load circuits connected in parallel comprising a capacitor connected in parallel to the discharge lamp; and the discharge lamp provided in the load circuit. A connection means that can be connected by changing the type and the number of connections, and a voltage output to drive the pair of switching elements, each being provided in the choke coil of the discharge lamp load circuit.
A secondary winding, an fV conversion circuit for converting the output voltage of the secondary winding into a DC voltage corresponding to the oscillation frequency thereof,
Control means for controlling the current of the discharge lamp based on the output of the -V conversion circuit, wherein the connection means connects the discharge lamps having substantially the same rated current, different rated voltage and different rated discharge lamp power. Sometimes, for each of the load circuits, the combination of the discharge lamps in each of the load circuits is the same, and the output power corresponding to the rated output power of each of the discharge lamps regardless of the number of connected discharge lamps. It is designed to light up.

The connection of the discharge lamps of the load circuit by the connecting means is such that a plurality of discharge lamps having a low rated voltage are connected in series, and at least one of the discharge lamps having a high rated voltage is connected.

Further, the connecting means connects the plurality of discharge lamps to the discharge lamp load circuit in series with a voltage generated in a secondary winding provided in a choke coil of the discharge lamp load circuit when the discharge lamps are connected in series. When only one discharge lamp is connected so as to heat each filament of the plurality of discharge lamps, the connection can be selected so as not to heat the filament.

Further, when there are a plurality of discharge lamp load circuits, the resonance frequencies of the plurality of discharge lamp load circuits are determined to be substantially the same.

Further, the voltages at the time of normal lighting of the plurality of secondary windings for driving the switching elements of the inverter circuit are determined so as to be substantially the same.

Further, a choke coil is connected between the discharge lamp and the coupling capacitor.

A diode having an anode connected to a terminal of the coupling capacitor not connected to the DC power supply and a cathode having a cathode connected to the positive electrode of the DC power supply, and a terminal of the coupling capacitor not connected to the DC power supply. And a diode whose anode is connected to the negative electrode of the DC power supply.

Further, the fV conversion circuit is provided with voltage reduction means for reducing the output voltage of the fV conversion circuit by a predetermined value.

Further, the characteristics of the fV conversion circuit are such that a larger output voltage can be obtained as the oscillation frequency of the inverter circuit is smaller.

[0023]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 FIG. 1 is a circuit diagram showing a configuration of a discharge lamp lighting device according to Embodiment 1 of the present invention, and FIG. 2 is an operation waveform diagram. In FIG. 1, 1 is a DC power supply obtained from a commercial power supply, 2 and 3 are switching elements made of MOSFETs constituting an inverter circuit,
L100 is a discharge lamp load circuit. Discharge lamp load circuit L1
In 00, 5 is a choke coil, 6 is a terminal block a,
Discharge lamps of type A connected to b, c, d via sockets (not shown), and 10 is a discharge lamp of type A connected to terminal blocks e, f, g, h via sockets , 7 are capacitors connected between the terminal block b and the terminal block h, and 8 is a coupling capacitor connected between the terminal block g and the negative electrode of the DC power supply 1. 5S3 is a secondary winding of the choke coil 5,
One end is connected to a terminal block e and the other end is connected to a terminal block c via a capacitor 15.

The choke coil 5 is further provided with secondary windings 5S1 and 5S2 indicated by the polarities shown in the drawing, and resistors 14 and 14, respectively, so that the switching elements 2 and 3 are alternately turned ON / OFF. And a resistor 13 connected between the gate and the source (shown by broken lines to indicate the coupling between the primary winding and the secondary winding of the choke coil 5). The type A discharge lamp is, for example, FHT42EX, the rated discharge lamp current is 0.320 A, the rated discharge lamp voltage is 135 V, and the rated discharge lamp power is 42 W. In addition, an equivalent diode that is built in parallel between the drain and the source of the switching elements 2 and 3 is not shown. A starting circuit for starting the inverter is not shown.

Reference numeral 100 denotes an fV conversion circuit as frequency-voltage conversion means for converting the oscillation frequency into a DC voltage, and 101 changes the oscillation frequency of the switching elements 2 and 3 based on the output of the fV conversion circuit 100. This is a control circuit that is control means for controlling the current of the discharge lamps 6 and 10 by performing the control. In the fV conversion circuit 100, 50 is a diode in which the anode is connected to the secondary winding 5S2 of the choke coil 5 and the cathode is connected to one end of the capacitor 52, and the other end of the capacitor 52 is connected to the negative electrode of the DC power supply 1. Is done. 53
Is a resistor having one end connected to the cathode of the diode 50 and the other end connected to the cathode of the Zener diode 54, and the anode of the Zener diode 54 is connected to the negative electrode of the DC power supply 1. 55 is a capacitor connected in parallel to the Zener diode 54, and 57 is one end of the choke coil 5
The other end is connected to one end of the resistor 56 at the next winding 5S2.
The other end of the resistor 56 is connected to the negative electrode of the DC power supply 1.

Reference numeral 59 denotes a transistor whose emitter is the negative electrode of the DC power supply, whose base is at the connection point of the resistors 56 and 57, and whose collector is the Zener diode 5 via the resistor 60.
4 cathode. 61 is a capacitor connected between the collector and the emitter of the transistor 59; 62 is an operational amplifier (hereinafter referred to as OP AMP); its non-inverting input terminal is connected to the collector of the transistor 59 and its inverting input terminal is connected to the cathode of the diode 63; Is done. OP A
The output of MP62 is connected to the anode of diode 63. 65 is a capacitor connected between the cathode of the diode 63 and the negative electrode of the DC power supply 1.

In the control circuit 101, 67 is a resistor connected in parallel with the capacitor 65, 69 is a variable three-terminal regulator, 68 is a resistor connected between the inverting input terminal (REF terminal) of the variable regulator 69 and the cathode, 70 Is a resistor having one end connected to the cathode of the variable three-terminal regulator 69, and the other end connected to the gate of the switching element 3 via the cathode of the diode 71. In addition,
The variable three-terminal regulator is, for example, HA17431 manufactured by Hitachi.
Series correspond to this.

The basic operation of the discharge lamp lighting device according to the first embodiment of the present invention will be described below with reference to FIGS.
FIG. 2A shows a capacitor 61 when the oscillation frequency is small.
(B) is the voltage of the capacitor 65 corresponding to FIG. (A), (c) is the voltage of the capacitor 61 when the oscillation frequency is large, and (d) is (c) of FIG. , The voltages of the capacitors 65 corresponding to.

In FIG. 1, when a DC power supply 1 is turned on, switching elements 2 and 3 are alternately driven at a high frequency by a starting circuit (not shown), and discharge lamps 6 and 10 connected in series are switched on. Light. At this time, f−
In the V conversion circuit 100, a voltage is applied to the base of the transistor 59, whose polarity is inverted every half cycle generated in the secondary winding 5S2 of the choke coil 5, so that the transistor 59 is turned on and off every half cycle. . As a result, while the transistor 59 is OFF, the capacitor 6
1 are connected to both ends of a capacitor 55 as shown in FIG.
Is integrated with the resistor 60 to obtain a triangular wave. The peak voltage of the triangular wave increases when the OFF period of the transistor 59 is long, and decreases when the OFF period of the transistor 59 is short as shown in FIG. The voltage of the capacitor 61 is changed to OP AMP6
2. Capacitor 6 because peak is detected by diode 63
A DC voltage corresponding to the peak voltage of the triangular wave of the capacitor 61 is obtained at both ends of the capacitor 5. FIG. 2 (a) and (c)
(B) and (d) respectively correspond to the triangular wave. That is, a DC voltage corresponding to the oscillation frequency is obtained in the capacitor 65.

Next, in FIG. 1, the case where two discharge lamps 6 and 10 of the model A are replaced and mounted with two discharge lamps of the model B having the same rated current and the lower rated voltage of the discharge lamps will be described. 3 and FIG. In FIG. 3, the discharge lamps 6 and 10 of type B are, for example, FHT32EX, the rated discharge lamp current is 0.320 A, the rated discharge lamp voltage is 100 V, and the rated discharge lamp power is 32 W. FIG. 4A is an operation characteristic diagram of the conventional example, and FIG. 4B is an operation characteristic diagram of the discharge lamp lighting device of the first embodiment.

FIG. 4 shows an outline of the basic operation. Conventionally, as shown in FIG. 4A, the discharge lamp is changed from a discharge lamp of type A having a high rated voltage to a model having a low rated voltage. B
When replaced with the discharge lamp of the above, the lamp is lit at a lower oscillation frequency than the frequency when the discharge lamp of type A is mounted,
Although the discharge lamp current increased and the power of the type B discharge lamp increased from the rated power (WLB), in the discharge lamp lighting device according to the present embodiment, the fV conversion circuit 100 and the control circuit 101 perform the operations shown in FIG. As shown in (b), the oscillation frequency of the discharge lamp of type B is increased to lower the discharge lamp current, so that the oscillation frequency and the discharge current of the discharge lamp of type A are the same. The power (WLB) of the discharge lamp is not increased above the rated power (WLB).

When the discharge lamp is replaced with a discharge lamp of type B having a lower rated voltage as shown in FIG. 3, the oscillation frequency of the inverter circuit becomes lower as shown in FIG. Although the voltage becomes higher than that of the model A, if the resistors 68 and 67 of the control circuit 101 are appropriately selected, the variable three-terminal regulator 69 can be a high voltage with the model A of the discharge lamp mounted. It does not operate at the oscillating frequency, and is set so that the cathode voltage decreases when the rated voltage corresponds to the low oscillating frequency at which the type B discharge lamp is mounted.

Then, the current for driving the gate of the switching element 3 is bypassed via the diode 71, the resistor 70, and the variable three-terminal regulator, so that the ON period of the switching element 3 is shortened. That is, as shown in FIG. 4B, since the oscillation frequency is increased, it is possible to suppress an increase in the current of the discharge lamp when the discharge lamp of the type B is replaced and mounted.
Here, the f-V conversion circuit 100 is set so that the discharge lamp power when the discharge lamp of the type B is mounted is the rated output power.
Output Voltage Characteristics and Control Circuit 1 for Oscillation Frequency
If the resistors 67, 68, and 70 of No. 01 are properly selected, regardless of whether the discharge lamp of the model A or the discharge lamp of the model B is mounted, the lamp is lit at the output power corresponding to the rated output power. can do.

The filament of the discharge lamp 6 connected to the terminal blocks c and d of the discharge lamp 6 via a socket, the discharge lamp 1
The discharge lamp 10 filament connected to the terminal blocks e and f of No. 0 via a socket is a secondary winding 5S of the choke coil 5.
Since the filament is heated by the voltage generated in 3, the filament can be prevented from being disconnected at an early stage due to the cold start of the filament, and the blackening of the discharge lamp tube wall can be prevented.

Further, in FIG. 1, two discharge lamps 6 and 10 of the type A are connected to one discharge lamp of the type C having a high rated voltage and a rated current of the discharge lamps equal or substantially equal as shown in FIG. A case where the lamp is replaced and mounted will be described. In this case, when one discharge lamp is mounted, one end of the discharge lamp 6 is mounted on the terminal blocks a and b, and the other ends are mounted on the terminal blocks g and h, as shown in the figure. The terminal blocks c, d, e, and f are not connected to the filament of the discharge lamp 6. Here, the type C discharge lamp is, for example, FHT57EX, and the rated discharge lamp current is 0.320 A.
The rated discharge lamp voltage is 182V, and the rated discharge lamp power is 57W. The rated voltage 182 V is the same as the model B shown in FIG.
Of the discharge lamps 6 and 7 is approximately equal to a total of 200V of the rated voltage 100V.

As described above, at least one discharge lamp having a high rated voltage is connected, and the lighting of the discharge lamp of the model C can be controlled at substantially the rated current by the action of the fV conversion circuit. In addition,
Since the terminal blocks c, d, e, and f are not connected to the filament of the discharge lamp 6, loss can not be caused by the voltage generated in the secondary winding 5S3 of the choke coil 5.

If the fV conversion circuit 100 is not operated when the rated currents of the discharge lamps are substantially equal, the inverter circuit oscillates when a discharge lamp of the type (model) with the lowest rated voltage is mounted. The frequency is minimized and the lamp current is maximized. Under these conditions, if the operating conditions such as the electrical withstand characteristics of the circuit components of the discharge lamp lighting device and the temperature rise of the discharge lamp lighting device are confirmed, the f-V corresponding to the oscillation frequency of the inverter oscillation circuit of the present invention can be obtained. The characteristic of the output voltage of the conversion circuit 100 is that the smaller the oscillation frequency of the inverter oscillation circuit is, the larger the output voltage is obtained, the oscillation frequency of the inverter circuit is increased, and the operation is performed in a direction to suppress the current of the discharge lamp. Can be. Therefore, the characteristics of the fV conversion circuit 100 are opposite to the characteristics of the fV conversion circuit 100, that is, the failure mode of the fV conversion circuit 100 is smaller than that of the method in which the current of the discharge lamp is increased to adjust the rated output power of the discharge lamp. Can be more secure.

As described above, according to the present embodiment, 1
Not only can different types of discharge lamps with different rated voltages (approximately the same rated current and different rated voltage) be installed and replaced, but also by appropriately selecting the terminal block of the lighting device to which the discharge lamp is connected Either two lights or one light can be turned on.

The secondary winding 5S2 of the choke coil 5
Drive the switching element at the same time, and at the same time use the voltage as the power supply for the fV conversion circuit to obtain a detection voltage corresponding to the oscillation frequency of the inverter circuit. And can be made inexpensive and miniaturized.

The characteristics of the output voltage of the fV conversion circuit 100 are controlled such that the smaller the oscillation frequency of the inverter oscillation circuit is, the larger the output voltage is obtained and the oscillation frequency of the inverter circuit is increased to suppress the current of the discharge lamp. Direction, and the characteristics of the fV conversion circuit 100 are the reverse of the characteristics, that is, the fV conversion circuit 100 increases the current of the discharge lamp so that the fV conversion circuit 100 adapts the rated output power of the discharge lamp. Conversion circuit 10
0 can be made more secure against failure modes.

Further, since a dedicated CT for driving the switching element is not required, the cost can be reduced and the size can be reduced. When two discharge lamps are connected in series, the secondary winding of the choke coil 5 heats the filament of the discharge lamp by 5S3 to prevent early disconnection due to cold start of the filament and early blackening of the discharge lamp tube wall. At the same time, by appropriate selection of the terminal block, in the case of one lamp connection, it is possible to suppress unnecessary loss due to the secondary winding 2S3.

In FIG. 1 showing the circuit of the first embodiment, the switching elements 2 and 3 are connected to an n-channel MO.
The case where the switching element 2 is an n-channel MOSFET and the switching element 3 is a so-called complementary configuration of a p-channel MOSFET, and the secondary winding 5 of the choke coil 5 is described.
Even if the voltage generated at s1 is used as a common driving power supply for these two switching elements and the fV conversion circuit 100 and the control circuit 101 are provided in the secondary winding 5s1, the same effect as that of the first embodiment can be obtained. .

In this embodiment, the discharge lamp load circuit L
Although the types of the 100 discharge lamps 6 and 10 are the same, the types may be changed so that the sum of the voltages is substantially the same.

Embodiment 2 FIG. 6 is a circuit diagram showing a configuration of a discharge lamp lighting device according to Embodiment 2 of the present invention.
In the figure, elements having the same function as in the first embodiment are denoted by the same reference numerals, and description thereof is omitted. In the figure, L100a
Is a discharge lamp load circuit having the same configuration as the discharge lamp load circuit L100. 5a is a choke coil, 6a and 10a are model A
, A condenser 7a, a coupling capacitor 8a, a secondary winding 5aS3 of a choke coil 5a,
5a is a capacitor, which corresponds to a component of the discharge lamp load circuit L100. Also, the discharge lamps 6, 10, 6a,
10a shows a case where a discharge lamp of type A is mounted. Here, the type A discharge lamp is, for example, FHT42E.
In X, the rated discharge lamp current is 0.320 A, the rated discharge lamp voltage is 135 V, and the rated discharge lamp power is 32 W.

Further, terminal blocks a1, b1, c1, d1, e
1, f1, g1, h1 are terminal blocks a, b, c, d,
e, f, g, and h. The secondary windings 5as1, 5as2, 5as3 of the choke coil 5a correspond to the secondary windings 5s1, 5s2, 5s3 of the choke coil 5, respectively. Reference numerals 16 and 17 denote resistors corresponding to the resistors 13 and 14, respectively, and the secondary windings 5as1 and 5as of the choke coil 5a.
As2 is connected so as to drive the gates of the switching elements 2 and 3 in parallel with the voltages generated in the secondary windings 5s1 and 5s2 via these resistors. Also,
51 of the fV conversion circuit 100 is 2 of the choke coil 5a.
A diode whose anode is connected to the next winding 5as2,
Its cathode is connected to the cathode of diode 50. 58 is a secondary winding 5as of the choke coil 5a.
2 is connected to one end of the resistor, and the other end is connected to a connection point between the resistor 57 and the resistor 56.

Hereinafter, the operation of the discharge lamp lighting device according to the second embodiment of the present invention will be described with reference to FIG. In FIG. 6, when the DC power supply 1 is turned on, the switching elements 2 and 3 are alternately driven at a high frequency by a starting circuit (not shown) and are connected in series with the discharge lamps 6, 10 and the discharge lamps 6a, 10a. Lights up. In this case, the switching elements 2 and 3 are secondary windings 5s1 and 5s of the choke coil 5.
2 and secondary windings 5as1, 5as of the choke coil 5a
2, the fV conversion circuit 100 is driven in parallel by the secondary winding 5s2 of the choke coils 5 and 5a,
Since the frequency signal generated at 5as2 is obtained from the voltage wired-ORed by the resistors 57 and 58, it can be driven at the frequency corresponding to the discharge lamp type A and can be lit at the rated current of the discharge lamp type A.

Here, even if the discharge lamp of any one of the discharge lamp load circuits is removed due to a life failure or the like, the switching elements 2 and 3 are connected to the secondary windings 5s1 and 5s2 of the choke coil 5 and the choke coil 5a. Since the driving is performed in parallel with the voltage generated in the secondary windings 5as1 and 5as2, the discharge lamp load circuits L100 and L100 can be operated even if the driving voltage from one of the choke coils 5 and 5a is lost.
a, if any one of the remaining discharge lamp load circuits is normally lit, it can be regarded as substantially the same circuit as in the first embodiment. It can be driven at the corresponding frequency and can be lit at the rated current of the discharge lamp type A.

Next, in FIG. 6, all of the discharge lamps mounted on the discharge lamp load circuit are changed from the type A to the discharge lamps of the type B having the same or almost the same rated current of the discharge lamp and the lower rated voltage. The case of replacement mounting will be described with reference to FIG.
In FIG. 7, the discharge lamp of type B is, for example, FHT32EX.
And the rated discharge lamp current is 0.320 A and the rated discharge lamp voltage is 1
00V, rated discharge lamp power is 32W. In this case, the switching elements 2, 3 are the secondary windings 5s1, 5s2 of the choke coil 5 and the secondary winding 5a of the choke coil 5a.
are driven in parallel by the voltage generated in s1, 5as2,
The fV conversion circuit 100 converts a frequency signal generated in the secondary windings 5s2 and 5as2 of the choke coils 5 and 5a into a resistor 5
Since the voltage is obtained from the wired-OR voltage at 7, 58, the switching element 2,
3 can be driven at a frequency corresponding to the discharge lamp type B, and can be turned on at almost the rated current of the discharge lamp type B.

Further, in FIG. 6, the discharge lamp load circuit L
FIG. 8 illustrates a case where the discharge lamp 100 and L100a are replaced with one discharge lamp of the model C having a higher rated voltage and the same rated current as the discharge lamp of the model A and having a higher rated voltage. When one discharge lamp is mounted, as shown, the terminal blocks a, b,
a1, b1 is connected to one end of the discharge lamp, and terminal blocks g, h, g1, h
Attach the other end to 1. Also, terminal blocks c, d, e, f, c
No filament of the discharge lamp is connected to 1, d1, e1, and f1. Here, the type C discharge lamp is, for example, FHT57E.
In X, the rated discharge lamp current is 0.320 A, the rated discharge lamp voltage is 182 V, and the rated discharge lamp power is 57 W. Note that the rated voltage 182V is substantially equal to the total 200V of the rated voltages 100V of the discharge lamps 6 and 7 of the type B shown in FIG.

As described above, by connecting one discharge lamp having a high rated voltage, the lighting of the discharge lamp of the model C can be controlled at substantially the rated current by the action of the fV conversion circuit.

As described above, according to the present embodiment, even if one of the plurality of discharge lamp load circuits L100 and L100a is removed, the discharge lamp currents of the remaining discharge lamp load circuits are removed. Does not fluctuate, and
Even if one discharge lamp load circuit is removed from a plurality of discharge lamp load circuits for power saving, the discharge lamp currents of the remaining discharge lamp load circuits can be normally lit. Further, since a dedicated CT for driving the switching element is not required, the cost can be reduced and the size can be reduced.

If the resonance frequency of the plurality of discharge lamp load circuits and the voltages of the secondary windings respectively corresponding to the plurality of choke coils are selected to be substantially the same when the same discharge lamp is mounted, fV The output characteristics of the conversion circuit 100 are also substantially the same, and the difference in characteristics between a plurality of discharge lamp load circuits when different discharge lamps are mounted can be reduced.

In this embodiment, the discharge lamp load circuit L
Although the types of the discharge lamps 6, 106a, 10a of 100 and 100a are the same, the discharge lamp load circuits L100 and L100
The types may be changed such that the sum of the voltages of the discharge lamps a is substantially the same. In FIG. 6 showing the circuit of the second embodiment, the case where the switching elements 2 and 3 are constituted by n-channel MOSFETs has been described.
ET, switching element 3 is p-channel MOSFET
And a voltage obtained by connecting the voltages generated in the secondary windings 5s1 and 5as1 of the choke coils 5 and 5a in parallel via a resistor as a common driving power supply for these two switching elements. Next winding 5s
1, 5as1, fV conversion circuit 100 and control circuit 1
01, the same effect as that of the second embodiment can be obtained.

Embodiment 3 FIG. 9 is a circuit diagram showing a configuration of a discharge lamp lighting device according to Embodiment 3 of the present invention. In the figure, elements having the same functions as those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted. The figure shows the first embodiment.
In FIG. 1, the diode 20 has a cathode connected to the connection point between the discharge lamp 10 and the coupling capacitor 8 and the anode connected to the negative electrode of the DC power supply 1. The anode is connected to the connection point, and the cathode is connected to the positive electrode of the DC power supply 1. The discharge lamps 6 and 10 are, for example, discharge lamps having the same model name as the discharge lamp of the model name A.

In the figure, when the DC power supply 1 is turned on,
The switching elements 2 and 3 are alternately driven at a high frequency by a starting circuit (not shown), and the discharge lamps 6 and 10 connected in series are turned on. Here, when one or both of the discharge lamps 6 and 10 reach the end of life due to the consumption of the discharge material of the discharge lamp filament, the discharge current of the discharge lamp decreases. However, since the equivalent impedance increases, the sharpness of the resonance of the discharge lamp load circuit L100 increases, the current flowing through the discharge lamp load circuit L100 increases, and a large voltage is generated at both ends of the coupling capacitor 8 as compared with the normal lighting. I do.

Here, the value of the coupling capacitor is appropriately selected, and the peak value of the voltage generated in the coupling capacitor 8 at the end of the life of the discharge lamp is higher than the positive voltage of the DC power supply 1 or lower than the negative voltage. If the current is flowing out or flowing into the DC power supply 1 through the newly added diodes 20 and 21 and the forward voltage drop of the diodes 20 and 21 is ignored, the voltage of the capacitor 8 becomes DC. As a result, the increase in the current of the discharge lamp load circuit can be suppressed. That is, according to the third embodiment, the action of the newly added diodes 20 and 21 suppresses the increase in the current of the discharge lamp at the end of its life, and at the same time, the discharge lamp at the time of normal lighting.
The first embodiment is capable of controlling the current to correspond to the rated current of the mounted discharge lamp even when different types of discharge lamps having substantially the same rated current are mounted by the operation of the -V conversion circuit and the control circuit 101. The same effect can be obtained.

FIG. 10 is a circuit diagram in which the diodes 20 and 21 described in FIG. 9 are newly added to the circuit diagram in FIG. 5 described in the first embodiment, and the discharge lamp load circuit L100 at the end of the life of the discharge lamp. At the same time as suppressing the current, the current can be controlled to the rated current of the single mounted discharge lamp C.

Embodiment 4 FIG. FIG. 11 is a circuit diagram showing a configuration of a discharge lamp lighting device according to Embodiment 4 of the present invention. In the figure, elements having the same functions as those in FIG. 6 of the second embodiment are denoted by the same reference numerals, and description thereof will be omitted.

FIG. 11 is a circuit diagram of FIG. 6 described in the second embodiment. In the discharge lamp load circuit L100, the diodes 20 and 21 described in FIG.
The diode 110 is newly provided with diodes 20a and 21a, which can suppress an increase in the current of the discharge lamp load circuit at the end of the life of the discharge lamp and can control the current to the rated current of the mounted discharge lamp.

FIG. 12 shows a case where a discharge lamp of type C is replaced and mounted in place of the discharge lamp of type A in the circuit diagram of FIG. It is possible to suppress an increase in current and at the same time control the rated current of the mounted discharge lamp.

Embodiment 5 FIG. 13 is a circuit diagram showing a configuration of a discharge lamp lighting device according to Embodiment 5 of the present invention, and FIG. 14 is a waveform diagram for explaining the operation. FIG.
In the following description, elements having the same functions as those of the first embodiment shown in FIG. Numeral 80 denotes a zener diode which is a newly added voltage reduction means having a collector connected to the cathode of the transistor 59 and an anode connected to the non-inverting input terminal of the OP AMP 62.

The operation of the discharge lamp lighting device according to the fifth embodiment of the present invention will be described below with reference to FIGS. FIG.
4A shows the voltage of the capacitor 61 when the conversion coefficient of the fV conversion circuit is small, FIG. 4C shows the voltage of the capacitor 61 when the conversion coefficient of the fV conversion circuit is large, and FIG. Is a capacitor 65 corresponding to FIGS.
Are shown.

In FIG. 13, when the DC power supply 1 is turned on, the switching elements 2 and 3 are alternately driven at a high frequency by a starting circuit (not shown), and the discharge lamp is turned on. Here, when a different type of discharge lamp is replaced and mounted, the oscillation frequency changes as described in the first embodiment. A change in the oscillation frequency is Δf, and a change in the output of the fV circuit 100 obtained by the change is ΔV, fV
Assuming that the conversion coefficient of the circuit 100 is ΔV / Δf, the larger the conversion coefficient, the larger the change in the output voltage with respect to the change in the frequency, and the greater the discrimination performance when a different type of discharge lamp is replaced and mounted.

For this purpose, the resistor 60 and the capacitor 6
When the value of 1 is appropriately selected and the characteristic of FIG. 14A is changed to the characteristic of FIG. 14C, the conversion coefficient ΔV / Δf increases, but the absolute value of the output voltage of the fV circuit 100 for the same frequency is obtained. Will also increase. However, since the voltage of the non-inverting input terminal built in the variable three-terminal regulator 69 is fixed, the Zener diode 80 having the Zener voltage VZD is used.
Is added, the same output voltage can be obtained by increasing the conversion coefficient ΔV / Δf as shown in FIG.

As described above, according to the present embodiment, f-
Since the conversion coefficient of the V conversion circuit can be increased,
The discrimination ability of different types of discharge lamps can be made excellent. Even when a general-purpose OP AMP is used instead of the variable three-terminal regulator 69, the same effect can be obtained by inserting the zener diode 80 because the input terminal voltage is limited.

In the fifth embodiment, the discharge lamp load circuit L100 is connected to the connection point between the discharge lamp 10 and the coupling capacitor 8 and the DC power supply 1 as shown in the circuit diagram of FIG. Diode 2 between the positive and negative electrodes of
The same effect can be obtained even in a configuration in which 1 and 20 are connected.

Embodiment 6 FIG. FIG. 15 is a circuit diagram showing a configuration of a discharge lamp lighting device according to Embodiment 6 of the present invention, and FIG. 16 is a waveform diagram for explaining the operation. In the figure, elements having the same functions as those in FIG. Reference numeral 81 denotes a newly added Zener diode having a cathode connected to the cathode of the Zener diode 63 and an anode connected to the inverting input terminal of the variable three-terminal regulator 69.

The operation of the discharge lamp lighting device according to the fifth embodiment of the present invention will be described below with reference to FIGS. FIG.
6 (a) is the voltage of the capacitor 61 when the conversion coefficient of the fV conversion circuit is small, FIG. 6 (b) is the voltage of the capacitor 65 corresponding to FIG. 6 (a), and FIG. The voltage of the capacitor 61 when the conversion coefficient of the conversion circuit is large,
(D) is the voltage of the capacitor 65 corresponding to FIG.
FIG. 7E shows the anode voltage of the Zener diode 81 when the voltage in FIG.

In FIG. 15, when the DC power supply 1 is turned on, the switching elements 2 and 3 are alternately driven at a high frequency by a starting circuit (not shown), and the discharge lamp is turned on. Here, when a different type of discharge lamp is replaced and mounted, the oscillation frequency changes as described in the first embodiment. As described in the fourth embodiment, fV
When the conversion coefficient of the circuit 100 is increased by ΔV / Δf, the absolute value of the output voltage of the fV circuit 100 for the same frequency also increases as shown in FIGS.

However, since the voltage of the non-inverting input terminal built in the variable three-terminal regulator 69 is fixed, if a zener diode 81 having a zener voltage VZD is added, as shown in FIGS. Conversion coefficient ΔV
By increasing / Δf, the same output voltage can be applied to the inverting input terminal of the variable three-terminal regulator 69.

As described above, according to the present embodiment, f-
Since the conversion coefficient of the V conversion circuit can be increased,
It is possible to improve the discrimination ability of different types of discharge lamps. Further, even when a general-purpose OP AMP is used instead of the variable three-terminal regulator 69, the same effect can be obtained by inserting the zener diode 81 because the input terminal voltage is limited.

In the sixth embodiment, the discharge lamp load circuit L100 is connected to the connection point between the discharge lamp 10 and the coupling capacitor 8 and the DC power supply 1 as shown in the circuit diagram of FIG. Diode 2 between the positive and negative electrodes of
The same effect can be obtained even in a configuration in which 1 and 20 are connected.

Embodiment 7 FIG. 17 is a circuit diagram showing a configuration of a discharge lamp lighting device according to Embodiment 7 of the present invention. In the figure, elements having the same functions as those in FIG. 11 of the fourth embodiment are denoted by the same reference numerals, and description thereof is omitted. In the present embodiment, the order of connection of the discharge lamp in which the choke coil and the capacitor are connected in parallel in the discharge lamp load circuit of FIG. 11 described in the fourth embodiment is changed. That is,
A discharge lamp, a choke coil, and a coupling capacitor, in which a capacitor is connected in parallel from a connection point of the switching elements 2 and 3, are arranged in this order.

By arranging as shown in the figure, if the lighting device is connected to the terminal block a to which the discharge lamp 6 is connected by the wiring ca1, wiring from the terminal block a to the terminal block a1 to which the discharge lamp 6a is connected by the wiring ca2. can do. That is, since it is not necessary to wire two separate lines from the lighting device to the discharge lamp 6 and the discharge lamp 6a, the number of wires from the lighting device to the discharge lamp and the number of output connectors of the lighting device can be reduced.

Although FIG. 17 illustrates the case where there are two discharge lamp load circuits, even when there are three discharge lamp load circuits,
The output line from the lighting device can be a common ca1, and the number of wires from the lighting device to the discharge lamp and the number of output connectors of the lighting device can be reduced.

[0076]

Since the present invention is configured as described above, it has the following effects.

An inverter circuit comprising a DC power supply, and a half-bridge circuit having a pair of switching elements for converting DC supplied from the DC power supply into a high-frequency current;
A discharge lamp load circuit including a choke coil, at least one discharge lamp lit by high-frequency current from the inverter circuit, a series circuit in which coupling capacitors are respectively connected in series, and a capacitor connected in parallel to the discharge lamp. A connection means provided in the load circuit and connectable by changing the type and the number of connections of the discharge lamp, and a connection means provided in the choke coil of the discharge lamp load circuit to output a voltage for driving the pair of switching elements. A secondary winding; an fV conversion circuit for converting the output voltage of the secondary winding into a DC voltage corresponding to the oscillation frequency; and controlling the current of the discharge lamp based on the output of the fV conversion circuit. Control means for connecting the discharge lamps having the same rated current, substantially the same rated voltage, and different rated lamp powers. Regardless of the number of connected discharge lamps, the lamps are lit with output power corresponding to the rated output power of each of the discharge lamps, so that a single lighting device has approximately the same rated current and a plurality of types with different rated voltages Not only can the discharge lamp (model name) be replaced and mounted, but also two or one can be turned on by appropriately selecting the connection means for connecting the discharge lamp. In addition, a power source for the fV conversion circuit can be obtained with a simple configuration, and it is possible to reduce the size and cost.
Further, it is possible to make the fV conversion circuit 100 safer against a failure mode. Further, since a dedicated CT for driving the switching element is not required, the cost can be reduced and the size can be reduced.

Further, an inverter circuit comprising a DC power supply, a half-bridge circuit having a pair of switching elements for converting DC supplied from the DC power supply into a high-frequency current, a choke coil, and a high-frequency current from the inverter circuit. A discharge lamp, a series circuit in which coupling capacitors are respectively connected in series, and a plurality of discharge lamp load circuits connected in parallel comprising a capacitor connected in parallel to the discharge lamp; and the discharge lamp provided in the load circuit. A connection means that can be connected by changing the type and the number of connections, and a voltage output to drive the pair of switching elements, each being provided in the choke coil of the discharge lamp load circuit.
A secondary winding, an fV conversion circuit for converting the output voltage of the secondary winding into a DC voltage corresponding to the oscillation frequency thereof,
Control means for controlling the current of the discharge lamp based on the output of the -V conversion circuit, wherein the connection means connects the discharge lamps having substantially the same rated current, different rated voltage and different rated discharge lamp power. Sometimes, in each of the load circuits, the connection is made such that the sum of the rated voltages of the discharge lamps of each of the load circuits is substantially equal, regardless of the number of connected discharge lamps,
Since the lamps are lit at the output power corresponding to the rated output power of each of the discharge lamps, even if one of the plurality of discharge lamp load circuits is removed, the remaining discharge lamp load circuits are removed. Can be prevented from fluctuating. In addition, even if one of the plurality of discharge lamp load circuits is removed for power saving to remove power, the discharge lamp currents of the remaining discharge lamp load circuits are almost the same as when all discharge lamp currents are mounted. Current lighting is possible.

Further, an inverter circuit comprising a DC power supply, a half-bridge circuit having a pair of switching elements for converting DC supplied from the DC power supply into a high-frequency current, a choke coil, and a high-frequency current from the inverter circuit. A discharge lamp, a series circuit in which coupling capacitors are respectively connected in series, and a plurality of discharge lamp load circuits connected in parallel comprising a capacitor connected in parallel to the discharge lamp; and the discharge lamp provided in the load circuit. A connection means that can be connected by changing the type and the number of connections, and a voltage output to drive the pair of switching elements, each being provided in the choke coil of the discharge lamp load circuit.
A secondary winding, an fV conversion circuit for converting the output voltage of the secondary winding into a DC voltage corresponding to the oscillation frequency thereof,
Control means for controlling the current of the discharge lamp based on the output of the -V conversion circuit, wherein the connection means connects the discharge lamps having substantially the same rated current, different rated voltage and different rated discharge lamp power. Sometimes, for each of the load circuits, the combination of the discharge lamps in each of the load circuits is the same, and the output power corresponding to the rated output power of each of the discharge lamps regardless of the number of connected discharge lamps. Because it was turned on,
Even if one discharge lamp load circuit is removed from the plurality of discharge lamp load circuits, the discharge lamp currents of the remaining discharge lamp load circuits can be prevented from fluctuating. In addition, even if one of the plurality of discharge lamp load circuits is removed for power saving to remove power, the discharge lamp currents of the remaining discharge lamp load circuits are almost the same as when all discharge lamp currents are mounted. Current lighting is possible.

The connection of the discharge lamps in the load circuit by the connecting means is such that a plurality of discharge lamps having a low rated voltage are connected in series, and at least one of the discharge lamps having a high rated voltage is connected. The lighting can be performed with the output power corresponding to each rated output power.

The connecting means connects the plurality of discharge lamps to the discharge lamp load circuit in series with a voltage generated in a secondary winding provided in a choke coil of the discharge lamp load circuit. In order to heat the filament of each of the plurality of discharge lamps, when only one discharge lamp is connected, the connection can be selected so as not to heat the filament. Premature blackening of the discharge lamp tube wall can be prevented, and in the case of single lamp connection by appropriate selection of the connection means, wasteful loss due to the secondary winding can be suppressed.

When a plurality of discharge lamp load circuits are provided, the resonance frequencies of the plurality of discharge lamp load circuits are determined to be substantially the same. The difference in characteristics between the load circuits when different discharge lamps are mounted can be reduced.

Further, since the voltages at the time of normal lighting of the plurality of secondary windings for driving the switching elements of the inverter circuit are determined to be substantially the same, the output characteristics of the fV conversion circuit are also substantially the same. The difference in characteristics between the plurality of discharge lamp load circuits when different discharge lamps are mounted can be reduced.

Since the choke coil is connected between the discharge lamp and the coupling capacitor, the number of wires from the lighting device to the discharge lamp and the number of output connectors of the lighting device can be reduced.

A diode whose anode is connected to a terminal of the coupling capacitor not connected to the DC power supply and whose cathode is connected to the positive electrode of the DC power supply, and a terminal of the coupling capacitor which is not connected to the DC power supply. And a diode whose anode is connected to the negative electrode of the DC power supply. Thus, the discharge lamp suppresses an increase in current at the end of its life, and at the same time, the fV conversion circuit during normal lighting and control. Due to the operation of the circuit, even when different types of discharge lamps having substantially the same rated current are mounted, it is possible to control the current to correspond to the rated current of the mounted discharge lamp.

Further, since the fV conversion circuit is provided with voltage reduction means for reducing the output voltage of the fV conversion circuit by a predetermined value, the conversion coefficient of the fV conversion circuit can be increased. Therefore, the ability to discriminate different types of discharge lamps can be improved.

Further, the characteristics of the fV conversion circuit are such that a larger output voltage can be obtained as the oscillation frequency of the inverter circuit is smaller, so that the fV conversion circuit is only operated in the direction of suppressing the current of the discharge lamp. The fV converter circuit has the opposite characteristic, that is, it is more secure against the failure mode of the fV converter circuit as compared with a method of increasing the current of the discharge lamp and adapting the rated current of the discharge lamp. Can be.

[Brief description of the drawings]

FIG. 1 is a circuit diagram (when a discharge lamp type A is mounted) of a discharge lamp lighting device according to a first embodiment of the present invention.

FIG. 2 is a circuit waveform diagram illustrating an operation of the discharge lamp lighting device according to the first embodiment of the present invention.

FIG. 3 is a circuit diagram (when a discharge lamp type B is mounted) of the discharge lamp lighting device according to the first embodiment of the present invention.

FIG. 4 is an operation explanatory diagram illustrating an operation of the discharge lamp lighting device according to the first embodiment of the present invention and a conventional example.

FIG. 5 is a circuit diagram (when a discharge lamp type C is mounted) of the discharge lamp lighting device according to the first embodiment of the present invention.

FIG. 6 is a circuit diagram (when a discharge lamp type A is mounted) of a discharge lamp lighting device according to a second embodiment of the present invention.

FIG. 7 is a circuit diagram (when a discharge lamp type B is mounted) of a discharge lamp lighting device according to a second embodiment of the present invention.

FIG. 8 is a circuit diagram (when a discharge lamp type C is mounted) of a discharge lamp lighting device according to a second embodiment of the present invention.

FIG. 9 is a circuit diagram (when a discharge lamp type A is mounted) of a discharge lamp lighting device according to a third embodiment of the present invention.

FIG. 10 is a circuit diagram (when a discharge lamp type C is mounted) of a discharge lamp lighting device according to a third embodiment of the present invention.

FIG. 11 is a circuit diagram (when a discharge lamp type A is mounted) of a discharge lamp lighting device according to a fourth embodiment of the present invention.

FIG. 12 is a circuit diagram (when a discharge lamp type C is mounted) of a discharge lamp lighting device according to a fourth embodiment of the present invention.

FIG. 13 is a circuit diagram of a discharge lamp lighting device according to a fifth embodiment of the present invention.

FIG. 14 is a circuit waveform diagram illustrating an operation of the discharge lamp lighting device according to the fifth embodiment of the present invention.

FIG. 15 is a circuit diagram of a discharge lamp lighting device according to a sixth embodiment of the present invention.

FIG. 16 is a circuit waveform diagram illustrating an operation of the discharge lamp lighting device according to the sixth embodiment of the present invention.

FIG. 17 is a circuit diagram of a discharge lamp lighting device according to a seventh embodiment of the present invention.

FIG. 18 is a circuit diagram of a conventional discharge lamp lighting device.

FIG. 19 is a power supply circuit diagram of the discharge lamp lighting device.

[Explanation of symbols]

1 power supply, 2 and 3, switching element (SW element),
5, 5a choke coil, 6, 10, 6a, 10a
Discharge lamp, 7, 7a capacitor, 8, 8a capacitor, 13, 14, 16, 17 resistor, 15, 15a capacitor, L100, L110 discharge lamp load circuit,
0, 21, 20a, 21a Diode, 80, 81
Zener diode, 100 fV conversion circuit, 101
Control circuit, ah terminal block.

   ────────────────────────────────────────────────── ─── Continuation of front page    F term (reference) 3K072 AA02 AB08 AB09 AC02 AC11                       BA03 BC01 CB02 DB01 DB03                       DB09 DC07 DD03 DD04 DE02                       DE07 GA02 GB12 GC02 HA05                       HA06

Claims (11)

[Claims] An inverter circuit comprising a DC power supply, a half-bridge circuit having a pair of switching elements for converting DC supplied from the DC power supply to a high-frequency current, a choke coil, and a high-frequency current from the inverter circuit. A discharge lamp load circuit including at least one discharge lamp, a series circuit in which coupling capacitors are respectively connected in series, and a capacitor connected in parallel to the discharge lamp; and a type of the discharge lamp provided in the load circuit. Connecting means that can be connected by changing the number of connections, and provided on the choke coil of the discharge lamp load circuit,
A secondary winding that outputs a voltage for driving the pair of switching elements; an fV conversion circuit that converts an output voltage of the secondary winding into a DC voltage corresponding to the oscillation frequency; and an fV conversion circuit. Control means for controlling the current of the discharge lamp based on the output of the discharge lamp, wherein the connection means connects the discharge lamps having substantially the same rated current, different rated voltage, and different rated discharge lamp power. A discharge lamp lighting device characterized in that the discharge lamp is lit at an output power corresponding to each rated output power of the discharge lamp, regardless of the number of connected discharge lamps. 2. An inverter circuit comprising a DC power supply, a half-bridge circuit having a pair of switching elements for converting DC supplied from the DC power supply into a high-frequency current, a choke coil, and a high-frequency current from the inverter circuit. And a plurality of discharge lamp load circuits connected in parallel comprising a series circuit in which coupling capacitors are respectively connected in series and a capacitor connected in parallel to the discharge lamp; and the discharge lamp provided in the load circuit. Connecting means that can be connected by changing the type and the number of connections; a secondary winding provided on each of the choke coils of the discharge lamp load circuit and outputting a voltage for driving the pair of switching elements; An fV conversion circuit for converting the output voltage of the winding into a DC voltage corresponding to the oscillation frequency; and an output of the fV conversion circuit. Control means for controlling the current of the discharge lamp on the basis of the above, wherein the connection circuit connects the discharge lamps having substantially the same rated current, different rated voltage and different rated discharge lamp power, and In each case, the connection is made such that the sum of the rated voltages of the discharge lamps of each of the load circuits is substantially equal, and the output power corresponding to each of the rated output powers of the discharge lamps regardless of the number of connected discharge lamps A lighting device for a discharge lamp, characterized in that the device is lit by a lamp. 3. An inverter circuit including a DC power supply, a half-bridge circuit having a pair of switching elements for converting DC supplied from the DC power supply into a high-frequency current, a choke coil, and a high-frequency current from the inverter circuit. And a plurality of discharge lamp load circuits connected in parallel comprising a series circuit in which coupling capacitors are respectively connected in series and a capacitor connected in parallel to the discharge lamp; and the discharge lamp provided in the load circuit. Connecting means that can be connected by changing the type and the number of connections; a secondary winding provided on each of the choke coils of the discharge lamp load circuit and outputting a voltage for driving the pair of switching elements; An fV conversion circuit for converting the output voltage of the winding into a DC voltage corresponding to the oscillation frequency; and an output of the fV conversion circuit. Control means for controlling the current of the discharge lamp based on the load circuit, wherein the connection means connects the discharge lamps having substantially the same rated current, different rated voltage, and different rated discharge lamp power. In the above, the combination of the discharge lamps in each of the load circuits is the same, and the discharge lamps are lit at an output power corresponding to the rated output power of each of the discharge lamps, regardless of the number of connected discharge lamps. Discharge lamp lighting device. 4. The connection of the discharge lamp of the load circuit by the connecting means is characterized in that a plurality of discharge lamps having a low rated voltage are connected in series, and at least one of the discharge lamps having a high rated voltage is connected. The discharge lamp lighting device according to claim 1. 5. A connecting means for connecting a plurality of discharge lamps to a discharge lamp load circuit in series with a voltage generated in a secondary winding provided in a choke coil of the discharge lamp load circuit. 5. When only one discharge lamp is connected so as to heat each filament of said plurality of discharge lamps, the connection can be selected so as not to heat said filament. Discharge lamp lighting device according to any of the above. 6. The discharge lamp lighting according to claim 1, wherein when a plurality of discharge lamp load circuits are provided, the resonance frequencies of the plurality of discharge lamp load circuits are determined to be substantially the same. apparatus. 7. The voltage of a plurality of secondary windings driving a switching element of an inverter circuit during normal lighting is determined so as to be substantially the same.
7. The discharge lamp lighting device according to any one of 6. 8. The method according to claim 1, wherein the choke coil is connected between the discharge lamp and the coupling capacitor.
8. The discharge lamp lighting device according to any one of 7. 9. A diode having an anode connected to a terminal of the coupling capacitor not connected to the DC power supply and a cathode having a cathode connected to the positive electrode of the DC power supply, and a terminal of the coupling capacitor not connected to the DC power supply. The discharge lamp lighting device according to any one of claims 1 to 8, further comprising: a diode connected to a cathode and an anode connected to a negative electrode of the DC power supply. 10. The fV conversion circuit according to claim 1, further comprising a voltage reduction means for reducing an output voltage of the fV conversion circuit by a predetermined value. Discharge lamp lighting device. 11. The discharge lamp lighting according to claim 1, wherein a characteristic of the fV conversion circuit is such that a larger output voltage can be obtained as the oscillation frequency of the inverter circuit is smaller. apparatus.