JP2000123982A - Discharge lamp lighting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a discharge lamp lighting device applicable to a discharge lamp having different rated values with one device. SOLUTION: A discharge lamp lighting device includes a DC power supply 1, an inverter circuit 2 for generating a high frequency current from the DC power supply 1, a discharge lamp loading circuit 5 for lighting a discharge lamp with the inverter circuit 2, a current detecting circuit 6 for detecting a current flowing the discharge lamp loading circuit 5, an error amplifier 9 for feeding a control signal in accordance with the output of the current detecting circuit 6 and the reference voltage of a reference voltage circuit 14 and an inverter driving circuit 3 for controlling the inverter circuit 2 with the control signal and controlling a current flowing in the discharge lamp loading circuit 5. The reference voltage circuit 14 comprises a reference voltage generation part 15 for generating a plurality of reference voltages and a reference voltage selection part 20 for selecting the reference voltage so that a current suitable to a rated value for the discharge lamp can be supplied by changing the reference voltage.

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 an inverter circuit.

[0002]

2. Description of the Related Art FIG. 6 shows a circuit diagram of a conventional discharge lamp lighting device. In the drawing, 1 is a DC power supply for rectifying and smoothing a commercial power supply to obtain a DC current, 2 is an inverter circuit including switching elements 2a and 2b such as MOS FETs, 3 is an inverter drive circuit for driving the inverter circuit 2, 4 is a coupling capacitor connected to the output side of the inverter circuit 2, 5 is a discharge lamp load circuit including a choke coil 5a, a starting capacitor 5b and a discharge lamp 5c, and 6 is a detection resistor 7
And an integrating circuit 8 having a resistor 8a and a capacitor 8b
(High-pass filter) and discharge lamp load circuit 5
, A current detection circuit for detecting a net current flowing through the amplifier, 9 is an error amplifier, 10a and 10b are resistors and capacitors for integration in the error amplifier 9, and the output voltage of the integration circuit 8 is connected to the inverting input terminal of the error amplifier 9. A reference voltage is input to a non-inverting input terminal from a reference voltage circuit 14 including a stabilized reference voltage DC power supply 11 and divided resistors 12 and 13, and a difference between the two voltages is determined by an error amplifier. The signal is amplified at 9 and fed back to the inverter drive circuit 3 as a control signal.

FIG. 7 shows a configuration example of a DC power supply 1 for obtaining a DC current from a commercial power supply. As shown in the drawing, an AC current output from a commercial power supply 1a is full-wave rectified by a diode bridge 1b, smoothed by a smoothing capacitor 1c, and output to a load circuit as a DC current. .

Hereinafter, the operation of the conventional circuit shown in FIG. 6 will be described. In the figure, when an inverter drive circuit 3 drives an inverter circuit 2, a DC current supplied from a DC power supply 1 is converted into a high-frequency current, supplied to a discharge lamp load circuit 5, and a discharge lamp 5c is turned on. . At this time, since the coupling capacitor 4 is connected to the discharge lamp load circuit 5, ON of the switching elements 2a and 2b,
In conjunction with the OFF, an AC current flows in the detection resistor 7 in the forward and reverse directions (regeneration direction) as shown in FIG. 8, and if the circuit loss is ignored, this effective component (forward and reverse directions) (Hereinafter referred to as a net current) is consumed as electric power by the discharge lamp 5c.

On the other hand, as for the current detected by the detection resistor 7, the sum (net current) of the forward and reverse currents is detected by the integration circuit 8, and the corresponding voltage is input to the inverting input terminal of the error amplifier 9. Is done. Further, a non-inverting input terminal of the error amplifier 9 is connected to the reference voltage DC power supply 1 from the reference voltage circuit 14.
1 is divided by the dividing resistors 12 and 13, and a reference voltage generated by the dividing resistors 12 and 13 is input. In this manner, the error amplifier 9 amplifies the voltage difference between the reference voltage and the output voltage from the integrating circuit 8, and integrates the voltage. And is fed back as a control signal to the inverter driving circuit 3 so that the switching frequency of the inverter circuit 2 is controlled by the inverter driving circuit 3 so that the DC power is released from the DC power source 1. The high-frequency current supplied to the lamp load circuit 5 is adjusted. That is, the DC power supply 1
When the output voltage of the inverter circuit 2 is constant, the high-frequency current supplied to the discharge lamp load circuit 5 is controlled by the switching frequency of the inverter circuit 2, so that the switching frequency of the inverter circuit 2 is controlled to If the output voltage is kept equal to the reference voltage, the power supplied to the discharge lamp 5c can be kept constant.

[0006]

However, the conventional discharge lamp lighting device shown in FIG.
Since the reference voltage output from 4 is fixed for each lighting device, in order to correspond to discharge lamps having different rated values, a plurality of types of components such as the choke coil 5a and the starting capacitor 5b are prepared in advance, When changing circuit constants according to the rated value of the discharge lamp to be installed, or when expanding the product line, it is necessary to prepare various types of discharge lamp lighting devices corresponding to the rated value of the discharge lamp. There is a problem that the parts management and the inventory management of the products at the time become complicated, and the management cost increases.

[0007] Further, when the discharge lamp lighting device is changed to a discharge lamp having a different rated value for the purpose of increasing illuminance and saving power after the installation, it is necessary to newly replace and install the discharge lamp lighting device. However, there is also a problem that the purchase cost and the operation cost increase.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems of the conventional apparatus, and a first object of the present invention is to provide a discharge lamp lighting device having a plurality of different rated values in a discharge lamp lighting device. An object of the present invention is to provide a discharge lamp lighting device that can be applied to electric lights and can reduce management costs such as parts management during production.

A second object of the present invention is to provide a discharge lamp lighting device capable of responding to a change in the rated value of the discharge lamp even after installation.

It is a third object of the present invention to provide a discharge lamp lighting device capable of easily changing the rated value of the discharge lamp.

[0011]

According to the present invention, there is provided a discharge lamp lighting apparatus comprising:
An inverter circuit for converting a DC supplied from the DC power supply into a high-frequency current; a discharge lamp load circuit for lighting a discharge lamp with the high-frequency current from the inverter circuit; and a current detection for detecting a current flowing in the discharge lamp load circuit A reference voltage circuit that generates a reference voltage; an error amplifier that generates a control signal based on an output from the current detection circuit and a reference voltage from the reference voltage circuit; and a control signal from the error amplifier. An inverter drive circuit for controlling the inverter circuit to control the current flowing through the discharge lamp load circuit to a current value corresponding to the reference voltage, wherein the reference voltage circuit is rated for the discharge lamp. A plurality of different reference voltages corresponding to the values are configured to be input to the error amplifier, and a reference voltage provided in the reference voltage circuit is provided. Those configured to select the reference voltage by the selection unit.

Further, a discharge lamp lighting device according to the present invention comprises:
The reference voltage circuit includes a reference voltage DC power supply and a dividing resistor that divides the voltage of the reference voltage DC power supply, and generates a plurality of different reference voltages corresponding to a preset rated value of the discharge lamp. The reference voltage generator includes a reference voltage generator and a reference voltage selector that selects the reference voltage generated by the reference voltage generator and inputs the selected reference voltage to the error amplifier.

[0013] Further, a discharge lamp lighting device according to the present invention comprises:
The reference voltage circuit, comprising: a reference voltage DC power supply; a dividing resistor that divides the voltage of the reference voltage DC power supply; and a reference voltage selecting unit connected in parallel to the dividing resistor. By selecting a divided resistor to be bypassed, a plurality of different reference voltages corresponding to a preset rated value of the discharge lamp are output from the reference voltage circuit.

Further, in the discharge lamp lighting device according to the present invention, a selection switch is used as the reference voltage selection unit.

Further, a discharge lamp lighting device according to the present invention comprises:
A conductive line (jumper line) is used as the reference voltage selection unit.

Further, a discharge lamp lighting device according to the present invention comprises:
The reference voltage circuit is provided on a circuit board on which the error amplifier is mounted.

Further, in the discharge lamp lighting device according to the present invention, the circuit board on which the reference voltage selection section is mounted is housed in a case, an opening is provided in the case, and the reference voltage selection section is inserted through the opening. It is configured such that the setting status can be checked and the setting can be changed.

Further, a discharge lamp lighting device according to the present invention comprises:
The conductive line is provided on a circuit board on which the error amplifier is mounted, the circuit board is housed in a case, and further, a working hole is provided on the circuit board on which the conductive line is mounted. Thus, it is possible to confirm and set the setting status of the conductive wire.

Further, a discharge lamp lighting device according to the present invention comprises:
The operation portion of the reference voltage selection section is arranged in the order of the reference voltage.

[0020]

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. In the figure, reference numeral 1 denotes a DC power supply for obtaining a DC current by rectifying and smoothing a commercial power supply, 2 denotes an inverter circuit including switching elements 2a and 2b such as MOS FETs, 3
Are inverter drive circuits for driving the inverter circuit 2, 4
Is a coupling capacitor connected to the output side of the inverter circuit 2, 5 is a discharge lamp load circuit including a choke coil 5a, a starting capacitor 5b and a discharge lamp 5c, 6 is a detection resistor 7
And an integrating circuit 8 having a resistor 8a and a capacitor 8b
(High-pass filter) and discharge lamp load circuit 5
, A current detection circuit for detecting a net current flowing through the error amplifier; 9 is an error amplifier; 10a and 10b are resistors and capacitors for integration in the error amplifier 9; The reference voltage is input to the non-inverting input terminal from the reference voltage circuit 14, and
The difference between the two voltages is amplified by the error amplifier 9 and fed back to the inverter drive circuit 3 as a control signal.

In the first embodiment, the reference voltage circuit 14 divides the stabilized voltage of the reference DC power supply 11 by the divided resistors 12a, 12b, 12c and 13 to divide the rated voltage of the discharge lamp 5c. (For example, 32W, 40W, 45
W), a reference voltage generator 15 for setting and generating three reference voltages in advance, and a reference voltage suitable for the rated value of the discharge lamp 5c among the three reference voltages generated by the reference voltage generator 15. And a selection switch 20 which is a reference voltage selection unit to select and input to the error amplifier 9.

The operation of the first embodiment will be described below. In the figure, when an inverter drive circuit 3 drives an inverter circuit 2, a DC current supplied from a DC power supply 1 is converted into a high-frequency current, supplied to a discharge lamp load circuit 5, and a discharge lamp 5c is turned on. . At this time, since the coupling capacitor 4 is connected to the discharge lamp load circuit 5,
In conjunction with ON and OFF of the switching elements 2a and 2b, the discharge lamp load circuit 5 is provided with a forward direction (DC power supply 1 → switching element 2a → coupling capacitor 4 → discharge lamp load circuit 5 → detection resistor 7 → DC power supply 1). ) And reverse direction (coupling capacitor 4 → switching element 2b → discharge lamp load circuit 5)
→ The alternating current of the coupling capacitor 4) flows.

On the other hand, at this time, an alternating current similar to that shown in FIG. 8 flows through the detecting resistor 7, and the integrating circuit 8 detects the sum (net current) of the forward and reverse currents of the alternating current, Is input to the inverting input terminal of the error amplifier 9.
If the circuit loss is neglected, the effective component (net current) of the alternating current is consumed as electric power by the discharge lamp 5c, just like the conventional example.

The non-inverting input terminal of the error amplifier 9 has
3 generated by the reference voltage generator 15 of the reference voltage circuit 14
From among the three reference voltages, a reference voltage corresponding to the rated value of the mounted discharge lamp 5c is selected and input by the selection switch 20 (in FIG. 1, the uppermost switch is ON). In this way, the error amplifier 9 amplifies the voltage difference between the reference voltage and the output voltage from the integrating circuit 8 and integrates the voltage difference by the integrating resistor 10a and the capacitor 10b, and feeds it back to the inverter driving circuit 3 as a control signal. The switching frequency of the inverter circuit 2 is controlled by the inverter driving circuit 3 so that the output voltage of the integrating circuit 8 becomes equal to the reference voltage. A high-frequency current (net current) suitable for the value is supplied and kept constant.

As described above, according to the first embodiment, the configuration is such that the net current flowing through the discharge lamp load circuit 5 can be controlled by the reference voltage input from the reference voltage circuit 14, and the reference switch Since a plurality of different reference voltages can be output from the voltage circuit 14, the net current supplied to the discharge lamp load circuit 5 can be kept substantially constant at a value suitable for the rated value of the discharge lamp 5c. By switching the switch 20, it is possible to obtain a discharge lamp lighting device applicable to discharge lamps having various rated values with the same discharge lamp lighting device. In addition, this eliminates the need to provide various types of components and discharge lamp lighting devices, and has the effect of reducing management costs such as component management during production.

Further, by switching the selection switch 20 even after the discharge lamp lighting device is installed, the discharge lamp lighting device can be adapted to discharge lamps having different rated values. This has the effect of reducing costs.

Further, the reference voltage generated by the reference voltage generating section 15 is set in advance to the rated value (for example,
32 W, 40 W, and 45 W), so that adjustment of the reference voltage is not required.
Since 0 is used, there is an effect that a discharge lamp lighting device whose rated value can be easily changed is obtained. Further, since the reference voltage can be changed any number of times by the selection switch 20, there is an effect that a discharge lamp lighting device which can be used for a long time and has excellent resource efficiency can be obtained.

Embodiment 2 FIG. 2 shows a second embodiment of the present invention in which
The example which connected in parallel to a, 12b, and 12c is shown. In the figure, reference numeral 16 denotes a dividing resistor connected in series to the dividing resistors 12a, 12b, 12c, and 13. In the second embodiment, the selection switch 20 includes the dividing resistors 12a, 12a, 12c, and 12c.
12b and 12c, which are connected in parallel to each other, and turn on and off the respective switches of the selection switch 20 so that the divided resistor 12
A, 12b, and 12c are bypassed, so that the division ratio of the divided resistors on both sides of the output terminal of the reference voltage connected to the error amplifier 9 changes, and the reference voltage is changed.
The same or corresponding parts as those in FIG. 1 are denoted by the same reference numerals, and description thereof is omitted. Also, the operation is exactly the same as that of the first embodiment, and the description is omitted.

Thus, according to the second embodiment, the following effects can be obtained in addition to the effects obtained in the first embodiment. That is, since the input impedance of the error amplifier 9 is generally very large, in the example shown in the first embodiment, a minute current continues to flow through each contact of the selection switch 20 for a long period of time. In order to maintain a stable reference voltage for a long time under conditions, it is necessary to minimize the contact resistance against aging. Had to use. However, according to the second embodiment, the selection switch 20 is connected to the dividing resistor 1
2a, 12b, and 12c are connected in parallel, so that the current flowing through the divided resistor from the reference voltage DC power supply 11 flows through the selection switch 20, and the current value required to maintain stability over time. Can be flowed,
A relatively inexpensive selection switch 20 can be used, which is advantageous in terms of cost, and has an effect of improving reliability because of high durability against aging.

FIG. 2 shows an example in which each switch of the selection switch 20 is provided in parallel between the upstream side of each of the divided resistors 12a, 12b, and 12c and the ground. , 12b, 12c may be connected so as to bypass them. In this case, various types of division ratios can be obtained by switching each switch, and a discharge lamp lighting device capable of coping with more rated values with a small number of division resistors. The effect is obtained.

Embodiment 3 FIG. 3 shows, as Embodiment 3 of the present invention, an example in which the above-mentioned reference voltage selecting section is constituted by a conductive line (jumper line) 21. In the figure, 21
Denotes a conductive line (jumper line), and connects one output terminal of the reference voltage generating unit 15 and the error amplifier 9 to a conductive line (jumper line) 2.
1, the reference voltage suitable for the rated value of the mounted discharge lamp 5c is selected from the three reference voltages generated by the reference voltage generator 15, and the error amplifier 10
It is configured to be input to. The same or corresponding parts as those in FIG. 1 are denoted by the same reference numerals, and description thereof is omitted. Also, the operation is exactly the same as that of the first embodiment, and the description is omitted.

FIGS. 4A and 4B are a cross-sectional view and a plan view, respectively, showing a specific mounting state of the conductive wires 21 on the circuit board 22 in the third embodiment. In the figure, 21 is a conductive wire, 22 is a circuit board on which the conductive wire 21 is mounted, and 23 is a working hole formed in a portion of the circuit board 22 on which the conductive wire 21 is mounted. Of the conductive wire 21 can be visually checked and cut from the back surface (the surface opposite to the mounting surface). In the third embodiment, the reference voltage circuit 14 including the conductive line 21 and the reference voltage generator 15 is mounted on the same circuit board 22 as the error amplifier 9, and the circuit board 22 is formed of metal or the like. Is stored in the case 24.

Thus, according to the third embodiment, the following effects can be obtained in addition to the effects obtained in the first embodiment. That is, as already pointed out in the second embodiment, in the example shown in the first embodiment, a minute current continues to flow through each contact of the selection switch 20 for a long period of time. In order to maintain stable operation against changes, it was necessary to use an expensive selection switch having gold-plated contacts.
However, according to the third embodiment, an inexpensive jumper wire 21 can be used instead of this, which has an advantage in terms of cost, and has an effect of improving reliability because of high durability against aging. is there.

Since the reference voltage circuit 14 including the reference voltage selection unit such as the conductive line 21 is mounted on the same circuit board 22 as the circuit board 22 on which the error amplifier 9 is mounted, the conductive line 2
It is possible to prevent the output of the discharge lamp 5c from becoming unstable due to the fluctuation of the minute current flowing in 1 or the like due to disturbance noise, and to reduce the noise countermeasure cost as compared with the case where the reference voltage selection unit is installed on a separate substrate. There are advantages that can be done. In addition, since the circuit board 22 is housed in the case 24, the risk of damaging the circuit board 22 when the discharge lamp 5c is replaced or the like is reduced, and if the case 24 is formed of metal, noise due to discharge of the discharge lamp 5c is reduced. There is also an effect of further reducing the influence of.
In the first and second embodiments, if the selection switch 20 is mounted on the circuit board 22 on which the error amplifier 9 and the like are mounted, exactly the same effects can be obtained.

Further, in the third embodiment, since the working holes 23 are formed in the portions of the circuit board 22 where the conductive wires 21 are mounted, even after the component mounting surface of the circuit board 22 is covered with the case 24. Without removing the case 24, the arrangement of the conductive wires 21 and the selection status of the reference voltage can be visually checked, and if necessary, the conductive wires 21 can be cut using the working holes 23, and a suitable discharge can be performed. There is an effect that the rated value of the light can be changed.

Although FIG. 4 shows an example in which the work holes 23 are provided in the circuit board 22 to check the conductive lines 21 and the like, as shown in FIG. An opening 25 may be provided in a corresponding portion. In this case, even if the selection switch 20 is used as the reference voltage selection means, the selection state of the reference voltage can be checked or the reference voltage can be changed with the case 24 attached. effective. Alternatively, the opening 25 may be provided at another position, and the selection switch 20 may be operated by a string or the like.

In the first to third embodiments, the error amplifier 9 is connected to the integrating capacitor 1.
Although an example in which 0b is added has been described, if the integration constant of the integration circuit 8 is appropriately selected, the function of integration of the error amplifier 9 becomes unnecessary, and the capacitor 10b can be replaced by a resistor for amplification. Further, the function of the integration circuit 8 may be integrated in the error amplifier 9.

In the first to third embodiments, the number of reference voltages input to the error amplifier 9 is three.
The same effect can be obtained even if two or four or more types are used. Further, the discharge lamp load circuit 5
As an example, one lamp is used, but the invention may be applied to two or more lamps having the same rating.

A semiconductor switch may be used in place of the selection switch 20 and the conductive line (jumper line) 21 as the reference voltage selection unit. Further, the selection switch 20 (including a rotary switch or the like) and a conductive line may be used. If the arrangement of the operation parts of the reference voltage selection unit such as the (jumper line) 21 (the switch unit of the selection switch 20 and the arrangement of the jumper lines 21) is arranged in the order of the reference voltage, that is, the rated value of the applicable discharge lamp, There is also an advantage that errors in operating the selection switch 20 and the conductive wire 21 can be reduced.

[0040]

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

A current supplied from the inverter circuit to the discharge lamp load circuit is controlled by a reference voltage output from the reference voltage circuit, and a plurality of reference voltages corresponding to discharge lamps having different rated values from the reference voltage circuit. Since the discharge lamp lighting device is configured to be able to output a voltage, it is possible to obtain a discharge lamp lighting device capable of supporting a discharge lamp having various rated values with one discharge lamp lighting device. There is no need to prepare, and parts management at the time of production and product inventory management become easy, and the management cost is reduced. In addition, even after the discharge lamp lighting device is installed, it can be adapted to discharge lamps with different rated values, so there is no need to replace or install a new discharge lamp lighting device when changing the rated value of the discharge lamp, and purchase costs and operation This has the effect of reducing costs.

Also, since the reference voltage circuit is configured to output a plurality of reference voltages suitable for discharge lamps having different preset rated values, it is not necessary to adjust the reference voltage, and it is easy to change the rated value. There is an effect that a simple discharge lamp lighting device can be obtained.

Further, since the reference voltage selection section is connected in parallel with the divided resistor, stable operation with respect to aging can be obtained, and a highly reliable discharge lamp lighting device can be obtained.

Further, since a selection switch is used as the reference voltage selection section, a discharge lamp lighting device which can easily cope with a change in the rated value of the discharge lamp can be obtained, and the reference voltage can be changed by the selection switch any number of times. Because possible
There is an effect that a discharge lamp lighting device which can be used for a long time and has excellent resource efficiency can be obtained.

Further, since a conductive wire is used as the reference voltage selecting section, a discharge lamp lighting device which can easily cope with a change in the rated value of the discharge lamp can be obtained. There is an effect that a stable operation with respect to the change can be obtained and a highly reliable discharge lamp lighting device can be obtained.

Further, since the reference voltage circuit is provided on the circuit board on which the error amplifier is mounted, a minute current flowing through the reference voltage selection unit and the like fluctuates due to disturbance noise.
It is possible to prevent the output of the discharge lamp from becoming unstable, and to reduce the cost for noise reduction as compared with the case where the discharge lamp is installed on a separate substrate.

Further, since the circuit board on which the reference voltage selection section is mounted is housed in a case and an opening is provided in the case, damage to the circuit board is prevented and the case is not removed without removing the case. There is also an effect that the setting status of the reference voltage selection unit can be confirmed and the setting can be changed from the opening.

Further, the conductive wires are provided on a circuit board on which the error amplifier is mounted, the circuit board is housed in a case, and a working hole is formed on the circuit board on which the conductive wires are mounted. It is configured so that the setting status of the conductive wire can be checked and cut from the working hole, so that even after the component mounting surface of the circuit board is covered with the case, the case is not removed. Thus, there is an effect that the arrangement of the reference voltage selection section and the selection status of the reference voltage can be confirmed, and the rated value of a suitable discharge lamp can be changed.

Further, since the operation portions of the reference voltage selection section are arranged in the order of the reference voltages, there is an effect that errors in selecting the reference voltage by the reference voltage selection section can be reduced.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing a configuration of a first embodiment of the present invention.

FIG. 2 is a circuit diagram showing a configuration of a second embodiment of the present invention.

FIG. 3 is a circuit diagram showing a configuration of a third embodiment of the present invention.

FIG. 4 is a configuration diagram showing a state of being mounted on a circuit board according to Embodiment 3 of the present invention;

FIG. 5 is a configuration diagram showing another mounted state on a circuit board according to Embodiment 3 of the present invention.

FIG. 6 is a circuit diagram showing a configuration of a conventional discharge lamp lighting device.

FIG. 7 is a circuit diagram showing a configuration of a DC power supply of a conventional discharge lamp lighting device.

FIG. 8 is a waveform diagram of a current flowing through a detection resistor of a conventional discharge lamp lighting device.

[Explanation of symbols]

 Reference Signs List 1 DC power supply 2 Inverter circuit 3 Inverter drive circuit 5 Discharge lamp load circuit 6 Current detection circuit 9 Error amplifier 11 DC power supply for reference voltage 12, 12a, 12b, 12c Dividing resistor 13 Dividing resistor 14 Reference voltage circuit 15 Reference voltage generation Part 16 Divided resistor 20 Selection switch (Reference voltage selection part) 21 Conductive wire (Reference voltage selection part) 22 Circuit board 23 Work hole 24 Case 25 Opening

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Yoshitaka Igarashi 5-1-1, Ofuna, Kamakura City, Kanagawa Prefecture Inside Mitsubishi Electric Lighting Co., Ltd. (72) Ryoji Minagawa 5-1-1, Ofuna, Kamakura City, Kanagawa Mitsubishi Electric Lighting Co., Ltd. (72) Inventor Shinsuke Funayama 5-1-1, Ofuna, Kamakura City, Kanagawa Prefecture Mitsubishi Electric Lighting Co., Ltd. F-term (reference) 3K072 AA02 AB09 BA03 BB01 BC01 DB03 EB07 GA03 GB12 GC04 HB03

Claims (9)

[Claims] 1. A DC power supply, an inverter circuit for converting DC supplied from the DC power supply to a high-frequency current, a discharge lamp load circuit for lighting a discharge lamp by the high-frequency current from the inverter circuit, and the discharge lamp load A current detection circuit that detects a current flowing through the circuit, a reference voltage circuit that generates a reference voltage, an error amplifier that generates a control signal based on an output from the current detection circuit and a reference voltage from the reference voltage circuit, A discharge lamp lighting device comprising: an inverter drive circuit that controls the inverter circuit based on a control signal from the error amplifier and controls a current flowing in the discharge lamp load circuit to a current value corresponding to the reference voltage.
The reference voltage circuit is configured so that a plurality of different reference voltages corresponding to the rated value of the discharge lamp can be input to the error amplifier, and a reference voltage selection unit provided in the reference voltage circuit selects a reference voltage. Discharge lamp lighting device characterized by the above-mentioned. 2. The reference voltage circuit according to claim 1, wherein the reference voltage circuit includes a reference voltage DC power supply and a dividing resistor that divides the voltage of the reference voltage DC power supply. A reference voltage generator for generating a reference voltage, and a reference voltage selector for selecting a reference voltage generated by the reference voltage generator and inputting the reference voltage to the error amplifier. 2. The discharge lamp lighting device according to claim 1. 3. The reference voltage circuit includes: a reference voltage DC power supply; a division resistor for dividing a voltage of the reference voltage DC power supply; and a reference voltage selection unit connected in parallel to the division resistance. A plurality of different reference voltages corresponding to a preset rated value of the discharge lamp are output from the reference voltage circuit by selecting a bypass resistor in the reference voltage selection unit. The discharge lamp lighting device according to claim 1. 4. The discharge lamp lighting device according to claim 1, wherein a selection switch is used as said reference voltage selection unit. 5. The method according to claim 1, wherein a conductive line (jumper line) is used as said reference voltage selecting section.
Item 4. The discharge lamp lighting device according to any one of Items 3 to 3. 6. The discharge lamp lighting device according to claim 1, wherein said reference voltage circuit is provided on a circuit board on which said error amplifier is mounted. 7. A circuit board on which the reference voltage selection unit is mounted is housed in a case, an opening is provided in the case, and the setting status of the reference voltage selection unit can be checked and changed from the opening. The discharge lamp lighting device according to any one of claims 1 to 6, wherein the discharge lamp lighting device is configured to be configured as follows. 8. The circuit according to claim 1, wherein the conductive line is provided on a circuit board on which the error amplifier is mounted, the circuit board is housed in a case, and a working hole is formed on the circuit board on which the conductive line is mounted. 6. The discharge lamp lighting device according to claim 5, wherein the work hole is provided so that the setting status of the conductive wire can be checked and cut from the work hole. 9. The method according to claim 1, wherein the operation portions of the reference voltage selection section are arranged in the order of the reference voltages.
Item 9. The discharge lamp lighting device according to any one of Items 8 to 8.