JPH11307290A - Discharge lamp lighting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inexpensive discharge lamp lighting device capable of using differently rated fluorescent lamps having the same shapes and sizes as a compatible fluorescent lamp by a very simple control only, without adding any extensive circuit. SOLUTION: A high frequency power is supplied to a load circuit 6 including a lamp FL1, FL2 from an inverter circuit 4. The inverter circuit 4 is equipped with a power transistor Q3 and an inverter control circuit 5 to switch on and off the power transistor Q3. The inverter control circuit 5 switches the frequency of the inverter circuit 4 by switching on and off a switch SW, and thereby, a differently rated fluorescent lamps having the same shapes and sizes can be used as a compatible lamp by a very simple control only, without adding any extensive circuit.

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 apparatus using a plurality of types of fluorescent lamps having the same shape, the same size, and different ratings, as compatible lamps.

[0002]

2. Description of the Related Art Generally, a discharge lamp such as a fluorescent lamp has a F
HF32 (Hf dedicated dual rated lamp of 32W and 45W), FLR40S (rated 40W), FL40SS / 3
7 (rated 37 W) and FPL 36 (rated 36 W). Not only are there structural differences in size, shape, filament structure, and the like, but there are also differences in electrical characteristics such as lamp voltage and lamp current in steady state, starting voltage in starting, and preheating current characteristics in preheating. As a result, a dedicated discharge lamp lighting device is used not only in the Japanese market, but also in overseas markets, in a 1: 1 relationship with the product name of the fluorescent lamp (for each fluorescent lamp shape and according to the rating difference). Was.

However, a conventional straight tube rapid type general lamp (eg FLR40S: lamp current 380 mA, lamp voltage 105 V, rated 40 W) and power saving lamp (FL)
R40S / 36: lamp current 400 mA, lamp voltage 9
(For example, 0402, rated 36W), a difference of about 10% may be shared by one type of lighting device (such as ESX4021HK-5ENH manufactured by Matsushita Electric Works, Ltd.).

[0004] However, the tube diameter is 15.9 mm, commonly known as T5.
A fluorescent lamp called (hereinafter referred to as a T5 lamp) is characterized in that it has the same shape and the same size, but has a difference of l: 1.4 times or more. To give an example, in the tube length 4 feed system of the T5 lamp, the lamp with the larger rating (hereinafter H
O lamp) is 54 W (lamp current 400 mA, lamp voltage 135 V), and the smaller rated lamp (hereinafter H
E lamp) is 28 W (lamp current 170 mA, lamp voltage 165 V), and there is approximately twice the rated difference between the two. Therefore, the FLR40S and FLR40S / 3
The lighting device cannot be shared as in the case of the handling of No. 6.

In order to share lamps of different ratings, a starting voltage is applied in a stepwise manner at the time of starting, as shown in Japanese Patent Publication No. 7-68664, and the type of the lamp is changed at the lighting timing. In some cases, the lamp rating is determined and a lamp rating is given according to the lamp type.

In the lighting device disclosed in Japanese Patent Publication No. Hei 6-12714, a plurality of types of fluorescent lamps having substantially the same rated lamp current and different rated lamp voltages are used as compatible lamps, and the output VI characteristics are steep. It has a drooping constant current characteristic.

A lighting device for supplying a constant lamp current, wherein the lamp diameters are equal and the lamp currents are equal (255 mA)
An apparatus for lighting a dedicated lamp (T8 lamp) is provided.

[0008] Japanese Patent Publication No. 7-66864 discloses that the type of fluorescent lamp is detected by the starting voltage. However, the starting voltage of the fluorescent lamp not only changes greatly even when the ambient temperature changes, but also as in the present case. In the case where various types of fluorescent lamps are present, there is a problem that if the type of the fluorescent lamp is detected only by the difference in the starting voltage, there is a high risk of malfunction.

In such a conventional example, it is necessary to store the characteristics of each fluorescent lamp by a microcomputer or the like, which requires a very large-scale apparatus, and is not practical because of the high cost and difficulty of control. There was a problem.

Further, the lamp described in Japanese Patent Publication No. Hei 6-12714 does not cover a lamp having a greatly different rated current, such as an HE lamp and an HO lamp.

[0011] Further, a lamp for lighting a fluorescent lamp having the same tube diameter and the same lamp current has a problem that it cannot cope with a case where the lamp current is different with the same shape and the same size.

[0012]

However, as described above, the difference between the ratings of fluorescent lamps of the same shape and dimensions, called T5 lamps, is 1: 1.4 times or more. It was necessary to consider the problem of insertion error due to

When the difference between the ratings is l: 1.4 times or more, it is very difficult to satisfy the respective lamp ratings at the same time and to make both lamps compatible, so it is necessary to add a large countermeasure circuit, and There was a problem in terms of cost and the cost of a single product.

Further, using a discharge lamp lighting device comprising different inverter circuits corresponding to various lamps,
As the types of discharge lamp lighting devices increase, they become more complicated to use, and it is necessary to manufacture discharge lamp lighting devices in small quantities by producing other types of products. A low-cost and reliable product could not be provided.

Further, since each product is designed from the ground up, there are inconveniences such as complicated design.

The present invention has been made in view of the above points, and an object of the present invention is to provide a fluorescent lamp of the same shape and the same size having a different rating only by a very simple control without adding a large circuit. Lights can be used as compatible lamps,
An object of the present invention is to provide a low-cost discharge lamp lighting device.

[0017]

In order to achieve the above object, a first aspect of the present invention is to adapt a plurality of types of fluorescent lamps having the same shape and the same size and different ratings, and to rectify and smooth a commercial power supply. A power supply circuit for obtaining a DC power supply, one or more switch elements connected to the power supply circuit, and an LC resonance circuit, wherein the one or more switch elements perform a switching operation at a high frequency to perform the above-described operations via the LC resonance circuit. Inverter circuit for supplying high-frequency power to the fluorescent lamp, and control means for variably controlling the oscillation frequency of the inverter circuit so that the rating of each applicable lamp is obtained when at least each of the plurality of types of fluorescent lamps is turned on. The output power of the inverter circuit is controlled by variably controlling the oscillation frequency of the inverter circuit. Low-cost discharge lamp lighting that supplies fluorescent lamps from the circuit and enables fluorescent lamps of the same shape and dimensions with different ratings to be used as compatible lamps with only very simple control without extensive circuit addition The device can be provided.

According to a second aspect of the present invention, in the first aspect of the invention, a type discriminating means for discriminating the type of the fluorescent lamp is provided. This eliminates the need for a user or the like to manually set the type of fluorescent lamp, thereby improving usability.

According to a third aspect of the present invention, in the second aspect of the present invention, the type discriminating means detects a filament resistance value of each fluorescent lamp and discriminates a type based on the resistance value. In addition to the effect of the invention of claim 2, the type of the fluorescent lamp can be easily determined with a simple circuit configuration.

According to a fourth aspect of the present invention, in the second aspect of the present invention, the type determining means detects a lamp voltage or a lamp current when each of the fluorescent lamps is turned on, and determines a type based on the detected voltage or the detected current. The type of the fluorescent lamp can be easily determined with a simple circuit configuration in addition to the effect of the invention of claim 2.

According to a fifth aspect of the present invention, in any one of the first to fourth aspects of the present invention, the control means sets the L level before starting the fluorescent lamp.
The oscillation frequency of the inverter circuit is set to a preheating frequency higher or lower than the resonance frequency of the C resonance circuit, a preheating current is applied to the filament of the fluorescent lamp, and the oscillation frequency is set to a starting frequency closer to the resonance frequency than the preheating frequency. When starting the fluorescent lamp and controlling the oscillation frequency in the slow region of the LC resonance circuit, the higher the rating, the lower the preheating frequency and the higher the starting frequency. In addition to the effects of any of the inventions, an appropriate preheating current and starting voltage can be supplied according to the type of each fluorescent lamp, and further, several types of fluorescent lamps can be started without overloading the inverter circuit. it can.

According to a sixth aspect of the present invention, in any one of the first to fourth aspects of the present invention, the control means sets the L level before starting the fluorescent lamp.
The oscillation frequency of the inverter circuit is set to a preheating frequency higher or lower than the resonance frequency of the C resonance circuit, a preheating current is applied to the filament of the fluorescent lamp, and the oscillation frequency is set to a starting frequency closer to the resonance frequency than the preheating frequency. When starting the fluorescent lamp and controlling the oscillation frequency in the early phase region of the LC resonance circuit, the larger the rating, the higher the preheating frequency and the lower the starting frequency, wherein the starting frequency is lowered. In addition to the effects of any of the inventions, an appropriate preheating current and starting voltage can be supplied according to the type of each fluorescent lamp, and further, several types of fluorescent lamps can be started without overloading the inverter circuit. it can.

According to a seventh aspect of the present invention, in any one of the first to fourth aspects of the present invention, the control means variably controls the switching frequency and the DC output of the power supply circuit according to the result of the determination by the type determination means. As a feature, in addition to the operation of any one of the first to fourth aspects of the present invention, the rating of each of a plurality of types of fluorescent lamps can be more easily obtained.

According to an eighth aspect of the present invention, in any one of the first to fourth aspects of the present invention, the control means variably controls the switching frequency and the resonance condition of the LC resonance circuit according to the result of the determination by the type determination means. Characterized in that:
In addition to the effects of any one of the inventions described above, the ratings for each of a plurality of types of fluorescent lamps can be obtained more easily.

According to a ninth aspect of the present invention, in any one of the first to eighth aspects of the present invention, the control means may control the output of any type of fluorescent lamp of another type having a smaller rating than that of the fluorescent lamp. The oscillation frequency is varied so as to be substantially the same as the rated output of the lamp, and in addition to the effects of the invention of claims 1 to 8, the output is substantially the same as the rated output of another type of fluorescent lamp having a small rating. Such light control becomes possible.

[0026]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First, the present invention relates to a straight pipe type having a pipe diameter of 1 mm.
The T5 lamp, which is 6 mm (maximum 17 mm), is operated at a high frequency. There are two types of T5 lamps having the same shape and dimensions but different ratings. It has a technical purpose to be shared by inverters.

That is, as described in the prior art, there is a lamp having a rated difference of about 10% such as the FLR40S and the FLR40S / 36 having the same shape and the same size, but the rated difference of the power consumption of the lamp is at least 1. The quadruple lamp is the first in the Japanese market. The two lamps having the same shape, the same size, and different ratings are 14 W of the HE lamp shown in FIG. 2A and 24 of the HO lamp shown in FIG.
W, similarly, 21W of the HE lamp and 39W of the HO, 28W of the HE lamp and 54W of the HO lamp, and 35 of the HE lamp.
It can be understood that there are combinations of W and 49 W of the HO amplifier, and there are differences in lamp current, filament resistance value, and equivalent resistance.

An embodiment of a discharge lamp lighting device according to the present invention for sharing such a lamp having the same shape and size will be described below.

(Embodiment 1) This embodiment has a circuit configuration shown in FIG. 1 and includes a commercial AC power supply AC, a full-wave rectifier circuit 1,
It includes a chopper circuit 2, a chopper control circuit 3, an inverter circuit 4, and an inverter control circuit 5. The AC voltage of the commercial frequency is rectified by the full-wave rectifier circuit 1 via the filter circuit 9 and boosted and smoothed by the chopper circuit 2 to generate a DC voltage. This DC voltage is converted into a high frequency by the inverter circuit 4. The inverter circuit 4 includes an LC resonance circuit including an inductor L4 and capacitors C11 and C11 ', and a T5 lamp (hereinafter, simply referred to as a "lamp") F as a fluorescent lamp connected in series with two lamps by the resonance current.
L1 and FL2 are driven at a high frequency. Lamp FL1, F
By lighting L2 at a high frequency of several tens of kHz, it is possible to increase the light output, reduce the size of the device, reduce audible noise, suppress flickering, and immediately turn on the light.

The chopper circuit 2 includes an inctor L3 for storing electromagnetic energy, a switching element Q1 composed of a power MOSFET, a backflow prevention diode D1, and smoothing capacitors C4 and C5. Thus, when the switching element Q1 is turned on, the output voltage of the full-wave rectifier circuit 1 is applied to the inductor L3,
3, the current flowing in the line 3 increases linearly, and the electromagnetic energy is accumulated in the inctor L3. Then, when the switching element Q1 is turned off, an induced electromotive voltage is generated in the incubator L3 by the electromagnetic energy stored in the inductor L3. This induced electromotive voltage is added to the output voltage of the full-wave rectifier circuit 1, and the capacitors C4, C5
Charge. As a result, a boosted smooth DC voltage is obtained across both ends of the capacitors C4 and C5. In this embodiment, the output voltage is set to be 400V. In the present embodiment, a power supply circuit is configured by the full-wave rectifier circuit 1 and the chopper circuit 2.

The chopper control circuit 3 controls the on / off of the switching element Q1 of the chopper circuit 2 by detecting the current flowing through the chopper circuit 2 and the output voltage of the chopper circuit 2. The chopper control circuit 3 includes a general-purpose integrated circuit IC1 (UC3852 manufactured by Unit Road Co., Ltd.) and a group of external components.

The inverter circuit 4 includes a bipolar power transistor Q2, a power MOSFET Q3, a diode D2, an inductor L4, capacitors C8, C11 and C1.
This is a so-called self-excited separately-excited control type inverter circuit composed of a half-bridge inverter circuit including 1 ', C12 and a transformer T1. Here, inductor L4 (inductance value =
3.3 mH) and the capacitors C11 and C11 '(combined capacitance value = 5.1 nF) constitute an LC series resonance circuit.

The inductor L4 and the capacitors C11 and C1
An oscillating current flowing through the load circuit 6 having 1 ', C12, the transformer T1, and the lamps FL1 and FL2 is fed back from the secondary winding n2 of the ingector L4 to the base of the power transistor Q2, and the power transistor Q2 is turned on and off. The power MOSFET Q3 is turned on and off by the inverter control circuit 5. The inverter circuit 4 oscillates at a high frequency, and power of the oscillation frequency is supplied to the lamps FL1 and FL2 of the load circuit 6 via the transformer Tl, and the lamps FL1 and FL2 are turned on.

The inverter control circuit 5 is a dedicated integrated circuit IC2 (for example, AN6766K manufactured by Matsushita Electronic Components).
And peripheral electronic components, and are configured to start the inverter circuit 4, preheat the lamps FL1 and FL2, and change the oscillation frequency of the inverter circuit 4. The oscillation frequency of the inverter circuit 4 is controlled by changing the ON period of the power MOSFET Q3. Power MOSFE
The ON period of TQ3 starts immediately after the power transistor Q2 is turned off. The turn-off of the power transistor Q2 is detected by the inverter control circuit 5 when the parasitic diode Da of the power MOSFET Q3 is turned on. The control voltage of the integrated circuit IC2 is a resistor R
The power is supplied from a power supply unit composed of a power supply 11, a Zener diode ZD1, and a capacitor C10. In this embodiment, a lamp voltage detection circuit 7 connected to a secondary winding provided in the transformer T1 and an intermittent oscillation timer circuit 8 are provided.

The lamp voltage detecting circuit 7 comprises a lamp FL1,
It detects a large increase in the terminal voltage associated with an increase in the discharge resistance at the end of the life of FL2, and functions to limit the output voltage of the inverter circuit 4 when the detected voltage reaches a specified threshold. The threshold value of the detection voltage in the lamp voltage detection circuit 7 is set so as to protect the inverter circuit 4 from overvoltage.

The intermittent oscillation timer circuit 8 includes a lamp FL1,
It is provided to stop the operation of the inverter circuit 4 when the FL2 is removed, and to apply a starting voltage to the inverter circuit 4 to restart it when the lamps FL1 and FL2 are reinstalled. The details of the operation will be described below.

First, the operation of the chopper circuit 2 will be described. When the commercial AC power supply AC is connected to the circuit described above,
In the chopper control circuit 3, the capacitor C17 is charged by the output of the full-wave rectifier circuit 1 through the resistor R12. The voltage across the capacitor C17 becomes the power supply voltage of the integrated circuit IC1,
When the voltage rises above the operating voltage (about 15 V) of the integrated circuit IC1, the integrated circuit IC1 outputs a control signal from the sixth terminal, which is a control terminal, turns on the switching element Q1 for a predetermined period, and turns the chopper circuit 2 on. Start. In the chopper control circuit 3, after starting, the induced power of the secondary winding N2 of the inductor L3 provided in the chopper circuit 2 charges the capacitor C17 through the diode D6, and the integrated circuit IC
Power supply to the power supply terminal which is the seventh terminal of No. 1 is maintained. The on period of the switching element Q1 is equal to 3
A resistor R17 connected to the terminal No. 4, a capacitor C18 connected to the terminal No. 4, and the output voltage of the chopper circuit 2 applied to the feedback terminal which is the terminal No. 1 of the integrated circuit IC1 are connected to the resistors R20 and R21 and the variable resistor VR1. And the voltage obtained by voltage division.

The switching element Q1 is turned on by a control signal output from the sixth terminal at a timing determined by the terminal voltage of the resistor R1 applied to the second terminal of the integrated circuit IC1. The terminal voltage of the resistor R1 is applied to the second terminal, and this voltage indicates a current flowing through the chopper circuit 2 with the negative side of the inverter circuit 4 as a reference (ground potential). The terminal voltage of the resistor R1 is compared with a reference voltage by the integrated circuit IC1, and the voltage of the inductor L3
Is released, and it is determined whether or not the output current of the chopper circuit 2 has become substantially zero. The integrated circuit IC1 is
When it is detected that the output current of the chopper circuit 2 has become almost zero, a control signal for turning on the switching element Q1 is output from the sixth terminal, and the switching element Q1 is turned on for the ON period set as described above. I do. As described above, the switching element Q1 is 40 to 100 k
Hz on and off at high frequency
Feedback control is performed so as to stabilize the DC voltage across the terminals 4 and C5. However, the output voltage of the chopper circuit 2 is higher than the peak voltage of the commercial AC power supply AC, and is kept constant regardless of the fluctuation of the commercial AC power supply AC.

The resistors R2 and R3 are connected to the switching element Q1.
Is provided in order to limit the gate current of the switching element Q1 and prevent a malfunction of the switching element Q1. The integrated circuit IC1 is
It has an offset terminal as an eighth terminal, and is connected to a feedback terminal as a first terminal via a resistor R18 and a capacitor C19. The resistor R18 and the capacitor C19 set the offset of the operational amplifier incorporated in the integrated circuit IC1.

By operating the chopper circuit 2 as described above, a high-frequency current having a sawtooth waveform without a pause period flows through the inductor L3. This high-frequency current is smoothed by the filter circuit 9 to make the input current a sine wave, and almost coincides with the phase of the voltage waveform of the commercial AC power supply AC. As a result, the power factor is improved by removing the high-frequency component. Let it.

Next, the inverter control circuit 5 will be described. The capacitor C10 of the inverter control circuit 5 is a resistor R
The voltage across the capacitor C10 is applied to the power supply terminal, which is the first terminal of the integrated circuit IC2, as an operating voltage. The upper limit of this voltage is limited by Zener diode ZD1. The above operating voltage is about 10
V, the integrated circuit IC2 becomes a power MOSFET.
TQ3 can be turned on. put it here,
After the operation of the integrated circuit IC1, the integrated circuit IC2 operates with a delay by the time constant of the resistor R11 and the capacitor C10 set in association with the resistor R12 and the capacitor C17 of the chopper control circuit 3. The power MOSFET Q3 is an integrated circuit I
It is controlled so that it is turned on only during the period set by C2. When the power MOSFET Q3 is turned off, the power transistor Q2 is turned on for a predetermined time determined by the components of the inverter circuit 4, and thereafter, the power MOSFET Q3 is controlled to be turned on again. Thus, the power MOSFET Q3 and the power transistor Q2 are alternately turned on and off at a high frequency. The on / off frequency changes in the range of 22 to 50 kHz. The output of the inverter circuit 4 is supplied to the lamps FL1 and FL2 via the transformer T1 and the resonance circuit, and a high-frequency voltage is applied to the lamps FL1 and FL2. It is.

Thus, during the initial operation period, the oscillation frequency of the inverter circuit 4 is set higher than the resonance frequency of the LC resonance circuit. This allows the lamps FL1, FL
2, a preheating voltage lower than the starting voltage is applied, and the filament on the power supply side is preheated. This preheating period is set by the capacity of the capacitor C24, and the above-mentioned power supply-side fragment is preheated by the current flowing from the secondary winding of the transformer T1 through the capacitors C11 and C11 'for resonance. On the other hand, the non-power supply side filament is preheated by the current flowing from the separately provided secondary winding through the capacitor C12. The capacitor C12 is provided to prevent an overcurrent from flowing when a short circuit occurs in the filament or the transistor. The preheating is usually performed within about one second after the power is turned on, and after the preheating, the power MOSFET Q3 is controlled such that the ON period is extended as compared with the time of the normal operation. As a result, the inverter circuit 4 operates at an oscillation frequency close to the resonance frequency of the resonance circuit, and applies a starting voltage to the lamps FL1 and FL2. After that, the inverter circuit 4 sets the lamp FL
1 and FL2 continue to operate at substantially the same oscillation frequency until lighting.

The operation of the inverter circuit 4 will be described in more detail. When the voltage applied to the first power supply terminal increases, the integrated circuit IC2 generates a reference voltage. This reference voltage will be described later in connection with the operation of the power MOSFET Q3. Immediately after the chopper circuit 2 starts,
Power transistor Q2 and power MOSFET Q3
Are both kept in the off state, during which the output voltage of the chopper circuit 2 is between the both ends of the resistor R7 and the power MOS.
The voltage is applied between the source and the drain of the FET Q3. The voltage between the source and the drain of the power MOSFET Q3 is divided by the resistors R4 to R6, and the voltage across the resistor R6 is applied to the 18th terminal of the integrated circuit IC2. Integrated circuit IC2
When the terminal voltage of the capacitor C24 applied to the eleventh terminal rises to about 0.5 V and the voltage across the resistor R6 becomes lower than the reference voltage, the output of the 22nd terminal of the integrated circuit IC2 becomes H level. . The H-level output at terminal 22 provides a start pulse to the gate of power MOSFET Q3 through resistor R10, turning on power MOSFET Q3. At this time, the power transistor Q2 is kept off. When the power MOSFET Q3 is turned on,
In the inverter circuit 4, the capacitor C9 and the transformer T1
Primary winding, resonance inductor L4, power MOSF
Current flows through ETQ3 and resistor R9. Therefore, the voltage between both ends of the resistor R9 rises, and this voltage is applied to the current detection terminal which is the 20th terminal of the integrated circuit IC2, and when the voltage exceeds a reference edge pressure set separately inside the integrated circuit IC2, the integrated circuit IC2 Of the internal timer operates, and the output voltage of the internal timer becomes H level. Timed time of the internal timer is determined by a resistor R _HE connected via an external attached resistor R20 and the capacitor C21 and the switch SW to the pin 2 of the integrated circuit IC 2. Where the internal timer is
It has a function of extending the ON period of the power MOSFET Q3 longer than the ON period obtained by the start pulse. That is, the power MOSFET Q3 is turned on only for a short time when the internal timer is not operating. When the output of the internal timer goes to L level after a preset time interval has elapsed, the integrated circuit IC2 sets the output of the 22nd terminal to L level and turns off the power MOSFET Q3. While the power MOSFET Q3 is on, a voltage is generated in the secondary winding n2 of the inductor L4 so that the power transistor Q2 is reverse-biased and kept off. Conversely, when the power MOSFET Q3 is turned off, a voltage of the opposite polarity is generated in the secondary winding n2, the power transistor Q2 is forward biased, and the power transistor Q2 is turned on. Thus, the inverter circuit 4 starts outputting the oscillation current or the oscillation voltage.

Regarding the operation of the inverter circuit 4, when the drain current stops and the power MOSFET Q3 is turned off, the inductor L4 tries to keep the current flowing in the same direction, so that the secondary winding n2 of the inductor L4 has the opposite polarity. A voltage is induced. The current caused by the induced voltage flows through the diode D2. Therefore, the power transistor Q2 is forward biased by the voltage induced in the secondary winding n2 and turns on. When the current decreases to zero, the capacitor C9 functions as a power supply, and causes a collector current to flow through the power transistor Q2. When the collector current becomes a predetermined multiple of the base current, the power transistor Q2 becomes unsaturated. Therefore, the induced voltage of the secondary winding n2 decreases the base current of the power transistor Q2 until the on state of the power transistor Q2 cannot be maintained. Even after the power transistor Q2 is turned off, the inductor L4 is connected to the primary winding of the transformer T1, the DC power supply including the chopper circuit 2, and the power MOSFET Q3.
To continue flowing current in the same direction through the parasitic diode Da. When the parasitic diode Da conducts, the voltage between the source and the drain decreases to zero, and accordingly, the voltage applied to the voltage monitor terminal, which is the 18th terminal of the integrated circuit IC2, also decreases. As a result, the voltage between both ends of the resistor R6 becomes lower than the reference voltage set inside the integrated circuit IC2, and the integrated circuit IC2 turns the output of the output terminal, which is the 22nd terminal, to the H level to turn on the power MOSFET Q3. As a result, a drain current flows through the power MOSFET Q3. After the drain current starts flowing, a voltage is generated across the resistor R9, and this voltage is applied to the current detection terminal which is the 20th terminal of the integrated circuit IC2,
This voltage is compared to a reference voltage. If the voltage to be compared exceeds the reference voltage, the internal timer of the integrated circuit IC2 operates for a preset time period, and the power MOS
The ON period of the FET Q3 is timed, and then the integrated circuit IC
2 controls the power MOSFET Q3 to turn off. As described above, the power MOSFET Q3
And the power transistor Q2 is alternately turned on at a high frequency.
The lamps FL1 and FL2 are turned on through a resonance circuit formed by the transformer T1, the inductor L4, and the capacitors C11 and C11 '.

Next, the operation of the lamp voltage detecting circuit 7 will be described. When the lamps FL1 and FL2 approach the end of life, the lamp current decreases, the lamp voltage increases, and the output voltage of the inverter circuit 4 also increases. Therefore, the induced voltage of the secondary winding of the transformer T1 increases, and the voltage across the resistor R33 connected in series to the secondary winding via the diode D5 and the resistor R32 increases. The voltage across the resistor R33 is input to the fifteenth terminal of the integrated circuit IC2 and is set to a predetermined threshold value (for example, set to 5 V inside the integrated circuit IC2).
Is compared to When the voltage of the resistor R33 exceeds this threshold,
The output of the output terminal which is the 22nd terminal of the integrated circuit IC2 is L
Level, and the power MOSFET Q3 is turned off, or the output is set to the H level intermittently within a predetermined time. In this way, the oscillation of the inverter circuit 4 stops or the lamp voltage is limited.
Therefore, by providing the lamp voltage detection circuit 7, the integrated circuit IC2 can know that the life of the lamps FL1 and FL2 is nearing the end, and stop or limit the operation of the inverter circuit 4, At the end of life, the lamp voltage rises as it approaches a no-load state, but it is possible to protect circuit elements from such overvoltage. Therefore, the power transistor Q2 and the power MOSFET Q3 are prevented from being damaged by overvoltage, and the inductor L4 and the primary winding of the transformer T1 are prevented from being overheated.

Next, the operation of the intermittent oscillation timer circuit 8 will be described. If one of the lamps FL1 and FL2 is removed for replacement while the apparatus is in operation, the resonance capacitors C11 and C11 'are disconnected and the inverter circuit 4 stops. That is, the capacitor C1
When C1 'is cut off, no resonance circuit is formed, and the secondary winding of the transformer T1 is opened to increase the inductance of the primary winding. As a result, the inductor L
4, the current flowing through the power transistor Q2 and the power MOSFET Q2 cannot be sufficiently supplied to the base of the power transistor Q2.
Both are off. If this state continues, the user generally replaces the lamp and restarts the lamp. At this time, since the lamp needs to be preheated, a time delay occurs until the lamp is turned on. However, in the configuration of the present embodiment, the provision of the intermittent oscillation timer circuit 8 eliminates such an operation. The reason will be described below. The intermittent oscillation timer circuit 8 includes a bipolar transistor Q4 having a collector connected to one end of a resistor R11 connected to the full-wave rectifier circuit 1 via a resistor R31.
And the collector of this transistor Q4 is integrated circuit I
It is also connected to the twelfth terminal of C2. The base of the transistor Q4 is connected to the power MOSFET Q through resistors R22 and R23.
3, and a capacitor C25 is connected between the base and the emitter of the transistor Q4. That is, the capacitor C25 is connected in series with the resistors R22 and R23, and this series circuit is connected in parallel between the drain and the source of the power MOSFET Q3. When the inverter circuit 4 supplies a high frequency voltage, the capacitor C
25 is constantly charged by an alternating current passing through the power transistor Q2 and the primary winding of the transformer T1, and a resistor R2
2. A forward bias is applied through R23 to keep the transistor Q4 on. At this time, the twelfth terminal of the integrated circuit IC2 becomes L level.

On the other hand, when the lamps FL1 and FL2 are removed and the capacitors C11 and C11 'are disconnected, the operation of the inverter circuit 4 is stopped and the power transistor Q
2 and the power MOSFET Q3 are both turned off, the capacitor C25 is rapidly charged by the current flowing from the chopper circuit 2 through the resistors R7, R22 and R23.
Attempt to turn on transistor Q4 by forward biasing. As a result, the transistor Q4 turns on and the capacitor C25 is discharged, and the capacitor C25 is charged again through the above path. In this way, the capacitor C25 repeatedly charges and discharges, and the integrated circuit I25
The input of H level and L level is alternately applied to the twelfth terminal of C2. The terminal No. 12 of the integrated circuit IC2 is H
Each time the level rises, a start pulse with a predetermined time width is set to 2
Power MOSFE is output from the output terminal that is the second terminal.
It is configured to turn on TQ3. Therefore, when the lamps FL1 and FL2 are removed and no load is applied and the resonance circuit is not formed, the transformer T1
With the secondary winding disconnected, the primary winding and inductor L4 function to limit the current to power MOFSETQ3. That is, the voltage across the resistor R6 cannot rise to the reference voltage, and the internal timer cannot extend the ON time of the power MOSFET Q3 to the extent necessary to start the oscillating operation of the inverter circuit 4. As described above, after the lamps FL1 and FL2 are removed, the integrated circuit IC2 is always reset so that the inverter circuit 4 can be restarted at any time, and the power transistor Q2 is reset.
The power MOSFET Q3 is repeatedly turned on and off while the power MOSFET 2 is kept off.

When the lamps FL1 and FL2 are mounted, the voltage across the resistor R10 immediately rises to the reference voltage, and the internal timer extends the on-time of the power MOSFET Q3 to turn on the power transistor Q2 by the above operation. To be able to That is, the inverter circuit 4 operates again, and the high-frequency voltage is changed to the lamps FL1 and FL2.
It is applied to

Finally, the point which is the gist of the present invention will be described. In the present embodiment, as described above, the power MOSFE
The time limit of the internal timer of the integrated circuit IC2 that determines the ON period of TQ3, that is, the oscillation frequency of the inverter circuit 4 can be switched by the resistor R _HE connected to the second terminal of the integrated circuit IC2 via the switch SW. I have. That is, when the switch SW is turned on, the switch SW is connected to the resistor R20.
The resistor R _HE is connected in parallel with the resistor R 20, and the combined resistance of the resistor R _HE is smaller than that of the resistor R 20 alone, so that the oscillating frequency of the inverter circuit 4 becomes higher. Frequency decreases. For example, rating 28
FIG. 3 shows the relationship between the oscillating frequency of the inverter circuit 4 and the lamp current in the HE lamp of W and the HO lamp of 54 W rating.
The following relationship is established. In this case, the rating difference between the two types of lamps is 1: 1.9. Here, the lamp FL
When an HE lamp is used as 1 and FL2, the switch SW is turned on. The oscillation frequency of the inverter circuit 4 when the switch SW is turned on is about 65 kHz (= fHE), and the rated current (about 170 mA) flows through the HE lamp at this time as shown in FIG. On the other hand, when the HO lamp is used, the switch SW may be turned off. When the switch SW is turned off, the oscillation frequency of the inverter circuit 4 becomes about 50 kHz (= fHO), and the rated current (about 400 mA) of the HO lamp is reduced. can get. In this case, LC
The resonance frequency of the resonance circuit is about 28 kHz.

Since the oscillation frequency of the inverter circuit 4 is varied by the switch SW so that the rating of each applicable lamp can be obtained when each of the plurality of lamps is turned on. The rated output corresponding to each lamp is supplied from the inverter circuit 4 to the lamp by varying the oscillation frequency, and lamps of the same shape and the same size with different ratings only by very simple control without adding a large circuit. And a low-cost discharge lamp lighting device that can be used as a compatible lamp.

The on / off of the switch SW may be manually switched by the user in accordance with the type of lamp to be used, or a means for detecting the type of lamp may be provided as described in a later embodiment. May be switched automatically. Also, by changing the oscillation frequency of the inverter circuit as described above, a 14 W rated HE lamp having a tube length of 2 feet and a HO lamp rated at 24 W can be shared, or a 21 W rated tube having a tube length of 3 feet can be used.
Needless to say, it is also possible to design such that the E lamp and the fixed 39W HO lamp are shared, or the constant 35W HE lamp having a tube length of 5 feet and the rated 49W HO lamp are shared.

By the way, in addition to the combination of the boost chopper circuit 2 and the self-excited half-bridge type inverter circuit as described above, the LC impedance element forming the resonance circuit as shown in FIG. The one using a so-called high-frequency charging type inverter circuit that changes in accordance with the power supply voltage of the AC power supply AC, or the one switching element of a half-bridge type inverter circuit is also used as a switching element of a chopper circuit, that is, a so-called common use 5, and both switching elements Q1 'and Q2' of a half-bridge type inverter circuit as shown in FIG.
A device using a so-called dual-purpose inverter circuit that also uses Q2 'as a chopper circuit, a device using a so-called full-bridge type inverter circuit in which four switching elements are connected in a bridge shape, a switching element There is an infinite number of LC resonance circuit combinations even in the case of using a so-called one-stone type inverter circuit having only one, or using a push-pull type inverter circuit. 20kHz-1
It is clear that the HE lamp and the HO lamp can be shared by one lighting device by changing the frequency in the range of 00 kHz.

(Embodiment 2) In this embodiment, a lamp FL connected to a load circuit 6 as shown in the block diagram of FIG.
A lamp type discriminating circuit 10 for discriminating the type (HE lamp and HO lamp), and the inverter control circuit 5 variably controls the oscillation frequency of the inverter circuit 4 according to the discrimination result by the lamp type discriminating circuit 10. This eliminates the need for the user to manually switch the switch SW according to the type of lamp.

FIG. 7 shows a specific example of the lamp type determination circuit 10. Note that the configurations of the chopper circuit 2, the chopper control circuit 3, the inverter circuit 4, and the inverter control circuit 5 are basically the same as those in the first embodiment, and thus the description thereof is omitted. As shown in FIGS. 2A and 2B, the HE lamp and the HO lamp have different filament resistance values. That is, the filament resistance of the HE lamp is 40
Whereas the filament resistance of the HO lamp is 12Ω. Thus, the lamp type determination circuit 10 of the present embodiment utilizes the difference in the filament resistance value to set
The types of the E lamp and the HO lamp are determined.

The lamp type discriminating circuit 10 is connected to one filament of the lamp FL as shown in FIG. 7, and the output terminal of the full-wave rectifier circuit 1 is turned on for a short time after the commercial AC power supply AC is turned on and before preheating. And a DC voltage is applied between the filaments to determine the type. Switching elements Q5 to Q8, which are bipolar transistors, a thyristor SCR, a comparator CP3, and resistors R35 to R4
0, capacitors C20 to C23 and diodes D10 and D11
Etc.

When the switch 11 is turned on, the commercial AC power
Is applied, the pulsating output voltage of the full-wave rectifier circuit 1 is applied to the capacitor C20 via the resistors R35 and R36, and the capacitor C20 is charged. Almost simultaneously, the capacitor C21 is charged via the resistor R39. The two switching elements Q5 and Q6 are turned on by the charging voltage of the capacitor C21, and the switching element Q7 is also turned on when the switching element Q5 is turned on. Then, the voltage across the charged capacitor C20 is applied from the switching element Q7 to the filament of the lamp FL via the diode D10, and the capacitor C20 → diode D10 → filament → resistance R37 → diode D11 → switching element Q
Current flows through the path of 6 → R38 → C20.
At this time, the resistance R depends on the difference in the resistance value of the filament.
There is a difference in the voltage across 38. Therefore, by comparing the voltage across the resistor R38 with the reference voltage Vr by the comparator CP3, it is possible to determine the type of the lamp FL based on the difference in the filament resistance value.

The output terminal of the comparator CP3 is connected to the gate of the thyristor SCR. For example, if an HE lamp having a larger filament resistance value is connected as the lamp FL, the output of the comparator CP3 becomes H level, The SCR turns on. as a result,
The capacitor C23 is charged via the thyristor SCR,
The charging voltage of the capacitor C23 is input to the inverter control circuit 5 as a lamp type determination signal. The inverter control circuit 5 controls the oscillating frequency of the inverter circuit 4 to be high when the determination signal of the H level is input,
A rated current is supplied to a lamp FL composed of an E lamp.

On the other hand, if an HO lamp having a smaller filament resistance value is connected as the lamp FL, the thyristor SCR does not turn on because the output of the comparator CP3 becomes L level. Therefore, since the capacitor C23 is not charged, the L level determination signal is input to the inverter control circuit 5. When the L-level discrimination signal is input, the inverter control circuit 5 controls the oscillation frequency of the inverter circuit 4 to lower so as to supply the rated current to the lamp FL including the HO lamp.

The capacitor C22 is charged via the resistor R40 by discharging the capacitor C20. Here, the time constant of the resistor R40 and the capacitor C22 is equal to that of the capacitors C20 and C20.
21 is set to be longer than the charging time of the resistor R40.
And a capacitor C22 constitute a timer circuit. When the voltage across the capacitor C22 rises and the switching element Q8 turns on, the switching element Q8 is turned on before the inverter control circuit 5 starts preheating the lamp FL.
5, the base currents of Q6 are pulled out, and all of the switching elements Q5 to Q7 are turned off.
0 is disconnected from the lamp FL and the full-wave rectifier circuit 1. Therefore, the lamp type determination circuit 10 does not affect the preheating and lighting operation of the lamp FL at all.

As described above, in the present embodiment, the lamp type discriminating circuit 10 for discriminating the lamp type based on the difference in the filament resistance value is provided, and the inverter control circuit 5 operates according to the discrimination result of the lamp type discriminating circuit 10. Since the oscillating frequency of the inverter circuit 4 is automatically variably controlled, the user manually operates the switch S as in the first embodiment.
There is an advantage that usability can be improved by eliminating the trouble of switching W.

In this embodiment, the filament resistance is detected before the lamp FL is preheated. However, in order to further simplify the control, the filament resistance is detected after the lamp FL is turned on. Is also good.

(Embodiment 3) In this embodiment, as shown in the block diagram of FIG. 8, a lamp type discriminating circuit 10 similar to that of Embodiment 2 and a chopper circuit 2 according to the discrimination result by this lamp type discriminating circuit 10 are used. And a chopper correction circuit 12 for supplying a correction signal to the chopper control circuit 3 for changing the output voltage of the chopper control circuit 3. The variable control of the oscillation frequency of the inverter circuit 4 by the inverter control circuit 5 according to the type of the lamp, and the chopper correction circuit The variable control of the output voltage of the chopper circuit 2 is performed by the chopper control circuit 12 and the chopper control circuit 3 to improve controllability. Note that the configurations of the chopper circuit 2, the chopper control circuit 3, the inverter circuit 4, the inverter control circuit 5, and the lamp type discriminating circuit 10 are basically the same as those in the first and second embodiments, and therefore the description thereof is omitted.

The chopper correction circuit 12 outputs a correction signal corresponding to the determination signal from the lamp type determination circuit 10 to the chopper control circuit 3. For example, when the type of lamp is an HE lamp, a correction signal for lowering (stepping down) the output voltage of the chopper circuit 2 is output to the chopper control circuit 3, and the chopper control circuit 3 receiving the correction signal
Then, the output voltage of the chopper circuit 2 is reduced by controlling the switching element Q1. When the type of lamp is a HO lamp, a correction signal for increasing (boosting) the output voltage of the chopper circuit 2 is output to the chopper control circuit 3,
Upon receiving the correction signal, the chopper control circuit 3 controls the switching element Q1 to increase the output voltage of the chopper circuit 2.

The inverter control circuit 5 varies the oscillation frequency of the inverter circuit 4 according to the discrimination signal from the lamp type discrimination circuit 10 as described in the second embodiment.

FIG. 9 shows the resonance characteristics of the HE lamp and the HO lamp when the output voltage of the chopper circuit 2 (that is, the input voltage of the inverter circuit 4) is changed. Curves A and B in FIG. Resonance characteristics of the HE lamp and the HO lamp when the voltage is relatively low, and curves C and D respectively show resonance characteristics of the HE lamp and the HO lamp when the output voltage is relatively high. As is clear from the figure, when the output voltage of the chopper circuit 2 becomes relatively high, the lamp current _Ila increases, and when the oscillation frequency of the inverter circuit 4 becomes relatively high, the lamp current _Ila decreases. Thus, as shown in FIG. 9, when the HE lamp is used, the inverter control circuit 5 controls the oscillation frequency of the inverter circuit 4 to be higher (changes the oscillation frequency from f1 to f1 + Δf) than when the HO lamp is used. The control circuit 3 performs control to lower the output voltage of the chopper circuit 2 (change the resonance characteristic from the curve C to the curve A) according to the correction signal from the chopper correction circuit 12. Further, when the HO lamp is used, the inverter control circuit 5 performs control to lower the oscillation frequency of the inverter circuit 4 (changes the oscillation frequency from f1 + Δf to f1) as compared with when the HE lamp is used, and the chopper control circuit 3 controls the chopper correction circuit 12 Control to increase the output voltage of the chopper circuit 2 (change the resonance characteristic from the curve B to the curve D) in accordance with the correction signal from the CPU.

As described above, if both the oscillation frequency of the inverter circuit 4 and the output voltage of the chopper circuit 2 are variably controlled according to the type of the lamp, the HE lamp and the HO
With optimum lamp rated for each of the lamp is obtained, there is an advantage that controllability can be improved to be able to obtain a large variable amount of the lamp current I _la a ([Delta] I _la) as shown in FIG.

In this embodiment, the case where the control is performed in only one direction has been described. For example, when the HE lamp is used, the oscillation frequency of the inverter circuit 4 is further increased to increase the output voltage of the chopper circuit 2 slightly. It is also possible to obtain a rated output. As described above, the method of controlling the oscillation frequency of the inverter circuit 4 and the output voltage of the chopper circuit 2 that can obtain the rated output according to the type of the lamp is not limited to that of the present embodiment, and any combination is possible. it is obvious.

(Embodiment 4) In this embodiment, as shown in the block diagram of FIG. 10, a lamp type discriminating circuit 10 similar to that of Embodiment 2 and an inverter circuit 4 according to the discrimination result by the lamp type discriminating circuit 10. And a resonance switching circuit 13 for switching the resonance characteristics by changing the capacitance component of the LC resonance circuit included in the control circuit. The variable control of the oscillation frequency of the inverter circuit 4 by the inverter control circuit 5 according to the type of the lamp, and the resonance switching circuit 13 to control the switching of the resonance characteristics, thereby improving the controllability. Note that the configurations of the chopper circuit 2, the chopper control circuit 3, the inverter circuit 4, the inverter control circuit 5, and the lamp type discriminating circuit 10 are basically the same as those in the first and second embodiments, and therefore the description thereof is omitted.

The resonance switching circuit 13 is a lamp type discriminating circuit 1
The capacitance component of the LC resonance circuit included in the inverter circuit 4 is varied according to a discrimination signal from 0. When the type of lamp is an HE lamp, the capacitance component of the LC resonance circuit is increased, and the HO lamp is increased. If, the capacitance component of the LC resonance circuit is reduced. In order to change the capacitance component, an appropriate means such as connection / disconnection of the capacitance component by a switch in the LC resonance circuit can be used.

The inverter control circuit 5 varies the oscillation frequency of the inverter circuit 4 according to the discrimination signal from the lamp type discrimination circuit 10 as described in the second embodiment.

FIG. 11 shows the resonance characteristics of the HE lamp and the HO lamp when the capacitance component of the LC resonance circuit is switched. Curves E and F in FIG. 11 show the case where the capacitance component is relatively increased. The curves G and H respectively show the resonance characteristics of the HE lamp and the HO lamp when the capacitance component is relatively reduced. As is clear from the figure, when the capacitance component of the LC resonance circuit relatively increases, the lamp current _Ila increases, and when the oscillation frequency of the inverter circuit 4 relatively increases, the lamp current _Ila decreases. Therefore, as shown in FIG. 11, when the HE lamp is used, the inverter control circuit 5
In addition to performing control to increase the oscillation frequency of the inverter circuit 4 (changing the oscillation frequency from f1 to f1 + Δf) as compared with when the lamp is used, the resonance switching circuit 13 increases the capacitance component of the LC resonance circuit (by changing the resonance characteristics from a curved line). Change to curve e). When the HO lamp is used, the inverter control circuit 5 lowers the oscillation frequency of the inverter circuit 4 than when the HE lamp is used (the oscillation frequency is changed from f1 + Δf to f1).
Control), and the resonance switching circuit 13
The capacitance component of the C resonance circuit is reduced (the resonance characteristic is changed from curve C to curve C).

As described above, according to the lamp type,
Variable control of both oscillation frequency and capacitance component of data circuit 4
If you do, each of HE lamp and HO lamp
In addition to this, an optimum lamp rating is obtained, and FIG.
As shown in FIG. _la(ΔI_laLarge
It is said that controllability can be improved because it can be taken tightly
There are advantages.

In this embodiment, the case where the control is performed in only one direction has been described. However, for example, when the HE lamp is used, the oscillation frequency of the inverter circuit 4 is further increased and the capacitance component is slightly reduced by the resonance switching circuit 13. It is also possible to obtain the rated output by increasing it. As described above, the method of controlling the oscillation frequency of the inverter circuit 4 and the capacitance component of the LC resonance circuit that can obtain the rated output according to the type of the lamp is not limited to that of the present embodiment, and any combination is possible. it is obvious.

(Fifth Embodiment) In the second to fourth embodiments, the type is determined from the difference in the filament resistance value of the lamp. In the present embodiment, the lamp voltage is detected and the type of the lamp is determined from the lamp voltage. Is determined. FIG. 12 shows a block diagram of the present embodiment,
A lamp type discriminating circuit 10 'for detecting a lamp voltage and discriminating the type is provided, and the inverter control circuit 5 variably controls the oscillation frequency of the inverter circuit 4 according to the discrimination result by the lamp type discriminating circuit 10'. ing. In the illustrated configuration, a lamp type correction circuit 14 is provided. The lamp type correction circuit 14 has the same configuration and operation as the chopper correction circuit 12 described in the third embodiment or the resonance switching circuit 13 described in the fourth embodiment, but does not include the lamp type correction circuit 14. Is also good.

FIG. 13 shows a specific example of the lamp type determining circuit 10 '. In the illustrated circuit configuration, the configuration of the chopper circuit 2, the chopper control circuit 3, and the inverter control circuit 5 is basically the same as that of the first embodiment except that a half-bridge type inverter circuit of so-called separately excited other control is used for the inverter circuit 4. Therefore, the description is omitted. Although the illustrated circuit configuration exemplifies a circuit that does not include the chopper type correction circuit 14, it is needless to say that the chopper type correction circuit 14 may be included. FIG.
As shown in (a) and (b), the HE lamp and the HO lamp have different lamp voltages during steady operation.
For example, the lamp voltage of an HE lamp rated at 28 W is 167
In contrast to V, the lamp voltage of the HO lamp rated at 54 W is 135 V. Therefore, the lamp type discriminating circuit 10 'of the present embodiment utilizes the difference in the lamp voltage to generate H
The types of the E lamp and the HO lamp are determined.

The lamp type determination circuit 10 'charges the capacitor C30 via the diode D5 and the resistor R32 with the induced voltage generated in the secondary winding of the transformer T1, as shown in FIG. Is compared with the reference voltage Vr by the comparator CP4 to determine the type of the HE lamp and the HO lamp.
The output of the comparator CP4 is the inverter control circuit 5
The inverter control circuit 5 variably controls the on / off frequency (oscillation frequency) of the switching elements Q2 ′ and Q3 ′ according to the type of lamp, and obtains a rated output according to the type of lamp. The detection may be performed several tens of seconds after the lighting of the lamps FL1 and FL2 using a timer circuit. It is also possible to detect the lamp current instead of the lamp voltage and determine the type of the lamp from the difference in the lamp current.

As described in the first embodiment, when the lamps FL1 and FL2 approach the end of their life, the lamp current decreases, the lamp voltage increases, and the inverter circuit 4 '
, The induced voltage of the secondary winding of the transformer T1 increases, and the voltage across the capacitor C30 of the lamp type determination circuit 10 'abnormally increases. Therefore, in the present embodiment, a Zener diode ZD2 that is turned on when the voltage across the capacitor C30 rises abnormally, and a fault detection that outputs a fault detection signal (Emiless detection signal) to the inverter control circuit 5 when the Zener diode ZD2 turns on. And a circuit 15. In the inverter control circuit 5, when an abnormality detection signal is input from the abnormality detection circuit 15, the operation of the inverter circuit 4 is stopped or limited. As a result, at the end of the service life, the lamp voltage rises near the no-load state, but the circuit elements can be protected from such overvoltage.

(Embodiment 6) In this embodiment, an example of an optimal preheating and starting operation for sharing the HE lamp and the HO lamp with one lighting device will be described.

FIG. 14 shows an HE lamp having a rating of 28 W and a 54 W rating provided with a starting auxiliary plate (a so-called proximity conductor for starting).
3 shows the relationship between the starting voltage of the HO lamp, the preheating current, and the lamp voltage during normal lighting. As is clear from the figure, at the time of preheating, the HO lamp requires more preheating current (preheating voltage) than the HE lamp, and at the time of starting, the starting voltage of the HO lamp is lower than that of the HE lamp. Such a difference is very characteristic as a relationship unique to the T5 lamp.

By the way, since the resistance component of the LC resonance circuit included in the inverter circuit is infinite before the lamp is turned on, there is no difference between the HE lamp and the HO lamp as the intrinsic resistance at the time of preheating and starting. However, H
The E lamp and the HO lamp have the above-described differences, and the difference becomes a problem when two types of lamps are used in common. In order to solve such a problem, it is desirable to control the oscillation frequency of the inverter circuit at the time of preheating and at the time of starting according to the types of the HE lamp and the HO lamp. In particular, a high starting voltage is required at the time of starting, and since application of the high voltage adversely affects the life design of the inverter circuit, it is desirable to minimize the application of the high voltage.

Therefore, as shown in FIG. 15, when the HE lamp and the HO lamp are used in common, the method of applying the preheating voltage and the starting voltage is characterized by variably controlling the oscillation frequency of the inverter circuit. It is.

When the lamp is preheated and started in the late region of the LC resonance circuit included in the inverter circuit, the higher the rating, the lower the preheating frequency (the oscillation frequency of the inverter circuit at the time of preheating) and the more the start. The control to increase the frequency (the oscillation frequency of the inverter circuit at the time of starting) is performed by the inverter control circuit. Specifically, the preheating frequency and the starting frequency of the HE lamp are respectively set to fpre (H
E) and fosc (HE), and the preheating frequency and starting frequency of the HO lamp are expressed as fpre (HO) and fosc (HO), respectively, as shown in FIG.
fpre (HE) and the starting frequency is fosc (HE) <fosc (HO)
The oscillation frequency of the inverter circuit is controlled by the inverter control circuit so that

Alternatively, the LC included in the inverter circuit
When preheating and starting the lamp in the phase advance region of the resonance circuit, the inverter control circuit may perform control such that the higher the rating, the higher the preheating frequency and the lower the starting frequency. Specifically, the preheating frequency is fpre (HO)> fpre (HE)
Then, the oscillation frequency of the inverter circuit is controlled by the inverter control circuit so that the starting frequency becomes fosc (HE)> fosc (HO).

The HO lamp having a high rating has a large amount of stress because the lamp power is normally larger than that of the HE lamp. However, by performing the above control,
Since the stress design at the start of the HO lamp having the smaller starting voltage can be made more leeway, in the design of the discharge lamp lighting device that shares the HE lamp and the HO lamp, the so-called CR (overall use of parts by dual use) is generally adopted. Cost reduction).

(Embodiment 7) In the present embodiment, dimming control when an HO lamp is used will be described. Usually HO
The lamp has a rated power of 1.4 times or more of the HE lamp,
The luminous flux is also set higher than the HE lamp (see FIGS. 2A and 2B). Hereinafter, a HO lamp rated at 54 W will be described as an example.

Generally, to perform dimming with a discharge lamp lighting device having an inverter circuit, a method of variably controlling the input voltage of the inverter circuit, a method of variably controlling the oscillation frequency of the inverter circuit, and the inverter circuit are provided. There is a method of variably controlling the duty ratio of the switching element,
In any case, dimming can be performed by controlling the lamp current.

A HO lamp rated at 54 W is usually 337 Ω
Has a fixed resistance of about 400 mA at the time of rated lighting.
A luminous flux of 5000 lm (this is defined as 100%) is emitted at a lamp current of.

FIG. 16 shows the result of dimming by controlling the lamp current by the above method. That is,
In order to obtain the same luminous flux (2800 lm) as a HO lamp with a rating of 54 W and a HE lamp with a rating of 28 W, when dimming is performed by varying the oscillation frequency of the inverter circuit between 47 kHz and 60 kHz, the oscillation as shown in FIG. Frequency is about 47
At kHz, the lamp current of the HO lamp is about 170 mA
The fixed resistance value was 800Ω, and dimming was possible.

As described above, it is possible in principle to handle the HO lamp in the same manner as the HE lamp, and it is also possible to use a single type of discharge lamp lighting device instead of two types of applicable lamps.

[0090]

According to the first aspect of the present invention, there is provided a power supply circuit for obtaining a DC power supply by rectifying and smoothing a commercial power supply by using a plurality of types of fluorescent lamps having the same shape and the same size and having different ratings, and An inverter circuit comprising one or more switch elements to be connected and an LC resonance circuit, wherein the one or more switch elements perform high-frequency switching operation to supply high-frequency power to the fluorescent lamp via the LC resonance circuit; Control means for variably controlling the oscillation frequency of the inverter circuit so as to obtain the rating of each compatible lamp when each of the plurality of types of fluorescent lamps is turned on, so that the oscillation frequency of the inverter circuit is reduced. By variably controlling with the control means, the rated output corresponding to each fluorescent lamp is supplied from the inverter circuit to the fluorescent lamp, and a large circuit is added. Permits the use of fluorescent lamps having the same shape the dimensions different ratings as compatible lamp only a very simple control, there is an effect that a low cost discharge lamp lighting device can be provided. According to the second aspect of the present invention, the type of the fluorescent lamp is provided with a type determining means for determining the type of the fluorescent lamp. Therefore, in addition to the effect of the first aspect of the present invention, for example, a user or the like manually sets the type of the fluorescent lamp. There is no need to take such trouble, and there is an effect that the usability can be improved.

According to a third aspect of the present invention, the type determining means includes:
Since the filament resistance value of each fluorescent lamp is detected and the type is determined based on the resistance value, the type of the fluorescent lamp can be easily determined with a simple circuit configuration in addition to the effect of the invention of claim 2. effective.

[0092] According to a fourth aspect of the present invention, the type discriminating means includes:
Since the lamp voltage or lamp current at the time of lighting each fluorescent lamp is detected and the type is determined based on the detected voltage or detected current, in addition to the effect of the invention of claim 2, the fluorescent lamp has a simple circuit configuration. There is an effect that the type can be easily determined.

According to a fifth aspect of the present invention, the control means sets the oscillation frequency of the inverter circuit to a preheating frequency higher or lower than the resonance frequency of the LC resonance circuit before starting the fluorescent lamp, and controls the filament of the fluorescent lamp. When a preheating current is passed, the oscillation frequency is set to a starting frequency closer to the resonance frequency than the preheating frequency to start the fluorescent lamp, and when the oscillation frequency is controlled in the slow region of the LC resonance circuit, the higher the rating, the higher the preheating frequency. And the starting frequency is increased, so that in addition to the effects of any one of claims 1 to 4, an appropriate preheating current and starting voltage can be supplied according to the type of each fluorescent lamp,
Further, there is an effect that several types of fluorescent lamps can be started without overloading the inverter circuit.

According to a sixth aspect of the present invention, the control means sets the oscillation frequency of the inverter circuit to a preheating frequency higher or lower than the resonance frequency of the LC resonance circuit before starting the fluorescent lamp, and controls the filament of the fluorescent lamp. When a preheating current is passed, the oscillation frequency is set to a starting frequency closer to the resonance frequency than the preheating frequency to start the fluorescent lamp, and when the oscillation frequency is controlled in the fast phase region of the LC resonance circuit, the higher the rating, the higher the preheating frequency. And the starting frequency is lowered, so that in addition to the effects of any one of claims 1 to 4, an appropriate preheating current and starting voltage can be supplied according to the type of each fluorescent lamp,
Further, there is an effect that several types of fluorescent lamps can be started without overloading the inverter circuit.

According to a seventh aspect of the present invention, the control means variably controls the switching frequency and the DC output of the power supply circuit according to the result of the determination by the type determining means.
In addition to the effects of any one of the inventions described above, there is an effect that the rating of each of a plurality of types of fluorescent lamps can be more easily obtained.

According to an eighth aspect of the present invention, the control means variably controls the switching frequency and the resonance condition of the LC resonance circuit according to the result of the determination by the type determination means.
In addition to the effects of any one of the inventions of (1) to (4), there is an effect that the rating of each of a plurality of types of fluorescent lamps can be more easily obtained.

According to a ninth aspect of the present invention, the control means oscillates such that the output of any type of fluorescent lamp is substantially the same as the rated output of another type of fluorescent lamp having a smaller rating than the fluorescent lamp. Since the frequency is variable, in addition to the effects of the first to eighth aspects of the present invention, there is an effect that dimming can be performed so as to be substantially the same as the rated output of another type of fluorescent lamp having a small rating.

[Brief description of the drawings]

FIG. 1 is a specific circuit diagram showing a first embodiment.

FIG. 2 shows the characteristics of a T5 lamp used in the lamp,
(A) is the HE lamp, and (b) is the HO lamp.

FIG. 3 is an explanatory diagram for explaining the operation of the above.

FIG. 4 is a circuit diagram showing another configuration of the above.

FIG. 5 is a circuit diagram showing still another configuration of the above.

FIG. 6 is a block diagram showing a second embodiment.

FIG. 7 is a specific circuit diagram of the above.

FIG. 8 is a block diagram showing a third embodiment.

FIG. 9 is an explanatory diagram for explaining the operation of the above.

FIG. 10 is a block diagram showing a fourth embodiment.

FIG. 11 is an explanatory diagram for explaining the above operation.

FIG. 12 is a block diagram showing a fifth embodiment.

FIG. 13 is a specific circuit diagram of the above.

FIG. 14 is an explanatory diagram for explaining the operation of the sixth embodiment.

FIG. 15 is an explanatory diagram for explaining the above operation.

FIG. 16 is an explanatory diagram for explaining the operation of the seventh embodiment.

[Explanation of symbols]

 2 Chopper circuit 3 Chopper control circuit 4 Inverter circuit 5 Inverter control circuit 6 Load circuit IC2 Integrated circuit SW switch

Claims (9)

[Claims] 1. A power supply circuit for obtaining a DC power supply by rectifying and smoothing a commercial power supply using a plurality of types of fluorescent lamps having the same shape and dimensions and different ratings, and one or more power supply circuits connected to the power supply circuit. An inverter circuit including a switch element and an LC resonance circuit, wherein the one or more switch elements perform high-frequency switching operation to supply high-frequency power to the fluorescent lamp via the LC resonance circuit, and at least the plurality of types of fluorescent lamps Control means for variably controlling the oscillation frequency of the inverter circuit so as to obtain the rating of each applicable lamp when each of them is turned on. 2. The discharge lamp lighting device according to claim 1, further comprising a type determination unit configured to determine a type of the fluorescent lamp. 3. The discharge lamp lighting device according to claim 2, wherein said type discriminating means detects a filament resistance value of each fluorescent lamp and discriminates the type based on said resistance value. 4. The apparatus according to claim 2, wherein said type discriminating means detects a lamp voltage or a lamp current when each of the fluorescent lamps is turned on, and discriminates the type based on the detected voltage or detected current. Discharge lamp lighting device. 5. The control device according to claim 1, wherein the control means is configured to control the LC before starting the fluorescent lamp.
Set the oscillation frequency of the inverter circuit to a preheating frequency higher or lower than the resonance frequency of the resonance circuit, pass a preheating current to the filament of the fluorescent lamp, and set the oscillation frequency to a starting frequency closer to the resonance frequency than the preheating frequency. 2. The method according to claim 1, wherein when the fluorescent lamp is started and the oscillation frequency is controlled in the slow region of the LC resonance circuit, the higher the rating, the lower the preheating frequency and the higher the starting frequency.
The discharge lamp lighting device according to any one of claims 1 to 4. 6. The control means according to claim 1, further comprising:
Set the oscillation frequency of the inverter circuit to a preheating frequency higher or lower than the resonance frequency of the resonance circuit, pass a preheating current to the filament of the fluorescent lamp, and set the oscillation frequency to a starting frequency closer to the resonance frequency than the preheating frequency. 2. The method according to claim 1, wherein, when the fluorescent lamp is started and the oscillation frequency is controlled in the fast phase region of the LC resonance circuit, the higher the rating, the higher the preheating frequency and the lower the starting frequency.
The discharge lamp lighting device according to any one of claims 1 to 4. 7. The discharge lighting operation according to claim 1, wherein said control means variably controls a switching frequency and a DC output of a power supply circuit in accordance with a result of the determination by the type determination means. apparatus. 8. The discharge lighting according to claim 1, wherein the control means variably controls the switching frequency and the resonance condition of the LC resonance circuit according to the result of the determination by the type determination means. Lighting device. 9. The control means according to claim 1, wherein the oscillation frequency is varied so that the output of any type of fluorescent lamp is substantially the same as the rated output of another type of fluorescent lamp having a lower rating than the fluorescent lamp. The discharge lamp lighting device according to any one of claims 1 to 8, wherein