JPH02284395A - Lighting apparatus for multiple lamps - Google Patents

Abstract

PURPOSE:To eliminate dispersion of light output of each lighting load by providing an output compensation means consisting of a detecting part for detecting the output of at least one high frequency converting circuit and a compensation part for receiving a detection signal of the detecting part and compensates and controls the output of the other high frequency converting circuit in the same device. CONSTITUTION:An output compensation means 12 consisting of a detecting part 12A for detecting the output of at least one high frequency converting circuit 10A and a compensation part 12B for receiving a detection signal of the detecting part 12A and compensates and controls the output of the other high frequency converting circuit 10B is provided in the same device 20. Differential output between the output of the high frequency converting circuit 10A to a lighting load 11A and the output of the high frequency converting circuit 10B to lighting loads 11B, 11C is thus eliminated by the output compensation means 12. Dispersion in the light output between the lighting loads is thus eliminated.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a multi-light lighting fixture in which a plurality of high-frequency lighting devices are incorporated into the same fixture.

[Prior Art] FIG. 3 shows a schematic configuration of a conventional lighting load control device. In this device, a dimmer 40 including a phase control element such as a triac is inserted on the power input side of a plurality of lighting equipment 20, and the lighting This is a phase control type light control device that controls the light of the fixture 20. 1. is a preheating wiring for sending the power supply voltage as it is to the filament preheating circuit section of the lighting fixture 20, regardless of the dimming level.

Although this type of phase control type lighting load control device can be constructed relatively inexpensively, it requires a phase control element for dimming.
Phase control largely divides a half cycle of the power supply voltage into a current-carrying section and a current-stopping section, so there is a problem in that the input current waveform is distorted, and the lighting equipment 20
This reduces the input voltage to the lighting fixture 20.
For example, in the device shown in Fig. 3, in order to obtain a stable preheating voltage, the preheating wiring 11 is provided, and the dimmer The output side of 40 is 3 wires. In addition, phase control makes the rise of the power supply voltage waveform steeper, so noise (
and noise) level increases.

Therefore, recently, as shown in FIG. 4, a high frequency conversion circuit 1 consisting of a transistor inverter or the like is used as a ballast, and each lighting fixture 20 is supplied with the voltage of an alternating current power supply AC through a power line e.
, e, and a separate dimming signal line 12.
1, a dimming signal is supplied from the dimming circuit 4 to the control circuit 3 of the high frequency conversion circuit 1, and the lighting fixture 20 is controlled in accordance with the operation of the operating section (for example, the variable resistor VR) of the dimming circuit 4. A four-wire dimming system has been proposed in which the light can be adjusted arbitrarily using the This system focuses on the fact that the high-frequency conversion circuit 1, which serves as a ballast, originally has a controllable switching element such as a transistor, and attempts to use this switching element for dimming control. This solves all the disadvantages of the phase-controlled dimming system mentioned above.

However, in this system, a new problem, which had not been previously anticipated, was discovered: that outputs tend to vary between each lighting device (between each ballast).

This point will be explained in detail below.

FIG. 5 is a circuit diagram of the dimming circuit 4 used in the device shown in FIG. 4, and FIG. 6 is an operating waveform diagram thereof. In this dimmer circuit 4, a step-down transformer Tf from an alternating current power supply AC,
Diode bridge DB for full wave rectification, resistor R for current limiting
, a smoothing electrolytic capacitor C is charged, and the charging voltage is regulated by a voltage regulating Zener diode ZD, thereby obtaining a DC power source E. This DC power supply E is voltage-divided by a variable resistor VR and applied as a reference voltage Vr to the non-inverting input terminal of the comparator IC6.

The triangular wave oscillator 9 powered by the DC power source E includes a capacitor, a resistor that charges the capacitor with the current from the DC power source E, and a switching circuit that discharges the capacitor when the charging voltage of the capacitor reaches a predetermined voltage. The voltage Vc obtained across the capacitor is applied to the inverting input terminal of the comparator IC. The voltage Vc obtained by this triangular wave oscillator 9 is not a strict triangular wave, but is a voltage that increases nonlinearly with respect to the time axis, as shown in FIG. 6(a). Comparator ■CI.

The output terminal of is connected to the base of the transistor Q1° via a resistor R13. The emitter of the transistor Q ++ is connected to the negative pole of the DC power supply E, and the collector is connected to the positive pole of the DC power supply E through a resistor R14, and to the base of the transistor Q I 2 through a resistor R15. ing. The collector of transistor Q + 2 is connected to the positive pole of DC power supply E, and the emitter is connected to the negative pole of DC power supply E through resistor R16.

Then, a dimming signal Sn is obtained from both ends of the resistor RSS. In other words, transistor Q + + and resistor R,,,R,
4 constitutes a common emitter type inverting amplifier circuit, which includes transistor Q + 2 and resistor R + s + Rl.
8 constitutes a grounded collector (emitter follower) type impedance conversion circuit.

The operation of the dimming circuit 4 will be described below with reference to FIG. FIG. 6(a) shows the reference voltage Vr obtained from the variable resistor VR and the voltage Vc obtained from the triangular wave oscillator 9.
It shows the relationship between The reference voltage Vr can be set to any voltage.

When the voltage Vc obtained from the triangular wave oscillator 9 is lower than the reference voltage Vr, the output terminal of the comparator IC is “
Since the transistor Q becomes "High" level, the transistor Q is turned on, its collector potential drops, and the dimming signal Sn becomes "Low" level.On the other hand, the voltage Vc obtained from the triangular wave oscillator 9 is lower than the reference voltage Vr. When the output terminal of the comparator IC becomes high, the output terminal of the comparator IC becomes the "Low" level, so the transistor Q is turned off, its collector potential rises, and the dimming signal Sn becomes the "Higl+" level. A dimming signal Sn as shown in FIG. 4(b) is obtained.

Here, the voltage height of the dimming signal Sn is, for example, about 10 cm, and the frequency is, for example, about IKHz.

Since the reference voltage Vr can be set to any voltage by operating the variable resistor VR, the on-duty of the dimming signal Sn varies from the minimum value shown in Figure 7(a) to the value shown in Figure 7(b). In Figure 6, S is the on-duty (
t,/T) x 100 = 10% signal, S,. is a signal with on-duty (t2/T)XI00=90%. That is, S,,S,. These are dimming signals such that when the variable resistor VR of the dimming circuit 4 is adjusted, the on-duty of the dimming signal Sn becomes 10% and 90%, respectively. FIG. 8 shows a dimming signal S output from the dimming circuit 4.

~S10 and its on-duty relationship is shown. That is, the dimming signal is S, ~S,. When adjusted in the range of , the on-duty of the dimming signal changes linearly in the range of 10% to 90%.

FIG. 9 shows a control circuit 3 for performing dimming control in response to a dimming signal with a variable on-duty as described above.
The structure of the lighting fixture 20 provided with this is illustrated. The circuit configuration will be explained below. A transistor Q2, which is a main switching element, is connected to both ends of the DC power supply E. Series circuits Q, are connected in parallel, and diodes D + and D 2 are connected in antiparallel to each transistor Q, , Q, respectively. A load circuit is connected to both ends of the transistor Q2 via a coupling capacitor Cd for cutting off the DC component and a current transformer CT for feeding back the load current. The load circuit is a lighting load 2 consisting of a discharge lamp.
, an inductor L1 for current limiting and resonance, a capacitor C2 for resonance, and a capacitor C for resonance and preheating current conduction.The load current is an oscillating current. This oscillating current flows through the primary winding of the current transformer CT. Therefore, a voltage whose polarity changes according to the oscillating current flowing through the load circuit is induced in the secondary winding of the current transformer CT, and this induced voltage is applied between the base and emitter of the transistor Q2 via the resistor R7. hand,
Switching transistor Q2. The output signal of the control circuit 3 is supplied to the base of the transistor Q. In the control circuit 3, the voltage across the transistor Q is detected by the resistor R3゜R1, and the voltage across the transistor Q is detected.
, the transistor Q is turned on for a predetermined period of time after the voltage across the terminals falls.

This high frequency conversion circuit 1 includes a startup circuit for starting an automatic oscillation operation when the DC power source E1 is turned on. In this startup circuit, when the power is turned on, the capacitor C1 is charged via the resistor R5, and when the charging voltage reaches the breakover voltage of the two-terminal thyristor Q, the two-terminal thyristor Q1 is turned on, and the two terminals are connected to the base of the transistor Q.
A base current is caused to flow through the terminal thyristor Q1 to first turn on the transistor Q and start the oscillation operation.

The operation of the circuit shown in FIG. 9 will be explained below. When the power is turned on, transistor Q is activated by the startup circuit.

is turned on, and the voltage across it becomes "Low" level. As a result, the control circuit 3 is triggered, its output becomes a "High" level, and the transistor Q is maintained in an on state. When the transistor Q is turned on, the diode D0 becomes conductive and the capacitor C1 is no longer charged, so that the starting circuit stops. At this time, the secondary winding of the current transformer CT is connected to the base of the transistor Q2.
Since the transistor Q2 is wound with a polarity such that a reverse bias voltage is applied between the emitters, the transistor Q2 maintains an off state. The output becomes "Low" level, and transistor Q is turned off. When transistor Q is turned off, the collector current of transistor Q decreases, and the residual inductance of inductor L generates an opposite induced voltage, and the oscillating currents flowing through inductor L tend to flow in the same direction. Diode D becomes conductive. Furthermore, the secondary winding of the current transformer CT generates a reverse induced voltage, so that the transistor Q2 is forward biased, and the transistor Q2 is turned on.

When the current in diode D1 becomes zero, capacitor Cd
A current flows through the transistor Q2 using the accumulated charge as a power source. At this time, the core of the inductor Ll is linearly magnetized toward the saturation magnetic flux. Eventually, when the core reaches saturation magnetic flux, the inductance suddenly moves towards zero,
As a result, the amount of time change in the collector current of transistor Q2 becomes infinite. When the collector current of the transistor Q2 reaches hfe times the base current, the transistor Q2 becomes unsaturated, the base current fed back from the current transformer CT decreases, and the transistor Q2 turns off. Even after the transistor Q2 is turned off, the oscillating current flowing through the inductor tends to flow in the same direction, so the diode D2 becomes conductive and the load circuit, capacitor Cd, and DC power source E
Current flows through path 1. When the diode D2 conducts, the voltage across the transistor Q becomes zero, so the control circuit 3 is triggered and the output of the control circuit 3 becomes 'High.
h" level, and the transistor Q is forward biased. After the oscillating current flowing through the diode D2 becomes zero, a current flows from the DC power supply E1 through the path of the capacitor Cd, the load circuit, and the transistor Q3.

Thereafter, by repeating the above-described operation, the oscillation operation of the inverter is continued.

Next, the control circuit 3 is a monostable multi-pie break I made of a general-purpose integrated M circuit (for example, μPD4538 manufactured by NEC Corporation).
It is equipped with C. This monostable multivibrator IC
, the falling trigger input terminal B is “'High”
After changing from the level to II Lo, I+ level, output terminal Q is at High" level and output terminal q is at Low" level for a certain period of time. In this embodiment, the voltage across the transistor Q is It is detected by dividing the voltage with a series circuit of resistors R3 and R4, and monostable multivibrator I
This is used as the trigger signal for C. The time when the output terminal Q of the monostable multivibrator ■C becomes "High" level (the time when the output terminal q becomes "Low" level) is determined by the time constant of the resistor R1 and the capacitor C1. The output terminal Q is connected to the base of a driving transistor Q4, and the output terminal q is connected to the base of a driving transistor Q5. The collector of transistor Q is the DC power supply E2
The emitter of transistor Q5 is connected to the positive terminal of DC power supply E2.
The emitter of transistor Q4 and the collector of transistor Q5 are connected to the negative terminals of transistor Q
, connected to the base of. Therefore, the monostable multivibrator IC operates as a timer circuit for determining the on period of the transistor Q. A diode D3 and a resistor R are connected to the connection point of the monostable multivibrator IC's time constant setting resistor R5 and capacitor C4.
The output of the operational amplifier IC2 is connected through 5. The operational amplifier IC2 is an impedance converter having an inverting input terminal connected to an output terminal, and outputs the voltage of the capacitor C1 applied to the non-inverting input terminal with a low impedance. The capacitor C6 has a resistor R for discharging the charge.
1 are connected in parallel and are charged by the output voltage of the operational amplifier IC3. The operational amplifier IC is an impedance converter having an inverting input terminal connected to an output terminal, and outputs the voltage of the capacitor C6 applied to the non-inverting input terminal with a low impedance. The capacitor C6 is charged by a constant current from the current mirror circuit 8 including the transistors Q, , Q@, and is discharged when the transistor Q6 connected in parallel to both ends is turned on. A constant current supplied from the current mirror circuit 8 to the capacitor C6 is passed from the DC power supply E2 to the transistor Q through the resistor R.
The current flowing through 3 is the same. Inl[bias] is applied to the base of the transistor Q6 by a voltage obtained by dividing the voltage of the DC power supply E2 by resistors R, , , R,.

A transistor Q7 is connected in parallel to both ends of the resistor R3, and when the transistor Qt is turned on by the output of the dimming circuit 4, the forward bias of the transistor Q6 disappears, and the transistor Q6 is turned off. At this time, the capacitor C6 is charged by a constant current from the current mirror circuit 8, and its charging voltage V increases linearly. The waveform of the charging voltage V of the capacitor C6 is a triangular wave with a constant frequency and a voltage rise period equal to the on-time width of the dimming signal. Therefore, as the on-time width of the dimming signal becomes longer, the peak value of the charging voltage V1 of the capacitor C6 becomes higher. The operational amplifier IC2゜IC, capacitor C5, and resistor R7 are connected to the charging voltage V of the capacitor C6,
The output voltage (2) is the peak DC voltage of the charging voltage (2) of the capacitor C6. Therefore, as shown in FIG. 10, the output voltage V2 is a voltage that changes linearly in proportion to the on-duty of the dimming signal of the dimming circuit 4.・When duty is 10%, V2-Vza
, at 90%, v,=v,b. Also,
The resistor R1 is a control resistor, which forms a current path in parallel with the resistor R1 according to the output voltage (2), and increases the charging current of the capacitor C4 as the output voltage (2) increases, thereby controlling the monostable multivibrator IC. , the time constant of , is controlled to be small.

Therefore, when the on-duty of the dimming signal increases, the on-time width of the transistor Q3 becomes shorter, and the light output of the lighting load 2 decreases.

[Problems to be Solved by the Invention] The on-duty of the dimming signal from the dimming circuit 4 and the light output (lamp current) when the light output of the lighting load 2 is controlled using the device shown in FIG. As is clear from the figure, the optical output shows a nonlinear change with respect to the change in the on-duty of the dimming signal.
FIG. 12 shows the waveform of the collector current Ic and the waveform of the base voltage vb of the transistor Q. in this way,
The waveform of the collector current Ic of the transistor Q is a current waveform that is nonlinear with respect to the time axis. This is because the collector current Ic of the transistor Q is part of the resonant current waveform including the load.

Therefore, even if the conduction period of transistor Q is changed linearly, the current flowing through the load will not change linearly. Figure 13 shows that the base voltage vb of transistor Q is 0.
．． An example of a change in the collector current Ie is shown when the collector current Ie is changed for each period of IT. As is clear from FIG. 13, when the conduction period of transistor Q is in the range of T-0.8T, the collector current of transistor Q is 1. The waveform of e does not change much, and in the range of 0.6 to 0.4T, the waveform of 0. Although each IT is controlled, the waveform of the collector current Ie of the transistor Q changes greatly.

In other words, the transistor Q changes depending on the on-duty of the dimming signal Sn from the dimming circuit 4.

By changing the on-time width of the lighting load 2, the light output of the lighting load 2 changes, and the desired dimming state can be obtained. However, what should be noted here is that the conventional light output as shown in FIG. In the dimming system, the same voltage is applied to each lighting fixture 20 by controlling the phase of the alternating current voltage of the commercial power supply AC, whereas in the dimming system shown in FIG. The inductor L in the high frequency conversion circuit 1 of
Since the switching time width of the oscillating current determined by the capacitor 02 and the like is individually controlled for each high frequency conversion circuit 1, there is less variation in the output of each high frequency conversion circuit 1 compared to a phase control dimming system. This is a point that is likely to occur.

This situation occurs not only when multiple lighting devices of the same type are connected in parallel to a power source and dimming is controlled continuously or stepwise as described above, but also when lighting devices of different types (for example, 40W fluorescent lamps and If lighting devices (for 110W fluorescent lamps) are connected in parallel to the same power source and the dimming is controlled all at once using the same dimming signal, a more serious problem may occur. In other words, different types of lighting devices have significantly different dimming characteristic curves as shown in FIG. There is a fear of giving. In particular, when different types of lighting devices are installed in the same appliance, differences in brightness between the lighting devices are likely to be noticeable, and a solution to this problem has been desired.

The present invention has been made in view of the above points, and its purpose is to provide a multi-light lighting fixture in which a plurality of high-frequency conversion circuits for lighting the lighting loads are incorporated into the same fixture, in which each lighting load is The objective is to eliminate variations in optical output.

[Means for Solving the Problems] In the present invention, in order to solve the above problems, the first
As shown in the figure, it includes a switching element for oscillation, an LC oscillation circuit that supplies an oscillating current from a power source to a load by turning on and off the switching element, and a control unit that controls the on-time width of the switching element. Detecting the output of at least one high frequency conversion circuit 10A in a multi-lamp lighting fixture comprising a plurality of high frequency conversion circuits 10A and 10B in the fixture 20 and each high frequency conversion circuit F8I OA and 10B connected in parallel to the same power source. The present invention is characterized in that an output correction means 12 is provided in the same instrument 20, which is composed of a detection section 12A that performs the detection, and a correction section 12B that receives the detection signal of the detection section 12A and corrects and controls the output of another high frequency conversion circuit 10B. That is.

[Function] Since the present invention is configured as described above, the output difference between the output from the high frequency conversion circuit 10A to the lighting load 11A and the output from the high frequency conversion circuit 10B to the lighting load 11B and IIC is This is eliminated by the output correction means 12, and variations in the light output of the lighting loads 11A, 11B, and 11C within the same fixture 20 are eliminated. Therefore, as shown by the broken line in FIG. 1, from the dimming circuit 4 to the dimming signal lines 12.1. Each high frequency conversion circuit 10A, IO
Even when the same dimming signal is supplied to the light output terminals H, it is possible to control the light output of each of the lighting loads 11A, 11B, and 11G at a similar rate of change.

[Embodiment Fig. 2 is a circuit diagram of an embodiment of the present invention.
A is a high frequency conversion circuit for lighting one lamp, and 10B is a high frequency conversion circuit for lighting two lamps.

The circuit configuration of the high frequency variation circuit 10A will be described below. Diode bridge D B for commercial AC power supply AC
+ AC input terminal is connected. At the DC output end of the diode bridge DB, there is a transistor Q, which is a main switching element.2. Q3 series circuits are connected in parallel,
Each transistor Q2. A diode D is connected to Q, respectively.
, D, are connected in antiparallel. A coupling capacitor C is connected across the transistor Q2 to cut the DC component.
A load circuit is connected via d and a current transformer CT for feeding back the load current. The load circuit is composed of an LC resonance circuit including a discharge lamp 11, an inductor L1 for current limiting and resonance, a capacitor C2 for resonance, and a capacitor C2 for resonance and preheating current, and the load current is an oscillating current and an LC resonance circuit. Become. This oscillating current is transmitted through a current transformer CT,
flows through the primary winding of. Therefore, a voltage whose polarity changes depending on the oscillating current flowing through the load circuit is induced in the secondary winding of the current transformer CT, and this induced voltage is applied between the base and emitter of the transistor Q2 via the resistor R2. Then, the transistor Q2 is switched.

The output signal of the control circuit is supplied to the base of the transistor Q. The control circuit includes a monostable multivibrator IC made of a general-purpose integrated circuit (for example, μPD4538 manufactured by NEC Corporation). This monostable multivibrator IC has a falling trigger input terminal B that is “Hi”.
After changing from gh''' level to lLoIII+ level, output terminal Q remains at ``High'' level for a certain period of time.
In this embodiment, in which the output terminal q is at the "Low" level, the voltage across the transistor Q is divided by a series circuit of resistors R3 and R4, and the voltage across the transistor Q is divided by the resistor R1? A monostable multivibrator IC,
It is used as a trigger signal. Monostable multivibrator■Time for output terminal Q of C1 to be at “High” level (
The time when the output terminal q becomes “Low” level is determined by the resistance R.
9 and the time constant of the capacitor C1. The operating power supply voltage of the monostable multivibrator IC is obtained by lowering the output voltage of the diode bridge DB using a resistor R1 and charging the capacitor C3. The output terminal Q of the monostable multivibrator IC is connected to the base of the driving transistor Q through a resistor R19,
The output terminal q is connected to the base of a driving transistor Q via a resistor R2°. The collector of transistor Q is connected to the positive terminal of capacitor C1 via resistor R+a.
The emitters of transistor Q, are respectively connected to the negative terminal of capacitor CI, and the emitter of transistor Q, and the collector of transistor Q5 are connected to the base of transistor Q,. Therefore, the monostable multivibrator IC operates as a timer circuit for determining the on period of the transistor Q.

When the power is turned on, the voltage on capacitor C7 is at a low level, so monostable multivibrator IC1 is triggered and transistor Q, turns on. When transistor Q3 turns on, the secondary winding of current transformer CT, ,
Since it is wound with a polarity that applies a reverse bias voltage between the pace emitter of transistor Q2, transistor Q2 maintains an off state. After a predetermined period of time, the monostable multivibrator IC, The Q output is “
The level becomes L os"", and the transistor Q is turned off. When transistor Q is turned off, the collector current of transistor Q decreases, and the residual inductance of inductor L1 generates an opposite induced voltage, and the oscillating current flowing through inductor L1 tries to flow in the same direction, so diode D1 conducts. Further, the secondary winding of the current transformer CT+ generates an opposite induced voltage, so that the transistor Q2 is forward biased, and the transistor Q2 is turned on. When the current in diode D becomes zero, current flows through transistor Q using the accumulated charge in capacitor Cd as a power source. At this time, the core of the inductor L1 is linearly magnetized toward the saturation magnetic flux. Eventually, when the core reaches saturation magnetic flux, the inductance sharply moves toward zero, and as a result, the amount of time change in the collector current of transistor Q2 becomes infinite. When the collector current of the transistor Q2 reaches hfe times the base current, the transistor Q2 becomes unsaturated, the base current fed back from the current transformer CT decreases, and the transistor Q2 turns off. Even after transistor Q2 is turned off, the oscillating current flowing through inductor L1 tends to flow in the same direction, so diode D2 becomes conductive and current flows through the path of the load circuit, capacitor Cd, and diode bridge DB. When diode D2 conducts, the voltage across transistor Q becomes zero, thus triggering monostable multivibrator I C+ and forward biasing transistor Q. After the oscillating current flowing through the diode D2 becomes zero, a current flows from the diode bridge DB through the path of the capacitor Cd, the load circuit, and the transistor Q. Thereafter, by repeating the above-described operation, the oscillation operation of the inverter is continued.

Next, the high frequency conversion circuit 10B for lighting two lamps has basically the same configuration as the high frequency conversion circuit 10A for lighting one lamp, but the load circuit is the same as that of the high frequency conversion circuit 10A for lighting two fluorescent lamps. ．． 1. The difference is that it includes a series circuit.

The current flowing through the capacitor C3' for resonance and preheating current flows to the primary winding of the preheating transformer T, and the output of the secondary winding of the preheating transformer T causes the preheating current to flow to the common side filament of the 12° fluorescent lamp. is energized.

Further, the difference is that the time constant circuit of the monostable multivibrator IC, ° is supplied with the output voltage ■c of the correction section 12B. Therefore, the high frequency conversion circuit 10 for lighting two lamps
The on-time width of the transistor Q3° in B is controlled according to the output voltage VC of the correction section 12B.

Next, the configuration of the detection section 12A will be explained.

First, the primary winding of the current transformer T2 is connected to the load current path and preheating current path of the fluorescent lamp eI in the high frequency conversion circuit 10A with the polarities shown.

Therefore, the secondary winding of the current transformer T2 has the fluorescent lamp 1
Lamp current 11 obtained by subtracting the preheating current from the load current of 1
．． is detected. According to this lamp current IN, capacitor C5 is charged via diode D4 and resistor R2. As a result, the fluorescent lamp l is connected to both ends of the capacitor C4.
A detection voltage VA corresponding to the lamp current If is obtained.

Next, the configuration of the correction section 12B will be explained.

The primary winding of the current transformer T2° is connected to the load current path and the preheating current path of the fluorescent lamp b in the high frequency conversion circuit 10B with the polarities shown. This current transformer T
Due to the 2° secondary winding output, diode D9 and resistor R2
Capacitor C8 is charged via □, and capacitor C6
A detection voltage VB corresponding to the lamp current of the fluorescent lamp 12, 1° is obtained at both ends of the line.

The detected voltages vA and v8 are differentially amplified by a differential amplifier circuit ICa consisting of resistors R2) to R26 and an operational amplifier, and an output voltage Vc is obtained at the capacitor C1°.

The detection section 12A and the correction section 12B constitute an output correction means 12. The operation will be explained below.

If the output of the fluorescent lamp 11 in the high frequency conversion circuit 10A for lighting one lamp increases due to fluctuations in the power supply voltage, variations in parts, changes in ambient temperature, etc., the output of the fluorescent lamp 11 in the high frequency conversion circuit 10A for lighting one lamp increases. Voltage VA increases.

Fluorescent lamp 12 in high frequency conversion circuit 10B for lighting two lamps
．． The detected voltage VB by the current transformer T2° which detects the lamp current of 1 is compared with the detected voltage A, and the difference between the rain detection voltages vA and v is outputted by the differential amplifier circuit IC. The output voltage of the differential amplifier circuit IC is Vc” (V
s VA)(R2s/Rzi), therefore,
As the detection voltage vA increases, the output voltage ■c decreases, and the output pulse width of the monostable multivibrator I C+'' determined by this output voltage ■c increases.

This increases the conduction period of the transistor Q,', and the fluorescent lamp e2. i.

The lamp current increases. If the lamp current of the fluorescent lamp 11 decreases, the fluorescent lamp 12
．． The lamp current for 1 s also decreases. Therefore, it is possible to reduce variations in output between the fluorescent lamp 11 lit by the high frequency conversion circuit 10A and the fluorescent lamp 12.1:l lit by the high frequency conversion circuit 10B, and all fluorescent lamps 11 to
1. The same level of light output can be obtained from.

In addition, the output pulse width of the monostable multivibrator IC, IC,' in the high frequency conversion circuits 10A and 10B is as follows.
By adding a circuit as described in the conventional example (FIG. 9) to the time constant circuit, it is possible to make the time constant variable, and by using the dimming signal obtained from the same dimming circuit 4, fluorescent lamp
I~! The light output of , can be made variable. Each fluorescent light! , ~l, a smoothing capacitor may be connected in parallel to the DC output ends of the diode bridges DB, , DBl°.

In the above embodiment, the lamp current of the fluorescent lamp II is detected in the high frequency conversion circuit 10A for lighting one lamp, and the high frequency conversion circuit 10B for lighting two lamps is detected so that the light output is the same.
However, conversely, the operation of the high frequency conversion circuit 10A for lighting one lamp may be controlled by detecting the lamp current of the high frequency conversion circuit 10B for lighting two lamps.

Further, in the embodiment, each high frequency conversion circuit 10A.

The output of 10B was detected by the lamp current through the current transformers T 2 and T 2', but the fluorescent lamp t+, 12.1
The optical output of No. 3 may be detected by an optical semiconductor element such as a photodiode.

Note that the scope of application of the present invention is not limited to the dimmable discharge lamp lighting device as in the embodiment, and is not limited to the dimmable discharge lamp lighting device as in the embodiment, but is applicable to a high-frequency conversion circuit that controls the on-width of an oscillation switching element in parallel. As long as the lighting device operates, it can be applied even when the output of the high frequency conversion circuit is not variably controlled. However, the load of the high frequency conversion circuit is limited to the lighting load in the present invention.

Moreover, the control of the switching element for oscillation in the high frequency conversion circuit does not matter whether the switching element is self-excited or separately excited, or the specific circuit, as long as the on-width of the switching element is controlled.

[Effects of the Invention] As described above, in the present invention, a plurality of high frequency conversion circuits each including an LC oscillation circuit and having a control section for the on-time width of a switching element are provided in the same device, and each high frequency conversion circuit is In a multi-lamp lighting fixture in which circuits are connected in parallel to the same power source and a lighting load is lit by the high frequency output thereof, there is provided a detection unit that detects the output of at least one high frequency conversion circuit, and a detection unit that receives a detection signal from this detection unit. Since the output correction means consisting of a correction unit that corrects and controls the output of other high-frequency conversion circuits is provided in the same fixture, even if there are variations in component constants of each high-frequency conversion circuit, each high-frequency conversion circuit can control the output of each illumination. This has the effect of suppressing variations in the output to the loads, and therefore preventing variations in the light output of a plurality of lighting loads built into the same fixture.

In addition, by supplying a common dimming signal to each high frequency conversion circuit,
If the present invention is applied to a system that controls dimming of each lighting load, the light output of each lighting load built into the same fixture will be dimmed and controlled at the same rate of change in accordance with the dimming signal. This eliminates the feeling of discomfort to the user.

[Brief explanation of drawings]

Figure 1 is a block circuit diagram showing the basic configuration of the present invention, Figure 2 is a block circuit diagram showing the basic configuration of the present invention.
3 is a block circuit diagram of a conventional example, FIG. 4 is a block circuit diagram of another conventional example, and FIG. 5 is a circuit diagram of a dimming circuit used in the same. Figure 6 is an operation waveform diagram of the same as above, Figures 7 and 8 are explanatory diagrams of operation of the same as above, Figure 9 is a circuit diagram of a high frequency conversion circuit used in the same as above, and Figures 10 and 11 are explanations of operation of same as above. Figures 12 and 13
The figure is an operation waveform diagram same as above. 10A, 10B are high frequency conversion circuits, 11A, 11B, I
IC is the lighting load, 12A is the detection section, 12B is the correction section, 1
2 is an output correction means, and 20 is a lighting fixture.

Claims (1)

[Claims] (1) High-frequency conversion that includes a switching element for oscillation, an LC oscillation circuit that supplies an oscillating current from a power source to a lighting load through the on/off operation of this switching element, and a control unit that controls the on-time width of the switching element. A detection unit for detecting the output of at least one high-frequency conversion circuit, and a detection signal of the detection unit in a multi-light lighting fixture comprising a plurality of circuits in the fixture and each high-frequency conversion circuit connected in parallel to the same power source. 1. A multi-lamp lighting fixture, characterized in that the same fixture includes an output correcting means comprising a correcting section that corrects and controls the output of another high-frequency conversion circuit based on the received signal.