JPH02285965A - Inverter - Google Patents

Abstract

PURPOSE:To eliminate fluctuation of output of a plurality of loads by providing an output correcting means comprising a correcting section for receiving a signal from a detecting section and correcting the output from another high frequency converting circuit. CONSTITUTION:When the output from a fluorescent lamp l1 in a high frequency converting circuit 10A for lighting a single lamp increases, detected voltage VA also increases. Voltages VB, VA of fluorescent lamps l2, l3 in a high frequency converting circuit 10B for lighting two lamps, detected based on the lamp current, are compared each other then the difference between them is produced from a differential amplifier IC8. Output voltage VC decreases as the detected voltage VA increases thus increasing the lamp current of the fluorescent lamps l2, l3. By such arrangement, fluctuation of output from the fluorescent lamps l1, l2, l3 can be suppressed and approximately some degree of light output is obtained from all fluorescent lamps l1-l3.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an inverter device suitable for operating a plurality of loads in parallel.

[Conventional technology]

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 devices 20, and by operating the operation part (for example, a variable resistor VR) of the dimmer 40, This is a phase control type dimming device that dims the lighting device 20. fl is a preheating wiring for sending the power supply voltage as it is to the filament preheating circuit section of the lighting device 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 that the input current waveform is distorted, and the lighting device 20
This reduces the input voltage to the lighting device 20.
For example, in the device shown in Fig. 3, in order to obtain a stable preheating voltage, it becomes difficult to control various aspects of the lighting device. The output side of the optical device 40 has three wires. In addition, phase control makes the rise of the power supply voltage waveform steeper, so
The 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 device 20 is supplied with the voltage of an alternating current power supply AC through a power line 1.
．． 1. It is supplied as is via the dimming signal line 1. ,
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 device 20 is controlled in response to 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 a non-inverting input terminal of a comparator IC.

The triangular wave oscillator 9, which is powered by a DC power source E, includes a capacitor, a resistor that charges the capacitor with a current from the DC power source E3, 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. Comparator IC.

The output terminal of is connected to the base of transistor 9 via resistor R13. The emitter of the transistor Q11 is connected to the negative pole of the DC power supply E, and the collector is connected to the resistor R.
It is connected to the positive terminal of a DC power supply E through a resistor R+S, and to the base of a transistor Q12 through a resistor R+S. The collector of the transistor Q1□ is connected to the positive electrode of the DC power source E3, and the emitter is connected to the negative electrode of the DC power source E through a resistor R7. And resistance R
A dimming signal Sn is obtained from both ends of I6. In other words, the transistor Q + + and the resistors R13 and R14 constitute a common emitter type inverting amplifier circuit, and the transistor Q l and the resistors Rls and R1@ constitute a common collector type (
This constitutes an 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 Va obtained from the triangular wave oscillator 9 is less than or equal to the reference voltage V, the output terminal of the comparator IC is
Since the level becomes ``High'', the transistor Q is turned on, its collector potential drops, and the dimming signal Sn becomes ``Low'' level. On the other hand, when the voltage Vc obtained from the triangular wave oscillator 9 becomes higher than the reference voltage V', the output terminal of the comparator IC becomes "Low" level.

is turned off, its collector potential rises, and the dimming signal Sn becomes "High" level. As a result, 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 1 KHz.

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 the figure, S is the on-duty (
t,/T) x 100 = 10% signal, SIO is an on-duty (h/T) x 100 = 90% signal. That is, S,,S,. For example, when adjusting the variable resistor VR of the dimming circuit 4, the dimming signal Sn
These are dimming signals whose on-duty is 10% and 90%, respectively. FIG. 8 shows the relationship between the dimming signals 81 to S1° outputted from the dimming circuit 4 and their on-duty. In other words, if the dimming signal is adjusted in the range of S, ~S1°, the on-duty of the dimming signal will be 1
It changes linearly in the range of 0% 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 device 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 source E1. Series circuits Q, are connected in parallel, and each transistor Q, ,Q, has a diode D1. Dz are connected in antiparallel. 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 includes a lighting load 2 consisting of a discharge lamp;
Inductor L for current limiting and resonance Capacitor C2 for resonance
, L including resonance and preheating 'XX flow capacitor C3
It is composed of a C resonant circuit, and 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 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. and switches the transistor Q. transistor Q,
An output signal from the control circuit 3 is supplied to the base of the control circuit 3. In the control circuit 3, the voltage across the transistor Q is detected by the resistor R1R1, and the transistor Q is turned on for a predetermined period of time after the voltage across the transistor Q falls.

This high eyebrow wave variable m circuit 1 is provided with a starting circuit for starting self-excited oscillation operation when the DC power source El is turned on. In this startup circuit, when the power is turned on, capacitor C1 is charged via resistor R3, and when the charging voltage reaches the breakover voltage of 2-terminal thyristor Q1, 2-terminal thyristor Q is turned on, and 2 terminals are connected to the base of 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.

turns on, and the voltage across it goes to “Low” level.
As a result, the control circuit 3 is triggered, its output goes to "High" level, and the transistor Q3 is kept on. When the transistor Q is turned on, the diode D0 becomes conductive, and the capacitor C1 becomes Since it is no longer charged, the startup circuit stops.At this time, the secondary winding of the current transformer CT is wound with a polarity that applies a reverse bias voltage between the base and emitter of the transistor Q2. Q2 maintains the off state. After a predetermined time set by the dimming circuit 4 has elapsed, the output of the control circuit 3 becomes "Low" level, and the transistor Q3 becomes off state. The transistor Q is turned off. Then, the collector current of the transistor Q decreases, causing the inductor, and the residual inductance of the inductor generates an opposite induced voltage, and the oscillating current flowing through the inductor tries to flow in the same direction, so that the diode D1 becomes conductive. Further, as the secondary winding of the current transformer CT generates an opposite induced voltage, the transistor Q2 is forward biased, and the transistor Q2 is turned on.

When the current in diode D 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 is magnetized linearly toward the saturation magnetic flux. Eventually, when the core reaches saturation magnetic flux, the inductance rapidly goes towards zero, and
As a result, the amount of time-opening 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 Q is turned off. Even after the transistor Q2 is turned off, the oscillating current flowing through the inductor L1 tends to flow in the same direction, so the diode D2 becomes conductive and the load circuit, capacitor Cd, and DC power source E
A current flows through the path of . When the diode D2 conducts, the voltage across the transistor Q3 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 D becomes zero, the current flows from the DC power supply E through the path of the capacitor Cd, the load circuit, and the transistor Q. flows.

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

Next, the control circuit 3 is a monostable multivibrator I made of a general-purpose integrated circuit (for example, μPD4538 manufactured by NEC Corporation).
Equipped with C+. This monostable multivibrator ■C
1, after the falling trigger input terminal B changes from the 'High' level to the 'Low' level, the output terminal Q is at the 'High' level and the output terminal is at the 'Low' level for a certain period of time.
In this embodiment, the transistor Q
, is detected by dividing the voltage across it by a series circuit of resistors R, , R, and is used as a trigger signal for the monostable multivibrator IC. Monostable multivibrator IC
.

The time for the output terminal Q to reach the "High" level (the time for the output terminal q to reach the "Lom" level) is determined by the time constant of the resistor R9 and the capacitor C4. The output terminal Q is connected to the base of the driving transistor Q, and the output terminal Q
is connected to the base of the driving transistor Q. The collector of transistor Q4 is connected to the positive pole of DC power supply E2, the emitter of transistor Q is connected to the negative pole of DC power supply E2, and the emitter of transistor Q and the collector of transistor Q are connected to the base of transistor Q3. There is. Therefore, monostable multivibrator IC1 operates as a timer circuit for determining the on period of transistor Q3. The output of the operational amplifier IC is connected to the connection point between the time constant setting resistor R6 of the monostable multivibrator IC and the capacitor C4 via a diode D and a resistor R1. 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 C5 applied to the non-inverting input terminal with a low impedance. A charge discharging resistor R2 is connected in parallel to the capacitor C2, and is charged by the output voltage of the operational amplifier IC. 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 C applied to the non-inverting input terminal with a low impedance. Capacitor C, is transistor Q,
, Q, when the transistor Q, which is charged by a constant current from the current mirror circuit 8 and connected in parallel to both ends, is turned on.

Charge is discharged. The constant current supplied from the current mirror circuit 8 to the capacitor C1 is the same as the current flowing from the DC power supply E2 to the resistor R8 via the transistor Q. A forward bias is applied to the base of the transistor Q by a voltage obtained by dividing the voltage of the DC power supply E2 by resistors R+o and Rs.

A transistor Q7 is connected in parallel to both ends of the resistor R, and when the transistor Q is turned on by the output of the dimming circuit 4, the forward bias of the transistor Q disappears and the transistor Q6 is turned off. At this time, capacitor CG is charged by a constant current from current mirror circuit 8, and its charging voltage Vl increases linearly. The waveform of the charging voltage (1) of the capacitor C6 is a triangular wave whose frequency is constant and whose voltage rise period is 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, the capacitor C2, and the resistor R7 are the charging voltage of the capacitor C,
The output voltage V2 is the peak DC voltage of the charging voltage v1 of the capacitor C6. Therefore, as shown in FIG. 10, the output voltage 2 is a voltage that changes linearly in proportion to the on-duty of the dimming signal of the dimming circuit 4. On When duty is 10%, ■2=V2a
, when it is 90%, it is v2-V2b. Also,
The resistor R6 is a control resistor, which forms a current path in parallel with the resistor R7 according to the above output voltage (2), increases the charging current of the capacitor C4 as the output voltage V2 rises, and controls 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 Q becomes shorter, and the light output of the lighting load 2 decreases.

[5M to be solved by the invention] On-duty of the dimming signal from the dimming circuit 4 and 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 the original waveform M, which 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 Ic is shown when the collector current Ic is changed for each period of IT. As is clear from FIG. 13, when the conduction period of transistor Q3 is in the range T to 0.8T, the waveform of the collector current Ic of transistor Q does not change much, and in the range 0.6 to 0.4T. Then, in the same way, 0. Even though each IT is controlled, the waveform of the collector current re 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 device 20 by controlling the phase of the AC voltage of the commercial power supply AC, whereas in the dimming system shown in FIG. Inductor L1 in 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 5-phase control type 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 10W 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 risk that it will cause

The present invention has been made in view of these points, and its purpose is to provide an inverter device that can eliminate variations in the output of a plurality of loads driven by high frequency conversion circuits operated in parallel. It is about providing.

[Means for Solving the Problems] In the present invention, in order to solve the above problems, the first
As shown in the figure, a switching element for oscillation, an I-C oscillation circuit that supplies an oscillating current from a power supply to a load through the on/off operation of this switching element, and a control unit that controls the on-time width of the switching element. In an inverter device comprising a plurality of high frequency conversion circuits 10A and 10B connected in parallel to the same power supply AC, a detection unit 12A detecting the output of at least one high frequency conversion circuit 10A;
The present invention is characterized in that it is provided with output correction means [2] comprising a correction section 12B which receives a detection signal from the detection section 12A and corrects and controls the output of another high frequency conversion circuit 10B.

[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 load 11A and the output from the high frequency conversion circuit 10B to the load 11B is determined by the output correction means 12. 11A for each load, IIB
This reduces the variation in output. Therefore, as shown by the broken line in FIG. 1, each high frequency conversion circuit 10A, 10
This makes it possible to control the outputs of the loads 11A and 11B at the same rate of change even when the same dimming signal is supplied to the loads 11A and 11B.

[Embodiment] Figure 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 conversion circuit 10A will be described below. The AC input end of the diode bridge DB is connected to the commercial AC power supply AC. diode bridge DB
, a main switching element transistor Q2. Q, are connected in parallel, and each transistor Q2. Q, each has a diode D1. D
2 are connected in antiparallel. 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 includes a discharge lamp 11, an inductor L1 for current limiting and resonance, a capacitor C2 for resonance, and a capacitor C1 for resonance and preheating current.
The load current is an oscillating current. This oscillating current is one of the current transformers CT,
Flows through the next winding. Therefore, the current transformer CT
A voltage whose polarity changes according to the oscillating current flowing through the load circuit is induced in the secondary winding of , and this induced voltage is passed through the resistor R.
2 between the base and emitter of the transistor Q2 to switch the transistor Q2. The output signal of the control circuit is supplied to the base of the transistor Q. The control [1li1 circuit is equipped with a monostable multivibrator IC made of a general-purpose collector circuit (for example, μPD4538 manufactured by NEC Corporation). In this monostable multivibrator IC1, after the falling trigger input terminal B changes from the "High" level to the "Low" level, the output terminal Q is at the "High" level and the output terminal q is at the "Low" level for a certain period of time. In the three examples,
The voltage across the transistor Q is divided by a series circuit of resistors R,,R, and a CR is made up of a resistor R11 and a capacitor C1.
It is used as a trigger signal for a monostable multivibrator IC via a circuit. Monostable multivibrator ■C5
The time for the output terminal Q to reach the °I High 11 level (the time for the output terminal q to reach the "Low" level) is determined by the time constant of the resistor R9 and the capacitor C4. In addition,
The operating power supply voltage of the monostable multivibrator C1 is obtained by lowering the output voltage of the diode bridge DB through a resistor R9 and charging the capacitor C1.

Output terminal Q of monostable multivibrator IC+ is resistor R
1i to the base of the driving transistor Q4, and its output terminal port is connected to the base of the driving transistor Q through a resistor R2°. transistor Q
, is connected to the positive terminal of capacitor C9 via resistor R1°.

The emitters of transistor Q5 are respectively connected to the negative terminal of capacitor C4, and the emitters of transistor Q and the collector of transistor Q5 are connected to the base of l-transistor Q. Therefore, the monostable multivibrator IC operates as a timer circuit for determining the on period of transistor Q3.

When the power is turned on, since the voltage on capacitor C1 is at a low level, monostable multivibrator C1 is triggered and transistor Q is turned on. When the transistor Q is turned on, the secondary winding of the current 1 to the lance CT is wound with a polarity that applies a reverse bias voltage between the base and emitter of the transistor Q2.

After a predetermined period of time, the Q output of the monostable multivibrator IC remains OFF.
level, and transistor Q3 turns off. When transistor Q is turned off, the collector current of transistor Q decreases, and the residual inductance of inductor L1 generates a reverse induced voltage, which causes the inductor to
Since the oscillating currents flowing in both try to flow in the same direction, the diode D becomes conductive. Further, the secondary winding of the current transformer CTl 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,
The transistor Q uses the accumulated charge of the capacitor Cd as a power source.
A current flows through 2. At this time, the core of the inductor is magnetized linearly toward the saturation magnetic flux. Eventually, when the core reaches saturation magnetic flux, the inductance rapidly goes 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 transistor Q2 reaches hfe times the base current, transistor Q2 becomes unsaturated, and the current transformer CT,
The base current fed back from transistor Q2 decreases and
is turned off. Even after transistor Q2 is turned off, the oscillating current flowing through the inductor 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 DB1. When diode D2 conducts, the voltage across transistor Q becomes zero, so monostable multivibrator I
C, is triggered and transistor Q, becomes forward biased. After the vibration flowing through the diode D2 becomes zero, the capacitor Cd is connected to the diode bridge DB.
, the load circuit, and the transistor Q, a current flows through the path.

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 for the two fluorescent lamps 12 and 13. 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 from the secondary winding of the preheating transformer T causes the fluorescent lamp 12! A preheating current is applied to the common side filament of .

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

Therefore, the secondary winding of the current transformer T2 has the fluorescent lamp 1
Lamp current IN obtained by subtracting the preheating current from the load current of 1
, is detected. According to this lamp current Il, the capacitor C3 is charged via the diode D and the resistor R21. As a result, a detected voltage vA corresponding to the lamp current 111 of the fluorescent lamp r is obtained across the capacitor C1.

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

Fluorescent lamp 12 in high frequency conversion circuit 10B. The primary winding of the current transformer T2' is connected to the load current path and the preheating current path of the system with the polarities shown. The secondary winding output of this current transformer T2'' causes diode D2 and resistor R
22, capacitor C6 is charged, and capacitor C
At both ends of P2.6 are fluorescent lights P2.6. (A detection voltage of 7 days is obtained according to the lamp current of lz.

The detected voltages vA and vB are differentially amplified by a differential amplifier circuit IC consisting of resistors R2ff to R2G and an operational amplifier, and an output voltage c is obtained at the capacitor C+a.

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 rl in the high frequency conversion circuit 10A for lighting one lamp increases due to fluctuations in power supply voltage, variations in parts, changes in ambient temperature, etc., the current transformer T2 detects the lamp current of the fluorescent lamp 11. Voltage vA
becomes larger.

Fluorescent lamp 1 in high surface, wave conversion circuit 10B for lighting two lamps
．． , l, the current 1 Herance Tx' for detecting the lamp current of
The detected voltage 7 days is compared with the detected voltage vA, and the difference between the rain detection voltages vA and v is outputted by the differential amplifier circuit Ice. The output voltage of the differential amplifier circuit IC is Vc''
(Va VA) (Rzs/ Rz:+) Tonal,
When the detection voltage vA increases, the output voltage ■
c becomes smaller, and the output pulse width of the monostable multivibrator IC,' determined by this output voltage c becomes larger. This increases the conduction period of the transistor Q, and increases the lamp current of the fluorescent lamp. If the lamp current of the fluorescent lamp 11 decreases, the fluorescent lamps 12, 1 . The lamp current also decreases. Therefore, the fluorescent lamp 11 is lit by the high frequency conversion circuit 10A, and the fluorescent lamp 12 is lit by the high frequency conversion circuit 10B. All-fluorescent lamps can reduce variations in output with fluorescent lamps! , ~l, can obtain similar light output.

In addition, the output pulse width of the monostable multivibrator IC, IC,' in the high frequency conversion circuit 10A and IOB is as follows.
By adding a circuit such as that described in the conventional example (FIG. 9) to the time constant circuit, it can be made variable, and the dimming signal obtained from the same dimming circuit 4 can be used to control fluorescent lamps!
1-1. The light output can be made variable. In order to reduce flicker in each of the fluorescent lamps L to L, a smoothing capacitor may be connected in parallel to the DC output ends of the diode bridges DB, DB1'.

In the above embodiment, the lamp current of the fluorescent lamp 11 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 set 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.

10B output to current transformer T2. Detected by lamp current through T2°, fluorescent lamp 1! , , 12, and 13 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. In the field of driving, it can be applied even when the output of the high frequency conversion circuit is not variably controlled. Furthermore, the load of the high frequency conversion circuit is not limited to the lighting load; for example, when multiple high frequency conversion circuits that drive motors are connected in parallel to a power supply, the output difference between each high frequency conversion circuit can be suppressed. This makes it possible to suppress speed differences between the motors.

Moreover, the control of the switching element for oscillation in the high frequency conversion circuit does not matter whether the switching element is an automatic type, a separately excited type, etc., or a specific circuit, as long as its ON width is controlled.

[Effects of the Invention] As described above, in the present invention, when a plurality of high frequency conversion circuits including LC oscillation circuits and equipped with a controller for controlling the on-time width of a switching element are operated in parallel, at least one a detection unit that detects the output of the high frequency conversion circuit;
Since we have provided an output correction means consisting of a correction section that receives the detection signal from this detection section and corrects and controls the outputs of other high-frequency conversion circuits, even if there are variations in the component constants and temperature rise of each high-frequency conversion circuit, This has the effect of preventing large variations in the output from each high frequency conversion circuit to the load.

Note that if the present invention is applied to a system that controls the lighting loads using each high-frequency conversion circuit and supplies a common dimming signal to each high-frequency conversion circuit to control the dimming of each lighting load, each lighting load can be controlled. It is possible to prevent inconveniences such as the rate of change of light output greatly differing during light control and giving a sense 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. Fig. 6 is an operation waveform diagram of the same as above, Fig. 7 and Fig. 8 are explanatory diagrams of the same as above, Fig. 9 is a circuit diagram of the lighting device used in the above, and Figs. 10 and 11 are explanatory diagrams of the same as above. , FIG. 12, and FIG. 13 are operation waveform diagrams of the same as above. 10A and 10B are high frequency conversion circuits, 11A and IB are loads, 12A is a detection section, 12B is a correction section, and 2 is an output correction means.

Claims (1)

[Claims] (1) A high-frequency conversion circuit that includes a switching element for oscillation, an LC oscillation circuit that supplies an oscillating current from a power source to a load through on/off operations of the switching element, and a control unit that controls the on-time width of the switching element. In an inverter device consisting of multiple units connected in parallel to the same power source, there is a detection unit that detects the output of at least one high frequency conversion circuit, and a detection signal from this detection unit to correct the output of other high frequency conversion circuits. An inverter device characterized in that it is provided with an output correction means comprising a control correction section.