JPH06153513A - Inverter - Google Patents

Abstract

PURPOSE:To make it possible to adjust power supplied to a load without fluctuating a frequency, and lighten a discharge lamp, as a load, stably in a deep dimming state. CONSTITUTION:A set of serially connected switching elements S1 and S2 or S3 and S4 is connected to a DC power supply. An inductor L1, a capacitor C2, and a load (Z) are connected between each middle point of the switching elements S1 and S2 or S3 and S4. The switching elements S3 and S4 have an on-off timing range that is changed from the same phase to a 180-degree shifted phase with respect to a range of the switching elements S1 and S4. The concurrent on-state time of the switching elements S1 and S4 or S2 and S3 provided diagonally is changed so that the amount of power supplied to the load (Z) can be adjusted without shifting a switching frequency. At least, an on-state ratio of the switching elements S1 is made different from that of the switching element S2 so as to supply a DC factor to the load (Z) while power with imbalance between the positive and negative is fed to a resonance circuit. Consequently, a discharge lamp, for example as a load, is prevented from going out and a flickering state with shifting strips is reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inverter device for converting DC power into AC power by switching a switching element connected in a bridge.

[0002]

FIG. 21 shows a conventional half-bridge inverter device used as a discharge lamp lighting device. In this inverter device, the MO is provided at both ends of the DC power source E.
A switching circuit S ₁ and S ₂ composed of SFETs are connected in series, and a load circuit composed of at least a resonance circuit composed of an inductor L ₁ and a capacitor C ₂ and a discharge lamp La serving as a load is connected to a DC cutting capacitor C ₁ . It is connected to both ends of the switching element S ₂ via. Further, the DC cutting capacitor C ₁ is normally the capacitor C
_{Since it} is considerably larger than the capacitance of ₂ , it is not normally included in the resonance circuit, but may be included in the resonance circuit depending on its capacitance.

Under the control of the control circuit 1, the switching elements S ₁ and S ₂ of the inverter device shown in FIG.
As shown in (b), the DC power supply E is turned on and off alternately.
Is converted into an AC voltage (high frequency voltage in this case) and supplied to the discharge lamp La, and the discharge lamp La is lit at high frequency.
This operation will be described in detail below. Now, at time t ₀ , FIG.
If the control signal V ₁ of the control circuit 1 is at a high level as shown in (a) and the control signal V ₂ is at a low level as shown in (b), the switching element S ₁ is turned on and The switching element S ₂ is turned off. At this time, from the DC power source E, the switching element S ₁ , the inductor L ₁ , the DC cutting capacitor C ₁ , the capacitor C ₂
A current is supplied to the discharge lamp La through the path of the discharge lamp La.

At this time, the DC cut capacitor C ₁ is charged. Energy is also stored in the resonance circuit. The following description will be made on the case where the operating frequency of the inverter circuit is set to a range higher than the resonant frequency of the resonant circuit. In this case, the energy stored in the inductor L ₁ mainly affects the circuit operation as described below.

Then, time t₁Then, FIG. 22 (a)
As shown in, the control signal V of the control circuit 1₁Is low level,
Control output V as shown in FIG.₂Becomes high level
Switching element S₁Turns off and the switch
Holding element S₂Turns on. However, the above switching
Element S₁, S₂So, unlike a pure switch,
And the polarity of the opposite polarity (the polarity of the polarity opposite to that of the DC power supply E).
Pressure) is applied, the switching element S₂Originally
Current I_S2Direction (current direction indicated by arrow in FIG. 21)
The parasitic diode that has the function of sending a current in the opposite direction
Have a Therefore, the switching element S₂Turn on
The current does not turn on in the original direction,
L₂The energy stored in the switching element S₂of
The parasitic diode turns on. In other words, switching element
S₂Becomes conductive in the opposite direction. And indak
L₁By the action of passing an electric current in the same direction as before,
Inductor L₁Energy stored in the
Capacitor C₁, Capacitor C ₂And discharge lamp La, Sui
Touching element S₂Emitted in the path of the parasitic diode of
It That is, the operating frequency of the inverter circuit is the same as that of the resonant circuit.
Since it is set to a range higher than the vibration frequency, the load circuit
Operates as described above.

The inductor L₁The energy of
Switching element S ₂Is originally on
(Current I in the direction indicated by the arrow in FIG._S2Flows
State), DC-cutting capacitor C₁Accumulated in
Capacitor C for direct current cutting₁,I
Inductor L₁, Switching element S₂, Capacitor C ₂
And, in the path of the discharge lamp La, the current flowing in the opposite direction to that
Be done.

After that, at the time t ₂ , the control signal V ₁ of the control circuit ₁ becomes the high level and the control signal V ₂ becomes the low level as shown in FIG. 2B, as in the case of the time t ₀ . The switching element S ₁ is turned on and the switching element S ₂ is turned off. However, it should not turned on in the switching element S ₁ even when the flow direction original current I _S1 (direction indicated by an arrow in FIG. 21), the switching element S ₁ in the energy stored in inductor L ₁
The parasitic diode of turns on. That is, the switching element S ₁ is turned on in the opposite direction. Then, the energy accumulated in the inductor L ₁ is discharged through the path of the parasitic diode of the switching element S ₁ , the DC power source E, the capacitor C _{2, the} discharge lamp La, and the DC cutting capacitor C ₁ .

When the energy of the inductor L ₁ is released, the switching element S ₁ is turned on, and the DC power source E, the switching element S ₁ , and the inductor L are turned on.
₁ , a current flows through the path of the DC cut capacitor C ₁ , the capacitor C ₂ and the discharge lamp La. Hereinafter, by repeating the series of operations described above, the DC power supply E is converted into high frequency power, and the high frequency power is supplied to the discharge lamp La. At this time, the current I _L1 flowing through the inductor L ₁ is as shown in FIG.
As shown in.

In the above description, the time t₀in the case of
And the switching element S₁Does not turn on in the original current direction.
However, until then, the switching element S₁, S₂
Is turned on and off alternately during steady lighting, time t₀
Also in the switching element S ₁Parasitic diode
Inductor L₁Release energy stored in
And then the original switching element S₁Current I_S1But
It goes without saying that it turns on in the flowing direction. Also,
In the above description, the switching element S₁, S₂The parasitic da
Inductor L₁To release the energy of
Used switching element S₁, S₂In reverse parallel to
You may make it connect a diode.

[0010]

When the electric power (that is, the output of the inverter device) supplied to the load in the inverter device is changed, the switching elements S ₁ , S
Change the switching frequency of ₂ . In addition, when the load is the discharge lamp La as described above, the dimming control of the discharge lamp La is performed.

Here, when the switching frequencies of the switching elements S ₁ and S ₂ are set to a range higher than the resonance frequency of the resonance circuit as described above, if the switching frequency is lowered, the switching frequency becomes resonance of the resonance circuit. As the frequency approaches, the electric power supplied to the discharge lamp La increases. On the contrary, if the switching frequency is increased, the switching frequency becomes far from the resonance frequency of the resonance circuit, and the power supplied to the discharge lamp La becomes smaller.

However, when the DC power source E is formed by rectifying and smoothing the AC power source, the switching element S
_When the switching frequency of ₁ and S ₂ is changed, there is a problem that high frequency leaks to the AC power supply side. Therefore, a filter that prevents high-frequency components from leaking to the AC power supply side is provided at the input end of a diode bridge that rectifies the AC power supply. However, when the operating frequency of the inverter device changes as described above, there is a problem that the design of the filter for removing high frequency components becomes complicated.

Further, when the load is the discharge lamp La and the operating frequency of the inverter device is changed, the frequency of the light emitted from the discharge lamp La also changes accordingly, so that the other devices such as an infrared remote controller can operate. There is also the problem of adverse effects. Further, when the discharge lamp La is an HID lamp, there is a high possibility that an acoustic resonance phenomenon will occur due to a change in the output frequency, which causes a reliability-related problem such as destruction of the discharge lamp La. That is, as the operating frequency of the inverter device increases, the possibility that the HID lamp coincides with the frequency that causes the acoustic resonance phenomenon increases.

Therefore, as a conventional example improving this point, "Off-Line Application of Fixed-Frequency Clam" is used.
ped Mode Series Resonant Converter ”, IEEE Tansacti
on on Power Electronics, Vol.6; No. 1, January, 1991. In this conventional example, two series circuits of two switching elements are connected in parallel with a DC power source, and
A load circuit including at least an LC resonance circuit and a load is connected between the connection points of the switching elements of the respective series circuits, and the switching elements of the respective series circuits are alternately turned on and off so as not to be turned on at the same time. The ON / OFF timing of the switching element of the other series circuit is deviated from the ON / OFF timing of the above switching element.

The operation of the above conventional example will be described in detail in the section of the embodiment of the present invention. According to this conventional example, the electric power supplied to the load can be changed without changing the operating frequency. However, there is a problem that the above-mentioned conventional example is applied as a discharge lamp lighting device, and the discharge lamp La is extinguished in a state where the electric power supplied to the discharge lamp La is reduced at a low temperature. Therefore, there is a problem that the dimming range of the discharge lamp La is limited.

The present invention has been made in view of the above points, and it is an object of the present invention to adjust the electric power supplied to a load without changing the switching frequency of the switching element and to supply the electric power. An object of the present invention is to provide an inverter device that can stably operate a load even when it is kept small.

[0017]

According to the present invention, in order to achieve the above object, two sets of series circuits of two switching elements are connected in parallel with a DC power source, and connection points of the switching elements of each series circuit are connected. A load circuit including at least an LC resonance circuit and a load is connected between them, and the switching elements of the respective series circuits are alternately turned on and off so as not to be turned on at the same time. On the other hand, the on / off timing of the switching element of the other series circuit is set to 1 from the same phase.
Variable up to 80 degrees out of phase, at least 1
The on-period ratios of the switching elements of the series circuits of the sets are made different.

Incidentally, the on / off timing of the switching element of the other series circuit may be advanced with respect to the on / off timing of the switching element of the one series circuit, or the switching element of the other series circuit may be switched. The timing of turning on and off the element may be delayed. In addition, in order to operate the load in a stable manner according to the power supplied to the load, and in particular to operate the load stably when the power supplied to the load is reduced, the ratio of the ON period of the switching element of one series circuit Is preferably increased in accordance with the magnitude of the deviation between the on / off timing of the switching element of one series circuit and the on / off timing of the switching element of the other series circuit.

Further, when the ratio of the ON periods of the switching elements of one series circuit is changed in order to compensate for the power that is reduced by changing the ratio of the ON periods of the switching elements of one series circuit, the other It is preferable to change the ratio of the ON period of the switching elements of the series circuit to make the electric power supplied to the load substantially constant.

[0020]

According to the present invention, as described above, the on / off timing of the switching element of the other series circuit is shifted by 180 degrees from the on / off timing of the switching element of the other series circuit. By varying in the range up to, it is possible to change the simultaneous ON period of the switching elements in the diagonal position and adjust the power supplied to the load without changing the switching frequency,
Various problems associated with changing switching frequency are avoided. In addition, by changing the ratio of the ON period of the switching element of at least one of the series circuits,
The positive and negative electric power supplied to the LC resonance circuit is made unbalanced so that the energy stored in the LC resonance circuit can be supplied to the load as a DC component, and for example, extinguishing is prevented when the load is a discharge lamp.

Further, the ratio of the ON period of the switching element of one series circuit is determined by the deviation of the ON / OFF timing of the switching element of the other series circuit from the ON / OFF timing of the switching element of the one series circuit. By increasing the power according to the level, it is possible to increase the DC component applied to the load, especially when the power supplied to the load is reduced, and to stably operate the load.

Further, when the ratio of the ON periods of the switching elements of one series circuit is changed, the ratio of the ON periods of the switching elements of the other series circuit is changed,
If the electric power supplied to the load is made substantially constant, it becomes possible to supplement the electric power that decreases by changing the ratio of the ON periods of the switching elements of the one series circuit.

[0023]

【Example】

 (Embodiment 1) FIG. 1 shows an embodiment of the present invention. Example
Inverter device converts DC power into AC power
And the switching element S₁, S₂And switchon
Element S₃, S_FourConnected in series to both ends of DC power supply E
Switching element S₁, S ₂Connection point and switch
Element S₃, S_FourThe inductor L between the connection point₁
And capacitor C₂From a series resonant circuit consisting of
Is connected to the load circuit. The load Z is conden
SA C₂It is connected in parallel with. That is, this inverter
The device is a switching element S₁~ S_FourBridged
It has a so-called full bridge configuration.

In this type of normal full-bridge inverter device, the control circuit 1 alternately turns on a pair of switching elements S ₁ and S ₄ and switching elements S ₂ and S ₃ which are generally provided at diagonal positions. Turn off to supply alternating current to the load circuit. First, the operation of the general inverter device will be described in detail so that the operation of the present invention can be easily understood.

Now, at time t ₀ , the control signal V of the control circuit 1
₁ , V ₄ becomes high level, and the control signals V ₂ , V ₃ become low level. At this time, the switching elements S ₁ , S
₄ FIG. 2 (a), the turned on as shown in (d), the switching element S _2, S ₃ is the figure (b), turned off as shown in (c), from the DC power source E, the switching device S
_A current flows through the load Z through the path of ₁ , the inductor L ₁ , the capacitor C _{2, the} load Z, and the switching element S ₄ .

At time t ₂ , the control signals V ₁ and V _{4 of the} control circuit 1 become low level, and the control signals V ₂ and V ₃ become high level. Then, the switching elements S ₁ , S
₄ is turned off as shown in FIGS. 2 (a) and 2 (d), and the switching elements S ₂ and S ₃ are turned on as shown in FIGS. 2 (b) and (c). Here, when the switching frequency of the inverter device is set to a range higher than the resonance frequency of the resonance circuit formed by the inductor L ₁ and the capacitor C ₂ , as described in the section of the prior art, the charge is accumulated in the inductor L _1. Energy is inductor L ₁ and capacitor C
₂ and the load Z, the parasitic diode of the switching element S ₃ , the DC power source E, and the parasitic diode of the switching element S ₂ are discharged.

Then, the inductor L₁Energy of
When released, the switching element S ₂, S₃Is on
From the DC power supply E to the switching element S₃， Conden
SA C ₂And load Z, inductor L₁, Switching element
S₂In the path of, the electric current is sent in the opposite direction. Time
Tick t_FourThen, time t₀The control circuit 1 control
Signal V₁, V_FourGoes high and the control signal
V₂, V₃Becomes a low level, and the switching element
S₁, S_FourIs turned on and the switching element
S₂, S₃Turns off. Also at this time, inductor L
₁The energy stored in the inductor L₁,switch
Element S₁Parasitic diode, DC power supply E, switch
Element S_FourParasitic diode, capacitor C₂And negative
It is released in the path of the load Z.

The inductor L₁Release of energy
Later, from the DC power source E, the switching element S₁, Inda
Kuta L₁, Capacitor C₂And load Z, switching element
Child S _FourA current is applied to the load Z through the path. In addition,
When the barter device is operating normally, the time t₀
Inductor L₁Switch the stored energy of
Element S₁, S_FourEmitted through the parasitic diode of
Later, the switching element S₁, S_FourLoad current through
Supplied. In addition, the switching element S₁~ S_FourTo each
Connect a diode in anti-parallel and connect inductor L₁Energy of
Some also release Rugi.

By the way, in the case of the latter conventional inverter device described in the section of the prior art, when the electric power supplied to the load Z is changed, the series-connected switching shown in FIGS. 3 (a) and 3 (b) is performed. The on / off timings of the elements S ₁ and S ₂ are shifted from the on / off timings of the switching elements S ₃ and S ₄ shown in FIGS. The switching elements S ₁ and S ₂ and the switching elements S ₃ and S ₄ connected in series between the output terminals of the DC power source E are alternately turned on and off.

Further, the operation of this conventional inverter device will be described in detail. In addition, the following description is similar to the above case,
A case where the switching frequency of the inverter device is set higher than the resonance frequency of the resonance circuit will be described as an example. At time t ₀ , only the switching element S ₂ is turned on as shown in FIG. 3B, and the other switching elements S ₁ , S ₃ , and S ₄ are changed to those shown in FIGS. Both are off as shown. Therefore, no current is supplied to the load circuit.

At time t ₁ , the switching element S ₃ is turned on as shown in FIG.
A load current is supplied through the path of the switching element S ₃ , the capacitor C _{2, the} load Z, the inductor L ₁ , and the switching element S ₂ . At time t ₂ , the switching element S ₂ is turned off as shown in FIG. 3B, and the supply of the load current is stopped. In addition, switching S ₂
When the switching element S ₁ is turned off at the same time that the switching element S ₁ is turned on as shown in FIG.
₁ is applied. In this case, the energy stored in the inductor L ₁ causes the load current to flow in the same direction as before through the path of the inductor L ₁ , the parasitic diode of the switching element S ₁ , the switching element S ₃ , the capacitor C ₂ and the load Z. Is discharged, and the energy stored in the inductor L ₁ is released.

At time t ₃ , as shown in FIG.
Since the switching element S ₃ is turned off, the discharge of the energy stored in the inductor L ₁ in the above path is stopped. However, at this time, the switching element S _{4 is changed} to the one shown in FIG.
A control signal V ₄ is applied from the control circuit 1 so as to be turned on as shown in (d). Therefore, when the energy of the inductor L ₁ remains, the path of the inductor L ₁ , the parasitic diode of the switching element S ₁ , the DC power source E, the parasitic diode of the switching element S ₄ , the capacitor C _2, and the load Z is The above-mentioned release of energy is continued.

When the energy of the inductor L ₁ is released, both the switching elements S ₁ and S ₄ are turned on, and the DC power source E, the switching element S ₁ , and the inductor L are turned on.
₁ , capacitor C ₂ and load Z, switching element S ₄
In the path of, the load current in the opposite direction to that before is applied.
However, when the energy of the inductor L ₁ is almost discharged at the time t ₃ , the control signal V ₄ of the control circuit 1 becomes high level and at the same time, the switching element S ₄ is turned on. In this case, this time t ₃
Since the switching element S ₁ has already been turned on at time t
_{In 3} , the load current flows through the path of the DC power supply E, the switching element S ₁ , the inductor L ₁ , the capacitor C ₂ and the load Z, and the switching element S ₄ .

At time t ₄ , the switching element S ₁ is turned off and the supply of the load current through the above path is stopped.
At this time, at the same time, a control signal V _{2 for} turning on is applied from the control circuit 1 to the switching element S ₂ , and the inductor L ₁
The energy stored in the capacitor is discharged through the path of the parasitic diode of the inductor L ₁ , the capacitor C ₂ and the load Z, the switching element S ₄ , and the switching element S ₂ .

Time t_FiveThen, the switching element S_FourIs o
And switching as shown in Fig. 3 (c)
Element S₃The high-level control signal of the control circuit 1 that turns on the
Issue V ₃Is given. At this time, inductor L₁Energy of
If Lugi remains, inductor L₁, Conden
SA C₂And load Z, switching element S₃Parasitic dio
Mode, DC power supply E, switching element S₂Parasitic dio
In the inductor path,₁Release of energy
Be done. Then, when the energy is released, the direct current
Power supply E, switching element S₃, Capacitor C₂And negative
Load Z, inductor L₁, Switching element S₂The route
Then, the load current is passed.

Also in this case, at time t ₅ , the inductor L
_When the energy of ₁ is released, at time t ₅ ,
A load current flows through the path of the DC power source E, the switching element S ₃ , the capacitor C _{2, the} load Z, the inductor L ₁ and the switching element S ₂ . By repeating the above series of operations, the DC voltage output from the DC power supply E is converted into an AC voltage, and the AC voltage is supplied to the load circuit. In this inverter device, the simultaneous ON periods of the switching elements S ₁ and S ₄ and the switching elements S ₂ and S _{3 in} the diagonal position are shorter than in the case where they coincide as shown in FIG. The power supplied is reduced. In the case where is set higher than the resonant frequency of the resonant circuit to the switching frequency of the switching elements S ₁ to S ₄ are previously set lowest switching frequency of the switching elements S ₁ to S _4.

That is, in this inverter device, the switching elements S ₃ and S ₄ are turned on and off, and the switching elements S ₃ and S ₄ are turned on and off with respect to the on and off timings of the switching elements S ₁ and S ₂ .
By changing the timing of turning off, the time during which the switching elements S ₁ and S ₄ and the switching elements S ₂ and S ₃ are simultaneously turned on is changed to change the switching elements S _{1 to} S _1.
The power supplied to the load circuit can be changed without changing the switching frequency of ₄ . Therefore, it is easy to design a filter (not shown) that prevents leakage of high-frequency output to the AC power supply AC. Also, the load Z
Is a discharge lamp, the frequency of the light emitted by the discharge lamp does not change and does not adversely affect other devices such as an infrared remote controller. Furthermore, when the discharge lamp is an HID lamp, it is possible to reduce the risk of causing an acoustic resonance phenomenon due to a change in output frequency.

In the above description, the case where the switching phases of the switching elements S ₂ and S ₄ are delayed with respect to the switching phases of the switching elements S ₁ and S ₃ has been explained. The power supplied to the load circuit can be changed. However, in the above inverter device, when the load Z is a discharge lamp and the power supplied to the discharge lamp is reduced at a low temperature, the discharge lamp goes out and the dimming control range of the discharge lamp is narrowed. .

Therefore, in the present embodiment, in order to improve this point, as shown in FIG. 4, the ratio of the ON periods of the respective switching elements S ₁ and S ₂ , that is, the ON duty is made different. In addition, the switching elements S ₁ , S ₂
Are turned on and off in opposition. Also,
The ratio of the ON periods of the switching elements S ₃ and S ₄ is the same.

Time t₀In the period before
Child S₁, S_FourDC power supply
E, switching element S₁, Inductor L₁, Conden
SA C₂And load Z, switching element S_FourOn the route of negative
The load current is passed. Time t₀Then, the switching element S
_FourIs turned off, which causes the load current supply in the above path.
Salary is stopped. This time t₀Then, switching element
S₃The control circuit 1 controls the high-level control signal V₃Given by
Therefore, as is clear from the above description, the inductor L
₁The energy stored in the inductor L₁, Conden
SA C ₂And load Z, switching element S₃Parasitic dio
Mode, switching element S₁Is released by the route.

At time t ₁ , the switching element S ₁ is turned off, so that the release of energy from the inductor L _{1 in} the above path is stopped, and at the same time when the switching element S ₁ is turned off, the control circuit 1 is switched to the switching element S _2. in the control signal V ₂ is supplied with a high-level, the energy stored in inductor L ₁ is, inductor L _1, a capacitor C
₂ and the load Z, the parasitic diode of the switching element S ₃ , the DC power source E, and the switching element S ₂ are discharged. Then, when the energy of the inductor L ₁ is released, a load current flows through the path of the DC power source E, the switching element S ₃ , the capacitor C ₂ and the load Z, the inductor L ₁ , and the switching element S ₂ .

Time t₂And the switching element S₂, S₃
Turns off and the load current supply in the above path is stopped.
It At the same time, the switching element S₁, S_FourTurn on
Control signal V₁, V₂Is given, so
L₁The energy stored in the switching element S₁
Parasitic diode, DC power supply E, switching element S _Four
Parasitic diode, capacitor C₂And on the path of load Z
Is released. And inductor L₁The energy of
Then, the DC power source E, the switching element S₁, Inda
Kuta L₁, Capacitor C₂And load Z, switching element
Child S_FourThe load current flows through the path of.

At time t ₃ , the switching element S ₄ is turned off to stop the supply of the load current through the path, and at this time, the energy of the inductor L ₁ is switched to the switching element S ₃ as described at time t _0. Is emitted through the parasitic diode of. Here, the switching elements S ₁ , S ₂
Because are with different ratio of the ON period, than the time period for turning on the switching element S _1, S ₄ simultaneously as shown in FIG. 2 (e), the switching element S _2, S ₃ long period to turn on at the same time Become. Therefore, the switching element S
₁ and S ₄ are simultaneously turned on and the switching element S
₂ and the period in which S ₃ is turned on at the same time, the time during which the load current flows through the load circuit changes, and the energy stored in the inductor L ₁ differs. When the ON period of the switching element S ₂ is shorter than the ON period of the switching element S ₁ as in this embodiment, the switching elements S ₁ , S
_The energy stored in the inductor L ₁ increases at the same time when ₄ is turned on, and the DC component accompanying this energy is applied to the load circuit.

In FIG. 5, the ON period of the switching element S ₂ is shorter than the ON period of the switching element S ₁ , and the method described in FIG.
By changing the switching phases of the switching elements S ₂ and S ₄ with respect to the switching phases of ₁ and S _3, the time when the switching elements S ₁ and S ₄ and the switching elements S ₂ and S ₃ are simultaneously turned on is changed, The power supplied to the load circuit is changed to reduce the power supplied to the load Z. The operation in this case is the switching element S
_The same operation is performed except that the time for which ₁ , S ₄ and the switching elements S ₂ , S ₃ are simultaneously turned on is shorter than that in the case of FIG.

In the case of FIG. 3, the switching element S
₁, S₂Switching element rather than on / off phase of
S₂, S₃Although the on and off phases of are delayed,
In case of switching element S₁, S₂ON / OFF phase of
Switching element S₂, S _FourThe on and off phases of
The difference is that it is advanced, but the power supplied to the load Z is low.
The effect of reducing is the same. If you do this,
There is no need to change the tuning frequency
It does not cause the problems associated with changing the wavenumber. further,
Switching element S₁, S_FourSimultaneous ON period and switch
Holding element S₂, S ₃The length of the period of simultaneous on
Therefore, a DC component is applied to the load Z. This allows
If the load Z is a discharge lamp and the dimming state is deep at low temperature,
In this case, since the above DC component is applied to the discharge lamp,
Even if the flow is reduced, the DC lamp keeps the discharge lamp lit.
This makes it difficult for the discharge lamp to go out. Therefore, dimming
It is possible to widen the range.

[0046] Figure 6 is contrary to the case of FIG. 4, the switching ON period of the switching element S ₁ and shorter than the on period of the switching element S _2, the on-switching element S _1, S _2, than off phase The case where the on / off phases of the elements S ₃ and S ₄ are delayed is shown. In this case, as is apparent from FIG. 6, the simultaneous ON period of the switching elements S ₂ and S ₃ is longer than the simultaneous ON period of the switching elements S ₁ and S ₄ . For this reason, the inductor L ₁ stores a DC component having a polarity opposite to that of the above case. However, even if the polarities are different in this way, the effect of making the discharge lamp less likely to go out can be similarly obtained. In addition,
In this case, the switching elements S ₁ and S ₂ are turned on,
FIG. 7 shows a case where the on / off phases of the switching elements S ₃ and S ₄ are further delayed with respect to the off phase to reduce the power supplied to the load Z. Further, as shown in FIG. 8, similarly on period of the switching element S ₁ and the case of FIG. 2 longer than the ON period of the switching element S _2, the on-switching element S _1, S _2, than off phase The case where the on / off phases of the switching elements S ₂ and S ₃ are delayed is shown. Although detailed description is omitted, the same effect as in the above case can be obtained in this case as well.

Further, as shown in FIG. 9, it goes without saying that the same effect can be obtained even if the ratio of the ON periods of the switching elements S ₃ and S ₄ is changed. By the way, in the case described above, the energy storage state of the resonance circuit is unbalanced and the direct current component is applied to the discharge lamp. Was becoming. It is when the light is deeply dimmed that the discharge lamp easily goes out, so when the light is deeply dimmed, that is, as the power supplied to the discharge lamp decreases, the discharge lamp is applied It is preferable to increase the DC voltage applied.

In this case, the electric power supplied to the discharge lamp decreases because the on / off phases of the switching elements S ₃ , S ₄ change with respect to the on / off phases of the switching elements S ₁ , S _2. It's time to grow up. Therefore, the on-switching element S _1, S _2, with respect to off-phase, on the switching element S _3, S _4, with that change in off-phase increases, the ON period of the switching element S _1, S ₂ If the ratio of is greatly changed, the DC voltage applied to the discharge lamp can be increased as the electric power supplied to the discharge lamp decreases.

Specifically, as shown in FIGS. 2, 5 and 10, the on / off phases of the switching elements S ₃ and S ₄ change with respect to the on / off phases of the switching elements S ₁ and S _2. As the size increases, the switching element S ₁ ,
It suffices to greatly change the ratio of the ON period of S ₂ . That is, with respect to the operation state of FIG. 4, FIG. 5 can be regarded as a case where the power supplied to the discharge lamp is reduced, and FIG. 10 is viewed as a case where the power supplied to the discharge lamp is further reduced. be able to. As is apparent from these figures, the ratio of the ON periods of the switching elements S ₁ and S ₂ is largely changed, so that the energy storage state of the resonance circuit is further unbalanced, and accordingly, the release state is increased. The DC voltage applied to the lamp is increasing.

(Embodiment 2) In the above embodiments, a conceptual explanation is given.
However, in this embodiment, as shown in FIG.
Shows a specific example in which is a discharge lamp La. In addition, this implementation
An example is a switching element as shown in FIGS.
S₁, S₂Change the ratio of the ON period of the
Element S₁, S₂Switch on and off phases of
Element S ₃, S_FourWith advanced on and off phases
Then, in FIG. 13, when the power supplied to the discharge lamp La is reduced.
Indicates. The operation of this embodiment is similar to that of the above-mentioned embodiment.
Therefore, detailed description is omitted.

Here, the current I _L1 flowing through the inductor L ₁
As shown in FIGS. 12 (j) and 13 (j), the positive _peak value I _L1P is changed to the negative _peak value I _L1N by changing the ratio of the ON periods of the switching elements S ₁ and S _2. Higher than that of FIG.
As shown in (k), the peak value I of the lamp current I _La
LaP becomes higher than the negative _peak value I _LaN , and the discharge lamp La
It is shown that the electric power supplied to the discharge lamp La can be reduced by superimposing a direct current on the discharge lamp La.

FIG. 14 shows a specific circuit of the control circuit 1 in the above inverter device. The control circuit 1 includes an oscillating circuit 2 that generates a rectangular wave signal having a fundamental frequency, drive circuits 3 and 4 that drive switching elements S ₁ and S ₂ according to the output of the oscillating circuit 2, and an oscillating circuit 2. It is composed of a delay circuit 5 for producing a signal whose output is delayed by a certain time, and drive circuits 6, 7 for driving the switching elements S ₃ , S ₄ according to the output of the delay circuit 5.

The oscillator circuit 2 includes a timer IC 2a, an external resistor R _{11 of the} timer IC 2a, and variable resistors VR ₁₁ and VR.
₁₂ , a diode D ₁₁ , D _12, and a capacitor C ₁₁ , and generates the rectangular wave signal of FIG. Here, by adjusting the variable resistors VR ₁₁ and VR ₁₂ , the ratio of the high level period and the low level period of the rectangular wave signal can be changed.

The drive circuit 3 for driving the switching element S ₁ is turned on at the same time as the switching element S ₂ to turn on the DC power source E.
A dead-off circuit 31 that sets a dead-off period that prevents short-circuiting between them to the output Va of the oscillator circuit 2, and a level shift circuit 32 that level-shifts the output of this dead circuit 31 and supplies it to the switching element S _1. There is.

By the way, the above case has not been described.
Is connected in series to the DC power supply E
Element S₁, S₂And switching element S₃, S_FourAt the same time
If this is turned on, the power supply short-circuit condition will occur.
Switching element S for ₁, S₂Or switch
Element S₃, S_FourWhen is switched on and off
Is the switching element S₁, S₂Or switching
Element S₃, S_FourSo-called dead-off period when both are off
A space is provided.

[0056] dead-off circuit 31, a variable resistor VR ₁₃ ~
It is composed of VR ₁₅ , diodes D ₁₃ and D ₁₄ , a capacitor C ₁₂ and a buffer amplifier B ₁ . That is, the variable resistance V
Oscillation circuit 2 only for the time determined by the time constants of R ₁₃ , VR ₁₄ and capacitor C ₁₂ (the period from t _{0 to} t ₁ in FIG. 15).
The signal of FIG. 15C in which the rising edge of the output Va is delayed is created.

The level shift circuit 32 includes a transistor Q
_It comprises a current mirror circuit CM ₃ composed of _{11 to} Q ₁₄ , a buffer amplifier B _2, and a constant voltage circuit 33 composed of a Zener diode ZD ₁ and a capacitor C ₁₈ which make the voltage of the DC power source E a constant voltage. This level shift circuit 32
Now, with the current mirror circuit CM ₃ , the dead-off circuit 31
Instead the output of the current, to transmit a signal to the buffer amplifier B ₂ to operate at different potentials, giving the switching element S ₁ of the output of the buffer amplifier B ₂ as the control signal V _1.

The driving circuit 4 of the switching element S ₂ is constituted by a dead-off circuit 41 to set the dead-off time to prevent short-circuiting between the DC power source E and simultaneous ON and the switching element S ₁ to the output Va of the oscillation circuit 2 I am doing it. That is, since the reference potential of the switching element S ₂ matches the reference potential of the control circuit 1, the level shift circuit is not necessary.

The dead-off circuit 41 is an inverter gate.
Heart I₁, Variable resistance VR₁₆~ VR₁₈, Diode D₁₅，
D₁₆, Capacitor C₁₃And buffer amplifier B₃Consists of
There is. In this dead-off circuit 41, the inverter gate is
To I₁The output Va of the oscillator circuit 2 is inverted by
Vb is shown in FIG. 15B), the variable resistor VR₁₆, VR ₁₇
And capacitor C₁₃Time determined by the time constant of_Four
-T_FiveDelays the rising edge of the inverted signal Vb for the period indicated by
The signal shown in FIG. 15D is created. The delay circuit 5 is
At the time of delay for setting the time to delay the output Va of the oscillation circuit 2
Interval setting section 51 and the delay time of this delay time setting circuit 51
The output Va of the oscillator circuit 2 is delayed according to
And a delayed signal creating section 52 for creating a signal.

The delay time setting section 51 includes a variable resistor VR ₁₉ ,
VR _20, the diode D _17, capacitor C _14, constituted by an inverter gate I _3, I _4, a variable resistor VR ₁₉ and time determined by the time constant of the capacitor C ₁₄ (e.g., t ₀ in FIG. 15
The period indicated by −t ₂ ) is the time for delaying the output Va of the oscillation circuit 2. More specifically, the output Va of the oscillation circuit 2
From the rise of the capacitor C _{14 as} shown in FIG.
Charging is started, the voltage across the capacitor C ₁₄ is when it reaches the threshold voltage of the inverter gate I _3, the output Vd of the inverter gate I ₃ is as shown in FIG. 15 (f).

The delay signal creating section 52 includes a delay time setting section 5
1 Inverter gate I₃Output Vd and output of oscillator circuit 2
AND gate AND that takes AND with force Va₁And delay
Capacitor C to get time₁₅And Andgate AN
D₁Output Vg of capacitor C₁₅Current charging
Error circuit CM₁And capacitor C₁₅The voltage across the
Comparator CP to compare with pressure₁And the output of the oscillator circuit 2
Inverter gate I that inverts Va₂And the inverter
Heart I₂Output Vf and comparator CP₁Output Vi and
AND gate that takes AND of₂And AND gate
AND₂Output Vj and output Ve of the delay time setting unit 51
OR gate OR that takes the OR of₁And OR gate OR₁of
Output Vk and inverter gate I₂Output of Vf and
AND gate AND₃And AND gate AND₃
C according to the output Vl of ₁₅Karen discharging the
Tomirror circuit CM₂It consists of and.

The operation of the delay signal generator 52 will be described below. The AND gate AND ₁ outputs the output Vd of the inverter gate I ₃ of the delay time setting unit 51 shown in FIG.
And the output Va of the oscillation circuit 2 are ANDed, the output Vg of the AND gate AND ₁ is high for a period corresponding to the delay time set by the delay time setting unit 51, as shown in FIG. It becomes a level. This AND gate AND ₁
The capacitor C ₁₅ is charged by the current mirror circuit CM ₁ as shown in FIG. Here, since the reference voltage of the comparator CP ₁ is set to almost 0V, its output Vi is as shown in FIG.
It is kept at a high level as shown in (k).

At the time of the above-mentioned operation, the output Vf of the inverter gate I ₂ is at the low level as shown in FIG. 15 (h), so that the AND gate AND is shown in FIG.
The output Vj of ₂ is at low level. The output of the comparator CP ₁ is kept at high level while the capacitor C ₁₅ is being charged. Now, FIG. 15 (a)
When the output Va of the oscillating circuit 2 becomes low level as shown in FIG. ₃ , the output Vf of the inverter gate I ₂ becomes high level as shown in FIG. Therefore, the output Vj of the AND gate AND ₂ becomes high level as shown in FIG. As a result, even after the output Ve of the inverter gate I ₄ of the delay time setting unit 51 has fallen to the low level, the output Vk of the OR gate OR ₁ is kept at the high level as shown in FIG. 15 (m).

At this time, the output V of the AND gate AND ₃
When l becomes high level as shown in FIG. 15 (n), the current mirror circuit CM ₂ operates and discharge of the capacitor C ₁₅ is started. Here, since the mirror ratio of the current mirror circuit CM ₂ and the current mirror circuit CM ₁ is set to 1: 1, the delay time set by the delay time setting unit 51 is After the same time, the capacitor C ₁₅ is completely discharged.

When the capacitor C ₁₅ is completely discharged, the output Vi of the comparator CP ₁ becomes low level as shown in FIG. 15 (k). As a result, the output Vj of the AND gate AND ₂ becomes low level as shown in FIG. 15 (l), and the output Vk of the OR gate OR ₁ also becomes low level as shown in FIG. 15 (m). The output Vk of the OR gate OR ₁ causes the AND gate AND ₃
The output Vl of the current mirror circuit becomes low level as shown in FIG. 15 (n), and the operation of the current mirror circuit CM ₂ is stopped.

That is, the delay signal generating section 52
For the same amount of time as the time set in the time setting section 51,
Agate OR₁Set to delay the fall of the output Vk of
Is generated according to the delay time of the delay time setting circuit 51.
Create a signal in which the output Va of the vibration circuit 2 is totally delayed.
ing. Then, based on this signal Vk, the drive circuit 6,
7 is a switching element S₃, S _FourTo drive. switch
Element S₃The drive circuit 6 of FIG.
Bell shift circuit 62 and switching element S_Four
The drive circuit 7 is composed of a dead-off circuit 71.

The dead-off circuit 61 comprises an inverter gate I ₅ , variable resistors VR _{24 to} VR ₂₆ , a diode D ₂₀ ,
It is composed of D ₂₁ , a capacitor C _17, and a buffer amplifier B ₅ , and the rise of the output Vk of the OR gate OR ₁ is shown in FIG.
Delaying period indicated by the t ₂ -t ₃ and sets the dead-off period. Further, the level shift circuit 62 includes a current mirror circuit CM ₄ including transistors Q _{15 to} Q ₁₈ , a buffer amplifier B ₆ , a zener diode ZD ₂ for making the voltage of the DC power source E a constant voltage, and a capacitor C _19. And a voltage circuit 63.

The dead-off circuit 71 has a variable resistor VR._{twenty one}~
VR_{twenty three}, Diode D₁₈, D₁₉, Capacitor C₁₆And
Caffe amplifier B_FourOR gate OR₁of
The output rise obtained by inverting the output Vk is represented by t in FIG.₆-T₇
The dead-off period is set by delaying the period shown by. This
Then, the switching element S₁, S₂And Sui
Touching element S₃, S_FourON / OFF timing phase
The difference is time t in FIG.₁-T₃Given in. So
Then, the switching element S₁, S₂The ratio of the on period of
When variable, for example, the variable resistance VR in FIG.
₁₅Of the control signal V ₁The fall time of
Delayed and variable resistance VR₁₇Increase the resistance value of
Control signal V₂If you delay the rise time of
Good.

(Embodiment 3) The operation of still another embodiment of the present invention will be described with reference to FIG. The circuit configuration is the same as in FIG. In the case of each of the embodiments described above, the switching element S
_Although the direct current component was applied to the load circuit by changing the ratio of the ON periods of ₁ and S ₂ , in this case, the switching element S ₁ and
When the ratio of the ON period of S ₂ is changed, when the power supplied to the load Z is large (in the case of a discharge lamp, for example, at full lighting)
However, the electric power supplied to the load Z was reduced accordingly. Therefore, in order to improve this point, in this embodiment,
When the ratio of the ON periods of the switching elements S ₁ and S ₂ is changed, the ratio of the ON periods of the switching frequencies S ₃ and S ₄ is also changed accordingly.

For example, as shown in FIGS. 16 (a) and 16 (b), when the ON period of the switching element S ₁ is made longer than the ON period of the switching element S ₂ , FIG.
As shown in (d), the ON period of the switching element S ₄ is made longer than the ON period of the switching element S ₃ . In this way, the simultaneous ON periods of the switching elements S ₁ and S ₄ are lengthened to increase the power supplied to the load as a whole of the inverter device, and the ratio of the ON periods of the switching elements S ₁ and S ₂ is increased. It is possible to supply the same amount of electric power to the load Z as in the case where it is not changed.

FIG. 17 shows a case where the on / off timings of the switching elements S ₃ , S ₄ are delayed from the on / off timings of the switching elements S ₁ , S ₂ . Also in this case, similarly, as shown in FIGS. 17A and 17B, the ON period of the switching element S ₁ is changed to the switching element S ₂
When longer than the on-period, Fig. (C), is longer than the ON period of the switching element S ₃ to the ON period of the switching element S ₄ as shown in (d). With this configuration, it is possible to lengthen the simultaneous ON periods of the switching elements S ₁ and S ₄ and increase the power supplied to the load as a whole of the inverter device.

FIG. 18 shows that by changing the ratio of the ON periods of the switching elements S ₁ and S ₂ in FIG.
The discharge lamp La at the time to full lighting, that the power supplied to the load Z is reduced, as in the case described above, the switching frequency S ₃ in accordance with the ratio of the ON period switching device S _1, S ₂ , S ₄ side ON period ratio is changed to compensate.

Example 4 In FIG. 19, when the load is the discharge lamp La, a preheating capacitor C ₃ is connected to both ends of the filament of the discharge lamp La on the non-power supply side in addition to the capacitor C ₂ of the resonance circuit. It is a thing. In this case, when the discharge lamp La is not lit, a current flows through the filaments through a capacitor C _3, the discharge lamp La is lighted, since the drop voltage across the capacitor C _3, the current of the capacitor C ₃ is reduced , Pre-heating before lighting can be performed. Even with such a configuration, the above-described embodiments are applied, the discharge lamp La can be dimmed and turned on without changing the switching frequency of the switching elements S _{1 to} S ₄ , and the switching elements S ₁ and S _{2 are} turned on. By changing the ratio of the ON period of
It is possible to prevent the discharge lamp La from falling off.

FIG. 20 uses the inductor L ₂ for preheating shown in FIG. Even in this way, the discharge lamp L
The filament can be preheated before lighting a.
Moreover, the energy stored in the inductor L ₂ also changes by changing the ratio of the ON periods of the switching elements S ₁ and S ₂ , and the DC component superimposed on the discharge lamp La can be increased, and in the deep dimming state at low temperature. There is also an advantage that the extinguishing of the discharge lamp La can be better prevented.

In the above description, the case where the switching element is the FET has been described, but a bipolar transistor or a thyristor to which a diode is connected in antiparallel may be used. Further, it goes without saying that the DC power supply includes a power supply that is created by rectifying or smoothing an AC power supply.

[0076]

As described above, according to the present invention, the on / off timings of the switching elements of the other series circuit are deviated from the same phase by 180 degrees with respect to the on / off timings of the switching element of the one series circuit. Since it is variable in the range up to the phase, it is possible to adjust the power supplied to the load without changing the switching frequency by changing the simultaneous ON period of the switching elements in diagonal positions.
Various problems associated with changing the switching frequency can be avoided. Further, since the ON periods of the switching elements of at least one of the series circuits are made different, the positive and negative supply power to the LC resonance circuit is unbalanced, and the energy accumulated in the LC resonance circuit is loaded as a DC component. It is possible to prevent the lamp from going out when the load is a discharge lamp.

Further, the ratio of the ON period of the switching element of one series circuit is determined by the deviation of the ON / OFF timing of the switching element of the other series circuit from the ON / OFF timing of the switching element of the one series circuit. By increasing according to the degree, the DC component applied to the load can be increased especially when the power supplied to the load is reduced, and the load can be operated stably.

Further, when the ratio of the ON periods of the switching elements of one series circuit is changed, the ratio of the ON periods of the switching elements of the other series circuit is changed,
When the electric power supplied to the load is made substantially constant, it is possible to compensate for the electric power that decreases by changing the ratio of the ON periods of the switching elements of the one series circuit.

[Brief description of drawings]

FIG. 1 is a circuit diagram of an embodiment of the present invention.

FIG. 2 is an operation explanatory diagram when the power supplied to the load is the same as the above.

FIG. 3 is an operation explanatory diagram showing a method of varying the power supplied to the load without changing the switching frequency.

FIG. 4 is an operation explanatory diagram showing a method of applying a DC component to a load.

FIG. 5 is an operation explanatory diagram when a DC component is applied to the load and the power supplied to the load is changed without changing the switching frequency.

FIG. 6 is an operation explanatory diagram showing another method of applying a DC component to a load.

FIG. 7 is an operation explanatory diagram when the power supplied to the load is changed in the above.

FIG. 8 is an operation explanatory view showing still another method of applying a DC component to the load.

FIG. 9 is an operation explanatory view showing still another method of applying a DC component to the load.

FIG. 10: As the power supplied to the load is reduced,
It is an operation explanatory view when the direct-current component applied to a load is increased.

FIG. 11 is a specific circuit diagram when the load is a discharge lamp.

FIG. 12 is an explanatory diagram of an operation when almost the same is lit above.

FIG. 13 is an explanatory diagram of an operation during dimming of the above.

FIG. 14 is a specific circuit diagram of the above control circuit.

FIG. 15 is an operation explanatory view of the control circuit of the above.

FIG. 16 is an operation explanatory diagram showing a method in which the power supplied to the load is not reduced even if the ratio of the ON periods of the respective switching elements of the one series circuit changes.

FIG. 17 is an operation explanatory view showing another method in which the power supplied to the load is not reduced even if the ratio of the ON periods of the respective switching elements of the one series circuit changes.

FIG. 18 is a circuit diagram of FIG. 11, in which the ON period ratio of each switching element of one series circuit changes.
It is an operation explanatory view showing a method which does not reduce electric power supplied to a load.

FIG. 19 is a circuit diagram when a preheating capacitor is provided when the load is a discharge lamp.

FIG. 20 is a circuit diagram when a preheating inductor is provided when the load is a discharge lamp.

FIG. 21 is a circuit diagram of a conventional half-bridge inverter device.

FIG. 22 is an explanatory diagram of an operation of the above.

[Explanation of symbols]

E DC power supply S _{1 to} S ₄ Switching element L ₁ Inductor C ₂ Capacitor Z Load 1 Control circuit

[Procedure amendment]

[Submission date] October 1, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] Claim 4

[Correction method] Change

[Correction content]

[Procedure Amendment 2]

[Document name to be amended] Statement

[Name of item to be corrected] 0005

[Correction method] Change

[Correction content]

Then, at time t ₁ , FIG.
, The control signal V ₁ of the control circuit ₁ is low level,
As shown in FIG. 6B, the control output V ₂ becomes high level, the switching element S ₁ is turned off, and the switching element S ₂ is turned on. However, unlike the pure switch, the switching elements S ₁ and S ₂ are applied to the switching element S ₂ when a voltage having a polarity opposite to the normal polarity (voltage having a polarity opposite to the polarity of the DC power source E) is applied. Originally
Has a parasitic diode having a function of causing a current to flow in a direction opposite to the direction in which the current I _S2 flows (current direction indicated by an arrow in FIG. 21). Therefore, when the switching element S ₂ is turned on, the switching element S ₂ is not turned on in the original direction of the current, and a current flows through the parasitic diode of the switching element S ₂ by the energy accumulated in the inductor L ₂ . That is, the switching element S ₂ becomes conductive in the opposite direction. Then, the function to flow a current in the same direction as far inductor L _1, the energy stored in the resonant circuit,
A current flows through the path of the inductor L ₁ , the DC cut capacitor C ₁ , the capacitor C _{2, the} discharge lamp La, and the parasitic diode of the switching element S ₂ . That is, since the operating frequency of the inverter circuit is set to a range higher than the resonant frequency of the resonant circuit, the load circuit operates as described above.

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0006

[Correction method] Change

[Correction content]

When the current of the resonance circuit becomes zero
From the point , the switching element S ₂ becomes the original ON state (a state in which the current I _S2 flows in the direction shown by the arrow in FIG. 21), and the DC cut capacitor C ₁ and the resonance circuit capacitor are connected.
Using the electric charge accumulated in the capacitor C ₂ as a power source, a current in the opposite direction flows through the path of the DC cut capacitor C ₁ , the inductor L ₁ , the switching element S ₂ , the capacitor C ₂ and the discharge lamp La.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0007

[Correction method] Change

[Correction content]

After that, at the time t ₂ , the control signal V ₁ of the control circuit ₁ becomes the high level and the control signal V ₂ becomes the low level as shown in FIG. 2B, as in the case of the time t ₀ . The switching element S ₁ is turned on and the switching element S ₂ is turned off. However, even in this case, the switching element S ₁ does not turn on in the direction in which the original current I _S1 flows (the direction shown by the arrow in FIG. 21), and the resonance circuit S ₁ does not turn on.
The energy stored in the path turns on the parasitic diode of the switching element S ₁ . That is, the switching element S
₁ becomes a state of conducting in the opposite direction. Then, the energy stored in the resonant circuit, the parasitic diode of the switching element S _1, a DC power source E, a capacitor C ₂ and the discharge lamp La, the current flow in the path of the DC cut capacitor C ₁
Be done .

[Procedure Amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0008

[Correction method] Change

[Correction content]

When the current of the resonance circuit becomes zero
From the point, the switching element S ₁ is in the original ON state, and the DC power source E, the switching element S ₁ , the inductor L
₁ , a current flows through the path of the DC cut capacitor C ₁ , the capacitor C ₂ and the discharge lamp La. Hereinafter, by repeating the series of operations described above, the DC power supply E is converted into high frequency power, and the high frequency power is supplied to the discharge lamp La. At this time, the current I _L1 flowing through the inductor L ₁ is as shown in FIG.
As shown in.

[Procedure correction 6]

[Document name to be amended] Statement

[Correction target item name] 0009

[Correction method] Change

[Correction content]

In the above description, the time t₀in the case of
And the switching element S₁Does not turn on in the original current direction.
However, until then, the switching element S₁, S₂
Is turned on and off alternately during steady lighting, time t₀
Also in the switching element S ₁Parasitic diode
Depending onCurrent flows,Then the original switching element
S₁Current I_S1Will turn on in the direction
not. In the above description, the switching element S
₁, S₂The parasitic diode ofPass current through the resonant circuitFor
The switching element S₁, S₂Each in reverse parallel
You may make it connect a diode to.

[Procedure Amendment 7]

[Document name to be amended] Statement

[Correction target item name] 0012

[Correction method] Change

[Correction content]

However, when the DC power source E is obtained by rectifying and smoothing the AC power source, the switching elements S ₁ ,
When the switching frequency of S ₂ is changed, there is a problem that high frequency leaks to the AC power source side. Therefore, a filter that prevents high-frequency components from leaking to the AC power supply side is provided at the input end of a diode bridge that rectifies the AC power supply. However, when the operating frequency of the inverter device changes as described above, there is a problem that the design of the filter for removing high frequency components becomes complicated.

[Procedure Amendment 8]

[Document name to be amended] Statement

[Correction target item name] 0014

[Correction method] Change

[Correction content]

As a conventional example that can improve this point, "Off-Line Application of Fixed-Frequency Clam"
ped Mode Series Resonant Converter ”, IEEE Tansacti
on onPower Electronics, Vol.6; No.1, January, 1991. In this conventional example, two series circuits of two switching elements are connected in parallel with a DC power source, and
A load circuit including at least an LC resonance circuit and a load is connected between the connection points of the switching elements of the respective series circuits, and the switching elements of the respective series circuits are alternately turned on and off so as not to be turned on at the same time. Change the ON / OFF phase of the switching element of the other series circuit with respect to the ON / OFF timing of the switching element of
It is as that.

[Procedure Amendment 9]

[Document name to be amended] Statement

[Name of item to be corrected] 0015

[Correction method] Change

[Correction content]

The operation of the above conventional example will be described in detail in the section of the embodiment of the present invention. According to this conventional example, the electric power supplied to the load can be changed without changing the operating frequency. However, in a state in which applied in particular as a discharge lamp lighting device of a conventional example described above, squeezed reduce power supplied to the discharge lamp La at a low temperature, the discharge lamp La Shi Oko extinction
There is also a problem that flicker occurs due to moving stripes . Therefore, there is a problem that the dimming range of the discharge lamp La is limited.

[Procedure Amendment 10]

[Document name to be amended] Statement

[Correction target item name] 0018

[Correction method] Change

[Correction content]

Incidentally, the on / off timing of the switching element of the other series circuit may be advanced with respect to the on / off timing of the switching element of the one series circuit, or the switching element of the other series circuit may be switched. The timing of turning on and off the element may be delayed. In order to operate the load stably according to the power supplied to the load, especially when the power supplied to the load is reduced ,
The ratio of the ON period of the switching element of one series circuit is increased according to the magnitude of the phase difference between the ON and OFF timings of the switching element of the other series circuit with respect to the ON / OFF timing of the switching element of the one series circuit. Preferably.

[Procedure Amendment 11]

[Document name to be amended] Statement

[Correction target item name] 0019

[Correction method] Change

[Correction content]

Further, when the ratio of the ON periods of the switching elements of one series circuit is changed in order to compensate for the power that is reduced by changing the ratio of the ON periods of the switching elements of one series circuit, the other It is also possible to change the ratio of the ON periods of the switching elements of the series circuit to make the electric power supplied to the load substantially constant.

[Procedure Amendment 12]

[Document name to be amended] Statement

[Correction target item name] 0020

[Correction method] Change

[Correction content]

[0020]

According to the present invention, as described above, the on / off timing of the switching element of the other series circuit is shifted by 180 degrees from the on / off timing of the switching element of the other series circuit. By varying in the range up to, it is possible to change the simultaneous ON period of the switching elements in the diagonal position and adjust the power supplied to the load without changing the switching frequency,
Various problems associated with changing switching frequency are avoided. In addition, by changing the ratio of the ON period of the switching element of at least one of the series circuits,
The positive and negative supply power to the LC resonance circuit is unbalanced, and the energy stored in the LC resonance circuit can be supplied to the load as a direct current component. For example, when the load is a discharge lamp, it extinguishes or flickers due to moving stripes. To prevent
It also prevents flickering due to moving stripes.

[Procedure Amendment 13]

[Document name to be amended] Statement

[Correction target item name] 0021

[Correction method] Change

[Correction content]

Further, the ratio of the ON period of the switching element of one series circuit is determined by the change in the ON / OFF phase of the switching element of the other series circuit with respect to the ON / OFF timing of the switching element of the one series circuit. By increasing it according to the level, the DC component applied to the load is increased, especially when the power supplied to the load is reduced,
It enables stable operation of the load.

[Procedure Amendment 14]

[Document name to be amended] Statement

[Correction target item name] 0026

[Correction method] Change

[Correction content]

At time t ₂ , the control signals V ₁ and V _{4 of the} control circuit 1 become low level, and the control signals V ₂ and V ₃ become high level. Then, the switching elements S ₁ , S
₄ is turned off as shown in FIGS. 2 (a) and 2 (d), and the switching elements S ₂ and S ₃ are turned on as shown in FIGS. 2 (b) and (c). Here, when the switching frequency of the inverter device is set to a range higher than the resonance frequency of the resonance circuit including the inductor L ₁ and the capacitor C ₂ , the resonance circuit is stored in the resonance circuit as described in the section of the related art. Depending on the energy, inductor L ₁ and capacitor C
₂ flows through the paths of the load Z, the load Z, the parasitic diode of the switching element S ₃ , the DC power source E, and the parasitic diode of the switching element S ₂ .

[Procedure Amendment 15]

[Document name to be amended] Statement

[Name of item to be corrected] 0027

[Correction method] Change

[Correction content]

Then, the current of the resonance circuit becomes zero.
From that moment , the switching elements S ₂ and S ₃ are turned on, and the current from the DC power source E is reversed in the path of the switching element S ₃ , the capacitor C ₂ and the load Z, the inductor L ₁ , and the switching element S _2. Shed in the direction. At time t ₄ , the control signals V ₁ and V ₄ of the control circuit 1 become high level and the control signals V ₂ and V ₃ become low level, as in the case of time t ₀ , and the switching elements S ₁ and S 4 ₄ is turned on and the switching elements S ₂ and S ₃ are turned off. In this case, the energy stored in the resonant circuit, the inductor L _1, a parasitic diode of the switching element S _1, a DC power source E, a parasitic diode of the switching element S _4, the current flows through a path of the capacitor C ₂ and the load Z .

[Procedure Amendment 16]

[Document name to be amended] Statement

[Correction target item name] 0028

[Correction method] Change

[Correction content]

When the current of the resonance circuit becomes zero
From the point , a current flows from the DC power source E to the load Z through the path of the switching element S ₁ , the inductor L ₁ , the capacitor C ₂ and the load Z, and the switching element S ₄ . When the inverter device is operating normally, the time t
At time _0, after current flows through the parasitic diode of the switching element S _1, S _4, the switching element S
A load current in the positive direction is supplied via ₁ and S ₄ . Further, there is also one in which a diode is connected in antiparallel to each of the switching elements S _{1 to} S ₄ to allow a current of the resonance circuit to flow .

[Procedure Amendment 17]

[Document name to be amended] Statement

[Name of item to be corrected] 0030

[Correction method] Change

[Correction content]

Further, the operation of this conventional inverter device will be described in detail. In addition, the following description is similar to the above case,
A case where the switching frequency of the inverter device is set higher than the resonance frequency of the resonance circuit will be described as an example. At time t ₀ , the switching elements S ₂ and S ₄ are turned on as shown in FIG. 3B, and the other switching elements S ₁ and S ₃ are both turned off as shown in FIGS. 3A and 3C. Is. Therefore, no voltage is applied to the load circuit.

[Procedure 18]

[Document name to be amended] Statement

[Correction target item name] 0031

[Correction method] Change

[Correction content]

Time t₁Then, the same figure (c), (D)Shown in
Switching element S₃Is on, Switching element
S ₄ is offAs a result, DC power supply E and switching element
Child S ₃, Capacitor C₂And load Z, inductor L₁,
Switching element S₂The load current is supplied in the
It Time t₂Then, as shown in Fig. 3 (b),
Element S₂By turning off theVoltage to
Is no longer applied. Also switchingelementS₂Off of
At the same time, the switching element S₁Is shown in Fig. 3 (a).
Control signal V from control circuit 1₁Mark
Be added. In this case,Resonant circuitEnel accumulated in
Inductor L₁, Switching element S₁The parasitic da
Iod, switching element S₃, Capacitor C₂as well as
In the path of load Z, the load current flows in the same direction as before.
ReIt

[Procedure Amendment 19]

[Document name to be amended] Statement

[Name of item to be corrected] 0032

[Correction method] Change

[Correction content]

At time t ₃ , as shown in FIG.
The switching element S ₃ is turned off . The switching element S ₄ 3 control signal V ₄ from the control circuit 1 so as to turn on as shown in (d) is applied at the time of this. Therefore, when energy remains in the resonance circuit , the inductor L ₁ , the parasitic diode of the switching element S ₁ ,
DC power source E, parasitic diode of switching element S ₄ ,
A current flows through the path of the capacitor C ₂ and the load Z.

[Procedure amendment 20]

[Document name to be amended] Statement

[Correction target item name] 0033

[Correction method] Change

[Correction content]

AndWhen the current of the resonance circuit becomes zero
From the point, Switching element S₁, S _FourAre both on
DC power supply E, switching element S₁, Inductor L
₁, Capacitor C₂And load Z, switching element S_Four
In the path of, the load current in the opposite direction to that before is applied.
However, the time t₃At the time ofThe current in the resonant circuit is zero
WasIn this case, the control signal V of the control circuit 1_FourIs high level
At the same time, the switching element S_FourTurns on.
In this case, this time t₃Already switching element S
₁Is on, so time t₃, DC power supply E,
Switching element S₁, Inductor L₁, Capacitor C
₂And load Z, switching element S_FourIn the route of
FlowflowIt

[Procedure correction 21]

[Document name to be amended] Statement

[Correction target item name] 0034

[Correction method] Change

[Correction content]

At time t ₄ , the switching element S ₁ is turned off and the supply of the load current through the above path is stopped.
At this time, the applied control signal V ₂ to turn on the control circuit 1 simultaneously to the switching element S _2, the energy stored in the resonant circuit, the inductor L _1, a capacitor C ₂ and the load Z, the switching element S _4, switching A current flows in the path of the parasitic diode of the element S ₂ .

[Procedure correction 22]

[Document name to be amended] Statement

[Correction target item name] 0035

[Correction method] Change

[Correction content]

Time t_FiveThen, the switching element S_FourIs o
And switching as shown in Fig. 3 (c)
Element S₃The high-level control signal of the control circuit 1 that turns on the
Issue V ₃Is given. At this time,In the resonant circuitEnergy
If it remains, inductor L₁, Capacitor C₂
And discharge lamp Z, switching element S₃Parasitic Daio
, DC power supply E, switching element S₂Parasitic Daio
In the route ofCurrent flows. AndThe resonant circuit current is
After reaching zeroDC power supply E, switching element S₃,
Capacitor C₂And load Z, inductor L₁,switch
Element S₂The load current isflowIt

[Procedure amendment 23]

[Document name to be amended] Statement

[Correction target item name] 0036

[Correction method] Change

[Correction content]

[0036] By repeating the above SL series of operations, it converts the DC voltage which is an output of the DC power source E into an AC voltage,
AC voltage is supplied to the load circuit. In this inverter device, the simultaneous ON periods of the switching elements S ₁ and S ₄ and the switching elements S ₂ and S _{3 in} the diagonal position are shorter than in the case where they coincide as shown in FIG.
The power supplied to the is reduced. Note that the switching frequency of the inverter device is higher than the resonant frequency of the resonant circuit.
Set the lowest in the range .

[Procedure correction 24]

[Document name to be amended] Statement

[Name of item to be corrected] 0037

[Correction method] Change

[Correction content]

That is, in this inverter device, the switch
Holding element S₁, S₂For the on / off timing of
The switching element S₃, S_FourOn, offPhase
By changing the switching element S₁, S_FourOver
And switching element S₂, S ₃Butat the same timeTime to turn on
Change the switching element S₁~ S_FourSwitching
Change the power supplied to the load circuit without changing the frequency.
It can be transformed. Therefore, AC power supply A
A filter (not shown) for preventing leakage of high frequency output to C
It becomes easier to design The load Z is a discharge lamp.
In this case, the frequency of the light emitted by the discharge lamp changes and the infrared
Do not adversely affect other devices such as Mokon.
Yes. Furthermore, if the discharge lamp is a HID lamp,
There is little risk of causing acoustic resonance due to frequency changes.
I can do it.

[Procedure correction 25]

[Document name to be amended] Statement

[Correction target item name] 0040

[Correction method] Change

[Correction content]

Time t₀In the period before
Child S₁, S_FourDC power supply
E, switching element S₁, Inductor L₁, Conden
SA C₂And load Z, switching element S_FourOn the route of negative
The load current is passed. Time t₀Then, the switching element S
_FourIs turned off, which causes the load current supply in the above path.
Salary is stopped. This time t₀Then, switching element
S₃The control circuit 1 controls the high-level control signal V₃Given by
Therefore, as is clear from the above explanation,Resonant circuitStored in
Energy accumulatedBy, Inductor L₁, Conden
SA C ₂And load Z, switching element S₃Parasitic dio
Mode, switching element S₁On the routeCurrent flows.

[Procedure Amendment 26]

[Document name to be amended] Statement

[Correction target item name] 0041

[Correction method] Change

[Correction content]

At time t ₁ , the switching element S ₁ is turned off, so that the current in the path is stopped, and at the same time when the switching element S ₁ is turned off, the switching element S ₁ is turned off.
Since _second control signal V ₂ is supplied with a high-level control circuit 1, the energy stored in the resonant circuit, the inductor L _1, a capacitor C ₂ and the load Z, the parasitic diode of the switching element S _3, the DC power source E, A current flows through the parasitic diode path of the switching element S ₂ . Then, when the current of the resonance circuit becomes zero, the path of the DC power source E, the switching element S ₃ , the capacitor C ₂ and the load Z, the inductor L ₁ , and the switching element S ₂
Load current is applied.

[Procedure Amendment 27]

[Document name to be amended] Statement

[Correction target item name] 0042

[Correction method] Change

[Correction content]

Time t₂And the switching element S₂, S₃
Turns off and the load current supply in the above path is stopped.
It At the same time, the switching element S₁, S_FourTurn on
Control signal V₁, V₂Is given,Resonant circuit
Energy stored inBy, Switching element S₁
Parasitic diode, DC power supply E, switching element S _Four
Parasitic diode, capacitor C₂And on the path of load Z
Current flows. AndResonance circuit current is zero
From the moment, DC power supply E, switching element S₁, Inda
Kuta L₁, Capacitor C₂And load Z, switching element
Child S_FourThe load current isflowIt

[Procedure correction 28]

[Document name to be amended] Statement

[Correction target item name] 0043

[Correction method] Change

[Correction content]

[0043] At time t _3, by turning off the switching element S _4, the load current of the above path is stopped, by the energy of the resonance circuit at this point, the parasitic switching element S ₃ as described at time t ₀ Power through the diode
The flow flows . Since are at different ratio of on-period switching device S _1, S _2, found the following period for turning on the switching element S _1, S ₄ simultaneously as shown in FIG. 4 (e), the switching element S _It becomes longer than the period when ₂ and S ₃ are turned on at the same time. Therefore, the switching element S
₁ and S ₄ are simultaneously turned on and the switching element S
In a _{period 2,} S ₃ are turned on at the same time, the time the load current Ru into the load circuit changes, varies the energy accumulated in the resonant circuit. When the ON period of the switching element S ₂ is shorter than the ON period of the switching element S ₁ as in the present embodiment, the energy supplied to the resonance circuit increases when the switching elements S ₁ and S ₄ are simultaneously turned on, A direct current component accompanying this energy is applied to the load circuit.

[Procedure correction 29]

[Document name to be amended] Statement

[Correction target item name] 0044

[Correction method] Change

[Correction content]

In FIG. 5, the ON period of the switching element S ₂ is set shorter than the ON period of the switching element S ₁ , and the method described in FIG.
Switching element for switching phase of ₁ and S ₂
By varying the S _3, S ₄ of the switching phase, by varying the time when the switching element S _1, S ₄ and the switching elements S _2, S ₃ are turned on at the same time, to change the power supplied to the load circuit, a load The power supplied to Z is reduced. The operation in this case operates in the same manner except that the time during which the switching elements S ₁ and S ₄ and the switching elements S ₂ and S ₃ are simultaneously turned on is shorter than that in the case of FIG.

[Procedure amendment 30]

[Document name to be amended] Statement

[Name of item to be corrected] 0045

[Correction method] Change

[Correction content]

In the case of FIG. 3, the switching element S
₁, S₂Switching element rather than on / off phase of
S ₃ , S ₄ Although the on and off phases of are delayed,
In case of switching element S₁, S₂ON / OFF phase of
Than switching elementsS ₃ , S _FourThe on and off phases of
The difference is that it is advanced, but the power supplied to the load Z is low.
The effect of reducing is the same. If you do this,
There is no need to change the tuning frequency
It does not cause the problems associated with changing the wavenumber. further,
Switching element S₁, S_FourSimultaneous ON period and switch
Holding element S₂, S ₃The length of the period of simultaneous on
Therefore, a DC component is applied to the load Z. This allows
If the load Z is a discharge lamp and the dimming state is deep at low temperature,
In this case, since the above DC component is applied to the discharge lamp,
Even if the flow is reduced, the DC lamp keeps the discharge lamp lit.
The discharge lamp does not easily go out.Due to moving stripes
Reduces flickerIt Therefore, widen the dimming range
Is possibleStable lighting is possible.It

[Procedure correction 31]

[Document name to be amended] Statement

[Correction target item name] 0046

[Correction method] Change

[Correction content]

[0046] Figure 6 is contrary to the case of FIG. 4, the switching ON period of the switching element S ₁ and shorter than the on period of the switching element S _2, the on-switching element S _1, S _2, than off phase The case where the on / off phases of the elements S ₃ and S ₄ are delayed is shown. In this case, as is apparent from FIG. 6, the simultaneous ON period of the switching elements S ₂ and S ₃ is longer than the simultaneous ON period of the switching elements S ₁ and S ₄ . For this reason, the inductor L ₁ stores a DC component having a polarity opposite to that of the above case. However, even if the polarities are different in this way, the effect of making the discharge lamp less likely to go out can be similarly obtained. In addition,
In this case, the switching elements S ₁ and S ₂ are turned on,
FIG. 7 shows a case where the on / off phases of the switching elements S ₃ and S ₄ are further delayed with respect to the off phase to reduce the power supplied to the load Z. Further, as shown in FIG. 8, similarly on period of the switching element S ₁ and the case of FIG. 2 longer than the ON period of the switching element S _2, the on-switching element S _1, S _2, than off phase The case where the on / off phases of the switching elements S ₃ and S ₄ are delayed is shown. Although detailed description is omitted, the same effect as in the above case can be obtained in this case as well.

[Procedure correction 32]

[Document name to be amended] Statement

[Correction target item name] 0056

[Correction method] Change

[Correction content]

[0056] dead-off circuit 31, a variable resistor VR ₁₃ ~
It is composed of VR ₁₅ , diodes D ₁₃ and D ₁₄ , a capacitor C ₁₂ and a buffer amplifier B ₁ . That is, the variable resistance V
Oscillation circuit 2 only for the time determined by the time constants of R ₁₃ , VR ₁₄ and capacitor C ₁₂ (the period from t _{0 to} t ₁ in FIG. 15).
Create a signal of Figure 15 obtained by delaying the rise of the output Va of (c)
It

[Procedure amendment 33]

[Document name to be amended] Statement

[Name of item to be corrected] 0058

[Correction method] Change

[Correction content]

Switching element S₂The drive circuit 4 of
Itching element S₂And DC power supply E are short-circuited at the same time
The dead-off period that prevents
VaFromIt is composed of a dead-off circuit 41 to be set.
That is, the switching element S ₂ofmotionReference potential is control time
Since it matches the reference potential of path 1, the level shift circuit
Is not necessary.

[Procedure amendment 34]

[Document name to be amended] Statement

[Correction target item name] 0067

[Correction method] Change

[Correction content]

The dead-off circuit 61 is an inverter gate.
I_Five, Variable resistance VR_{twenty four}~ VR₂₆, Diode D₂₀，
D_{twenty one}, Capacitor C₁₇And buffer amplifier B_FiveConsists of
Yes, OR gate OR₁OutputInverted output of VmRise of
Of Figure 15t ₆ -t ₇ Delayed and dead
Set the off period. Further, the level shift circuit 62 is
Transistor Q₁₅~ Q₁₈Current mirror circuit C consisting of
M_FourAnd buffer amplifier B ₆And the voltage of DC power supply E
Zener diode ZD that turns into voltage₂And capacitor C₁₉
And a constant voltage circuit 63 consisting of

[Procedure amendment 35]

[Document name to be amended] Statement

[Correction target item name] 0068

[Correction method] Change

[Correction content]

The dead-off circuit 71 includes variable resistors VR ₂₁ to.
It is composed of VR ₂₃ , diodes D ₁₈ , D ₁₉ , capacitor C ₁₆ and buffer amplifier B ₄ , and the rise of the output obtained by inverting the output Vk of the OR gate OR ₁ is t ₂ −t _{3 in} FIG.
The dead-off period is set by delaying the period shown by. By doing so, the phase difference between the on and off timings of the switching elements S ₁ and S ₂ and the switching elements S ₃ and S ₄ is given as time t ₁ -t ₃ in FIG. When the ratio of the ON periods of the switching elements S ₁ and S ₂ is changed, for example, the resistance value of the variable resistor VR ₁₅ in FIG. 14 is increased to delay the falling time point of the control signal V ₁ and change it. The resistance value of the resistor VR ₁₇ may be increased to delay the rising time of the control signal V ₂ .

[Procedure correction 36]

[Document name to be amended] Statement

[Name of item to be corrected] 0072

[Correction method] Change

[Correction content]

FIG. 18 shows that by changing the ratio of the ON periods of the switching elements S ₁ and S ₂ in FIG.
The discharge lamp La at the time to full lighting, that the power supplied to the load Z is reduced, as in the case described above, the switching frequency S ₃ in accordance with the ratio of the ON period switching device S _1, S ₂ , S ₄ side ON period ratio is changed to compensate.

[Procedure amendment 37]

[Document name to be amended] Statement

[Correction target item name] 0073

[Correction method] Change

[Correction content]

Example 4 In FIG. 19, when the load is the discharge lamp La, a preheating capacitor C ₃ is connected to both ends of the filament of the discharge lamp La on the non-power supply side in addition to the capacitor C ₂ of the resonance circuit. It is a thing. In this case, when the discharge lamp La is not turned on, a current flows through the filament through the capacitor C ₃ and the switching element S ₁ ,
Change the phase of switching elements S ₃ and S ₄ with respect to S ₂ .
Then, when the output is increased and the discharge lamp La is lit, the voltage across the capacitor C ₃ is lowered, so that the current of the capacitor C ₃ is reduced and pre-heating before lighting can be performed. Even with this configuration, applying each embodiment described above, without changing the switching frequency of the switching elements S ₁ to S _4, can discharge lamp La dimmer lighting, the switching elements S _1, S ₂ It is possible to prevent the discharge lamp La from extinguishing and reduce the flicker due to the moving stripes by changing the ratio of the ON period of.

[Procedure amendment 38]

[Document name to be amended] Statement

[Correction target item name] 0075

[Correction method] Change

[Correction content]

In the above description, the case where the switching element is the FET has been described, but a bipolar transistor or a thyristor to which a diode is connected in antiparallel may be used. Further, it goes without saying that the DC power supply includes a power supply obtained by rectifying or rectifying and smoothing an AC power supply.

[Procedure amendment 39]

[Document name to be amended] Statement

[Correction target item name] 0076

[Correction method] Change

[Correction content]

[0076]

As described above, according to the present invention, the on / off timings of the switching elements of the other series circuit are deviated from the same phase by 180 degrees with respect to the on / off timings of the switching element of the one series circuit. Since it is variable in the range up to the phase, it is possible to adjust the power supplied to the load without changing the switching frequency by changing the simultaneous ON period of the switching elements in diagonal positions.
It is possible to avoid various problems associated with a change in switching frequency during steady lighting . Further, since the ON periods of the switching elements of at least one of the series circuits are made different, the positive and negative supply power to the LC resonance circuit is unbalanced, and the energy accumulated in the LC resonance circuit is loaded as a DC component. It is possible to prevent the extinction and flicker due to moving stripes when the load is a discharge lamp.

[Procedure amendment 40]

[Document name to be amended] Statement

[Correction target item name] 0077

[Correction method] Change

[Correction content]

Also, the ratio of the ON period of the switching element of one series circuit is determined by the magnitude of the phase change of the ON / OFF of the switching element of the other series circuit with respect to the ON / OFF timing of the switching element of the one series circuit. According to the above, the DC component applied to the load can be increased particularly when the power supplied to the load is reduced, and the load can be stably operated.

[Procedure Amendment 41]

[Document name to be corrected] Drawing

[Name of item to be corrected] Fig. 14

[Correction method] Change

[Correction content]

FIG. 14

Claims (5)

[Claims] 1. A series circuit of two switching elements is connected in parallel with two sets of a DC power source, and a load circuit consisting of at least an LC resonant circuit and a load is connected between the connection points of the switching elements of each series circuit, The switching elements of each series circuit are turned on alternately so as not to turn on at the same time,
Turn it off and turn on the switching element of one of the series circuits,
With respect to the off timing, the on / off timing of the switching element of the other series circuit is set to 180 from the same phase.
An inverter device characterized in that it is made variable within a range of up to a phase shift to change the ratio of ON periods of switching elements of at least one series circuit. 2. The on / off timing of the switching element of the other series circuit is set earlier than the on / off timing of the switching element of the one series circuit. Inverter device. 3. The inverter according to claim 1, wherein the on / off timing of the switching element of the other series circuit is delayed with respect to the on / off timing of the switching element of the one series circuit. apparatus. 4. The ratio of the ON period of the switching element of one series circuit is defined as the deviation of the ON / OFF timing of the switching element of the other series circuit from the ON / OFF timing of the switching element of the one series circuit. The inverter device according to claim 1, wherein the inverter device is increased in number according to the height. 5. When the ratio of the ON periods of the switching elements of one series circuit is changed, the ratio of the ON periods of the switching elements of the other series circuit is changed so that the electric power supplied to the load is substantially constant. The inverter device according to claim 1, wherein the inverter device comprises: