JPH10271845A - Power device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power device having smaller input current distortion and high power supply efficiency from an AC power source to a load circuit, by the use of a smaller number of parts. SOLUTION: Diodes D1 -D4 are bridge-connected and constitute a full-wave rectifier. Besides the AC ends of the full-wave rectifier, the series circuit of an AC power source Vs and a load circuit 1 is connected. Between the DC output ends of the full-wave rectifier, a filter capacitor C1 is connected, and switching elements Q1 , Q2 are connected to in parallel to the diodes D1 , D2 of one arm of the full-wave rectifier respectively. The switching elements Q1 , Q2 are turned on and off alternately by a high frequency. A capacitor C3 is connected between one of the DC output ends of the full-wave rectifier and the connection point of the AC power source Vs and the load circuit 1. Consequently, input current distortion decreases, since an input current is caused to flow over approximately the whole region of the period of the power source high frequencicly. Besides, a power supply efficiency is high, since power is directly supplied from the AC power source Vs to the load circuit 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power supply device for converting a DC voltage obtained by rectifying and smoothing an AC power supply to a high frequency and supplying it to a load.

[0002]

2. Description of the Related Art Japanese Patent Laid-Open Publication No.
There is a configuration shown in FIG. 51 described in Japanese Patent Publication No. 11056. This power supply device functions as a chopper circuit for rectifying and smoothing the AC power supply Vs to obtain a DC power supply and reducing input current distortion, and as an inverter circuit for converting the DC power supply to a high frequency and supplying it to the load circuit 1. And a full-wave rectifier in which _four diodes D _{1 to} D ₄ as rectifying elements are bridge-connected, and an AC power supply Vs is provided between the AC input terminals of the full-wave rectifier via an inductor L ₂ . connected Te, capacitor C ₁ for smoothing between the DC output ends of the full-wave rectifier is connected. further,
Switching elements Q ₁ and Q ₂ are respectively connected in parallel to a pair of diodes D ₁ and D ₂ constituting one arm of the full-wave rectifier, and a DC cut capacitor C ₃₀ and a load are connected between both ends of the switching element Q _2. A series circuit with the circuit 1 is connected.

[0003] The operation of this power supply will be briefly described. S
Switching element Q₁, Q_TwoIs controlled by a control circuit (not shown).
Is controlled to turn on and off alternately without turning on at the same time.
You. Switching element Q₁, Q_TwoOn and off
Frequency (switching frequency) Frequency of AC power supply Vs
(Power frequency) is set to a sufficiently high frequency
You. Now, the voltage V of the AC power supply Vs_inThe polarity of the arrow in the figure
The switching element Q₁But
When on, the AC power supply Vs → diode D_Three→ Switch
Ching element Q₁→ Inductor L_Two→ Route of AC power supply Vs
The current flows in. At this time, the inductor L_TwoEnergy
Stored. Next, the switching element Q₁Turns off
And the inductor L_Two→ AC power supply Vs → Diode D_Three→
Capacitor C ₁→ Diode D_Two→ Inductor L_TwoSutra
Road, inductor L_TwoThe energy stored in
You. That is, the voltage V of the AC power supply Vs_inInductor L_Two
Are added, and the capacitor C₁Is the power supply voltage Vs
Charge at a higher voltage. This kind of operation
To obtain a DC power supply having a boosted AC power supply Vs.
Functions as a chopper circuit.

On the other hand, a high frequency voltage is applied to the load circuit 1 when the switching elements Q ₁ and Q ₂ are turned on and off alternately. That is, when the ON switching element Q _1, a current flows through a path of the capacitor C ₁ → switching element Q ₁ → load circuit 1 → capacitor C ₃₀ → capacitor C _1, the capacitor C ₃₀ → load when the switching element Q ₂ is turned on The current flows through the path of the circuit ₁ → the switching element Q ₂ → the capacitor C ₃₀ , and the direction of the current flowing through the load circuit 1 alternates by turning on and off the switching elements Q ₁ and Q ₂ . Such an operation functions as an inverter circuit. Here, when the ON switching element Q _1, flowing through the current the same direction as a current and an inverter circuit as a chopper circuit to the switching element Q _1.

The voltage V of the AC power supply Vs_inThe polarity of the arrow in the figure
During the period opposite to the direction shown by_Two
Will be used as a chopper circuit. Sand
Switching element Q_TwoWhen the power is on, the AC power supply Vs →
Inductor L_Two→ Switching element Q_Two→ Diode D
_Four→ A current flows through the path of the AC power supply Vs and the inductor L_Two
Energy is stored in the switching element Q_TwoWhen off
And the inductor L_Two→ Diode D₁→ Capacitor C₁
→ Diode D_Four→ AC power supply Vs → Inductor L _TwoSutra
Road, inductor L_TwoThe energy stored in
Because

As described above, the switching elements Q ₁ , Q
Reference numeral ₂ is used for both the boost chobber circuit and the inverter circuit. As described above, since the switching elements Q ₁ and Q ₂ are shared between the chobber circuit and the inverter circuit, the number of components constituting the circuit is relatively small, the circuit configuration is simple, and the circuit can be provided at a relatively low cost. It has the advantage of becoming.

[0007]

[SUMMARY OF THE INVENTION However, in the circuit configuration described above, in the process for supplying power from an AC power source Vs to the load circuit 1, the steps of charging the capacitor C ₁ through the function as a chopper circuit from the AC power source Vs ,
2 the process of applying a high frequency voltage to the load circuit 1 through functions as an inverter circuit for the power supply the capacitor C ₁
Since there are two power conversion processes, the efficiency of power supply from the AC power supply Vs to the load circuit 1 is the product of the efficiencies of each power conversion process, and the power supply efficiency limit is sufficiently increased. Cannot do it.

Further, although the inductor L ₂ provided in order to provide a function as a chopper circuit, even though not an essential element in order to reduce the input current distortion, by the inductor L ₂ is present This leads to an increase in the number of parts and a loss of power, leading to a reduction in power supply efficiency. The present invention has been made in view of the above circumstances, and its purpose is to further simplify the circuit configuration and improve the power supply efficiency from the AC power supply to the load circuit while maintaining the function of reducing the input current distortion. It is to provide an enhanced power supply.

[0009]

According to a first aspect of the present invention, there is provided a full-wave rectifier constructed by connecting rectifying elements in a bridge, and a series connection of an AC power supply and a load circuit connected between AC terminals of the full-wave rectifier. Circuit, a first capacitor for smoothing connected between the DC output terminals of the full-wave rectifier, and a rectifying element of one arm of the full-wave rectifier, each of which is connected in parallel to the rectifying element and alternately at a frequency higher than the power supply frequency of the AC power supply. A first switching element and a second switching element that are turned on and off, and a second capacitor that is connected between a connection point between the AC power supply and the load circuit and at least one of the DC output terminals of the full-wave rectifier. Since the input current can flow over almost the entire power supply cycle, distortion of the input current is small, and power can be supplied directly from the AC power supply to the load circuit. Increases. Moreover, since the number of parts is smaller than that of the conventional configuration, and when the power is turned on, the charging current to the smoothing capacitor flows only via the load circuit,
The inrush current can be suppressed without adding a special circuit.

According to a second aspect of the present invention, a load circuit includes a transformer and a load connected to a secondary side of the transformer, and both ends of a primary winding of the transformer are both ends of the load circuit. In this configuration, since the load circuit has a transformer configuration, it is possible to remove a low-frequency component from a load provided on the secondary side of the transformer and flow a constant load current. Further, if the impedance on the primary side of the transformer is increased, the inrush current can be further reduced.

According to a third aspect of the present invention, the load circuit is connected between the first inductor, the discharge lamp connected in series to the first inductor, and the non-power supply side terminal of the discharge lamp, and resonates together with the first inductor. And a third capacitor constituting a circuit, wherein both ends of a series circuit of the first inductor and the discharge lamp are both ends of the load circuit. According to this configuration, since no transformer is used, there is no loss due to the transformer, and power supply efficiency to the load is further increased. In addition, when there is no load, a path for charging the first capacitor is not formed, so that when there is no load, the rush current becomes almost zero.

According to a fourth aspect of the present invention, the load circuit includes a second inductor connected between both ends. According to this configuration, since no transformer is used, there is no loss due to the transformer, and power supply efficiency to the load is further increased. In addition, the second inductor functions as a low-pass filter, and the current supplied to the load is less likely to be affected by fluctuations in the power supply voltage.

According to a fifth aspect of the present invention, there is provided a control circuit capable of adjusting an on / off switching frequency of the first switching element and the second switching element.
According to this configuration, it is possible to adjust the input current or the power supplied to the load while keeping the ON period of the switching element substantially constant. Therefore, if the load is a discharge lamp, control of dimming, preheating, starting, lighting, and the like can be performed. Further, when the power supplied to the load suddenly changes and stress is applied to the circuit components, this can be avoided by changing the switching frequency.

According to a sixth aspect of the present invention, there is provided a control circuit capable of adjusting the ON periods of the first switching element and the second switching element. According to this configuration, it is possible to adjust the input current or the power supplied to the load while keeping the switching frequency substantially constant.
Therefore, if the load is a discharge lamp, dimming is performed,
Control such as preheating, starting, and lighting can be performed. Further, when the power supplied to the load suddenly changes and stress is applied to the circuit components, this can be avoided by changing the switching frequency.

According to a seventh aspect of the present invention, the control circuit includes means for detecting a voltage between both ends of the first capacitor. The first switching element and the second switching element are controlled. According to this configuration, when the voltage between both ends of the first capacitor abnormally rises, the operation of the switching element is stopped or the output to the load is reduced, thereby preventing the circuit element from being stressed. can do. In addition, if the increase in the voltage across the first capacitor is suppressed and kept substantially constant, the power supply to the load is stabilized. Therefore, if the load is a discharge lamp, an optical output with less flicker can be obtained.

The invention according to claim 8 is provided with means for detecting a voltage corresponding to the voltage applied to the transformer, and the control circuit controls the first circuit so as to suppress an increase in the voltage applied to the transformer based on the detected voltage. And the second switching element. According to this configuration, when the applied voltage to the load rises abnormally or when the load is short-circuited, the operation of the switching element is stopped, or the output to the load is reduced, so that the It is possible to prevent stress from being applied.

According to a ninth aspect of the present invention, the control circuit includes means for detecting the voltage polarity of the AC power supply, and the control circuit controls the first switching element and the second switching element so that the input currents are substantially equal regardless of the voltage polarity of the AC power supply. Are controlled. According to this configuration, it is possible to control the input current for each half cycle of the power supply, so that the input current waveform can be approximated to a sine wave, and the input current distortion can be further reduced. Further, it is possible to reduce the output of the load as compared with the case where the switching element is controlled under a constant condition. If the load is a discharge lamp, deeper dimming (reducing the optical output) becomes possible. At the same time, dimming can be performed without changing the voltage between both ends of the first capacitor, so that abnormal stress can be prevented from being applied to the circuit components.

According to a tenth aspect of the present invention, there is provided a means for detecting a voltage between both ends of each rectifying element of one arm of the full-wave rectifier. Based on the detected voltage, the input current is independent of the voltage polarity of the AC power supply. The control circuit controls the first switching element and the second switching element so as to be substantially equal. According to this configuration, it is possible to improve the asymmetry of the input current for each power supply half cycle, and to make the input current waveform closer to the sine.
As a result, the peak value of the input current can be suppressed, and it is possible to prevent an abnormal stress from being applied to the filter circuit when providing the filter circuit for blocking high frequency.

An eleventh aspect of the present invention includes means for detecting a voltage between both ends of the second capacitor, and the control circuit includes
The first switching element and the second switching element are controlled so that the output to the load circuit is kept substantially constant based on the voltage across the capacitor. According to this configuration, since the output to the load can be kept substantially constant, stable operation of the load can be expected. In particular, when the load is a discharge lamp, an optical output with less flicker can be obtained.

According to a twelfth aspect of the present invention, there is provided a means for detecting a current flowing in a load circuit, wherein the first switching element and the second switching element are configured to keep the current flowing in the load circuit substantially constant based on the detected current. It controls the elements. According to this configuration, even when the voltage of the AC power supply fluctuates, the current supplied to the load can be made substantially constant, so that stable operation of the load can be expected. In particular, when the load is a discharge lamp, the fluctuation of the lamp current can be reduced to obtain an optical output with less flicker.

According to a thirteenth aspect of the present invention, there is provided means for varying the capacity of the second capacitor. According to this configuration, the input current can be adjusted according to the load, and the input current distortion can be reduced. For example, even when the load is a discharge lamp and dimming or switching of the load output is performed, the input current distortion can be reduced. In a fourteenth aspect, the load circuit includes a plurality of loads. According to this configuration, a plurality of loads can be driven simultaneously.

According to a fifteenth aspect of the present invention, in parallel with one of the first switching element and the second switching element,
Alternatively, a second load circuit is connected in parallel with the first capacitor. According to this configuration, the output to the second load circuit can be made substantially constant without special control, so that stable driving can be performed while simultaneously driving a plurality of loads. In particular, when the load is a discharge lamp, an optical output with less flicker can be obtained. Further, even if one of the discharge lamps comes off, the other discharge lamp can be kept on.
Further, the power supplied to each load can be set to an appropriate ratio. Also, even if the voltage of the AC power supply fluctuates,
The load current as a whole can be almost constant,
By reducing the pulsating current of the lamp current, a light output with less flicker can be obtained.

According to a sixteenth aspect of the present invention, at least one of the first switching element and the second switching element is self-excited by feedback of a current flowing through a load circuit. According to this configuration, the drive circuit of the switching element can be simplified or eliminated, so that the number of components can be further reduced. For example, if a transformer is provided in a load circuit and feedback is performed using an inductor provided on the secondary side of the transformer, the circuit automatically stops when an abnormality such as no load occurs. In addition, if the driving of one switching element is self-excited and the driving of the other switching element is separately controlled by an external signal, the power supplied to the load can be controlled. Control such as dimming and stopping can be easily performed.

According to a seventeenth aspect of the present invention, a series circuit of a pair of rectifiers is connected to the first capacitor separately from the rectifier, and a connection point of the rectifier in the series circuit is connected to one end of the AC power supply on the load circuit side. , And a fourth capacitor is connected between the connection point between the AC power supply and the second capacitor and the load circuit. According to this configuration, the voltage between both ends of the first capacitor is about the voltage of the AC power supply, and when the voltage of the AC power supply is high, it is possible to cope without using a high withstand voltage circuit element. As a result, in the configuration of claim 1 and the configuration of claim 17, the voltage of the AC power supply is 2 while using a common circuit board and components only by adding or deleting a small number of components.
It is possible to cope with the case where the difference is about twice. Even when the two are different in the voltage of the AC power supply, the voltages applied to the load circuits can be made substantially equal, so that substantially the same output can be obtained for AC power supplies of different voltages. Further, by modularizing the components, a circuit capable of supporting an AC power supply having different voltages can be constituted only by a combination of the modules.

According to the eighteenth aspect of the present invention, among the arms of the full-wave rectifier, the rectifying elements of the arm to which the first switching element and the second switching element are not connected alternately at a frequency higher than the power supply frequency. The third switching element and the fourth switching element that are turned on and off are connected in parallel. According to this configuration, surplus power can be regenerated to the power supply when the load suddenly decreases.

[0026]

BEST MODE FOR CARRYING OUT THE INVENTION

 (Embodiment 1) As shown in FIG.
Diodes D as current elements₁~ D_FourThe bridge
Equipped with a full-wave rectifier configured by connecting
A series circuit of the AC power supply Vs and the load circuit 1 is connected between the input terminals.
And a capacitor for smoothing between the DC output terminals of the full-wave rectifier.
Sa C₁Is connected. Also, the die that constitutes the full-wave rectifier
Aether D₁~ D_FourOf one arm on the load circuit 1 side
Constituting a pair of diodes D₁, D_TwoEach has a sui
Switching element Q₁, Q_TwoAre connected in parallel and switching
Element Q_TwoBetween both ends of the capacitor C_ThreeAnd load circuit 1
A series circuit is connected. Here, the capacitor C_ThreeOne end of
Is connected to the connection point between the AC power supply Vs and the load circuit 1, and
The end is the switching element Q_TwoAnd diode D_ThreeConnection point with
Connected to. Therefore, the conventional configuration shown in FIG.
In comparison, inductor L_TwoTo load circuit 1,
Capacitor C₃₀Instead of capacitor C_ThreeIn the configuration with
Become. However, the load circuit 1 is inductive, and
It is configured to have a function of accumulating lugi. Ma
The switching element Q₁, Q_TwoIs an npn type in FIG.
It is shown as a transistor.
The purpose is to make it easier to use, such as MOSFT
Of course, other switching elements may be used.
And Also, the switching element Q₁, Q_TwoShows
ON / OFF alternately without simultaneous ON by the control circuit
Is controlled as follows. Switching element Q ₁, Q_TwoOn
The off repetition frequency (switching frequency)
Frequency sufficiently higher than the frequency of the source Vs (power supply frequency)
The number is set in the same manner as in the conventional configuration.

Next, the operation will be described. First, the AC power supply Vs
Of the voltage Vin _in the direction indicated by the arrow in FIG.
This direction is referred to as positive polarity). FIGS. 2 to 6 show one cycle of the switching operation of the switching elements Q ₁ and Q ₂ during the steady operation.
2 to 6, the current paths are indicated by broken lines. The capacitor C ₁ is assumed to be charged immediately after the power is turned on.

As described above, the capacitor C₁Is charged
Therefore, as shown in FIG.₁But
Switching element Q when turned on_TwoTurns off, the condensate
Sa C ₁→ Switching element Q₁→ Load circuit 1 → Conden
Sa C_Three→ Capacitor C₁Current flows in the path of
A current flows through 1. In this process, the capacitor C_ThreeBut
Charged.

The voltage between both ends of the capacitor C ₃ is equal to the AC power supply Vs.
Becomes equal to the voltage across, the capacitor C ₃ current stops flowing, as shown in FIG. 3, via the diode D ₃ and the switching element Q ₁ from the AC power source Vs to a state in which a current flows in the load circuit 1. That is, the switching element Q at the switching element Q ₁ is turned on in the state of FIG. 3
₂ is off, and a current flows through a path of AC power supply Vs → diode D ₃ → switching element Q ₁ → load circuit 1 → AC power supply Vs. During this period, energy is stored in the load circuit 1.

Next, when the switching element Q ₁ is turned off, as shown in FIG. 4, the AC power supply Vs → the diode D ₃
A current flows through the path of the capacitor C ₁ → the load circuit 1 → the AC power supply Vs, so that the energy stored in the load circuit 1 is released and the capacitor C ₁ is charged. That is, since the both ends of the capacitor C ₁ is added voltage between the voltage and the voltage across the load circuit 1 of the AC power source Vs is applied, the voltage across the capacitor C ₁ is to be boosted higher than the voltage of the AC power source Vs Become. By the way, in the steady state, the capacitor C ₃
Since There has been charged, the capacitor C ₃ also in this period is to attempt to release the charge, the switching element Q
₁ is higher than the voltage across the voltage across the load circuit 1 capacitor C ₃ is when turned off, the capacitor C ₃ is hardly discharged. The switching element Q ₂ in this period may be off in on.

[0031] Once more the voltage across the capacitor C ₃ than the voltage across the load circuit 1 is the energy stored in the load circuit 1 is released is high (the switching element Q ₂ up to this point is controlled to be turned on 5), as shown in FIG. 5, the capacitor C ₃ is mainly composed of the capacitor C ₃ →
The charge is released through the path of the load circuit 1 → the switching element Q ₂ → the capacitor C ₃ . That is, a current flows through the load circuit 1 in the opposite direction to that before, and energy is accumulated in the load circuit 1.

Next, when the switching element Q ₂ is turned off, as shown in FIG. 6, the load circuit 1 → diode D ₁ →
A current flows through the path of the capacitor C ₁ → the capacitor C ₃ → the load circuit 1 and the energy stored in the load circuit 1 is released. Such pathways period in which a current flows in a higher period than the voltage across sum voltage of the capacitor C ₁ between the voltages across both ends of the load circuit 1 of the capacitor C _3. At this time, the switching element Q ₁ is may be off in on.

As described above, the condition for forming the current path shown in FIG. 6 is a period in which the voltage across the series circuit of the capacitor C ₃ and the load circuit 1 is higher than the voltage across the capacitor C _1. When energy stored in the load circuit 1 together with the charge of C ₃ is discharged is released, now it becomes higher towards the voltage across the capacitor C ₁ (the switching element Q ₁ up to this point to turn on Controlled). Therefore, the state returns to the state shown in FIG.

As described above, the switching elements Q ₁ , Q
_The alternating current flows through the load circuit 1 by the repetition of the on / off operation of ₂ . Also, when charging of the capacitor C _1, the sum voltage of the voltages across both ends of the load circuit 1 of the AC power source Vs to the operation of FIG. 3 because it is a state to be applied to the capacitor C _1, both ends of the capacitor C ₁ The voltage can be raised more than the voltage of the AC power supply Vs. further,
Since a path passing through the AC power supply Vs is formed during one cycle of the switching of the switching elements Q ₁ and Q ₂ , the input current from the AC power supply Vs can flow at a high frequency, and the input current distortion is prevented from increasing. can do.

Although the above operation has been described for the case where the AC power supply Vs has a positive polarity, the operation is substantially the same when the AC power supply Vs has a negative polarity. That is, when the switching element Q ₁ is turned on by a positive polarity with respect to power from the AC power source Vs through a path passing through the diode D ₃ as shown in FIG. 4 to the load circuit 1, a negative polarity switching element Q ₂ When turned on, AC power supply Vs →
It will be powered from an AC power source Vs to the load circuit 1 in a path through the load circuit 1 → diode D ₄ of the switching element Q ₂ → diode D _4. The route of the voltage is high period of the switching element Q _1, Q ₂ of the AC power source Vs than the voltage across the capacitor C ₃ irrespective off, AC power source Vs → capacitor C ₃ → the diode D ₄ → AC power source Vs in the capacitor C ₃ is charged.

[0036] Once the switching element Q ₂ is turned off, AC power source Vs → load circuit 1 → diode D ₁ → current flows through a path of the capacitor C ₁ → the diode D ₄ → AC power source Vs, the voltage across the capacitor C ₁ is The voltage is boosted from the power supply voltage Vs. Then, the energy stored in the load circuit 1 is released (switching element Q ₁ is controlled to turn on by this point), the capacitor C ₁ → switching element Q ₁ → load circuit 1 → capacitor C ₃ → current flows through a path of the capacitor C _1. This state is similar to the state shown in FIG. When the switching element Q ₁ is turned off, the energy stored in the load circuit 1, the load circuit 1 → capacitor C ₃ → the diode D ₂ → released in the path of the load circuit 1 (switching element Q ₂ up to this point on ), The energy stored in the load circuit 1 decreases. During the voltage across the capacitor C ₃ is higher than the voltage of the AC power source Vs, the energy of the capacitor C ₃ is discharged in a path of the capacitor C ₃ → load circuit 1 → switching element Q ₂ → capacitor C _3, the capacitor C ₃ When the voltage at both ends decreases and the voltage of the AC power supply Vs increases, the AC power supply Vs → the load circuit 1 → the switching element Q
₂ → diode D ₄ → current flows through the path of AC power supply Vs.

In short, when the AC power supply Vs has a negative polarity, the operation is slightly different from that when the AC power supply Vs has a positive polarity, but the operation is almost the same, and an alternating current can flow through the load circuit 1. Moreover, than the voltage across the AC power source Vs during the charging of the capacitor C ₁ can boost the voltage across the capacitor C _1, further an AC power source Vs during one cycle of the switching of the switching elements Q _1, Q ₂ By forming a path through which the input current from the AC power supply Vs flows at a high frequency, an increase in input current distortion can be prevented.

The capacitance of the capacitor C ₃ is set to be small enough to allow charging and discharging within one cycle of the switching operation of the switching elements Q ₁ and Q ₂ . That is, when the resonance current flowing through the capacitor C ₃ and the leakage transformer T ₁ of the primary winding and the resonant circuit composed is almost zero, by matching the on-off timing of the switching elements Q _1, Q ₂ In addition, switching loss can be reduced.

The load circuit 1 has a circuit shown in FIG.
Can be used. In the circuit shown in FIG.
Filter to the AC power supply Vs instead of the AC power supply Vs
2 is used. In other words, FIG.
In the configuration shown in FIG.
It corresponds to the output terminal of the circuit 2. In addition, each switching element
Q₁, Q_TwoAnd each diode D₁, D_TwoFor a parallel circuit with
The MOSFET is replaced with the switching element Q₁', Q_Two'age
Used. In this case, the diode D₁, D _TwoFunction of
Is realized by the parasitic diode inside the MOSFET.
You. This configuration allows the use of transistors and diodes.
Reduced the number of parts required from four to two.
It leads to reduction.

Thus, the filter circuit 2 has a turn ratio of 1:
A line choke LF ₁ with two windings of ₁ ,
Comprises a capacitor C ₂₃ connected between one end of the two windings at both ends of the AC power source Vs, an inductor LF ₂ connected in series to one of the windings. This filter circuit 2 constitutes a low-pass filter that passes a power supply frequency and blocks a switching frequency. By providing such a filter circuit 2, the high-frequency component of the input current can be suppressed to prevent high-frequency noise from flowing into the AC power supply Vs, and the input current waveform becomes close to a sine wave, and the input power factor Can be increased.

On the other hand, the load circuit 1 includes a leakage transformer T ₁ , a discharge lamp La ₁ such as a fluorescent lamp as a load having one end of each filament connected to both ends of a secondary winding of the leakage transformer T ₁ , the discharge lamp La ₁ of filaments for preheating connected between the other end comprising a capacitor C ₂ Prefecture. In the load circuit 1, both ends of the primary winding of the leakage transformer T ₁ becomes the input end. That is, one end of the primary winding of the leakage transformer T ₁ is diode D _3, D ₄
And the other end is connected to the switching element Q ₁ ′, Q
Connected to ₂ 'connection point. Capacitor C ₂ for preheating constitutes a resonant circuit together with the leakage Indatansu leakage transformer T _1. By using the load circuit 1 of this configuration, an relatively high voltage components of the frequency is applied to the discharge lamp La _1. This is a because the discharge lamp La ₁ relative inductance element consisting of a leakage transformer T ₁ is parallel connected, towards the high-frequency components such as the switching frequency than the low-frequency components such as power supply frequency This is because the voltage across the inkance element increases. Other, leakage transformer T
The resonance circuit is formed by _a leakage inductance and a capacitor C _2, also by the low-pass filter is constituted by a leakage transformer T ₁ and the capacitor C _3, the high frequency from the voltage applied to the discharge lamp La ₁ The components are removed. That is, the leakage transformer T
Since only a relatively low frequency components in case any secondary side components are contained in the frequency as the applied voltage component to the power supply frequency ₁ of the primary appears, it is applied to the discharge lamp La ₁ voltage less susceptible to variations due to the low-frequency component, the current flowing to the discharge lamp La ₁ becomes substantially constant.

FIG. 8 shows the operation waveform of each part of the circuit shown in FIG.
Shown in In the Figure is shown the operation of one cycle of the AC power source Vs, Fig. (A) the input voltage V _in and the input current I _in of the AC power source Vs, Fig. (B) The voltage across the capacitor C _3, FIG. (c) is Ranbu current flowing through the discharge lamp La _1, FIG. (d) shows a current flowing through the primary winding of the leakage transformer T _1, respectively. FIG As is apparent from, but the voltage across the capacitor C ₃ includes a voltage component of the AC power source Vs, the lamp current of the discharge lamp La ₁ is not significantly affected by the voltage component of the AC power source Vs .

[0043] A in leakage transformer T ₁ of the out 8 of the current flowing in the primary winding (d), B, in the vicinity of respective units shown in C the current flowing through the switching element Q _1, Q ₂ shown in FIG. When the AC power supply Vs has a positive polarity, the switching element Q near the peak of the voltage of the AC power supply Vs
The current waveform at ₁ 'is shown in FIG.
The current waveform at ₂ 'is as shown in FIG. Also,
When the AC power supply Vs has a negative polarity, near the peak of the voltage of the AC power supply Vs, the current waveform in the switching element Q ₁ ′ is as shown in FIG. 9C, and the current waveform in the switching element Q ₂ ′ is as shown in FIG. become. Switching element Q near zero crossing point of voltage waveform of AC power supply Vs
The current waveforms of ₁ ′ and Q ₂ ′ are both as shown in FIG. Is to vary depending on the leakage transformer T ₁ of the first voltage of the primary winding current flows the AC power source Vs as shown in FIG. 8 (d), the by AC power source Vs to the load circuit 1 is connected, leakage voltage transformer T ₁ of the primary winding an AC voltage applied to the power supply Vs is because is superimposed. However, the lamp current of the discharge lamp La ₁ as described above are not significantly affected by the voltage of the AC power source Vs. As can be seen from the comparison between Figure 1 and Figure 51, the circuit of this embodiment the inductor L ₂ when compared to the conventional construction is omitted,
The number of components is reduced, which leads to downsizing and cost reduction. Moreover, there is an effect of suppressing harmonic components of the input current as in the conventional configuration. Further, the power supply to the load circuit 1 in the conventional configuration a capacitor C _1, whereas it is necessary to charge the capacitor C ₁ by the power from the AC power source Vs, in this embodiment, an AC power source Since there is a process of directly supplying power to the load circuit 1 from Vs, the power supply efficiency increases accordingly. Further, the input current distortion can be further suppressed only by using the filter circuit 2 as shown in FIG.
High input power factors can also be obtained.

(Embodiment 2) In Embodiment 1, the load circuit
Leakage transformer T as 1₁The configuration including
However, as shown in FIG.₁Niyo
Ordinary transformer T _TwoAnd the transformer T
₁Inductor L in the primary winding of₁Are connected in series.
It works the same way. In other words, the leakage transformer
T₁L instead of the leakage inductance of₁And co
Capacitor C_TwoThis utilizes the resonance with. Other configurations
The operation is the same as in the first embodiment.

[0045] In Embodiment 3 In this embodiment, as shown in FIG. 11, leakage instead of the transformer T ₁ using the conventional transformer T _2, the inductor between the discharge lamp filament and a capacitor C ₂ of La ₁ the inserted up the L ₁ may be adopted. That is, the connecting the inductor L ₁ series in the secondary side of the transformer T _2. This arrangement also utilizes the resonance of the second embodiment similarly to the inductor L ₁ and capacitor C _2. Other configurations and operations are the same as those of the first embodiment.

(Embodiment 4) This embodiment is shown in FIG.
So, leakage transformer T₁And transformer T_TwoFor
Without the inductor L₁And discharge lamp La₁And in series
Connect the discharge lamp La ₁On the non-power side of the filament
Densa C_TwoIs connected to the load circuit 1. This structure
Also inductor L₁And capacitor C_TwoAnd the resonance circuit
It constitutes. In this configuration, the leakage
Transformer T₁And transformer T_TwoThere is no discharge lamp
La₁In the first embodiment, the leakage transformer T₁
The same as the current flowing in the primary winding (see FIG. 8 (d))
Will flow. That is, the discharge lamp La₁No
Pump current corresponds to the period of the voltage waveform of the AC power supply Vs.
The components will be superimposed.

Therefore, as shown in FIG. 13, the inductor L ₁ and the discharge lamp La ₁ are connected in series with the inductor L 1.
_It is desirable to adopt a configuration in which ₃ are connected in parallel. With this structure, since the impedance of the inductor L ₃ becomes larger the higher passing frequency, the inductor L ₃
, A component almost corresponding to the switching frequency appears. That is, the low-frequency component corresponding to the power supply frequency to the discharge lamp La ₁ is hardly applied, so that the high-frequency component corresponding to the switching frequency is primarily applied. Further, since a low-pass filter is formed by the inductor L ₃ and the capacitor C ₃ , this also allows the discharge lamp L ₃ to be driven by the voltage component of the AC power supply Vs.
it is possible to reduce the impact on a ₁ of the lamp current. That is, it is possible to obtain a substantially constant lamp current as shown in FIG. Other configurations and operations are the same as those of the first embodiment.

(Embodiment 5) In Embodiment 1, a series circuit of the capacitor C ₃ and the load circuit 1 is connected to the switching element Q ₂
(Q ₂ ′) is connected in parallel,
As shown in 4, a capacitor C instead of the capacitor C _3
3 ′ and a configuration in which a series circuit of a capacitor C ₃ ′ and a load circuit 1 is connected in parallel to a switching element Q ₁ (Q ₁ ′). In this configuration, the operation at the time of the positive polarity and the operation at the time of the negative polarity of the AC power supply Vs are reversed, but basically the same operation is performed. Other configurations and operations are the same as those of the first embodiment.

(Embodiment 6) In this embodiment, as shown in FIG. 15, the circuit shown in Embodiment 1 and the circuit shown in Embodiment 5 are provided side by side. The circuit 2 is shared. In such a configuration, when the on and off of the switching elements Q ₁ ′ and Q ₂ ′ are synchronized (that is, when they are simultaneously turned on and off), the AC power supply V
Since the input current from s becomes a combined current of both circuits, a substantially symmetric current waveform can be obtained when the AC power supply Vs has a positive polarity and a negative polarity. In addition, no matter which of the switching elements Q ₁ ′ and Q ₂ ′ is on, the current from the AC power supply Vs flows through one of the circuits, so that the input current is hardly idle. As a result, the peak value of the current flowing through the filter circuit 2 can be reduced (that is, the high-frequency current component in a state where the filter circuit 2 is not provided is reduced). It becomes possible.

In this embodiment, in the illustrated example, the first embodiment is used.
And the circuit of Embodiment 5 are used one by one,
More circuits may be used. In that case, it is desirable to provide both circuits in the same number. However, if the number of circuits increases, the above-described effect can be obtained as long as the number of circuits does not completely match as long as the number of circuits is substantially the same. Other configurations and operations are the same as those of the first embodiment.

(Embodiment 7) As shown in FIG. 16, this embodiment is a combination of the configurations of Embodiment 1 and Embodiment 5. That is, two capacitors C ₃ and C ₃
'Used, the capacitors C _3, C _{3' 3} is of the series circuit of the load circuit 1 and are connected respectively across the respective switching elements Q _1, Q _2. In this configuration, two capacitors C ₃ and C ₃ ′ connected in series are used as compared with the configuration using only one capacitor C ₃ and C ₃ ′ as in the configuration of each of the above-described embodiments. it, the capacitor C _3, C ₃ 'charging path to is branched, the charging current is the switching element Q _1', Q ₂ 'by comparison if only through the switching element Q _1', the current stress of the Q ₂ ' Can be reduced.

(Embodiment 8) In each of the embodiments described above, the case where the AC power supply Vs is a single-phase two-wire is exemplified. However, the AC power supply Vs may be another type, for example, a three-phase four-wire. . When the AC power supply Vs is a three-phase four-wire,
As shown in FIG. 7, three pairs of diodes D _{31 to} D ₃₃ and D _{41 to} D ₄₃ connected in series are used instead of the diodes D ₃ and D ₄ in the single-phase two-wire circuit shown in FIG. may be connected to one end of a voltage line of each AC power source Vs to the connection point of each pair of diodes _{D 31 ~D 33, D 41 ~D} 43.
The neutral line of AC power supply Vs is connected to load circuit 1. Accordingly, the diode _{D 31 ~D 33, D 41 ~D} 43 constitutes a full wave rectifier for a three-phase alternating current with a parasitic diode of the switching element Q ₁ ', Q _2'. Other configurations and operations are the same as those of the first embodiment.

(Embodiment 9) As shown in FIG. 18, the present embodiment has the same configuration as that of the embodiment 1 shown in FIG. 1, and uses the leakage transformer T shown in FIG. ₁ , a discharge lamp La ₁ and a capacitor C ₂ are used. In FIG. 18, the illustration of the filter circuit 2 is omitted.

In FIG. 18, a control circuit 3 for controlling the on / off of the switching elements Q ₁ ′ and Q ₂ ′ is shown.
Is illustrated. This embodiment is different from the first embodiment in that the control circuit 3 includes switching elements Q ₁ ′, Q
_The point is that the power supply to the load circuit 1 can be adjusted by using a device that can arbitrarily control a switching frequency, an ON time, a duty ratio, and the like for turning on and off the ₂ '. That is, the light output of the discharge lamp La ₁ is enabled can be a dimming control regulation. Here, the above-described control of the on-time means that the on-time is changed (generally, the off-time is kept constant), and the control of the duty ratio means that the ratio between the on-time and the off-time is made constant while the frequency is kept constant. Means to change.

That is, the control of the switching frequency means that the switching elements Q ₁ ′ and Q ₂ ′ are turned on and off as shown in FIG.
Means to shift to the on / off state. In the illustrated example, the switching frequency is shifted to the high frequency side. When in this manner varies the switching frequency, the relationship between the resonance frequency and the switching frequency of the resonant circuit is formed by the leakage inductance and the capacitor C ₂ of the leakage transformer T _1, the discharge lamp L
The power supplied to a ₁ changes, and the light output of the discharge lamp La ₁ can be controlled.

The control of the duty ratio means that the switching elements Q ₁ ′ and Q ₂ ′ are turned on and off as shown in FIG. 20A, for example, from the state where they are turned on and off as shown in FIG. It means to shift. That is,
The ratio between the on-time and the off-time is controlled while keeping the frequency constant. In the illustrated example, the duty ratio of the switching element Q ₁ ′ is reduced and the duty ratio of the switching element Q ₂ ′ is increased. With such control, the amount of input power from the AC power supply Vs can be changed, and as a result, the power supplied to the load circuit 1 can be adjusted.

By the way, the switching element Q₁', Q_Two'of
If only the switching frequency is controlled, the AC power supply Vs
The amount of input power supplied from the power supply to the load circuit 1 does not change
Since only the power changes, the power supplied to the load circuit 1 is small.
When control is performed to eliminate
Densa C₁Will increase. That is,
Capacitor C₁High withstand voltage is required for
Ching element Q₁', Q_Two'Stress increases. on the other hand,
When the duty ratio is controlled, the AC power supply Vs
Since the input electric energy is adjusted, the discharge lamp La₁Light output
Capacitor C even if reduced₁Voltage rises almost
Absent. However, the input current I from the AC power supply Vs_inIs positive
During the period of the polarity (the polarity indicated by the arrow in FIG. 18).
Source Vs → Diode D_Three→ Switching element Q '→ Load
Circuit 1 → Negative period through the path of AC power supply Vs
Is AC power supply Vs → load circuit 1 → switching element Q_Two'
→ Diode D_Four→ Because it passes through the path of the AC power supply Vs,
Switching element Q₁', Q _Two'
The input current I during the polarity period and the negative polarity period_inIs asymmetric
Become. As a result, the problem of increased input current distortion
Occurs.

Therefore, both the switching frequency and the duty ratio are controlled, and the switching elements Q ₁ ′ and Q ₂ ′ are turned on and off as shown in FIG. 21A, for example, as shown in FIG. 21B. It is desirable to shift to a state of turning on and off. Thus, by using the control of the switching frequency and the control of the duty ratio together,
Preventing extreme increase in the voltage across the capacitor C _1, and the input current can be prevented to become extremely asymmetric. Other configurations and operations are the same as those of the first embodiment.

(Embodiment 10) In Embodiment 9, when the ON / OFF duty ratio of the switching elements Q ₁ ′ and Q ₂ ′ is changed, the input current waveform changes depending on whether the AC power supply Vs has a positive polarity or a negative polarity. Is asymmetric, and the input current distortion is increased. In the present embodiment, this problem is solved by the following configuration.

The reason why the input current waveform is asymmetric between the positive polarity and the negative polarity is that the input current flows through the switching elements Q ₁ ′ and Q ₂ ′ that are different during the period between the positive polarity and the negative polarity of the AC power supply Vs. If the duty ratios of the switching elements Q ₁ ′ and Q ₂ ′ through which the input current flows during the positive polarity period and the negative polarity period are equal, the input current is also symmetric. Therefore,
In the present embodiment, the polarity of the voltage of the AC power supply Vs is determined, and the ON / OFF periods of the switching elements Q ₁ ′ and Q ₂ ′ are switched according to the polarity. For example, the period during which switching element Q ₁ ′ is turned on when AC power supply Vs has a positive polarity is the period during which switching element Q ₁ ′ is turned off when AC power supply Vs has a negative polarity.

Specifically, the configuration is as shown in FIG. Power supply polarity determination circuit 4 for determining the polarity of the voltage of AC power supply Vs
Includes a resistor R ₃₄ to R ₃₇ each pair of dividing the voltage between the anode potential and the potential of each end of the AC power source Vs of the capacitor C ₁ is the ground potential, each pair of resistors R ₃₄ to R ₃₇ It constituted by a comparator CP ₁ for generating a binary corresponding to the polarity of the voltage of the AC power source Vs output by comparing the potential of the connection point. Here, the resistance values of the resistors R ₃₄ to R ₃₇ is, R ₃₄
= R ₃₆ , R ₃₅ = R ₃₇
The positive s becomes a connection point potential of the resistors R _34, R ₃₅ is higher than the potential at the connection point of the resistors R _36, R _37, is a negative polarity becomes the opposite. In the configuration shown, the connection point of the resistors R ₃₄ and R ₃₅ is connected to the positive input terminal of the comparator CP ₁ , and the resistance R
_36, the connection point of R ₃₇ is from being connected to the negative input terminal of the comparator CP _1, AC power source Vs is output from the comparator CP ₁ when the positive polarity becomes H level. That is, when the voltage of the AC power source Vs changes as shown in FIG. 23 (a), the output of the output that is the power supply polarity determination circuit 4 of the comparator CP ₁ is as shown in FIG. 23 (b).

The two control signals output from the control circuit 3 are input to exclusive OR circuits XOR ₁ and XOR ₂ , respectively, and the exclusive OR with the output of the power supply polarity discriminating circuit 4 is output to each switching element Q _1. ', Q ₂ '. Therefore, regarding the signals used for controlling the on / off of the switching element Q ₁ ′, since the output of the power supply polarity discriminating circuit 4 is at the H level during the period when the AC power supply Vs has the positive polarity, the exclusive OR circuit XOR ₁ Output is control circuit 3.
Becomes what is obtained by inverting the logical value output from the AC power supply from the Vs negative polarity period of the output of the power supply polarity determination circuit 4 is at the L level, the output of the exclusive OR circuit XOR ₁ the control circuit 3 Becomes the logical value output from. The same applies to the signal used to control the on / off of the switching element Q ₂ ′. The exclusive OR circuit XOR ₂ is connected to the AC power supply Vs
Select whether to pass the logic value from the control circuit 3 as it is or to invert it according to the polarity of.

[0063] With the configuration described above, the AC power supply switching device to Q ₁ both waveforms in accordance with the voltage polarity of Vs ', Q _2' from reversing each period off of both switching elements Q ₁ ', Q _2' the By controlling the duty, even when the on-periods of the switching elements Q ₁ ′ and Q ₂ ′ are different, the input current can be made equal between the positive polarity period and the negative polarity period of the AC power supply Vs. As a result, input current distortion can be reduced. Other configurations and operations are the same as those of the first embodiment.

(Embodiment 11) This embodiment shows an example of control when the discharge lamp La1 provided in the load circuit ₁ is turned on. Discharge lamp L having filament (hot cathode)
The process of lighting a ₁ is preheating → starting → lighting,
In the preheating process, a current is mainly supplied to the filament, and in the starting process, a high voltage is applied between both filaments to start a discharge, and after the start of the discharge, a rated lighting is performed.

The above steps are performed by the switching element Q in the circuit configuration of the first embodiment shown in FIG. _This is realized by controlling ₁ ′ and Q ₂ ′ as shown in FIG. Figure 24 is a controls the switching frequency for the resonant frequency of the resonant circuit composed by the leakage inductance and the capacitor C ₂ of the leakage transformer T _1, are set high switching frequency.

[0066] At the time preheating are lowering the applied voltage of the greatly advance, the two ends of the discharge lamp La ₁ between the resonance frequency and the switching frequency is set high switching frequency as in FIG. (A). During start-up to reduce the difference between the resonant frequency by lowering the switching frequency than during preheating as in FIG (b), increasing the voltage applied to both ends of the discharge lamp La _1. In this manner, when the discharge lamp La ₁ with the lights, because the resonant frequency of the load circuit 1 is shifted to a lower frequency, drawing a switching frequency as the lamp current required for rated lighting of the discharge lamp La ₁ is obtained As shown in (c), the switching frequency is further reduced at the time of lighting (the switching frequency is lower than at the time of starting, but the relationship between the time of starting and the time of lighting is not always the same).

[0067] Further, as described in the embodiment 9, the switching element Q ₁ ', Q _2' can be adjusted power supplied to the discharge lamp La ₁ by controlling the duty ratio of the on-off of Thus, as shown in FIG.
By changing only the duty ratio without changing the switching frequency, preheating is performed by the control of FIG. 4A, starting is performed by the control of FIG. 5B, and rated lighting is performed by the control of FIG. It may be.

Further, as shown in FIG. 26, the on / off switching frequency and the duty ratio of the switching elements Q ₁ ′ and Q ₂ ′ may be controlled simultaneously. In this case, preheating is performed by the control of FIG. 7A, starting is performed by the control of FIG. 7B, and rated lighting is performed by the control of FIG. Here, when controlling the duty ratio, FIG.
It is desirable to determine the polarity of the AC power supply Vs and control the input current to be symmetrical between the positive polarity and the negative polarity as in the circuit configuration shown in FIG. Preheating using the circuit configuration shown in FIG. 22, the starting, by performing the lighting, while suppressing the increase in the voltage across the capacitor C _1, it is possible to reduce input current distortion.

[0069] (Embodiment 12) This embodiment, in the configuration of Embodiment 1 is obtained by considering the inrush current due to the power-on charging current flows into the capacitor C _1. That is, as shown in FIG. 27, a series circuit of a resistor R ₁ and a capacitor C ₃₁ is connected in parallel between both ends of a capacitor C ₁ , and the voltage across the capacitor C ₃₁ is used as a power supply of the control circuit 3. The configuration is different from that of the first embodiment. A power-on switch SW ₁ is connected between a connection point between the capacitor C ₃ and the load circuit 1 and one end of the AC power supply Vs.
Is inserted.

[0070] When the switch SW ₁ is turned on, the AC power source Vs is positive polarity period of the AC power supply Vs → diode D
₃ → Capacitor C ₁ → Parasitic diode of switching element Q ₂ ′ → Primary winding of leakage transformer T ₁ → Switch SW ₁ → Inrush current flows in the path of AC power supply Vs, and during negative polarity period, AC power supply Vs An inrush current flows on the path of the switch SW ₁ → the primary winding of the leakage transformer T ₁ → the parasitic diode of the switching element Q ₁ ′ → the capacitor C ₁ → the diode D ₄ → the AC power supply Vs.

[0071] As apparent from the above description, the rush current regardless of the polarity of the AC power source Vs, since those through the primary winding of the leakage transformer T _1, a leakage transformer T ₁ 1 winding of If the impedance is set sufficiently large, the inrush current can be suppressed without adding a special circuit. That is, the leakage transformer T
By increasing the number of turns of _the primary winding may be set large primary winding inductance by reducing the gap of the core.

By the way, the switch SW₁Turns on and exchanges
Immediately after the power supply Vs is turned on, the capacitor C₁Has
Capacitor C because no load is stored₁The voltage across
It is charged rapidly from 0V. The current flowing at this time suddenly
Although the input current, as described above, the leakage transformer T₁
Rush current is reduced by designing
Will be. However, almost immediately after power-on,
Element Q₁', Q_Two'Operates, the capacitor C₁
The charging current to the capacitor C₁Fully charged
The operation starts without being able to do so. for example
If switching element Q_TwoInrush current to parasitic diode
The switching element Q ₁'Is on
Then, the capacitor C₁Switching current
Element Q₁'Flows into the capacitor C₁Slow voltage rise
Will be.

Therefore, by providing the resistor R ₁ and the capacitor C ₃₁ and using the voltage across the capacitor C ₃₁ as a power supply for the control circuit 3, the switching elements Q ₁ ′ and Q 2 are switched until the voltage across the capacitor C ₁ rises. _It prevents ₂ 'from working. That is, as shown in FIG. 28, immediately after the power is turned on at time t ₀ ,
Although an inrush current flows as shown in (a), since the voltage V _C31 across the capacitor C _{31 serving} as a power supply of the control circuit 3 is 0 V (see FIG. 28 (b)), the control circuit 3 operates immediately after the power is turned on. do not do. When the charging of the capacitor C ₁ proceeds and the voltage V _C31 across the capacitor C ₃₁ exceeds the threshold value V _th set in the control circuit 3 at time t ₁ , the control circuit 3 starts operating, and FIG. The switching elements Q ₁ ′ and Q ₂ ′ are turned on and off as in d).

[0074] As described above, the switching element Q ₁ from the time t ₁ the power is turned rush current finishes flowing at time t ₀ ', Q _2' to start the control of the control circuit 3
Because they start operating is delayed from power point, it is possible to start the operation to recharge the capacitor C ₁ sufficiently. (Embodiment 13) In this embodiment, as shown in FIG.
In the circuit configuration of the first embodiment, the diodes D ₃ and D ₄
Voltage detection circuit 5 that outputs a voltage proportional to the voltage across the terminals
a, 5b and provided, are added to the voltage detection circuit 5c outputs a voltage proportional to the voltage across the capacitor C _3. The voltage detection circuit 5a, the output voltage of the 5b are alternatively selected by the changeover switch elements SW _2, the capacitor C after the output voltage selected is rectified by diode D ₃₁
It is smoothed by ₃₂ . Voltage across the capacitor C ₃₂ is input to the control circuit 3. Also, a changeover switch element SW
₂ is the AC power supply Vs detected by the power supply polarity determination circuit 4
Is switched in accordance with the polarity of.

The power supply polarity determining circuit 4 includes a voltage detecting circuit 5
The polarity of the AC power supply Vs is determined based on the output voltages b and 5c. That is, the voltage detecting circuit 5b, 5c is because detecting the potential difference between the end of the potential and the ground potential of the AC power source Vs (negative electrode potential of the capacitor C _1), both the voltage detecting circuit 5b,
The polarity of the AC power supply Vs can be known based on the output of 5c.

[0076] the construction described above, the voltage across the capacitor C ₃₂ is from will reflect the voltage across the diode D _3, D _4, it is possible to know the operational state of the circuit by the voltage. Therefore, the control circuit 3 performs control according to the operation state of the circuit by changing the switching frequency and the duty ratio for turning on and off the switching elements Q ₁ ′ and Q ₂ ′ according to the voltage across the capacitor C _32. .

The waveform of each part of the circuit shown in FIG. 29 is shown in FIG.
Shown in FIG (a) is an AC power supply voltage his type of Vs, Fig (b) is a voltage detection circuit 5a selected by the changeover switch elements SW ₂ which is controlled by the power supply polarity determination circuit 4,
The output voltage of 5b, FIG (c) is a voltage across V _C32 of the capacitor C _32. In FIG. 7B, a period Ta is a period during which the output voltage of the voltage detection circuit 5a is selected,
b indicates a period during which the output voltage of the voltage detection circuit 5b is selected. Figure 30 As is clear, it is possible to know about the peak value near or zero cross point of the AC power source Vs by the voltage across the capacitor C _32.

When the control is performed so as to improve the crest factor of the lamp current of the discharge lamp La ₁ , the peak value of the AC power supply Vs near the peak value of the AC power supply Vs based on the change in the voltage across the capacitor C _32. The switching frequency may be lowered, and the switching frequency may be set high near the zero cross point of the AC power supply Vs. Further, the duty ratio may be controlled instead of the switching frequency. In this case, the duty ratio is set to 5 near the peak value of the AC power supply Vs.
0%, and the ratio between the ON period and the OFF period may be increased near the zero cross point of the AC power supply Vs. further,
The switching frequency and the duty ratio may be changed simultaneously. If the crest factor is reduced in this way, the discharge lamp L
The flicker of the light output of a ₁ can be reduced.

Further, in order to prevent circuit components such as the switching elements Q ₁ ′, Q ₂ ′ and the capacitor C ₁ from being destroyed by the over voltage, the over voltage may be detected by the voltage across the capacitor C _32. It is possible. That is, the Agego the voltage across the capacitor C ₃₂ becomes abnormally high, the switching element Q ₁ ', Q _2' if stops oscillation, it is possible to avoid damage due to overvoltage. Other configurations and operations are the same as those of the first embodiment.

[0080] Incidentally (Embodiment 14), in the circuit configuration of embodiment 1, at a light load as in the case of performing the dimming the discharge lamp La _1, there may be a pause period occurs in the input current. That is, when the dimming degree increases (that is, when the optical output decreases), the pause period of the input current increases, and the input current distortion increases. Similarly, when the load increases, a large change occurs near the zero crossing point of the input current (the polarity of the input current is inverted while the input current is flowing), and a discontinuous waveform appears, so that the input current distortion increases. Will do. As described above, in a usage mode in which the load increases and decreases, the input current waveform changes due to the increase and decrease in the load.

Therefore, in the present embodiment, as shown in FIG. 31, in the circuit configuration of the first embodiment, an AC switch including a diode bridge DB ₂ and a transistor Tr ₂ (a diode bridge DB is connected between the collector and emitter of the transistor Tr ₂ ). a switching element which is non-polarized by connecting to the _second DC output terminal) to be connected in parallel a series circuit of a capacitor C ₃ "in the capacitor C _3. in this circuit, the on-off transistor Tr _2, the capacitor C ₃ and states that used alone, the capacitor C ₃ to the capacitor C ₃ "
Are connected in parallel.

[0082] In this configuration, when the load distortion occurs in the input current waveform becomes large, by increasing the combined capacitance connected in parallel with capacitor C ₃ "in the capacitor C _3, developed across the capacitor C ₃ by increasing the voltage, the input current waveform can be made close to sine wave. in addition, as shown in FIG. 32, "connected in series, the capacitor C _3" capacitor C ₃ to the capacitor C ₃ shown in FIG. 31 In this configuration, the transistor Tr ₂ is normally turned on, and the transistor Tr ₂ is turned off at light load to turn off the capacitors C ₃ and C ₃ ". the by reducing the series synthesized capacity, by reducing the voltage generated across the series circuit of the capacitor C _3, C ₃ ", be made close to the input current waveform to a sine wave Kill.

In the circuit configurations shown in FIGS. 31 and 32, the impedance of the capacitor C ₃ (C ₃ ) connected in series to the load circuit 1 is changed according to the increase or decrease of the load. In addition, these circuit configurations have the effect of suppressing fluctuations in the lamp current and preventing flickering.These circuit configurations are used as switching means when _one discharge lamp La1 is to have two types of output characteristics. is valid. in the present embodiment, the switching element Q ₁ by the control circuit 3 ', Q _2' exemplifies the case where the magnitude of the load is increased or decreased in accordance with the control of the on-off of the transistor Tr ₂ is It is determined according to the control state of the switching elements Q ₁ ′ and Q ₂ ′ by the control circuit 3. Other configurations and operations are the same as those of the first embodiment.

(Embodiment 15) In this embodiment, as shown in FIG. 33, in addition to the configuration of the ninth embodiment shown in FIG. The control circuit 3 controls the on / off switching frequency and the duty ratio of the switching elements Q ₁ ′ and Q ₂ ′ based on the output of the current detector 6 to detect the discharge lamp L.
It is intended to suppress the variation of the lamp current flowing in a _1.
The current detection unit 6 is realized by a device that inserts a low resistance into a circuit and uses a voltage between both ends, or a device that uses a secondary output of a current transformer.

In a period where the lamp current is relatively large, the switching frequency is increased to control the lamp current in a direction to decrease the lamp current, thereby suppressing the fluctuation of the lamp current and the fluctuation of the light output. . Other configurations and operations are the same as those of the first embodiment. (Embodiment 16) In this embodiment, as shown in FIG.
In the configuration of the seventh embodiment shown in FIG.
₃ and C ₃ '
provided with a b both voltage detection circuit 7a, the magnitude of the detected voltage at 7b compares determined by the comparator CP _3, by providing the judgment result to the control circuit 3, switching off of the switching element Q ₁ ', Q _2' The frequency and the duty ratio are changed. Here, the voltage detection circuits 7a and 7b output a voltage proportional to the average value of the voltage between both ends of the capacitors C ₃ and C ₃ ′, and the comparator CP ₃ calculates the average value of the positive and negative polarities of the input current. You can compare each other.

[0086] In this configuration, an AC power source when the input current I _in from the Vs is such that the asymmetric positive and negative polarities and as shown in FIG. 35 (a), the voltage across the capacitor C ₃ of the capacitor C ₃ ' In this case, control is performed so as to shorten the on-period of the switching element Q ₂ ′ and prolong the on-period of the switching element Q ₁ ′. Such control can be obtained input current I _in sinusoidal as shown in FIG. 35 (b). Here, Vin _in FIG. 35 is the voltage of the AC power supply Vs.

The asymmetry of the input current is determined by the capacitors C ₃ ,
It is possible to detect not only the voltage across C ₃ ′ but also the voltage across diodes D ₃ and D ₄ (see voltage detection circuits 5a and 5b in FIG. 29). When the voltage across the diode D ₃ is greater than the voltage across the diode D ₄ it is, 'as well as shorten the ON period of the switching element Q _1' switching element Q ₂ may be longer on period of. Again,
A sinusoidal input current Iin can be obtained similarly to the configuration shown _in FIG. Other configurations and operations are the same as those of the first embodiment.

(Embodiment 17) In this embodiment, in order to detect the asymmetry of the input current, as shown in FIG.
A current detection unit 8 is provided for detecting a current flowing between a connection point of the diodes D ₃ and D ₄ and the AC power supply Vs. As the current detection unit 8, a low resistance or a current transformer that is inserted into an electric circuit and detects a voltage between both ends is used. In this configuration, the control circuit 3 detects the direction and magnitude of the current, and adjusts the ON periods of the switching elements Q ₁ ′ and Q ₂ ′ based on the magnitude of the current in each direction, as in the sixteenth embodiment. You do it. In addition,
In the present embodiment are connected in parallel a capacitor C ₂ to resonate with the leakage inductance of the leakage transformer T ₁ to the primary winding of the leakage transformer T _1. Other configurations and operations are the same as those of the first embodiment.

(Embodiment 18) In this embodiment, as shown in FIG. 37, in the configuration of Embodiment 9 shown in FIG. 18, a series circuit of two resistors R ₁₀ and R ₁₁ is provided at both ends of a capacitor C _1. Are connected in parallel, the voltage between both ends of the capacitor C ₁ is divided, and the magnitude of a voltage obtained by the division and a preset reference voltage V _ref are compared and determined by the converter CP ₄ , and according to the output of the comparator CP ₄ , And on / off of the switching elements Q ₁ ′ and Q ₂ ′. The purpose of this embodiment detects the no-load conditions due to the discharge lamp half-wave lighting state at the end of life of La ₁ (so-called Emiresu state) and the end of life and the discharge lamp La ₁ is out, the output to the load circuit 1 To stop or reduce.

[0090] Thus, in the configuration shown in FIG. 37, Emiresu state and the capacitor C ₁ across the voltage in a no-load state increases resistance R _10, the reference voltage the voltage at the connection point of R ₁₁ V _ref
Exceeding the output of the comparator CP ₄ becomes H level, the control circuit 3 is the switching element Q ₁ ',
The on / off of Q ₂ ′ is stopped or the output is reduced to bring the discharge lamp La ₁ into the dimming lighting state.

To detect the Emiless state or the no-load state,
Capacitor C₁Instead of the voltage across
, Leakage transformer T₁To the detection winding n_ThreeIs established,
Detection winding n_ThreeInduced voltage of diode D₃₂Gained through
Signal level and reference voltage V _refAnd comparator C
P_FourMay be used for comparison. This place
Comparator CP_FourHas a leakage transformer T₁of
A voltage reflecting the instantaneous value of the current flowing through the primary winding is input.
Therefore, in the control circuit 3, the comparator CP_FourOutput
The data is taken in at a predetermined timing.

[0092] Further, as shown in FIG. 39, may be compared with the voltage across the reference voltage V _ref of the resistor R ₁₂ connected in series to the source of the switching element Q ₂ 'in the comparator CP _4. Also in this case, since the comparator CP ₄ detects the instantaneous value of the source current of the switching element Q ₂ ′, the control circuit 3 takes in the output of the comparator CP _{4 at} a predetermined timing.

In the configuration of the present embodiment, when the discharge lamp La ₁ comes off and goes into a no-load state, or when the discharge lamp La ₁ is consumed by the emitter of the filament of the discharge lamp La _{1, the} discharge lamp La ₁ is driven only by a half-wave of the AC power supply Vs. In the Emiless state where the light is no longer lit, it is possible to prevent the elements such as the switching elements Q ₁ ′ and Q ₂ ′ from being stressed and broken. (Embodiment 19) In each of the embodiments described above, the configuration of the separately-excited control type in which the switching elements Q ₁ and Q ₂ (Q ₁ ′, Q ₂ ′) are controlled by the control circuit 3 has been described. ,
As shown in FIG. 40, the switching elements Q ₁ and Q ₂ are self-excited.

That is, the leakage transformer T₁Pair
Feedback winding n₃₁, N₃₂And the leakage transformer T₁
Switching element according to the direction of the current flowing through the primary winding of
Child Q ₁, Q_TwoFeedback winding so that turns on and off alternately
n₃₁, N₃₂Has been set. However, at startup
The switching element Q is activated by a separately provided starting means 12.
_TwoIs forcibly turned on by the configuration shown in FIG.
Excitation control is possible. In this configuration, the load circuit 1
Cage transformer T₁Normal transformer T without using_TwoFor
Transformer T_TwoInductor L in the secondary winding of₁
In the configuration of the third embodiment (see FIG. 11) in which
Inductor L₁And a pair of feedback windings n₃₃, N₃₄, This
Feedback winding n₃₃, N₃₄Is the switching element Q₁, Q_Twoof
It is connected between the base and the emitter. In this configuration,
Nacta L₁Switching according to the direction of the current flowing through
Element Q₁, Q_TwoReturn winding so that it turns on and off alternately
Line n₃₃, N₃₄The winding direction is determined. With this circuit configuration
Is the discharge lamp La₁Is removed, the inductor L₁Has no current
Oscillation stops automatically because the flow stops
have. In this circuit configuration, as shown in FIG.
In the same manner as the circuit configuration shown in FIG.
You. According to the configuration of the present embodiment, an external control signal is applied.
And the control circuit 3 is not required.
There is an advantage that there is little. Other configurations and operations are implemented
Same as in the first embodiment.

(Embodiment 20) In this embodiment, as shown in FIG. 42, a switching element Q
₁ is self-excited and the switching element Q ₂ ′ composed of MOSFET is separately excited by a control signal from the control circuit 3 ′. The switching element Q ₁ is turned on and off by receiving the induced voltage of the feedback winding n ₃₅ provided in the leakage transformer T _1.

In this circuit configuration, since the control circuit 3 'is provided, the output to the load circuit 1 is reduced or the output is stopped by controlling the on / off operation of the switching elements Q ₁ and Q ₂ '. If only one switching element Q ₂ ′ is controlled, such a function can be realized, so that two switching elements Q ₁ , Q ₂ (Q
₁ ′, Q ₂ ′), the number of parts is reduced as compared with the case of separately controlled excitation. Other configurations and operations are the same as those of the first embodiment.

(Embodiment 21) This embodiment is different from FIG.
As shown, a plurality (two in each of the illustrated examples) of discharge lamps L
a₁La_TwoThis is an example of using the load circuit 1 having
These load circuits 1 correspond to any of the above-described embodiments.
However, it can be adopted. The load rotation shown in FIG.
Road 1 has two discharge lamps La₁, La_TwoOne of the flatfish
Connect one end of the
T₁Preheating winding n₃₆2 lights by connecting
Discharge lamp La₁, La_TwoAre connected in series, and
Discharge lamp La₁, La_TwoSeries transformer with leakage transformer
T₁And the discharge lamp La₁, L
a_TwoOne capacitor C in the series circuit _TwoConnected in parallel
is there.

The load circuit 1 shown in FIG.
Two load circuits 1 according to the first embodiment shown in FIG. 7 are connected in parallel.
Equivalent to In other words, two leakage transformers
S ₁₁, T₁₂Primary windings in parallel with each other
Zitrans T₁₁, T₁₂Lanterns La on the secondary winding of
₁, La_TwoAre connected in parallel, and each discharge lamp La₁,
La_TwoCapacitor C for resonance between filaments_{twenty one}, C
_{twenty two}Are connected.

[0099] Load circuit 1 shown in FIG. 43 (c), rather than a leakage transformer T ₁ using the conventional transformer T _2,
A series circuit consisting of an inductor L ₁₁ and the discharge lamp La ₁ Tokyo,
And a series circuit of an inductor L ₁₂ discharge lamp La ₂ Metropolitan are those having a structure in which parallel connection to the secondary winding of the transformer T _2, each of the discharge lamps La _1, of La ₂ is between the filaments for resonance The capacitors C ₂₁ and C ₂₂ are connected.

The load circuit 1 shown in FIG. 43D has two discharge lamps La ₁ and La ₂ connected to the secondary side of a leakage transformer T ₁ via a balancer L ₃ . That is, leakage of the one end of the secondary winding of the transformer T ₁ is connected to the tap of the balancer L _3, respectively discharge lamp La between the other end of each end and leakage secondary winding of the transformer T ₁ of the balancer L _{3 1} and La ₂ are connected. In addition, each discharge lamp L
Resonant capacitors C ₂₁ and C ₂₂ are connected between the filaments a ₁ and La ₂ , respectively. In this configuration, a resonance circuit is formed by the capacitors C ₂₁ and C ₂₂ , the leakage inductance of the leakage transformer T ₁ , and the inductance of the balancer L ₃ .

The load circuit 1 shown in FIG.
Transformer T_TwoInductor L for resonance in the primary winding of₁Directly
Column connected, inductor L₁The secondary winding provided in the discharge lamp L
a₁, La_TwoTo provide a preheating current to the filament
It is used as a preheating winding. Where the inductor
L₁Has three secondary windings used as preheating windings
You. Two discharge lamps La₁, La_TwoIs one filament
Are connected to each other, and a capacitor C is connected between the other ends.₄₁Through
And inductor L₁Are connected. Also, release
Light La₁, La_TwoTo each other filament
Capacitor C₄₂, C ₄₃Through the inductor L₁Secondary winding
Is connected. Transformer T_TwoDischarge lamp between the secondary windings
La₁, La_TwoSeries circuit and capacitor C for resonance_TwoWhen
Are connected. In this configuration, the inductor L
₁And capacitor C_TwoThus, a resonance circuit is formed.

By using the load circuit 1 configured as described above, it becomes possible to light a plurality of discharge lamps La ₁ and La ₂ . FIGS. 43A and 43B show the load circuit 1 including _two discharge lamps La ₁ and La ₂ .
A similar connection configuration can be adopted in the case of three or more lamps. The configuration other than the load circuit 1 can adopt the circuit configuration of each of the above-described embodiments.

(Embodiment 22) As shown in FIG. 44, this embodiment differs from the configuration of Embodiment 1 shown in FIG.
A series circuit of a load circuit 1a and the capacitor C _3a of DC blocking is obtained by parallel connection in addition to the one switching element Q ₂ '. Load circuit 1a includes the same manner as the load circuit 1 is connected to the discharge lamp La _1a of the secondary side of the leakage transformer T _1a, the configuration of connecting the capacitor C _2a for resonance between the filaments of the discharge lamp La _1a.

The operation relating to the load circuit 1 is the operation described in the first embodiment, and the load circuit 1a has the same operation as that of the conventional configuration shown in FIG. Load circuit 1a in steady state
The operation relating to will be briefly described. Now, when the switching element Q ₁ ′ is turned on, a current flows through the path of the capacitor C ₁ → the switching element Q ₁ ′ → the load circuit 1a → the capacitor C _3a → the capacitor C ₁ . During this period, the capacitor C _3a
Is charged.

On the other hand, immediately after the switching element Q ₁ ′ is turned off and the switching element Q ₂ ′ is turned on, the energy stored in the load circuit 1 a (leakage transformer T _{1 a} ) is released and the load circuit 1 a → A current flows through the path of the capacitor C _3a → the parasitic diode of the switching element Q ₂ ′ → the load circuit 1a. Thereafter, when the energy of the load circuit 1a is released, the discharge of the capacitor C _3a is started, and the capacitor C _3a → the load circuit 1a → the switching element Q ₂ ′ →
A current flows through the path of the capacitor _C3a , and a current flows in the load circuit 1a in a direction opposite to that of the current.

Next, the switching element Q_Two'Is off
Switching element Q₁'Turns on, the load circuit 1
a → switching element Q₁'Parasitic diode → condensed
Sa C₁→ Capacitor C_3a→ Load rotation on the path of the load circuit 1a
Road 1a (leakage transformer T _1aEnergy stored in)
Gis are released. The energy stored in the load circuit 1a is
When released, the capacitor C₁From switching element Q
₁'Returns to the state where current flows through the load circuit 1a
Accordingly, the direction of the current flowing through the load circuit 1a is reversed.
That is, the switching element Q₁', Q_Two'On and off
As a result, an alternating high-frequency current flows through the load circuit 1a.
Become.

The operation described above is performed by the capacitor C
_This is an operation of a half-bridge type inverter circuit using ₁ as a power supply, and a circuit including the load circuit 1a and the capacitor _C3a has no function of reducing input current distortion. That is, since the lamp current of the discharge lamp La _1a depends on the power supply voltage of the inverter circuit, the lamp current of the discharge lamp La _1a becomes substantially constant if the capacity of the capacitor C _{1 serving as} the power supply is sufficiently large. As a result, the combined optical output of the two discharge lamps La ₁ and La _1a has more fluctuation than the combined optical output of the _two discharge lamps La ₁ and La ₂ having the circuit configuration shown in FIG. Less. This is because, in the configuration shown in FIG. 43A, the light output of both discharge lamps La ₁ and La ₂ both fluctuates and the direction of change is the same, whereas in the present embodiment, one of the discharge lamps La ₁ and La ₂ changes. This is because the light output of La ₁ fluctuates, but the light output of the other discharge lamp La _1a does not fluctuate.

In the configuration of the present embodiment, even if one of the two discharge lamps La ₁ and La _1a comes off, the remaining discharge lamps will remain lit. For example, discharge lamp L
When a _1a is deviated, the resonance frequency of the resonance circuit formed by the inductance on the primary side of the leakage transformer T _1a and the capacitor C _2a is adjusted to be slightly advanced with respect to the switching frequency, so that the remaining frequency is reduced. Discharge lamp La
_The current flowing through the switching elements Q ₁ ′ and Q ₂ ′ when ₁ is turned on can be a combined current of a leading phase and a lagging phase, which is smaller than the lagging current flowing when only the discharge lamp La ₁ is turned on. The peak value of the current flowing through the switching elements Q ₁ ′, Q ₂ ′ can be suppressed.

If the frequency characteristics of the two discharge lamps La and La _1a are slightly shifted, a change in power supply and a change in load can be prevented.
The output can be kept almost constant. Other configurations and operations are the same as those of the first embodiment. (Embodiment 23) In this embodiment, as shown in FIG.
In the configuration of the first embodiment shown in FIG.
A lamp La ₃ for direct current lighting is connected between both ends of ₁ via a switching element Tr ₃ . Lamp La ₃
For example, an incandescent light bulb or the like can be used.

In this configuration, the lamp current flowing through the lamp La ₃ is substantially constant if the capacitance of the capacitor C ₁ is sufficiently large. Therefore, the fluctuation of the combined light output of the discharge lamp La ₁ and the lamp La ₃ is as follows. This is less than when the circuit configuration shown in FIG. In this circuit configuration, by turning on and off the switching element Tr _3, it is possible to arbitrarily control the ratio of the light output of the discharge lamp La ₁ and the lamp La _3. Other configurations and operations are the same as those of the first embodiment.

(Embodiment 24) In this embodiment, as shown in FIG. 46, one arm of a bridge circuit is formed together with diodes D ₃ and D _{4 in} addition to the circuit configuration of Embodiment 1 shown in FIG. Two additional diodes D ₅ and D ₆ are added, an AC power supply Vs is connected to the AC input terminal of the diode bridge formed by the diodes D _{3 to} D _6, and a connection between the AC power supply Vs and the load circuit 1 is made. It has included configuration a capacitor C ₄ of the DC cut.

The operation will be briefly described. Although the basic operation is the same as in Embodiment 1, by a capacitor C ₄ are connected in series to the load circuit 1, it is about half the voltage across the capacitor C ₃ is compared to the first embodiment. This is because the path for charging the capacitor C _3, the capacitor C ₁
→ Switching element Q ₁ → Load circuit 1 → Capacitor C ₄
→ path of capacitor C ₃ → capacitor C ₁ and AC power supply Vs → diode D ₃ → switching element Q ₁ → load circuit 1 → capacitor C ₄ → capacitor C ₃ → diode D
6 → There in a path of the AC power source Vs (period of the AC power source Vs is positive), the capacitor C _3, C ₄ in both pathways have been connected in series, the voltage across capacitor C4 and C ₃ of the capacitor C ₁ This is because the pressure is divided.

The diode D_Five, D₆Has established
As a result, AC power supply Vs → diode D_Three→ Capacitor C
₁→ Diode D₆→ AC power supply Vs (AC power supply Vs
Path) and the AC power supply Vs → diode D_Five
→ Capacitor C₁→ Diode D_Four→ AC power supply Vs
(When the power supply Vs has a negative polarity)
The capacitor C₁Of the AC power supply Vs
Peak value almost equal to the peak value.
And not. That is, the switching element Q₁ , Q _Two Is reduced
Will be done.

When the voltage of the AC power supply Vs is 100 V, the circuit configuration of the first embodiment is used, and the voltage is 200 V.
If so it is using the circuit configuration of this embodiment when a V, be different voltage of the AC power source Vs is, by simply changing only the presence or absence of the capacitor C ₄ and the diode D _5, D _6, other By using a common configuration, it is possible to realize a circuit having substantially the same operation characteristics.

That is, even if the voltage of the AC power supply Vs is different, a common circuit board is used,
For V, the configuration of this embodiment shown in FIG.
For 00V, diodes D ₅ and D ₆ and capacitor C
Remove and _4, the shorting portions removed the capacitor C ₄ with jumper wires, it is possible to easily realize the circuit configuration of the first embodiment shown in FIG.

Instead of using a common circuit board,
Common parts between the circuit configuration of state 1 and the circuit configuration of the present embodiment
47, and common parts as shown in FIG.
Module M₁, M_TwoAnd non-common modules
M_Three, M_FourAnd a common module M₁, M_Two
Module M of the non-common part_Three, M_FourReplace
To achieve 100V and 200V specifications
No. That is, module M ₁, M_Two, M_ThreeCombine
Then it becomes 100V specification, module M_ThreeMoji instead of
Wool M_FourUsing the module M₁, M_Two, M_FourPair of
It can be set to 200V specification by the combination. this
With such a configuration, the circuit structure of the 100 V specification and the 200 V specification
Most of the results can be shared.

Note that the voltage of the AC power supply Vs is 100 V and 2
It is not limited to 00V, for example, 120V and 24V
The circuit configuration can be shared by various combinations such as 0V, 120V and 200V. Incidentally, in the present embodiment, as shown in FIG. 48, the diode D ₇ and it is desirable to add a capacitor C _5. The diode D ₇ is for high frequency (high speed),
_4, is inserted between the common connection point of the anode and the capacitor C _1, C ₃ and the switching element Q ₂ of D _6. The capacitor C ₅ are intended small capacity, it is connected in parallel to the series circuit of the diode D _5, D _6. That is, the high-frequency current through the diode D ₇ is absorbed by the capacitor C _5, are Teimetsu stress applied to the diode bridge consisting of diodes D ₃ to D _6.

Another circuit configuration shown in FIG. 48 is shown in FIG.
Same as the first embodiment except that the AC power supply Vs and the diode
A filter circuit 2 is provided between the bridge circuit and the load circuit.
Leakage transformer T as 1₁And discharge lamp La₁To
We use what we have. Further, the circuit shown in FIG.
Switching element Q₁, Q_TwoAnd diode D₁, D _Two
Switching element consisting of MOSFET instead of
Q₁', Q_Two'Using diode D₁, D_TwoAs a switch
Ching element Q₁', Q_Two'Uses a parasitic diode.
Here, the diode D_Three~ D₆Is one package
Diode bridge DB_TenComposed of
And, as described above, the diode D₇And con
Densa C_FiveThe diode bridge D
B_TenCan be used at relatively low speed. other
The configuration and operation are the same as in the first embodiment.

(Embodiment 25) As shown in FIG. 49, this embodiment differs from the configuration of Embodiment 1 shown in FIG.
Not only diodes D ₁ and D ₂ but also diodes D ₃ and D
₄ , the switching elements Q ₃ and Q ₄ are also connected in parallel. With this configuration, power can be regenerated to the AC power supply Vs by the following operation.

The switching elements Q ₃ and Q ₄ are alternately turned on and off without being simultaneously turned on by a control circuit (not shown). During the period in which the switching element Q ₁ is on, the switching element Q ₄ is on and the switching element Q ₂ is on. switching element Q ₃ is controlled to be turned on during the period. In this configuration, when the operating state of FIG. 3 in the first embodiment (AC power source Vs is positive), switching element Q ₃ are in an off, since the switching element Q ₄ are capable of turning on, The path of the capacitor C ₁ → the switching element Q ₁ → the load circuit 1 → the AC power supply Vs → the switching element Q ₄ → the capacitor C ₁ can be formed, and the power can be regenerated to the AC power supply Vs.

[0121] When the AC power source Vs is negative polarity, the switching element Q ₄ during the on period of the switching element Q ₂
Is off and the switching element Q ₃ can be turned on, so that the capacitor C ₁ → the switching element Q
₃ → AC power supply Vs → Load circuit 1 → Switching element Q ₂
→ can be regenerated power to the AC power source Vs to a path of the capacitor C _1.

The switching element Q_Three, Q_FourWith
, The operation is the same as that of the first embodiment. The above
In each embodiment, the lamp is lit by high-frequency AC as a load
Discharge lamp La ₁But the load is the discharge lamp La₁To
It is not limited. Also, supply DC power to the load.
If you need
Transformer T₁Secondary output of full wave rectifier DB₁Rectify with
The load circuit 1 is configured to apply the obtained DC voltage to the load 5.
May be configured.

Note that the technical ideas of the above-described embodiments can be appropriately combined and used.

[0124]

According to the first aspect of the present invention, there is provided a full-wave rectifier configured by bridge-connecting rectifying elements, a series circuit of an AC power supply and a load circuit connected between AC terminals of the full-wave rectifier, A first capacitor for smoothing connected between the DC output terminals of the wave rectifier and a rectifying element of one arm of the full-wave rectifier are connected in parallel to each other and alternately turned on and off at a frequency higher than the power supply frequency of the AC power supply. A first switching element and a second switching element, and a second capacitor connected between a connection point between the AC power supply and the load circuit and at least one of the DC output terminals of the full-wave rectifier, Since the input current can flow over almost the entire power supply cycle, the input current distortion is small, and the power can be supplied directly from the AC power supply to the load circuit. There is a cormorant effect. In addition, the number of components is smaller than that of the conventional configuration, and the charging current to the smoothing capacitor flows only through the load circuit when the power is turned on, so that the rush current can be suppressed without adding a special circuit.

According to a second aspect of the present invention, the load circuit includes a transformer and a load connected to a secondary side of the transformer, and both ends of a primary winding of the transformer are both ends of the load circuit. Since the load circuit has a transformer configuration,
There is an advantage that a constant load current can flow by removing low frequency components to the load provided on the next side. Also, if the impedance on the primary side of the transformer is increased, there is an advantage that the inrush current can be further reduced.

According to a third aspect of the present invention, the load circuit is connected between the first inductor, the discharge lamp connected in series to the first inductor, and the non-power-supply-side terminal of the discharge lamp, and the load circuit resonates with the first inductor. A third capacitor constituting a circuit, and both ends of a series circuit of the first inductor and the discharge lamp become both ends of a load circuit. Since no transformer is used, there is no loss due to the transformer, and the load is not increased. There is an advantage that the power supply efficiency to the power supply is further increased. In addition, since no path for charging the first capacitor is formed when there is no load, there is an advantage that the rush current becomes almost zero when there is no load.

According to a fourth aspect of the present invention, the load circuit includes the second inductor connected between both ends. Since the transformer is not used, there is no loss due to the transformer, and the power supply efficiency to the load is further improved. There is an advantage of being higher.
In addition, there is an advantage that the second inductor functions as a low-pass filter, and the current supplied to the load is hardly affected by fluctuations in the power supply voltage.

According to a fifth aspect of the present invention, there is provided a control circuit capable of adjusting on / off switching frequencies of the first switching element and the second switching element.
There is an advantage that the input current can be adjusted or the power supplied to the load can be adjusted while keeping the ON period of the switching element substantially constant. As a result, if the load is a discharge lamp, control of dimming, preheating, starting, lighting, and the like can be performed. Further, when the power supplied to the load suddenly changes and stress is applied to the circuit components, this can be avoided by changing the switching frequency.

According to a sixth aspect of the present invention, there is provided a control circuit capable of adjusting the on-periods of the first switching element and the second switching element, and adjusting the input current while keeping the switching frequency substantially constant. This has the advantage that the power supplied to the load can be adjusted. As a result, if the load is a discharge lamp, dimming, control of preheating, starting, lighting, and the like can be performed. Further, when the power supplied to the load suddenly changes and stress is applied to the circuit components, this can be avoided by changing the switching frequency.

According to a seventh aspect of the present invention, there is provided means for detecting a voltage between both ends of the first capacitor, and the control circuit controls the second circuit so as to suppress a rise in the voltage between both ends of the first capacitor based on the detected voltage. The first switching element and the second switching element are controlled, and when the voltage across the first capacitor rises abnormally, the operation of the switching element is stopped or the output to the load is reduced. In addition, there is an advantage that stress can be prevented from being applied to the circuit components. Further, if the increase in the voltage across the first capacitor is suppressed to be kept substantially constant, there is an advantage that the power supplied to the load is stabilized. As a result, even if the load is a discharge lamp, an optical output with less flicker can be obtained.

The invention according to claim 8 further comprises means for detecting a voltage corresponding to the voltage applied to the transformer, and the control circuit controls the first circuit so as to suppress an increase in the voltage applied to the transformer based on the detected voltage. Control the switching element and the second switching element, and when the voltage applied to the load abnormally rises or when the load is short-circuited, the operation of the switching element is stopped or the output to the load is stopped. Has the advantage that it is possible to prevent stress on the circuit components.

A ninth aspect of the present invention is characterized in that the control circuit includes means for detecting the voltage polarity of the AC power supply, and the control circuit controls the first switching element and the second switching element so that the input currents are substantially equal regardless of the voltage polarity of the AC power supply. Since it is possible to control the input current for each half cycle of the power supply, the input current waveform can be approximated to a sine wave, and the input current distortion can be further reduced. is there. Further, it is possible to reduce the output of the load as compared with the case where the switching element is controlled under a constant condition. If the load is a discharge lamp, deeper dimming (reducing the optical output) becomes possible. At the same time, dimming can be performed without changing the voltage between both ends of the first capacitor, so that abnormal stress can be prevented from being applied to the circuit components.

According to a tenth aspect of the present invention, there is provided a means for detecting a voltage between both ends of each rectifying element of one arm of the full-wave rectifier. Based on the detected voltage, the input current is independent of the voltage polarity of the AC power supply. The control circuit controls the first switching element and the second switching element so as to be substantially equal to each other, so that it is possible to improve the asymmetry of the input current for each power supply half cycle. The sine has the advantage of being able to approach him. As a result, the peak value of the input current can be suppressed, and it is possible to prevent an abnormal stress from being applied to the filter circuit when providing the filter circuit for blocking high frequency.

An eleventh aspect of the present invention comprises means for detecting a voltage between both ends of the second capacitor, and wherein the control circuit comprises:
The first switching element and the second switching element are controlled so as to keep the output to the load circuit substantially constant based on the voltage between both ends of the capacitor, and the output to the load can be kept substantially constant. Therefore, there is an advantage that stable operation of the load can be expected. In particular, when the load is a discharge lamp, an optical output with less flicker can be obtained.

According to a twelfth aspect of the present invention, there is provided a means for detecting a current flowing in a load circuit, wherein the first switching element and the second switching element maintain the current flowing in the load circuit substantially constant based on the detected current. Since the element controls the element and the supply current to the load can be made substantially constant even when the voltage of the AC power supply fluctuates, there is an advantage that stable operation of the load can be expected. In particular,
When the load is a discharge lamp, the fluctuation of the lamp current can be reduced to obtain an optical output with less flicker.

The thirteenth aspect of the present invention comprises means for varying the capacity of the second capacitor. The advantage is that the input current can be adjusted according to the load and the input current distortion can be reduced. There is. For example, even when the load is a discharge lamp and dimming or switching of the load output is performed, the input current distortion can be reduced. Claim 1
In the invention of the fourth aspect, the load circuit includes a plurality of loads, and has an advantage that the plurality of loads can be driven simultaneously.

According to a fifteenth aspect of the present invention, in parallel with one of the first switching element and the second switching element,
Alternatively, the second load circuit is connected in parallel with the first capacitor, and the output to the second load circuit can be made substantially constant without any special control, so that it is stable while simultaneously driving a plurality of loads. There is an advantage that a suitable drive is possible. In particular, when the load is a discharge lamp, an optical output with less flicker can be obtained. Further, even if one of the discharge lamps comes off, the other discharge lamp can be kept on.
Further, the power supplied to each load can be set to an appropriate ratio. Also, even if the voltage of the AC power supply fluctuates,
The load current as a whole can be almost constant,
By reducing the pulsating current of the lamp current, a light output with less flicker can be obtained.

According to a sixteenth aspect of the present invention, at least one of the first switching element and the second switching element is self-excited by feedback of a current flowing through a load circuit. Since it can be simplified or eliminated, there is an advantage that the number of parts can be further reduced. For example, if a transformer is provided in a load circuit and feedback is performed using an inductor provided on the secondary side of the transformer, the circuit automatically stops when an abnormality such as no load occurs. In addition, if the driving of one switching element is self-excited and the driving of the other switching element is separately controlled by an external signal, the power supplied to the load can be controlled. Control such as dimming and stopping can be easily performed.

[0139] According to a seventeenth aspect of the present invention, a series circuit of a pair of rectifiers is connected to the first capacitor separately from the rectifier, and a connection point of the rectifier in the series circuit is connected to one end of the AC power supply on the load circuit side. And a fourth capacitor is connected between the connection point of the AC power supply and the second capacitor and the load circuit. The voltage across the first capacitor is about the voltage of the AC power supply. There is an advantage that it is possible to cope with a case where the voltage of the power supply is high without using a circuit element having a high withstand voltage. As a result, in the configuration of claim 1 and the configuration of claim 17, the voltage of the AC power supply is 2 while using a common circuit board and components only by adding or deleting a small number of components.
It is possible to cope with the case where the difference is about twice. Even when the two are different in the voltage of the AC power supply, the voltages applied to the load circuits can be made substantially equal, so that substantially the same output can be obtained for AC power supplies of different voltages. Further, by modularizing the components, a circuit capable of supporting an AC power supply having different voltages can be constituted only by a combination of the modules.

According to the eighteenth aspect, among the arms of the full-wave rectifier, the rectifying elements of the arm to which the first switching element and the second switching element are not connected alternately at a frequency higher than the power supply frequency. Since the third switching element and the fourth switching element that are turned on and off are connected in parallel, there is an effect that surplus power can be regenerated to the power supply when the load suddenly decreases.

[Brief description of the drawings]

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

FIG. 2 is an operation explanatory view of the above.

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

FIG. 4 is an operation explanatory view of the above.

FIG. 5 is an operation explanatory view of the above.

FIG. 6 is an operation explanatory view of the above.

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

8 is an operation explanatory diagram of the circuit shown in FIG. 7;

9 is an operation explanatory diagram of the circuit shown in FIG. 7;

FIG. 10 is a circuit diagram showing a second embodiment of the present invention.

FIG. 11 is a circuit diagram showing a third embodiment of the present invention.

FIG. 12 is a circuit diagram showing a fourth embodiment of the present invention.

FIG. 13 is a circuit diagram showing another example of the circuit.

FIG. 14 is a circuit diagram showing a fifth embodiment of the present invention.

FIG. 15 is a circuit diagram showing Embodiment 6 of the present invention.

FIG. 16 is a circuit diagram showing a seventh embodiment of the present invention.

FIG. 17 is a circuit diagram showing Embodiment 8 of the present invention.

FIG. 18 is a circuit diagram showing a ninth embodiment of the present invention.

FIG. 19 is a diagram illustrating the operation of the above.

FIG. 20 is an explanatory diagram of the operation of the above.

FIG. 21 is an explanatory diagram of the above operation.

FIG. 22 is a circuit diagram showing a tenth embodiment of the present invention.

FIG. 23 is another operation explanatory view of the above embodiment.

FIG. 24 is an operation explanatory view showing the eleventh embodiment of the present invention.

FIG. 25 is an explanatory diagram of the operation of the above.

FIG. 26 is an explanatory diagram of the above operation.

FIG. 27 is a circuit diagram showing a twelfth embodiment of the present invention.

FIG. 28 is an explanatory diagram of the operation of the above.

FIG. 29 is a circuit diagram showing a thirteenth embodiment of the present invention.

FIG. 30 is an explanatory diagram of the operation of the above.

FIG. 31 is a circuit diagram showing a fourteenth embodiment of the present invention.

FIG. 32 is a circuit diagram showing another example of the above circuit.

FIG. 33 is a circuit diagram showing a fifteenth embodiment of the present invention.

FIG. 34 is a circuit diagram showing a sixteenth embodiment of the present invention.

FIG. 35 is an explanatory diagram of the operation of the above.

FIG. 36 is a circuit diagram showing a seventeenth embodiment of the present invention.

FIG. 37 is a circuit diagram showing an embodiment 18 of the invention.

FIG. 38 is a circuit diagram showing another example of the above circuit.

FIG. 39 is a circuit diagram showing another example of the circuit.

FIG. 40 is a circuit diagram showing a nineteenth embodiment of the present invention.

FIG. 41 is a circuit diagram showing another circuit example of the above.

FIG. 42 is a circuit diagram showing a twentieth embodiment of the present invention.

FIG. 43 is a circuit diagram showing various circuit examples according to a twenty-first embodiment of the present invention.

FIG. 44 is a circuit diagram showing a twenty-second embodiment of the present invention.

FIG. 45 is a circuit diagram showing a twenty-third embodiment of the present invention.

FIG. 46 is a circuit diagram showing Embodiment 24 of the present invention.

FIG. 47 is a circuit diagram showing another configuration example of the above.

FIG. 48 is a circuit diagram showing another example of the above circuit.

FIG. 49 is a circuit diagram showing a twenty-fifth embodiment of the present invention.

FIG. 50 is a circuit diagram showing another example of a load according to the present invention.

FIG. 51 is a circuit diagram showing a conventional example.

[Explanation of symbols]

1 the load circuit 3 control circuit Vs AC power D ₁ to D ₆ diodes _{Q 1 ~Q 4, Q 1 '} , Q 2' switching element C ₁ capacitor C ₃ capacitor

Claims (18)

[Claims] 1. A full-wave rectifier configured by bridge-connecting a rectifying element, a series circuit of an AC power supply and a load circuit connected between AC terminals of the full-wave rectifier, and a DC output terminal of the full-wave rectifier. And a first switching element and a second switching element, which are connected in parallel to the first capacitor for smoothing and the rectifying element of one arm of the full-wave rectifier and are alternately turned on and off at a frequency higher than the power supply frequency of the AC power supply. And a second switching element connected between a connection point between the AC power supply and the load circuit and at least one of the DC output terminals of the full-wave rectifier.
A power supply device comprising: 2. A load circuit comprising: a transformer;
2. A load connected to the secondary side, wherein both ends of a primary winding of the transformer are both ends of a load circuit.
The power supply as described. 3. The load circuit includes a first inductor and a first inductor.
And a third capacitor connected between the non-power supply side terminals of the discharge lamp and a first inductor to form a resonance circuit together with the first inductor, wherein the first inductor and the discharge lamp are connected in series. 2. The power supply device according to claim 1, wherein both ends of the circuit are both ends of the load circuit. 4. The power supply device according to claim 1, wherein the load circuit includes a second inductor connected between both ends. 5. The power supply device according to claim 2, further comprising a control circuit capable of adjusting an on / off switching frequency of the first switching element and the second switching element. 6. The power supply device according to claim 2, further comprising a control circuit capable of adjusting an ON period of the first switching element and the second switching element. 7. A control circuit, comprising: means for detecting a voltage across the first capacitor, wherein the control circuit controls the first switching element and the first switching element so as to suppress a rise in the voltage across the first capacitor based on the detected voltage. 7. The power supply according to claim 5, wherein the second switching element is controlled. 8. A control device comprising: means for detecting a voltage corresponding to the voltage applied to the transformer, wherein the control circuit controls the first switching element and the second switching element to suppress an increase in the voltage applied to the transformer based on the detected voltage. The power supply device according to claim 2, wherein the power supply device controls two switching elements. 9. A control circuit for controlling a first switching element and a second switching element so that an input current is substantially equal irrespective of a voltage polarity of the AC power supply. 7. The power supply device according to claim 5, wherein 10. A means for detecting the voltage between both ends of each rectifying element of one arm of a full-wave rectifier, based on the detected voltage, so that the input currents become substantially equal regardless of the voltage polarity of the AC power supply. 7. The power supply device according to claim 5, wherein the control circuit controls a first switching element and a second switching element. 11. A control circuit for detecting a voltage between both ends of a second capacitor, wherein the control circuit performs the first switching so as to keep the output to the load circuit substantially constant based on the voltage between both ends of the second capacitor. The power supply device according to claim 5, wherein the power supply device controls the element and the second switching element. And means for detecting a current flowing in the load circuit, and controlling the first switching element and the second switching element so as to keep the current flowing in the load circuit substantially constant based on the detected current. The power supply device according to claim 5 or 6, wherein 13. The power supply device according to claim 2, further comprising means for changing a capacity of the second capacitor. 14. The power supply device according to claim 2, wherein the load circuit includes a plurality of loads. 15. A second load circuit is connected in parallel with any one of the first switching element and the second switching element or in parallel with the first capacitor. 4. The power supply device according to 4. 16. The power supply according to claim 2, wherein at least one of the first switching element and the second switching element is self-excited by feedback of a current flowing through a load circuit. apparatus. 17. A series circuit of a pair of rectifiers is connected to the first capacitor separately from the rectifier, and a connection point of the rectifier in the series circuit is connected to one end of the AC power supply on a load circuit side, 5. The power supply device according to claim 2, wherein a fourth capacitor is connected between a connection point between the power supply and the second capacitor and the load circuit. 18. A third circuit which turns on and off alternately at a frequency higher than the power supply frequency to each of the rectifying elements of the arm to which the first switching element and the second switching element are not connected among the arms of the full-wave rectifier. 5. The power supply device according to claim 2, wherein the switching element and the fourth switching element are connected in parallel.