JPH10271831A - Power supply unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress input harmonic distortion with a simple circuit configuration, and current passing through a switching element, and conduct stable starting and lighting of a lamp. SOLUTION: An input part is constituted so as to obtain a voltage doubler with diodes D1 , D2 for attainment of stability of a lamp. By turning on and off two switching elements Q1 , Q2 , high-frequency input current is passed to improve input harmonic distortion. A charging circuit including at least one inductor L1 is provided as a circuit for passing current except a load circuit if input current is larger than the load current to distribute the input current into two inductors L1 , L2 , thus it is possible to prevent switching current from increasing.

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 having less input current harmonics from a commercial AC power supply.

[0002]

2. Description of the Related Art Conventionally, there are many discharge lamp lighting devices which supply commercial power and input high frequency power using a discharge lamp as a load. FIG. 16 shows a circuit diagram of a conventional example.
38161). This circuit is an inverter device provided with a circuit to improve the input power factor by energizing the input current from the AC power source through the inverter load and the switching elements, the operation occurs in the capacitor C ₂ and the inductor L ₁ the voltage, input AC voltage Vin is in the vicinity of 0V, is that the input current Iin flows when the switching element Q ₂ is turned on. Capacitors C ₁ and C
₅ and the load La and the voltage generated in the inverter load consisting of the inductor L _2, the capacitor C ₂ and the inductor L ₁
Approximately equal to the voltage obtained by subtracting the voltage generated from the voltage of the smoothing capacitor C ₃ to the input voltage Vin becomes higher than that from the rectifier DB, capacitor C _1, the load La and the capacitor C _5, the inductor L _2, switching element Q
₂ , the current Id flows on the path returning to the rectifier DB.
When the input voltage Vin is near the peak, a current flows from the rectifier DB to a path returning to the rectifier DB via the diode D ₂ and the capacitor C ₃ in addition to the path described above, and the capacitor C ₃ is charged by the current. Is what is done.

However, in the case where the power supply voltage is 100 V and the rated tube voltage of the discharge lamp of the load is 70 to 80 V, the starting voltage and the stability of the lamp are reduced in the above-described conventional example because the degree of freedom of design is small. to obtain, as shown in FIG. 17, there is a case of using a step-up transformer T _1.

Further, as shown in FIG.
Lighting devices have also been proposed. This circuit is switched
Element Q₁, Q_TwoSwitching at high frequency
The current input from the AC power supply Vs₁To
Once charged, capacitor C ₁More capacitor C_ThreeFill in
The operation of charging is repeated at a high frequency. Polarity of AC power supply Vs
Is reversed, the input current is_TwoOnce charged
After the capacitor C_TwoFrom capacitor C_FourCharge
You. In this way, the voltage is doubled and the input current
By drawing in the lamp stability and input harmonics
The distortion can be improved with a simple circuit configuration.

FIG. 1 shows a circuit configuration of a voltage doubler configuration.
A circuit as shown in FIG.
No. 5885). In this circuit configuration, the AC power supply Vs
Filter circuit FT, diode D₁, D_Two, Conden
Sa C_Three, C_FourVoltage rectification. switch
Element Q₁, Q_TwoInput current is
Capacitor C₁(Or C_Two), Discharge lamp La, conden
Sa C_Five, Inductor L _TwoHigh frequency input via
Therefore, the input harmonic distortion is improved.

[0006]

In the conventional example of FIG. 16 [0008], in order to obtain the stability of the lamp, as shown in FIG. 17, since the step-up in the transformer T _1, a lamp current and lamp La turns ratio times the current of the combined current of the capacitor C _5, which is connected in parallel to flow to the primary side of the transformer T _1, there is a problem that the switching current increases. Further, in the conventional example shown in FIG. 18, since the current flowing through the lamp load, the combined current of the input current through the capacitor C ₁ or C ₂ flows through the inductor L _2, a problem that the switching current increases was there. Also,
In the conventional example shown in FIG. 19, the input current flows through the load, so that the lamp power is large. Also, with a load having a relatively small lamp current, a sufficient input current can be obtained. However, since the current of the capacitor input flows, there is a problem that the input harmonic distortion cannot be improved.

The present invention has been made to solve such a problem. The input section has a doubled voltage configuration to obtain lamp stability and to turn on and off two switching elements to provide a high-frequency input. By passing current,
The input harmonic distortion can be improved, and the drawn input current is drawn through a path different from the switching element to reduce the current flowing through the switching element. Further, the input current is caused to flow also in a path other than the lamp, so that the input harmonic distortion is improved without being affected by any lamp current and lamp power.

[0008]

According to the power supply device of the present invention,
In order to solve the above-mentioned problems, as shown in FIG.
First and second serially connected voltage doubler rectifiers.
Iod D₁, D_TwoAnd the first and second
2 diode D₁, D_TwoAt each end of the series circuit
Third and fourth diodes D_Three, D_FourConnected via
Smoothing capacitor C_Three, C_FourSeries circuit
First and second diodes D for voltage rectification₁, D_TwoSeries
Circuit and smoothing capacitor C_Three, C_FourEach midpoint of the series circuit
Between the AC power supply Vs connected between the
First and second diodes D₁, D_TwoAnd the above third and fourth
Diode D_Three, D_FourWith one end connected to the connection point
Pair impedance element C₁, C_TwoSeries circuit and the above
Smoothing capacitor C_Three, C_FourConnected to both ends of the series circuit
The first and second switches alternately turn on and off at high frequency.
Switching element Q₁, Q_TwoSeries circuit and the above switch
Element Q₁, Q_TwoOf the series circuit and the smoothing capacitor
C _Three, C_FourConnected to the midpoint of the series circuit
At least one capacitor C _FiveAnd inductor L_TwoComposed of
A load circuit including a resonant circuit to be connected;
Dacta L₁And a series circuit with
The pair of impedance elements C₁, C_TwoSeries
At the midpoint of the circuit, the connection point between the load circuit and the charging circuit
Connected to the AC power supply Vs.
Frequency input current to the first and second switching elements
Q₁, Q_TwoSo that the current flowing through the load
Distribution to the circuit and charging circuit, while reducing input harmonic distortion
Is performed.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION

(Embodiment 1) A circuit diagram of Embodiment 1 of the present invention is shown in FIG.
This circuit includes a low-frequency AC power supply Vs (about 50 Hz),
Diode D ₁ to D _4, capacitors C _3, C ₄ and voltage doubler rectifier circuit consisting of diodes D _1, D ₃ of the connection point and the diode D _2, D capacitor C ₁ connected between the connection point ₄ , C ₂ , a switching element Q ₁ , Q ₂ which is alternately switched on and off at a high frequency (about 50 kHz), and capacitors C ₁ , C ₂
The connection point between the capacitor C _3, an inductor L ₁ connected between the connection point of the C _4, capacitors C _1, C _2, a connection point of the inductor L ₁ and the connection point of the switching elements Q _1, Q ₂ inductor L ₂ is connected between, and is composed of a load circuit comprising a parallel circuit of the discharge lamp La and the capacitor C _5.

Next, the operation of this circuit will be described with reference to FIGS.
explain. First, the diode D of the AC power supply Vs₁, D_Three
The figure shows the operation near the peak when the AC power supply Vs has a positive polarity
2 will be described. In the figure, Q₁Is the switching element Q₁
The on / off state of_C1Is the capacitor C₁
Current flowing through_C3Is the capacitor C_ThreeCurrent flowing through
_L1Is the inductor L₁Current flowing through_C4Is the capacitor C
_FourCurrent flowing through_L2Is the inductor L_TwoCurrent flowing through
I_D1Is the diode D₁Shows the current flowing through the circuit. Sui
Switching element Q₁Is turned on, the inductor L₁,
L_TwoHas a regenerative current flowing through it and the capacitor C₁To
Inductor L₁Current I flowing through_L1And the inductor L_TwoTo
Flowing current I_L2Flows. This allows the
Densa C ₁Voltage V_C1Goes down. Also this
In the mode, the inductor L₁, L _TwoEnergy stored in
Is the regenerative current and the electrolytic capacitor C for smoothing_Three,
C _FourCharge. That is, the inductor L₁From conde
Sensor C₁, Diode D_Three, Capacitor C_ThreeThrough
Dacta L₁And the inductor L_TwoFrom Conden
Sa C₁, Diode D_Three, Capacitor C_Three, C_Four, Sui
Switching element Q₁Reverse diode, discharge lamp La and
Capacitor C_FiveThrough the inductor L_TwoTurn back to the path
Raw current flows. This is the mode of FIG.

Next, when the voltage V _C1 of the capacitor C ₁ decreases and the potential at the connection point between the diodes D ₁ and D ₃ becomes the same as the AC power supply Vs, an input current flows from the AC power supply Vs. In this mode, the input current flowing through the capacitor C _1, the current flowing through the inductor L ₁ I _L1
A current I _L2 divided into two parts flowing to inductor L _2. That is, a path from the AC power supply Vs to the AC power supply Vs via the diode D ₁ , the capacitor C ₁ , and the inductor L ₁ , and a path from the AC power supply Vs to the diode D ₁ and the capacitor C _1
1 , inductor L ₂ , discharge lamp La and capacitor C ₅ ,
An input current flows through a path returning to the AC power supply Vs via the switching element Q ₁ and the capacitor C ₄ . This is the mode of FIG.

[0012] Next, when the switching element Q ₁ is off, the switching element Q ₂ is turned ON, it load current in the switching element Q ₁ until flow through the reverse diode of the switching element Q _2, smooth to charge the capacitor C ₃ of use. That is, from the AC power supply Vs,
A path returning to the AC power supply Vs via the diode D ₁ , the capacitor C ₁ , and the inductor L ₁ , and a path from the AC power supply Vs to the diode D ₁ , the capacitor C ₁ , the inductor L ₂ , the discharge lamp La and the capacitor C ₅ , and the switching element Q AC power supply Vs via reverse diode ₂ and capacitor C ₃
Input current flows in the path returning to. This is the mode of FIG.

Next, a current flows in the inductors L ₁ and L ₂ in the opposite direction. In this case as well, the current I _L1 flowing through the inductor L ₁ and the current I _L2 flowing through the inductor L ₂ flow through the capacitor C ₁ . Synthetic current flows. That is, the capacitor C _1, diode D _3, capacitor C _3, together with the current flows through the inductor L ₁ in a path back to the capacitor C _1, the capacitor C _1, diode D _3, the switching element Q _2, the discharge lamp La and current flows through a path back to the capacitor C ₁ through the capacitor C _5, the inductor L _2. This is the mode of FIG. The above four modes are repeated by the high frequency switching operation of the switching elements Q ₁ and Q ₂ .

Next, diodes D ₁ and D ₁ of the AC power supply Vs
_{When the third} side has a negative polarity, it operates as shown in FIG.
In the figure, Q ₁ indicates the on / off state of the switching element Q ₁ , I _C2 indicates the current flowing through the capacitor C ₂ , I _C3
Is the current flowing through the capacitor C ₃ , I _L1 is the inductor L ₁
I _C4 is the current flowing through the capacitor C ₄ , I _C4
L2 is the current flowing through the inductor L _2, I _D2 diode D
_The current flowing through ₂ is shown. When the switching element Q ₁ is turned on is, the inductor L _1, L _2, and a regenerative current flows, the capacitor C ₂ and the current I _L1 flowing to inductor L _1, the synthesis of the current I _L2 flowing to inductor L ₂ Electric current flows. That is, from the AC power source Vs, an inductor L _1, a capacitor C _2, and path back to the AC power source Vs via the diode D _2, from the AC power source Vs, a capacitor C _4, reverse diode of the switching element Q _1, the discharge lamp La and capacitor C _5, the inductor L _2, a capacitor C _2, the input current flows through a path back to the AC power source Vs via the diode D _2. This is the mode of FIG.

[0015] Next, the inductor L _1, L _2, current flows in the reverse direction, even in this case, the capacitor C ₂ of the current I _L2 flowing in the current I _L1 and the inductor L ₂ flowing through the inductor L ₁ Synthetic current flows. That is, the inductor L ₁ from the capacitor C _2, the capacitor C _4, diode D ₄ with a current flows through a path back to the capacitor C ₂ through inductor L ₂ from the capacitor C _2, the discharge lamp L
a and capacitor C _5, the switching element Q _1, a current flows through a path back to the capacitor C ₂ through the diode D _4. This is the mode of FIG.

Next, when the switching element Q ₁ is off, the switching element Q ₂ is turned ON, the load current in the switching element Q ₁ is flowing through the reverse diode of the switching element Q ₂ before. In this mode, the energy stored in the inductors L ₁ and L ₂ becomes a regenerative current and charges the smoothing capacitors C ₃ and C ₄ . That is, the inductor L _1, a capacitor C _4,
Inductor L via diode D ₄ and capacitor C ₂
A path back to _1, the inductor L _2, the discharge lamp La and capacitor C _5, reverse diode of the switching element Q _2, a capacitor C _3, the capacitor C _4, the diode D
_4, current flows through the path back to the inductor L ₂ via the capacitor C _2. This is the mode of FIG.

Next, the capacitor C_TwoVoltage VC_C2Decreases
Go and diode D_Two, D_FourAC potential at connection point
When the potential becomes the same as the power supply Vs, the input current from the AC power supply Vs
Flows. In this mode, the capacitor C_TwoThrough
Input current flows through the inductor L₁Current I flowing through
_L1And inductor L_TwoCurrent I flowing through_L2Shunted. You
That is, from the AC power supply Vs, the inductor L₁, Conden
Sa C_Two, Diode D _TwoTo return to AC power supply Vs via
From the path and the AC power supply Vs, the capacitor C_Three, Switchon
Element Q_Two, Discharge lamp La and condenser C_Five, Indac
L_Two, Capacitor C_Two, Diode D_TwoExchange through
An input current flows in a path returning to the power supply Vs. This is
Mode. The above four modes are switching elements
Child Q₁, Q_TwoHigh frequency switching operation
returned.

As described above, in this circuit, the impedance is
Capacitor C₁, C _TwoIs the inductor L₁
Current I flowing through_L1And inductor L_TwoCurrent I flowing through_L2of
Charge and discharge are repeated at high frequency by the combined current,
To draw a current at a high frequency that is almost proportional to the value of Vs,
Input harmonic distortion is improved. In addition, with the voltage doubler rectifier circuit
The lamp can be started and turned on stably.
You.

The input current becomes maximum near the peak of the AC power supply Vs. However, in a circuit like the conventional example shown in FIG. 18, the current flowing through the switching element is usually a combined current of the load current and the charging current. whereas leads to an increase of the switching current, in the circuit, when the input current is such that greater than the load current, due to the provision of the inductor L ₁ as a circuit through a current in addition to the load circuit, the input current inductor current flowing in L ₁ I _L1 and the inductor L
Is diverted to a current I _L2 flowing to _2, the switching current is a current flow of substantial current flowing in the load circuit, it can avoid an increase in switching current.

In order to split the input current from the AC power supply Vs into the current I _L1 flowing through the inductor L ₁ and the current I _L2 flowing through the inductor L ₂ , the inductors L ₁ and L ₂ , the capacitors C ₁ , C ₂ , the resonance system constituted by C ₅ and the load may be set such that the relationship shown in FIG.
In the figure, I _C1 indicates a current flowing through the capacitor C ₁ , I _L1 indicates a current flowing through the inductor L ₁ , and I _L2 indicates a current flowing through the inductor L ₂ . In the circuits that operate as shown in FIGS. 2 and 3, if the input current is small, the smoothing electrolytic capacitors C ₃ and C ₄ cannot be sufficiently charged, and become a capacitor input, thereby deteriorating the input harmonic distortion. Therefore, since the input current flows through the capacitor C ₁ (or C ₂₎ it is necessary to set a sufficient amount, is by increasing the switching current of a problem such as heat generation, current I _L2 through the switching element Is the input current I flowing through the capacitor C _1.
The inductors L ₁ and L ₂ ,
It is necessary to set a resonance system including the capacitors C ₁ , C ₂ , C ₅ and the load. The resonance characteristics shown in FIG. 4, it is necessary to operate at a large frequency (frequency that is the I _C1> I _L2) than the frequency f _1, for example, above the operating at an operating frequency f ₂ shown in FIG. 4 Such effects can be obtained. That is, at the operating frequency f _2, the current I _L2 through the switching element, so that smaller than the input current I _C1 flowing through the capacitor C _1, may be set inductor L ₁ and the other constants.

The same effect can be obtained with the circuit as shown in FIG. 5, and in the case of performing multi-lamp lighting, for example, two-lamp lighting, the same effect can be obtained by using the circuit as shown in FIG. Needless to say,

(Embodiment 2) FIG. 7 shows a circuit diagram of Embodiment 2 of the present invention. This embodiment is obtained by adding a control circuit S for performing light control to the circuit of FIG. The circuit shown in Figure 7, by alternately conduct the switching element Q _1, Q ₂ at a high frequency, but the lamp La is intended to be high frequency lighting, the operating frequency of the switching elements Q _1, Q _2, duty, or Dimming can be performed by changing both.

First, in the control circuit S shown in FIG. 7, when the operating frequency of the switching elements Q ₁ and Q ₂ is changed, the resonance characteristics of the circuit of FIG. 7 are set as shown in FIG. When going to higher operating frequency, the current flowing through the current (inductor L ₂ through the switching element I
_L2 ) decreases, the load current decreases, and dimming can be performed. However, in order to always reduce the switching current even when dimming, the current I _L2 through the switching element, is necessary to change the operating frequency within the range smaller than the input current I _C1 flowing through the capacitor C ₁ is there. The variable operating frequency within the range of the rate of change with respect to the frequency of the current I _L2 through the change rate and switching elements with respect to the frequency of the input current I _C1 flowing through the capacitor C ₁ as shown in FIG. 8 is substantially equal If this is done, the input power Win also decreases in accordance with the decrease in the lamp power Wla, so that the relationship of Win = Wout is established within the dimming operation frequency range, and the voltage across the smoothing electrolytic capacitors C ₃ and C ₄ rises. Can be avoided.

In the control circuit S shown in FIG. 7, dimming can be performed even when the duty of the switching elements Q ₁ and Q ₂ is changed. As a way to change the duty,
There is a case where the dead time is provided as shown in FIG. 9B and a case where the dead time is complementary as shown in FIG. 9A. In each case, the load current varies with the change in duty as shown in FIG.
It changes as shown in (a) and (b).

In this case as well, the duty is within the variable range.
7 so that the relationship Win = Wout holds.
By setting the resonance constant of the circuit of
Sa C _Three, C_FourCan be prevented from rising. Also,
Capacitor C_Three, C_FourResonance to avoid voltage rise
And the current I through the switching element_L2Is a capacitor
C₁Current I flowing through_C1Resonance smaller than
If the constants do not match, the duty and operating frequency
If both of the numbers are variable, the capacitor C_Three, C _FourBoth ends of
Voltage rise can be avoided. According to the present embodiment, when the light is
Switching current can be reduced
And the capacitor C_Three, C_FourTo avoid the voltage rise
Wear.

(Embodiment 3) A circuit diagram of Embodiment 3 of the present invention is shown in FIG.
As shown in FIG. In this embodiment, the capacitor of the circuit of FIG.
Sa C₁, C_TwoConnection point and inductor L₁, L_TwoConnection point
Between the capacitors C₆And inductor L_ThreeOf the parallel circuit
It is connected. In the circuit of Figure 1, the lamp is in an Emiless state
In the case of a lamp that is in a state of
Capacitor C _FiveThe input power is
Capacitor C_Three, C_FourVoltage rises
You. Therefore, in the circuit of FIG. 11, the lamp is in the Emiless state.
In the case of such a lamp, the capacitor C_Three, C_FourOf both ends
The operating frequency is detected by the capacitor
C₆And inductor L_ThreeNear the resonance frequency of the parallel circuit
Then, the capacitor C₆And inductor L_ThreeParallel circuit
Increases the input current and decreases the input current.
Capacitor C_Three, C_FourCan be prevented from rising.

(Embodiment 4) FIG. 12 shows a circuit diagram of Embodiment 4 of the present invention. In this embodiment, during the connection point connection point between the inductor L _1, L ₂ of the capacitor C _1, C ₂ of the circuit of FIG. 1, the switching element Q ₃ is connected. FIG.
In the circuit of the case lamps, such as lamps Emiresu state, the output power is little, input power because the charging current flows through the capacitor C ₅ is ensured, the voltage across the capacitor C _3, C ₄ To rise. Therefore, in the circuit of Figure 12 is normally leave ON the switching element Q _3,
If the light is such as lamps Emiresu state, detects that the voltage across the capacitor C _3, C ₄ rises, whereupon OFF the switching element Q _3, since the input current does not flow, the capacitor C _3, C ₄ Can be prevented from rising.

Embodiment 5 FIG. 13 shows a circuit diagram of Embodiment 5 of the present invention. In this embodiment, the switching element Q ₃ is connected in parallel across the inductor L ₁ of the circuit of Figure 1. In the circuit of Figure 1, if the lamp is like lamps Emiresu state, the output power is little, input power because the charging current flows through the capacitor C ₅ is secured, at both ends of the capacitor C _3, C ₄ The voltage rises. Therefore, in the circuit of FIG. 13, normally, the switching element Q ₃
Is turned off, and when the lamp is like a lamp in an Emiless state, it is detected that the voltage between both ends of the capacitors C ₃ and C ₄ has risen, and the switching element Q ₃ is turned on.
Since the amplitude of Va is the potential of the connection point inductor L _1, L ₂ is eliminated, the capacitor C _1, C ₂ is not charged or discharged, the input current does not flow, the capacitor C _3,
It can be avoided an increase in the voltage across C _4.

(Embodiment 6) FIG. 14 shows a circuit diagram of Embodiment 6 of the present invention. In this embodiment, the capacitor C of the circuit of FIG.
₃ is replaced by a series circuit of electrolytic capacitors C ₃₁ and C ₃₂ having a double capacitance value, the capacitor C ₄ is replaced by a series circuit of electrolytic capacitors C ₄₁ and C ₄₂ having a double capacitance value, and capacitors C ₃₁ and C ₃₂ are replaced. And a diode D ₅ between the connection point of the inductors L ₁ and L ₂ , and the connection point of the inductors L ₁ and L ₂ between the connection point of the capacitors C ₄₁ and C _{42 and} the connection point of the inductors L ₁ and L _2.
6 is added.

The basic operation of this circuit is the same as that of the first embodiment, except that the potential Va at the connection point between the inductors L ₁ and L ₂ is Va.
Are connected to the potential Vb at the connection point between the capacitors C ₃₁ and C ₃₂ and the capacitors C ₄₁ and C ₄₁ by the clamp diodes D ₅ and D ₆ .
_It is clamped to the potential Vc at the connection point ₄₂ and swings between Vb and Vc at a high frequency.

The load circuit consists of a series circuit of the parallel circuit and the inductor L ₂ and capacitor C ₅ load, connected between the switching element Q _1, the connection point Q ₂ 'and the inductor L _1, L ₂ of the connection points Then, the difference between the potential Va at the connection point of the inductors L ₁ and L ₂ and the potential at the connection point of the switching elements Q ₁ and Q ₂ is applied. Since the potential Va at the connection point between the inductors L ₁ and L ₂ is clamped by the clamp diodes D ₅ and D ₆ , the voltage applied to the load circuit is also clamped and the output waveform is clamped.

[0032] In operation of the embodiment 1, the AC power source Vs is near the peak is to flow the input current through the capacitor C ₁ or C _2, operates in resonant current capacitor C ₁ or C ₂ is affected, the AC power source When Vs is near ground,
Since the input current hardly flows and run with resonance current capacitor C ₁ or C ₂ is not affected, the output current has a low frequency ripple.

However, in this embodiment, since the output waveform is clamped, the low frequency ripple of the output current is reduced. Therefore, by using the clamp diodes D ₅ and D ₆ shown in FIG. 14 with the resonance constant described in the first embodiment, it is possible to reduce the low-frequency ripple of the output current while reducing the switching current.

(Embodiment 7) The circuit diagram of Embodiment 7 of the present invention is the same as that of FIG. The basic operation is the same as that of the first embodiment. However, in the operation with the resonance constant described in the first embodiment, when the AC power supply Vs is near the peak, the capacitor C ₁ or C ₂
Since the input current flows through the, it operates in resonant current capacitor C ₁ or C ₂ is affected, the AC power source Vs is near ground, since the input current hardly flows, resonance capacitor C ₁ or C ₂ is not affected Because it operates with current, the output current has low frequency ripple. As described above, when the AC power supply Vs is near the peak, the capacitor C ₁
Or operates in inclusive resonance system and C _2, the AC power source Vs is in near ground, operates at a resonant system that does not include a capacitor C ₁ or C _2.

FIG. 15 shows a frequency characteristic diagram of the seventh embodiment of the present invention.
Shown in In FIG. 15, the capacitor C ₁Or C_TwoIncluding
The current value of the resonance system A and the capacitor C₁Or C_TwoContains
The frequency at which the current value of the resonant system B matches the operating frequency
Thus, the resonance constant is set. in this way,
The frequency at which the current values of the two resonance systems match is called the operating frequency
And to reduce the switching current,
Current I through switching element_L2Is the capacitor C₁
Current I flowing through_C1Smaller than
By setting the oscillation constant, the switching current can be reduced.
Therefore, the low frequency ripple of the output current can be reduced.

[0036]

According to the first aspect of the present invention, there is an effect that input harmonic distortion can be reduced with a simple circuit configuration, and since the voltage doubler configuration is used, stable starting of the lamp can be achieved.
There is an effect that lighting can be performed. In addition, since a charging circuit including at least one inductor is provided as a circuit that passes the current in addition to the load circuit when the input current becomes larger than the load current, the input current is divided into two inductors. As the switching current, a current corresponding to the current flowing in the load circuit flows, and an increase in the switching current can be avoided.

According to the second or third aspect of the present invention, the switching current can be reduced even in the case of dimming, and the rise of the voltage across the smoothing capacitor can be avoided. According to the fourth, fifth or sixth aspect of the invention, even when the lamp is a lamp in an Emiless state, it is possible to avoid an increase in the voltage across the smoothing capacitor. Claim 7 or 8
According to the invention, while reducing the switching current,
The low frequency ripple included in the output current can be reduced.

[Brief description of the drawings]

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

FIG. 2 is an operation waveform diagram when the AC power supply according to the first embodiment of the present invention has a positive polarity.

FIG. 3 is an operation waveform diagram when the AC power supply according to the first embodiment of the present invention has a negative polarity.

FIG. 4 is a diagram illustrating a frequency characteristic of a current flowing through the circuit according to the first embodiment of the present invention.

FIG. 5 is a circuit diagram showing a modification of the first embodiment of the present invention.

FIG. 6 is a circuit diagram showing an application example of the first embodiment of the present invention to a two-lamp parallel lighting system.

FIG. 7 is a circuit diagram according to a second embodiment of the present invention.

FIG. 8 is a diagram illustrating frequency characteristics of a current flowing through a circuit according to the second embodiment of the present invention.

FIG. 9 is a waveform chart showing how to change the duty according to the second embodiment of the present invention.

FIG. 10 is a characteristic diagram illustrating a change in load current with respect to a change in duty according to the second embodiment of the present invention.

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

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

FIG. 13 is a circuit diagram of a fifth embodiment of the present invention.

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

FIG. 15 is a frequency characteristic diagram according to the seventh embodiment of the present invention.

FIG. 16 is a circuit diagram of a first conventional example.

FIG. 17 is a circuit diagram of a second conventional example.

FIG. 18 is a circuit diagram of a third conventional example.

FIG. 19 is a circuit diagram of a fourth conventional example.

[Explanation of symbols]

Vs AC power source La discharge lamp Q _1, Q ₂ switching elements L _1, L ₂ inductor C _1, C ₂ capacitors C _3, C ₄ smoothing capacitor D _1, D ₂ voltage doubler rectifying diode D _3, D ₄ diodes

Continued on the front page (51) Int.Cl. ⁶ Identification code FI H05B 41/24 H05B 41/24 L 41/29 41/29 C

Claims (9)

[Claims] 1. A first voltage doubler rectifier connected in series.
And a second diode; and a series circuit of a smoothing capacitor connected to both ends of the series circuit of the first and second diodes for voltage doubling via third and fourth diodes, respectively. An AC power source connected between each middle point of the series circuit of the first and second diodes for voltage rectification and the series circuit of the smoothing capacitor; the first and second diodes for voltage doubling rectification; A series circuit of a pair of impedance elements having one end connected to a connection point of the third and fourth diodes; and a first and second series connected to both ends of the series circuit of the smoothing capacitor and alternately turned on and off at a high frequency. At least one capacitor and an inductor connected between a middle point of the series circuit of the switching elements and a middle point of the series circuit of the smoothing capacitor. A charging circuit including at least one inductor; and a charging circuit including at least one inductor. A high-frequency input current from the AC power source is distributed to the load circuit and the charging circuit so that the current flowing through the first and second switching elements is reduced. And a control device for controlling the input harmonic distortion to be reduced. 2. The power supply device according to claim 1, wherein the charging circuit is set such that a current flowing through the impedance element is larger than a current flowing through a load circuit. 3. The power supply according to claim 1, wherein the resonance circuit is set such that a change amount of the current flowing through the impedance element with respect to the frequency is equal to a change amount of the current flowing through the load circuit with respect to the frequency. apparatus. 4. A parallel circuit of a capacitor and an inductor is connected between a midpoint of the series circuit of the pair of impedance elements and a connection point between the load circuit and the charging circuit. Power supply. 5. The power supply device according to claim 1, wherein a switching element is connected between a middle point of the series circuit of the pair of impedance elements and a connection point between the load circuit and the charging circuit. 6. A switching element is connected between a middle point of the series circuit of the pair of smoothing capacitors and a connection point between the load circuit and the charging circuit.
The power supply as described. 7. A pair of clamp diodes comprising a diode connected to the anode side and a diode connected to the cathode side are connected to a middle point of the series circuit of the pair of impedance elements and a connection point of the load circuit. The power supply device according to claim 1, wherein 8. The power supply according to claim 1, wherein the output of the first resonance system including the impedance element and the output of the second resonance system not including the impedance element are controlled to be equal to each other. apparatus. 9. The power supply device according to claim 1, wherein a discharge lamp is used as a load.