JP2015139275A - Load drive device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce output ripples despite a one-converter circuit configuration.SOLUTION: A load drive device 1 includes: a rectification circuit BD1 for full-wave-rectifying an AC voltage to output a rectified voltage; a power factor improvement circuit 2 comprising a first rectifying element D1, a switching element Q1 and a first reactor L1 connected in series and comprising a second rectifying element D2, a third rectifying element D3 and a first smoothing capacitor C1 connected in series between both ends of the first reactor L1, to improve a power factor of the rectified voltage; a DC/DC converter 3 sharing a first series circuit comprising the switching element Q1, the first smoothing capacitor C1, and the third rectifying element D3 with the power factor improvement circuit 2, comprising a fourth rectifying element D4 connected in parallel therewith, and comprising a second reactor L2 and a second smoothing capacitor C2 connected in series, to apply a DC voltage to a load 10 connected in parallel with the second smoothing capacitor C2; and a drive control circuit 4 for controlling on/off the switching element Q1 to synchronize a buck/boost operation by the power factor improvement circuit 2 and a buck operation by the DC/DC converter 3.

Description

  The present invention relates to a high power factor load driving device for rectifying an AC voltage supplied from a commercial AC power source and supplying DC power to a load.

  It is strongly desired that a load driving device using a commercial AC power supply comply with harmonic current regulation. In order to solve the above-mentioned problem, a configuration in which a step-up chopper circuit having a power factor correction function is added to a step-down chopper circuit that outputs an arbitrary voltage to a load, that is, a two-converter power supply circuit is known. Yes. For example, paragraph 0018 of Patent Document 1 states that “the power factor correction circuit 3 includes a choke coil L1, a diode D1, a capacitor C1, a transistor Q1, and a current detection unit 7 connected in series, and a capacitor C1. Is supplied to the load DC / DC converter 5 as an output voltage Vpfc. However, since the circuit configuration disclosed in Patent Document 1 includes two chopper circuits, there is a problem that the number of parts increases and the apparatus itself increases in size.

  On the other hand, there is known a one-converter circuit configuration that can obtain an arbitrary output voltage while having a power factor improving function and can be miniaturized. For example, FIG. 6 of Patent Document 2 shows a one converter system without an input electrolytic capacitor as a conventional high power factor type switching power supply device.

JP 2010-115088 A JP 2002-300780 A

  However, in a load drive device equipped with a one-converter circuit, the input current waveform is sinusoidal by controlling the inductor current with a switch element so that it is proportional to the voltage waveform that is full-wave rectified by a rectifier circuit (diode bridge). Harmonics are suppressed by approximating the wave shape. Therefore, a voltage capacitor cannot be smoothed by arranging a large-capacity smoothing capacitor after the rectifier circuit. Therefore, there has been a problem that ripples in the AC frequency band appear in the converter output.

  Moreover, the load drive device provided with the circuit of 2 converter systems has the advantage that the ripple of an alternating frequency band does not appear in an output. However, since a control circuit is required for each, the number of components increases, and there is a problem that manufacturing costs such as component costs and assembly costs increase.

  Therefore, an object of the present invention is to provide a load driving device with a reduced output ripple while having a one-converter circuit configuration.

In order to solve the above-described problem, in the load driving device of the present invention, a rectifier circuit that outputs a rectified voltage obtained by full-wave rectification of an AC voltage, and a first rectifier element and a switch between a positive electrode and a negative electrode of the rectifier circuit. The element and the first reactor are connected in series, the second rectifier element, the third rectifier element, and the first smoothing capacitor are connected in series at both ends of the first reactor, and the force of the rectified voltage input from the rectifier circuit A power factor correction circuit for improving a power factor and a first series circuit composed of the switch element, the first smoothing capacitor, and the third rectifier element, and a fourth rectifier element is connected in parallel to the first series circuit. A DC / DC converter in which a second reactor and a second smoothing capacitor are connected in series at both ends of the third rectifying element, and a DC voltage is applied to a load connected in parallel to the second smoothing capacitor; And it controls the on-off switch element, and a control unit to perform synchronization and Buck and Buck by the power factor correction circuit according to the DC / DC converter.
Other means will be described in the embodiment for carrying out the invention.

  ADVANTAGE OF THE INVENTION According to this invention, the load drive device which reduced the output ripple can be provided, although it is a one converter circuit structure.

It is a circuit diagram which shows the load drive device in this embodiment. It is explanatory drawing of operation | movement of a load drive device. It is a wave form diagram in each part of a load drive device. It is the wave form diagram which expanded the time axis of the time domain A part of FIG. It is a circuit diagram which shows each modification of a load drive device. It is a circuit diagram which shows each modification of a load drive device.

Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings.
FIG. 1 is a circuit diagram showing a schematic configuration of a load driving device 1 according to an embodiment of the present invention.
As shown in FIG. 1, the load driving device 1 includes a rectifier circuit BD1, a power factor correction circuit 2, a DC / DC converter 3, and a drive control circuit 4.
The rectifier circuit BD1 is, for example, a diode bridge, and performs full-wave rectification on the AC voltage of the AC power supply Vac and supplies it to the power factor correction circuit 2.

The power factor correction circuit 2 improves the power factor by reducing the phase difference between the rectified voltage and the rectified current output from the rectifier circuit BD1, and raises or lowers the rectified output voltage to a predetermined DC voltage. / Applied to the DC converter 3.
The DC / DC converter 3 converts the direct current voltage stepped up / down by the power factor correction circuit 2 into a voltage and applies it to the load 10. The drive control circuit 4 controls the switching operation of the switch element Q1 to synchronize the step-up / step-down by the power factor correction circuit 2 and the step-down by the DC / DC converter 3.

  In the power factor correction circuit 2, a first rectifier element D1, a switch element Q1, and a first reactor L1 are connected in series between the positive electrode and the negative electrode of the rectifier circuit BD1. The switch element Q1 is, for example, an N-channel MOSFET (metal-oxide-semiconductor field-effect transistor). The anode terminal of the first rectifier element D1 is connected to the positive electrode of the rectifier circuit BD1. The cathode terminal of the first rectifier element D1 is connected to the drain terminal of the switch element Q1. The source terminal of the switch element Q1 is connected to the negative electrode of the rectifier circuit BD1 through the first reactor L1. A first smoothing capacitor C1, a second rectifier element D2, and a third rectifier element D3 are connected in series to both ends of the first reactor L1. One end of the first smoothing capacitor C1 is connected to the source terminal of the switching element Q1, and is connected to the anode terminal of the second rectifying element D2 via the first reactor L1. The other end of the first smoothing capacitor C1 is connected to the cathode terminal of the third rectifying element D3. The cathode terminal of the second rectifying element D2 is connected to the anode terminal of the third rectifying element D3. A reactor current IL1 flows through the first reactor L1.

The DC / DC converter 3 shares the first series circuit composed of the switching element Q1, the first smoothing capacitor C1, and the third rectifying element D3 with the power factor correction circuit 2. The DC / DC converter 3 further includes a fourth rectifying element D4, a second reactor L2, and a second smoothing capacitor C2. The fourth rectifier element D4 is connected in parallel to the first series circuit, and its cathode terminal is connected to the drain terminal of the switch element Q1. The second reactor L2 and the second smoothing capacitor C2 are connected in series to both ends of the third rectifier element D3. The cathode terminal of the third rectifier element D3 is connected to the positive terminal of the second smoothing capacitor C2 via the second reactor L2. The anode terminal of the third rectifier element D3 is connected to the negative terminal of the second smoothing capacitor C2.
A load 10 is connected in parallel to both ends of the second smoothing capacitor C2.

The drive control circuit 4 (control unit) outputs a drive signal having a frequency (switching frequency) much higher than the AC frequency of the AC power supply Vac to the gate terminal of the switch element Q1 to turn on / off the switch element Q1. It is. The drive control circuit 4 controls power factor improvement in the power factor improvement circuit 2 by controlling on / off of the switch element Q1. Further, the drive control circuit 4 sets the DC output voltage of the DC / DC converter 3 to a predetermined voltage or sets the DC output current of the DC / DC converter 3 to a predetermined current.
The drive control circuit 4 is connected to a third reactor L3 that is the secondary side of the transformer T1. The primary side of the transformer T1 is a second reactor L2. Thus, a reactor current detection signal that is an induced voltage is generated in the third reactor L3 in accordance with the reactor current IL2 flowing in the second reactor L2. This reactor current detection signal is input to the drive control circuit 4. The drive control circuit 4 controls the switch element Q1 so that the DC / DC converter 3 operates in the current critical mode based on the reactor current detection signal corresponding to the reactor current IL2. The third reactor L3 is a current detection unit that detects the reactor current IL2.

2A and 2B are explanatory diagrams of each current path in the load driving device 1. FIG.
FIG. 2A shows current paths W1, W2, and W3 when the switch element Q1 is on.
The current path W1 is a path through which the current flowing out from the positive output terminal of the rectifier circuit BD1 flows to the negative output terminal of the rectifier circuit BD1 via the first rectifier element D1, the switch element Q1, and the first reactor L1. This current accumulates magnetic energy in the first reactor L1.
The current path W2 is a path through which the current flowing out from the positive electrode of the first smoothing capacitor C1 flows to the negative electrode of the first smoothing capacitor C1 via the second reactor L2, the load 10, the fourth rectifying element D4, and the switching element Q1. is there. This current releases energy to the load 10 and accumulates magnetic energy in the second reactor L2.
The current path W3 is a path through which the current flowing out from the positive electrode of the second smoothing capacitor C2 flows through the load 10 to the negative electrode of the second smoothing capacitor C2. This current releases the electrostatic energy of the second smoothing capacitor C2 to the load 10. At this time, since the second rectifying element D2 and the third rectifying element D3 are reverse-biased, no current flows.

FIG. 2B shows current paths W4, W5, and W6 when the switch element Q1 is off.
The current path W4 is a path for discharging magnetic energy stored in the first reactor L1 and storing electrostatic energy in the first smoothing capacitor C1.
The current path W5 is a path for releasing the magnetic energy stored in the second reactor L2 to the load 10. The current path W6 is a path for accumulating electrostatic energy in the second smoothing capacitor C2. When the switch element Q1 is off, the discharge current of the first reactor L1 and the discharge current of the second reactor L2 flow through the third rectifying element D3 in a superimposed manner.

When the state of the switch element Q1 transitions from on to off, the current flowing through the first reactor L1 decreases with the passage of time, while the second rectifier element D2 and the third rectifier element D3 start from one end of the first reactor L1. And then flows to the positive electrode of the first smoothing capacitor C1. This current further flows from the negative electrode of the first smoothing capacitor C1 to the other end of the first reactor L1 (current path W4). With this current, the magnetic energy stored in the first reactor L1 is converted into electrostatic energy of the first smoothing capacitor C1.
Further, when the state of the switching element Q1 transitions from on to off, the current flowing in the second reactor L2 decreases from time to time while decreasing from the one end of the second reactor L2 to the load 10 (current path W5), or It flows to the other end of the second reactor L2 via the second smoothing capacitor C2 (current path W6). With these currents, the magnetic energy of the second reactor L2 is released to the load 10 through the current path W5 and is converted into electrostatic energy of the second smoothing capacitor C2 through the current path W6.

Note that, after the AC power supply Vac is turned on, the load driving device 1 controls the switching element Q1 to be turned on and off at a predetermined cycle until a steady state after a predetermined time has elapsed. Thereby, the load driving device 1 can store the sufficient electrostatic energy in the first smoothing capacitor C1 and the second smoothing capacitor C2 and can realize the above operation.
When the load driving device 1 stores sufficient electrostatic energy in the first smoothing capacitor C1 and the second smoothing capacitor C2 and transitions to a steady state, the DC / DC converter 3 operates in the current critical mode, and The switching element Q1 is turned on / off so that the rate improvement circuit 2 operates in the current discontinuous mode or the current critical mode.

FIGS. 3A to 3C are waveform diagrams for explaining the operation of the load driving device 1 and show waveforms over two cycles of AC input.
FIG. 3A shows a voltage waveform of the AC power supply Vac. The vertical axis represents the power supply voltage. The horizontal axis is a time axis, and shows the time common to FIGS. 3 (b) and 3 (c).
The voltage of the AC power supply Vac is a sine wave with a predetermined period.
FIG. 3B shows a waveform of the reactor current IL1 flowing through the first reactor L1. The vertical axis represents the reactor current IL1. The horizontal axis is a time axis, and shows the time common to FIGS. 3 (a) and 3 (c).
The envelope of reactor current IL1 is similar to the rectified waveform of AC power supply Vac and has the same cycle as the rectified waveform of AC power supply Vac. Reactor current IL1 is a triangular wave with a period faster than the period of the rectified waveform of AC power supply Vac. In FIG. 3B, the waveform of the reactor current IL1 is displayed in black for convenience.

FIG. 3C shows a waveform of the reactor current IL2 flowing through the second reactor L2. The vertical axis represents the reactor current IL2. The horizontal axis is a time axis, and shows the time common to FIGS. 3 (a) and 3 (b).
The envelope of reactor current IL2 is a direct current waveform. Reactor current IL2 is a triangular wave with a period faster than that of AC power supply Vac. In FIG. 3C, the waveform of the reactor current IL2 is displayed in black for convenience.

4A to 4D are diagrams in which the time axis of the time region A part in FIG. 3 is enlarged.
FIG. 4A shows a voltage waveform of the AC power supply Vac.
The voltage of the AC power supply Vac maintains a predetermined voltage in the time domain A part.
FIG. 4B shows a current waveform of the reactor current IL1.
At time t0, reactor current IL1 is zero. At this time, the switch element Q1 transitions from off to on.
In the period from time t0 to t1, switch element Q1 is in the on state, and reactor current IL1 increases substantially linearly. At this time, the reactor current IL1 flows through the current path W1 shown in FIG.

At time t1, the switch element Q1 transitions from on to off.
In the period from time t1 to time t2, switching element Q1 is in the off state, and reactor current IL1 decreases substantially linearly. At this time, the reactor current IL1 flows through a current path W4 shown in FIG.
At time t2, reactor current IL1 becomes zero.
In the period from time t2 to t3, the switching element Q1 is in the off state, and the reactor current IL1 maintains zero. Such an operation mode having a period of zero current is called a current discontinuous mode.
At time t3, the switching element Q1 transitions from off to on. Thereafter, reactor current IL1 has a repetitive waveform similar to that at times t0 to t3.

FIG. 4C shows a current waveform of the reactor current IL2.
At time t0, reactor current IL2 is zero. At this time, the switch element Q1 transitions from off to on.
In the period from time t0 to t1, switch element Q1 is in the on state, and reactor current IL2 increases substantially linearly. At this time, the reactor current IL2 flows through a current path W2 shown in FIG.
At time t1, the switch element Q1 transitions from on to off.
In the period from time t1 to time t3, the switching element Q1 is in the off state, and the reactor current IL2 decreases substantially linearly. At this time, reactor current IL2 flows through current paths W5 and W6 shown in FIG.
At time t3, reactor current IL2 is zero. At this time, the switch element Q1 transitions from off to on. That is, reactor current IL2 does not continue to be zero. Such an operation mode having no current zero period is called a current critical mode.
Thereafter, reactor current IL2 has a repetitive waveform similar to that at times t0 to t3.

FIG. 4D shows the gate voltage of the switch element Q1.
At time t0, the gate voltage of the switch element Q1 changes from L level to H level, and the switch element Q1 changes from off to on.
In the period from time t0 to t1, the gate voltage of the switch element Q1 is at the H level, and the switch element Q1 is in the on state.
At time t1, the gate voltage of the switch element Q1 changes from H level to L level, and the switch element Q1 changes from on to off.
In the period from time t1 to time t3, the gate voltage of the switch element Q1 is at L level, and the switch element Q1 is in the off state.
At time t3, the gate voltage of the switch element Q1 changes from L level to H level, and the switch element Q1 changes from off to on.
Thereafter, the gate voltage of the switch element Q1 has a repetitive waveform similar to that at times t0 to t3.

In order to realize such control, the drive control circuit 4 outputs an L level signal after outputting an H level signal to the gate terminal of the switch element Q1 for a predetermined time. This predetermined time corresponds to a period of time t0 to t1.
If the reactor current detection signal becomes zero when the L level signal is output to the gate terminal of the switch element Q1, the drive control circuit 4 outputs the H level signal again to the gate terminal of the switch element Q1. . By repeating such processing, the drive control circuit 4 can control the reactor current IL2 to the current critical mode.

  In the load driving device 1 of the present embodiment, the power factor improving operation of the power factor improving circuit 2 functions effectively. Therefore, even if a large capacity capacitor is used as the first smoothing capacitor C1, the power factor does not decrease. Therefore, since the first smoothing capacitor C1 can have a large capacity, ripples in the AC frequency band appearing at the converter output can be reduced.

  By reducing the output ripple, the stability of the output voltage and output current is improved. For example, when the load 10 is an LED (Light Emitting Diode) and the luminaire is driven by the load driving device 1, flickering and variations in brightness can be reduced.

  The power factor correction circuit 2 and the DC / DC converter 3 share the switch element Q1. Therefore, the circuit is simplified and the number of parts can be reduced, so that the apparatus can be miniaturized. Furthermore, the power conversion efficiency can be improved by controlling the DC / DC converter 3 in the critical mode. Since the heat generation of the switch element Q1 is reduced by improving the efficiency, it is easy to downsize the heat sink for heat dissipation and thus downsize the load driving device 1.

FIGS. 5A to 5C are circuit diagrams illustrating modifications of the load driving device.
FIG. 5A is a circuit diagram showing a load driving device 1A of a first modification.
The load driving device 1A of the first modification is obtained by replacing the connection position of the first rectifying element D1 of the load driving device 1 shown in FIG. 1 from the positive electrode side to the negative electrode side of the rectifier circuit BD1. The DC / DC converter 3A of the load driving device 1A is configured similarly to the DC / DC converter 3 shown in FIG.
1 A of load drives of a 1st modification operate | move similarly to the load drive apparatus 1 shown in FIG. 1, and there exists the same effect.

FIG. 5B is a circuit diagram showing a load driving device 1B of the second modification.
The load driving device 1B of the second modified example includes a DC / DC converter 3B different from the DC / DC converter 3 shown in FIG. 1, and is otherwise the same as the load driving device 1 shown in FIG.
Similar to the DC / DC converter 3 shown in FIG. 1, the DC / DC converter 3B shares the first series circuit including the switch element Q1, the first smoothing capacitor C1, and the third rectifier element D3 with the power factor correction circuit 2. The second reactor L2 and the second smoothing capacitor C2 are connected in series to both ends of the third rectifying element D3.
The DC / DC converter 3B is obtained by switching the connection between the second reactor L2 and the second smoothing capacitor C2 of the DC / DC converter 3 shown in FIG. That is, the positive electrode of the second smoothing capacitor C2 is connected to the cathode terminal of the third rectifying element D3. The negative terminal of the second smoothing capacitor C2 is connected to the anode terminal of the third rectifying element D3 via the second reactor L2. A load 10 is connected in parallel to the second smoothing capacitor C2.
The load driving device 1B according to the second modified example operates in the same manner as the load driving device 1 shown in FIG.

FIG. 5C is a circuit diagram showing a load driving device 1C according to a third modification.
In the load driving device 1C of the third modified example, the connection position of the first rectifying element D1 of the load driving device 1B of the second modified example shown in FIG. 5B is switched from the positive electrode side to the negative electrode side of the rectifier circuit BD1. Is. The DC / DC converter 3C of the load driving device 1C is configured similarly to the DC / DC converter 3B shown in FIG.
The load driving device 1C of the third modified example operates in the same manner as the load driving device 1 shown in FIG. 1 and has the same effects.

FIGS. 6A and 6B are circuit diagrams showing modifications of the load driving device.
FIG. 6A is a circuit diagram showing a load driving device 1D according to a fourth modification.
The load driving device 1D of the fourth modified example does not include the third reactor L3 of the load driving device 1 shown in FIG. 1, but includes a resistance element R1 instead. The resistance element R1 is connected in series between the second reactor L2 and the positive electrode of the second smoothing capacitor C2. A reactor current detection signal corresponding to the voltage at both ends is output from both ends of the resistance element R1. The drive control circuit 4 can detect the reactor current IL2 by measuring the voltage across the resistance element R1. The voltage across the resistance element R1 is a reactor current detection signal. The resistance element R1 is a current detection unit that detects the reactor current IL2.
The DC / DC converter 3D includes a first series circuit including a switching element Q1, a first smoothing capacitor C1, and a third rectifying element D3, and a second reactor L2 at both ends of the third rectifying element D3. The resistor element R1 and the second smoothing capacitor C2 are connected in series. The positive terminal of the second smoothing capacitor C2 is connected to the cathode terminal of the third rectifying element D3 via the second reactor L2 and the resistance element R1. The negative terminal of the second smoothing capacitor C2 is connected to the anode terminal of the third rectifying element D3. A load 10 is connected in parallel between the positive electrode and the negative electrode of the second smoothing capacitor C2. In the fourth modified example, since the resistance element R1 is used instead of the transformer T1 in FIG. 1, the load driving device 1D can be further reduced in size.

FIG. 6B is a circuit diagram showing a load driving device 1E of the fifth modification.
In the load driving device 1E and the DC / DC converter 3E of the fifth modified example, the resistance element R1 and the second reactor L2 of the load driving device 1D of the fourth modified example are connected in series in reverse order. Thus, even if it comprises so that resistive element R1 and the 2nd reactor L2 may be connected in reverse order with load drive device 1D of the 4th modification shown to Fig.6 (a), load drive of Fig.6 (a) is carried out. It operates in the same manner as the device 1D, and the same effect can be obtained.

The present invention is not limited to the above-described embodiment, and can be modified without departing from the spirit of the present invention. For example, there are the following (a) to (c).
(A) A current detection part is not limited to the said embodiment and various modifications, For example, you may use a Hall sensor etc.
(B) The switch element Q1 is not limited to the N-channel MOSFET, and any switch element may be used.
(C) The reactance of the first reactor L1 may be adjusted so that the reactor current IL1 operates in the current critical mode.

1, 1A to 1E Load drive device 2 Power factor improvement circuit 3, 3A to 3E DC / DC converter 4 Drive control circuit (control unit)
10 load BD1 rectifier circuit C1 first smoothing capacitor C2 second smoothing capacitor D1 first rectifier element D2 second rectifier element D3 third rectifier element D4 fourth rectifier element IL1, IL2 reactor current L1 first reactor L2 second reactor L3 second 3 reactors Q1 switch element R1 resistance element (current detector)
T1 transformer (current detector)
Vac AC power supply W1-W6 Current path

Claims (8)

A rectifier circuit that outputs a rectified voltage obtained by full-wave rectification of an AC voltage;
Between the positive electrode and the negative electrode of the rectifier circuit, a first rectifier element, a switch element, and a first reactor are connected in series,
A second rectifying element, a third rectifying element, and a first smoothing capacitor are connected in series to both ends of the first reactor,
A power factor correction circuit for improving the power factor of the rectified voltage input from the rectifier circuit;
Sharing a first series circuit composed of the switch element, the first smoothing capacitor, and the third rectifier element;
A fourth rectifying element is connected in parallel to the first series circuit;
A second reactor and a second smoothing capacitor are connected in series to both ends of the third rectifying element,
A DC / DC converter that applies a DC voltage to a load connected in parallel to the second smoothing capacitor;
A control unit that controls on / off of the switch element to synchronously perform step-up / step-down by the power factor correction circuit and step-down by the DC / DC converter;
A load driving device comprising: The controller is
The DC / DC converter operates in a current critical mode;
And controlling on / off of the switch element so that the power factor correction circuit operates in a current discontinuous mode or a current critical mode.
The load driving device according to claim 1, wherein A current detector for detecting a current flowing through the second reactor;
The control unit controls on / off of the switch element based on a reactor current detection signal output from the current detection unit so that the DC / DC converter operates in a current critical mode.
The load driving device according to claim 2, wherein The current detection unit is a transformer having the second reactor as a primary side,
The reactor current detection signal is output from the secondary side of the transformer,
The load driving device according to claim 3. The current detection unit is a resistance element connected in series to the second reactor,
The reactor current detection signal corresponding to the voltage across the resistance element is output,
The load driving device according to claim 3. In the off period of the switch element, the third rectifier element includes
The discharge current of the first reactor and the discharge current of the second reactor flow in a superimposed manner,
The load driving device according to any one of claims 1 to 5, wherein the load driving device is configured as described above. The second reactor is connected to the cathode side of the third rectifying element,
The second smoothing capacitor is connected to an anode side of the third rectifying element;
The load driving device according to any one of claims 1 to 6, wherein The second reactor is connected to the anode side of the third rectifying element,
The second smoothing capacitor is connected to a cathode side of the third rectifying element;
The load driving device according to any one of claims 1 to 6, wherein

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