KR102108478B1 - Module of voltage attenuation and the apparatus and the method for attenuating voltage - Google Patents

Abstract

The present invention relates to a voltage attenuation module with improved efficiency of voltage conversion, a voltage attenuation device, and a method thereof. The voltage attenuation module comprises: a first capacitor and a second capacitor; a voltage source charging an electric charge to at least one of the first capacitor and the second capacitor; a switch unit connecting the first capacitor and the second capacitor in series or in parallel in accordance with an operation mode; a first output unit connected to the second capacitor or connected to the first capacitor and the second capacitor in accordance with the operation mode; and a second output unit selectively connected to the first capacitor and the second capacitor in accordance with the operation mode.

Description

Voltage attenuation module and voltage attenuation device and its method for attenuating voltage

The present invention relates to a voltage attenuation module, a voltage attenuation device, and a method thereof, in particular, a voltage attenuation module and a voltage attenuation device that improves the efficiency of voltage conversion by supplying electric charge by using a voltage difference between the applied power and the entire output, and the same It's about how.

Internet of Thing's (IoT) and WSN (Wireless Sensor Network) related electronic devices are mostly battery-powered, standalone systems. To extend the battery life of these systems, nano-energy harvesting technology is being added to power systems. Many recent high-energy-density nanogenerators output a voltage level range of several tens of volts, and the voltage level varies widely according to mechanical stimuli. However, a harvester that produces a wide range of voltage levels cannot be directly connected to the battery charging circuit.

In addition, most inductor-based converters are used in the field of power electronics, but have the disadvantage that the conversion rate is dependent on the duty cycle, so that the conversion efficiency is greatly reduced when the conversion rate is high.

In addition, in an application with a high conversion ratio, a conventional DC-DC converter based on a switched capacitor (SC) provides only a limited conversion ratio, and thus has a limitation that cannot be used in a wide input voltage range.

(KR) Published Patent 10-2018-0117928 A

The present invention has been devised to solve the above problems, and is to provide a voltage attenuation module, a voltage attenuation device, and a method so as to have a conversion ratio with a high conversion efficiency over a wide voltage range.

The technical problems of the present invention are not limited to the technical problems mentioned above, and other technical problems not mentioned will be clearly understood by a person skilled in the art from the following description.

The voltage attenuation module according to an embodiment of the present invention for achieving the above object includes: a first capacitor and a second capacitor; a voltage source for charging charge to at least one of the first capacitor and the second capacitor; A switch unit connecting the first capacitor and the second capacitor in series or in parallel; A first output part connected to the second capacitor or the first capacitor and the second capacitor according to the operation mode, and a first selectively connected to the first capacitor and the second capacitor according to the operation mode It may include 2 outputs.

According to an embodiment of the present invention, the switch unit connects the first capacitor and the second capacitor in series in a first charging mode, and parallels the first capacitor and the second capacitor in a second charging mode and an attenuation mode. It may be connected to.

The switch unit according to an embodiment of the present invention includes a first switch disposed between one end of the voltage source and the first capacitor, and a seventh switch disposed between the other end of the second capacitor and one end of the first output unit. The first switch and the seventh switch may be turned on in the first charging mode and the second charging mode.

The switch unit according to an embodiment of the present invention includes a second switch disposed between one end of the first capacitor and one end of the second capacitor, wherein the second switch includes the second charging mode and the attenuation mode Can be turned on.

A switch unit according to an embodiment of the present invention, a third switch disposed between one end of the second capacitor and the second output unit; A fourth switch disposed between the other end of the first capacitor and one end of the second capacitor Switch; may include a fifth switch disposed between the other end of the first capacitor and the second capacitor, and a sixth switch disposed between the other end of the second capacitor and the ground.

The third switch and the sixth switch according to an embodiment of the present invention may be turned on in the attenuation mode.

The fourth switch according to an embodiment of the present invention is turned on in the first charging mode, and the fifth switch according to an embodiment of the present invention is turned on in the second charging mode and the attenuation mode Can be.

The voltage attenuation method according to another embodiment of the present invention comprises the steps of: checking an operation mode of the voltage attenuation module; when the identified operation mode is a first charging mode, the first capacitor and the second capacitor are connected in series. And connecting the other end of the second capacitor to a first output unit, and applying a voltage to one end of the first capacitor; And when the identified operation mode is an attenuation mode, connecting the first capacitor and the second capacitor in parallel, and outputting the voltage of the first capacitor and the voltage of the second capacitor to a second output unit. can do.

When the identified operation mode according to another embodiment of the present invention is the second charging mode, the first capacitor and the second capacitor are connected in parallel, and the other end of the first capacitor and the other end of the second capacitor are It is connected to the output unit, and may include applying a voltage to one end of the first capacitor and the second capacitor.

A voltage attenuation device according to another embodiment of the present invention includes an attenuation unit in which a plurality of voltage attenuation modules output attenuating an input voltage at a predetermined rate according to an operation mode are connected in series or in parallel; And a mode determination unit that determines an operation mode of each of the plurality of voltage attenuation modules according to a ratio between an input voltage and an output voltage of the attenuation unit, wherein each voltage attenuation module includes: a first capacitor and a second capacitor; A voltage source for charging charge to at least one of the first capacitor and the second capacitor; A switch unit for connecting the first capacitor and the second capacitor in series or parallel according to the operation mode; The second capacitor according to the operation mode It may include a first output connected to or connected to the first capacitor and the second capacitor, and a second output selectively connected to the first capacitor and the second capacitor according to the operation mode.

The mode determination unit according to another embodiment of the present invention, the first capacitor and the second capacitor in the first charging mode in series, the first capacitor and the second capacitor in the second charging mode and attenuation mode Can be connected in parallel.

The voltage attenuation module according to an embodiment of the present invention is based on a switched capacitor, so that a high voltage nanogenerator can be economically manufactured.

In addition, in the voltage attenuation device according to an embodiment of the present invention, since charge is supplied to the output through the capacitor stage by connecting the entire output to each voltage attenuation module, cascading loss can be eliminated, thereby reducing voltage attenuation efficiency Can increase.

Furthermore, by providing a plurality of operation modes with different attenuation ratios, and automatically searching for an optimal attenuation ratio for any input and output voltage, it is possible to determine the operation mode of the attenuation modules, thereby obtaining high efficiency over a wide output voltage range. have.

The effects of the present invention are not limited to the above-mentioned effects, and other effects not mentioned will be clearly understood by those skilled in the art from the following description.

1 is a block diagram of a voltage attenuation device according to an embodiment of the present invention.
2 is a circuit diagram of a voltage attenuation module according to an embodiment of the present invention.
3 is a view for explaining the operation of the first charging mode of the voltage attenuation module according to an embodiment of the present invention.
4 is a view for explaining the operation of the attenuation mode of the voltage attenuation module according to an embodiment of the present invention.
5 is a view for explaining the operation of the second charging mode of the voltage attenuation module according to an embodiment of the present invention.
6A is a block diagram of a voltage attenuation device in which a plurality of voltage attenuation modules are connected in series according to an embodiment of the present invention.
6B is a block diagram of a voltage attenuation device in which a plurality of voltage attenuation modules are connected in parallel according to an embodiment of the present invention.
7 and 8 are simulation results showing the efficiency of the voltage attenuation module according to an embodiment of the present invention.

The present invention can be applied to various changes and can have various embodiments, and specific embodiments will be described in detail with reference to the drawings. However, this is not intended to limit the present invention to specific embodiments, and should be understood to include all modifications, equivalents, and substitutes included in the spirit and scope of the present invention. In describing each drawing, similar reference numerals are used for similar components.

Terms such as first, second, A, and B may be used to describe various components, but the components should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from other components. For example, without departing from the scope of the present invention, the first component may be referred to as the second component, and similarly, the second component may also be referred to as the first component. The term and / or includes a combination of a plurality of related description items or any one of a plurality of related description items.

When a component is said to be "connected" to or "connected" to another component, it should be understood that other components may be directly connected or connected to the other component, but may exist in the middle. something to do. On the other hand, when a component is said to be "directly connected" or "directly connected" to another component, it should be understood that no other component exists in the middle.

The terms used in the present application are only used to describe specific embodiments, and are not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In this application, terms such as “include” or “have” are intended to indicate that a feature, number, step, operation, component, part, or combination thereof described in the specification exists, one or more other features. It should be understood that the existence or addition possibilities of fields or numbers, steps, operations, components, parts or combinations thereof are not excluded in advance.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by a person skilled in the art to which the present invention pertains. Terms, such as those defined in a commonly used dictionary, should be interpreted as having meanings consistent with meanings in the context of related technologies, and should not be interpreted as ideal or excessively formal meanings unless explicitly defined in the present application. Does not.

Throughout the specification and claims, when a part includes a certain component, this means that other components may be further included rather than excluding other components unless otherwise specified.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a block diagram of a voltage attenuation device according to an embodiment of the present invention.

The voltage attenuation device 100 according to an embodiment of the present invention may include an attenuation unit 110 and a mode determination unit 120.

The attenuation unit 110 may include a plurality of attenuation modules 111 to 113, and each attenuation module decompresses and outputs an input voltage at a predetermined rate according to an operation mode, and the mode determination unit 120 inputs The operation mode of each voltage attenuation module 111 to 113 is determined based on the ratio of the voltage and the output voltage.

 The operation modes of the attenuation modules 111 to 113 according to an embodiment of the present invention may include i) a first charging mode, ii) a second charging mode, and iii) a damping mode.

In the present specification, in the first charging mode and the second charging mode, the capacitors included in the attenuation modules 111 to 113 are charged, and in the attenuation mode, the voltage is reduced using charges charged in the capacitors. In the attenuation mode, the depressurized voltage is the voltage across the capacitor and is output through the output. At this time, attenuation ratio (or decompression ratio) in the attenuation mode is different depending on the type of the operation mode.

Throughout the specification, a type of an operation mode according to an embodiment of the present invention may be referred to as being divided into a first operation mode composed of a first charging mode and an attenuation mode, and a second operation mode composed of a second charging mode and an attenuation mode.

Hereinafter, the structure of the damping module 111 according to an embodiment of the present invention will be described with reference to FIG. 2.

2 is a circuit diagram of a voltage attenuation module according to an embodiment of the present invention.

The attenuation module 111 according to an embodiment of the present invention includes a first capacitor 250, a second capacitor 260, a voltage source 210, a first output unit 230, a second output unit 220 and a switch Includes wealth 241-247.

The voltage source 210 is indicated by V _IN and charges charges in at least one of the first capacitor 250 and the second capacitor 260 in the first charging mode and the second charging mode. The voltage source 210 may correspond to the output of the previous attenuation module or may be a voltage source located outside the attenuation module.

The switch units 241 to 247 may be composed of a plurality of switches, and each switch is turned on or off depending on the operation mode. The switch units 241 to 247 connect the first capacitor 250 and the second capacitor 260 in series or parallel according to the operation mode, and the voltage source 210, the first output unit 230, and the second output unit 220 may be selectively connected to the capacitor.

The first output unit 230 is indicated by V _out and outputs the final attenuation voltage of the voltage attenuation device 100, and the second output unit 220 is indicated by V _{out_S} and then outputs the voltage to be input to the attenuation module. .

The first switch 241 is disposed between the voltage source 210 and one end M1 of the first capacitor 250, and is turned on in the first charging mode and the second charging mode, and turned off in the attenuation mode. .

The second switch 242 is disposed between one end M1 of the first capacitor 250 and one end M2 of the second capacitor 260, and is turned on in the second charging mode and the attenuation mode. 1 Turns off in charging mode.

The third switch 243 is disposed between one end M2 of the second capacitor 260 and the second output unit V _{out_S} , and is turned on in the attenuation mode, and in the first charging mode and the second charging mode Turn-off.

The fourth switch 244 is disposed between the other end (M3) of the first capacitor 250 and one end (M2) of the second capacitor 260, is turned on in the first charging mode and the second charging mode and attenuation In mode, it is turned off.

The fifth switch 245 is disposed between the other end M3 of the first capacitor 250 and the other end M4 of the second capacitor 260, and is turned on in the second charging mode and the attenuation mode and charged first In mode, it is turned off.

The sixth switch 246 is disposed between the other end M3 of the second capacitor 260 and ground, and is turned on in the attenuation mode, and turned off in the first charging mode and the second charging mode.

The seventh switch 247 is disposed between the other end M4 of the second capacitor 260 and one end of the first output unit V _out , and is turned on in the first charging mode and the second charging mode, and attenuated Turn off in mode.

3 is a view for explaining the operation of the first charging mode of the voltage attenuation module according to an embodiment of the present invention, Figure 4 is a diagram illustrating the operation of the attenuation mode of the voltage attenuation module according to an embodiment of the present invention 5 is a view for explaining the operation of the second charging mode of the voltage attenuation module according to an embodiment of the present invention.

In the first operation mode according to an embodiment of the present invention, the operation of the attenuation mode illustrated in FIG. 4 is continued after the operation of the first charging mode illustrated in FIG. 3.

In the first charging mode, only the first switch 241, the fourth switch 244, and the seventh switch 247 are turned on, and the other switches are turned off. As a result, the first capacitor 250 and the second capacitor 260 are connected in series, the voltage source 210 is connected to one end (M1) of the first capacitor 250, the other end of the second capacitor (260) ( The first output unit 230 is connected to M4).

Therefore, the voltages of the entire capacitors including the first capacitor 250 and the second capacitor 260 become V _IN -V _out .

In the attenuation mode, only the second switch 242, the third switch 243, the fifth switch 245, and the sixth switch 246 are turned on, and the remaining switches are turned off. As a result, the first capacitor 250 ) And the second capacitor 260 are connected in parallel.

And one end (M1) of the first capacitor 250 and one end (M2) of the second capacitor 260 is connected to the second output unit 220, the other end (M3) and the second of the first capacitor (250) The other end M4 of the capacitor 260 is connected to ground.

In this case, the magnitude of the voltage applied to both ends of the first capacitor 250 and the second capacitor 260 by the law of preserving the amount of charge remains the same, so that the voltage V _{out_S} of the second output terminal 220 is It is determined by Equation 1.

[Equation 1]

이 적용될 수 있다.Therefore, in the first operation mode according to an embodiment of the present invention, the equation 1

This can be applied.

In the second operation mode according to an embodiment of the present invention, the operation of the attenuation mode illustrated in FIG. 4 is continued after the operation of the second charging mode illustrated in FIG. 5.

In the second charging mode, only the first switch 241, the second switch 242, the fifth switch 245, and the seventh switch 247 are turned on, and the other switches are turned off.

As a result, the first capacitor 250 and the second capacitor 260 are connected in parallel, and the voltage source 210 is provided at one end M1 of the first capacitor 250 and one end M2 of the second capacitor 260. The first outputs 230 and V _out are connected to the other end M3 of the first capacitor 250 and the other end M4 of the second capacitor 260.

Accordingly, the voltages of the first capacitor 250 and the second capacitor 260 become V _IN -V _out . In the attenuation mode, one end M1 of the first capacitor 250 and one end of the second capacitor 260 ( Since M2) is connected to the second output units 220 and V _{out_S} , the voltage V _{out_S} of the second output unit 220 is determined by Equation 2 below.

[Equation 2]

The attenuation mode of each voltage module 111 to 113 is determined by the ratio of the input voltage and the output voltage of the attenuation unit 110. For example, when there are three voltage modules, the operation mode according to the attenuation ratio is determined as shown in Table 1 below.

[Table 1]

In Table 1, each of R1, R2, and R3 corresponds to each of the voltage modules 111, 112, and 113, and in R1, R2, R3, 1 means a first operation mode (operation in an attenuation mode after the first charging mode) and , R1, R2, 0 in R3 means the second operating mode (the second charging mode and then operating in attenuation mode).

In Table 1, P indicates whether each of the voltage modules 111, 112, and 113 are connected in series or in parallel, 1 is parallel and 0 is connected in series.

As described above, the voltage attenuation device according to an embodiment of the present invention can eliminate cascading losses by connecting the entire output V _out to each voltage attenuation module when in the charging mode, thereby increasing the voltage attenuation efficiency. In addition, various damping ratios can be achieved by changing the operation mode.

Specific examples of the starting attenuation ratio in Table 1 will be described with reference to FIGS. 6A and 6B.

6A is a block diagram of a voltage attenuation device in which a plurality of voltage attenuation modules are connected in series according to an embodiment of the present invention, and FIG. 6B is a voltage in which a plurality of voltage attenuation modules according to an embodiment of the present invention are connected in parallel. It is a block diagram of an attenuation device.

More specifically, FIG. 6A shows a series connection in which the voltage V _{out_S} of the second output part enters the input of the next voltage attenuation module. 6B, the external input voltages V _IN and 210 enter the respective voltage attenuation modules 111 to 113, and the first series / parallel switch switch 361 and the second series / parallel switch switch 362 are shown. By being on, the voltage V _{out_S} of the second output part represents a parallel connection that becomes the total output voltage Vout, 230.

A case where the damping ratio is 1/11 will be described with reference to FIG. 6A. As shown in Table 1, the voltage attenuation modules 111 to 113 are connected in series (P = 0), and the first voltage attenuation module 111 and the second voltage attenuation module 112 are in the first operation mode. Working, the third voltage attenuation module 113 operates in the second operating mode.

이며, 제2 전압 감쇠 모듈(112)의 제2 출력부(V_{out_S2})의 전압은 제1 동작 모드에 의하여

가 된다. 제3 전압 감쇠 모듈(113)은 제1 출력부(V_out) 및 제2 출력부(V_{out_S3})가 단락되고, 제2 동작 모드에 따른 수학식 2에 의하여 제2 출력부(V_{out_S3})는

을 만족한다.Therefore, the voltage of the second output unit V _{out_S1} of the first voltage attenuation module 111 is determined by the first operation mode.

And the voltage of the second output unit V _{out_S2} of the second voltage attenuation module 112 is determined by the first operation mode.

Becomes. In the third voltage attenuation module 113, the first output unit V _out and the second output unit V _{out_S3} are short-circuited, and the second output unit V _{out_S3} is _expressed by Equation 2 according to the second operation mode.

Satisfies

이 되어, 감쇠비율 1/11을 달성할 수 있다.therefore,

This can achieve the damping ratio 1/11.

A case where the damping ratio is 1/3 will be described with reference to FIG. 6B. As shown in Table 1, the voltage attenuation modules 111 to 113 are connected in parallel (P = 1) and all operate in the first operation mode.

)과 같으므로,

을 만족한다. 즉, 감쇠비율 1/3을 달성할 수 있다.Accordingly, the first output unit V _out of the third voltage attenuation module 113 is the voltage of the second output unit V _{out_S3} (

), So

Satisfies That is, attenuation ratio 1/3 can be achieved.

Meanwhile, switches according to an embodiment of the present invention are implemented using a high voltage transistor capable of withstanding up to 45V.

The transistor is driven by a non-overlapping clock (Clock) of the opposite phase. According to an embodiment of the present invention, a clock swing value is maintained at an output voltage (VBAT) to limit switching loss, and a low voltage clock cannot be directly applied to transistors at different potentials. To overcome this problem, in one embodiment of the present invention, a cross coupled level shifter method, which is a known method, is adopted. In order to drive a PMOS, a P-type level shifter is used.

In order to see the suitability of the voltage attenuation module according to an embodiment of the present invention in a typical power electronics application, simulations were performed in the load current (I _LOAD ) range from 1.5mA to 42mA. In the case of the flying capacitor, an off-chip capacitor was selected, and the off-chip flying capacitor was set to a value of 2.5 μF. Off-chip flying capacitors have a parasitic capacitance of several pF orders, and 5 pF of parasitic capacitances are added to the top and bottom of each flying capacitor to take into account the effect of this.

7 and 8 are simulation results showing the efficiency of the voltage attenuation module according to an embodiment of the present invention.

7 is a constant current (I _LOAD ) of 42mA in the voltage attenuation module according to an embodiment of the present invention, the input voltage (V _IN ) is gradually changed from 12V to 42V, in the condition of output voltage (V _OUT ) = 5V, efficiency It is the result of experiment. Referring to FIG. 7, it can be seen that the voltage attenuation module according to the present invention has a peak efficiency of 85.7%, and the efficiency is 80.8% or more in the entire voltage range.

8 is a voltage attenuation module according to an embodiment of the present invention, the current (I _LOAD ) limited to 1.5mA, the input voltage (V _IN ) is gradually changed from 12V to 42V, the output voltage (V _OUT ) = 5V, efficiency It is the result of experiment. Referring to FIG. 8, it can be seen that the voltage attenuation module according to the present invention has an efficiency of 83% or more and a peak efficiency of 88.2% in the entire voltage range. That is, it can be seen that the voltage attenuation module according to an embodiment of the present invention has high efficiency even when the current is small.

For high-energy-density nanogenerators, the output current range is several milliamps, while in typical power electronics applications, the output current ranges from several mA to 40 mA. Thus, the converter according to the invention, with a load current range of several mA to 42 mA, can be an ideal next step converter in power electronics applications, and is also suitable for batteries for high voltage nanogenerator interfaces, IOT and WSN applications.

The above description is merely illustrative of the technical spirit of the present invention, and those skilled in the art to which the present invention pertains may make various modifications and variations without departing from the essential characteristics of the present invention. Therefore, the embodiments disclosed in the present invention are not intended to limit the technical spirit of the present invention, but to explain, and the scope of the technical spirit of the present invention is not limited by these embodiments. The scope of protection of the present invention should be interpreted by the claims below, and all technical spirits within the equivalent range should be interpreted as being included in the scope of the present invention.

100: voltage attenuation device
110: damping part
120: mode determination unit
111 ~ 113: 1st damping module ~ 3rd damping module
210: voltage source
220: second output
230: first output unit
240: switch unit
250: first capacitor
260: second capacitor

Claims (9)

In the voltage attenuation module,
A first capacitor and a second capacitor;
A voltage source that charges at least one of the first capacitor and the second capacitor;
A switch unit connecting the first capacitor and the second capacitor in series or in parallel according to an operation mode;
A first output part connected to the second capacitor or to the first capacitor and the second capacitor according to the operation mode, and
A voltage attenuation module including a second output part selectively connected to the first capacitor and the second capacitor according to the operation mode. According to claim 1, wherein the switch unit,
The voltage attenuation module, wherein the first capacitor and the second capacitor are connected in series in the first charging mode, and the first capacitor and the second capacitor are connected in parallel in the second charging mode and the attenuation mode. According to claim 2,
The switch unit may include a first switch disposed between one end of the voltage source and the first capacitor, and
And a seventh switch disposed between the other end of the second capacitor and one end of the first output unit,
The first switch and the seventh switch, the voltage attenuation module, characterized in that turned on in the first charging mode and the second charging mode. According to claim 2,
The switch unit includes a second switch disposed between one end of the first capacitor and one end of the second capacitor,
The second switch, the voltage attenuation module, characterized in that the turn-on in the second charging mode and the attenuation mode. According to claim 2,
The switch unit,
A third switch disposed between one end of the second capacitor and the second output unit;
A fourth switch disposed between the other end of the first capacitor and one end of the second capacitor;
A fifth switch disposed between the other end of the first capacitor and the other end of the second capacitor, and
And a sixth switch disposed between the other end of the second capacitor and ground,
The third switch and the sixth switch are turned on in the attenuation mode,
The fourth switch is turned on in the first charging mode,
Wherein the fifth switch is turned on in the second charging mode and the attenuation mode. A method for attenuating a voltage in a voltage attenuation module including a switch for connecting the first capacitor in series or in parallel according to an operation mode with the first capacitor and the second capacitor,
Checking an operation mode of the voltage attenuation module;
When the checked operation mode is the first charging mode, the first capacitor and the second capacitor are connected in series, the other end of the second capacitor is connected to the first output unit, and one end of the first capacitor is connected. Applying a voltage and
And when the identified operation mode is an attenuation mode, connecting the first capacitor and the second capacitor in parallel, and outputting the voltage of the first capacitor and the voltage of the second capacitor to a second output unit. Voltage attenuation method. The method of claim 6,
When the checked operation mode is the second charging mode, the first capacitor and the second capacitor are connected in parallel, and the other end of the first capacitor and the other end of the second capacitor are connected to a first output unit, and the And applying voltage to one end of the first capacitor and one end of the second capacitor. An attenuation unit in which a plurality of voltage attenuation modules that attenuate and output the input voltage at a predetermined rate according to the operation mode are connected in series or in parallel; And
And a mode determination unit for determining an operation mode of each of the plurality of voltage attenuation modules according to a ratio between an input voltage and an output voltage of the attenuation unit.
Each voltage attenuation module,
A first capacitor and a second capacitor;
A voltage source for charging charge to at least one of the first capacitor and the second capacitor;
A switch unit connecting the first capacitor and the second capacitor in series or in parallel according to an operation mode;
A first output part connected to the second capacitor or to the first capacitor and the second capacitor according to the operation mode, and
In the attenuation mode, the voltage attenuation device including a second output connected to the first capacitor and the second capacitor. The method of claim 8, wherein the mode determination unit,
The voltage attenuating device, wherein the first capacitor and the second capacitor are connected in series in the first charging mode, and the first capacitor and the second capacitor are connected in parallel in the second charging mode and the attenuation mode.

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