WO2023113195A1 - Switched capacitor converter - Google Patents

Abstract

The present invention relates to a switched capacitor converter, which can operate with high efficiency at a high voltage conversion ratio (for example, 4:1) and reduce switching loss. One aspect of the present invention relates to a switched capacitor converter comprising: a first circuit including at least one capacitor and at least one switch; and a second circuit formed of a circuit that is substantially the same as that of the first circuit, wherein corresponding switches at positions at which the first circuit and the second circuit correspond to each other are complementarily turned on/off with respect to each other, at least some of corresponding nodes at positions at which the first circuit and the second circuit correspond to each other have voltage states that are complementary to each other, and charge sharing switches are arranged at at least some of the corresponding nodes.

Description

switch capacitor converter

The present invention relates to a switched capacitor converter.

For ultra-fast charging of mobile systems (smartphones, tablets, etc.), switched-capacitor converters are widely used.

A switched capacitor converter is a circuit in which a semiconductor switching element (hereinafter simply referred to as a 'switch') and a capacitor are combined without using an inductor. It can be understood as a circuit that changes the relationship of However, it is not necessary to consider that a switched capacitor converter does not include an inductor in that a switched capacitor converter including a small size inductor is also partially studied, but in general, a switched capacitor converter does not use a large size inductor. It can reduce the size and achieve high efficiency. For this reason, switched capacitor converters are mainly used in converters operating at a voltage conversion ratio (ratio of input voltage to output voltage) of 2:1 in mobile systems.

However, due to the recent increase in power consumption in mobile systems and the tendency for the operating voltage of components (core, peripheral circuits, etc.) that consume power inside the system to decrease, converters with a voltage conversion ratio exceeding 2:1 are required. demands are increasing.

For example, with the introduction of USB PD (USB Power Delivery) and PPS (Programmable Power Supply), high-speed charging of large-capacity batteries used in smartphones and the like is possible while using a switched capacitor converter having a 2:1 voltage conversion ratio. That is, when using a low-cost standard 3A USB type-C cable and a switched capacitor converter having a 2:1 voltage conversion ratio, it is possible to achieve a battery charging current of 6A. However, in the wireless charging system, the magnetic core acts as an obstacle to high-speed charging, and the magnetic core used for wireless charging of smartphones is usually limited to a current of 1.25A or less for safety reasons. In this case, if a switched capacitor converter with a 2:1 voltage conversion ratio is used, the charging current is limited to 2.5A or less. However, consumers are demanding a larger charging current for faster charging, and this demand is leading to a demand for a converter having a voltage conversion ratio exceeding 2:1. For example, if a switched capacitor converter with a voltage conversion ratio of 4:1 is used, a charging current of 12A is possible while using a low-cost standard 3A USB type-C cable, and a magnetic current limited to 1.25A or less. Even a wireless charging system using a core can achieve a charging current of 5A.

As such, the demand for a switched capacitor converter having a voltage conversion ratio exceeding 2:1, eg, 4:1, is increasing, but a switched capacitor converter having a high voltage conversion ratio increases the voltage stress of the switch and the capacitor. In addition, there are problems such as relatively increasing size and decreasing efficiency due to an increase in the number of devices, so improvement is required.

For example, a method of implementing a voltage conversion ratio of 4:1 by connecting two switched capacitor converters having a voltage conversion ratio of 2:1 in series is known, but this method loses power in that power processing is performed twice. There is a problem with this many. As another example, in the case of a 4:1 Dickson switch capacitor converter, a high withstand voltage capacitor having a withstand voltage three times the output voltage Vo is required. High voltage capacitors are disadvantageous in terms of size and efficiency due to their large size, small effective capacitance and large parasitic resistance. Therefore, it is necessary to develop a switched capacitor converter capable of operating at a high voltage conversion ratio and having a small size and high efficiency.

In addition, it is also necessary to study a method for reducing the switching loss of the switched capacitor converter when operating at a high voltage conversion ratio. Switched-capacitor converters usually operate in a hard-switching manner in which switching losses occur. The switching loss is proportional to the square of the voltage change during on/off switching of the switch. In the case of a 2:1 voltage conversion ratio, the voltage change during switching is not large, so the switching loss does not occupy a relatively large proportion. When the voltage conversion ratio increases to 3:1 or 4:1, the amount of voltage change increases and the effect of switching loss on efficiency increases, so a method for reducing switching loss is also required.

One object of the present invention is to provide a switched capacitor converter that can operate with high efficiency at a high voltage conversion ratio (eg, 4:1).

One object of the present invention is to provide a switched capacitor converter capable of reducing switching loss.

The problem of the present invention is not limited to the above-described problem, and various problems not mentioned herein may be included in the present specification.

One aspect of the present invention is a first circuit including at least one capacitor and at least one switch; And a second circuit composed of a circuit substantially the same as the first circuit; including, but the corresponding switches of the first circuit and the second circuit at positions corresponding to each other are turned on/off complementary to each other, and the first circuit At least some of the corresponding nodes of the first circuit and the second circuit have voltage states complementary to each other, and a charge sharing switch is disposed on at least some of the corresponding nodes.

In the switched-capacitor converter, when the corresponding switches change their on/off states, there is a dead time period in which all of the corresponding switches are turned off, and the charge sharing switch may be turned on during the dead time period.

In the switched-capacitor converter, when the charge sharing switch is turned on during the dead time period, voltage values of the corresponding nodes may be substantially equal to each other.

In the switched-capacitor converter, switching loss when the corresponding switch changes an on/off state may be reduced by using the charge sharing switch so that the corresponding nodes have substantially the same voltage value during the dead time period.

In the switched-capacitor converter, a switch of the first circuit belongs to one of a first switch group turned on in a first state and a second switch group turned on in a second state, and the switch of the second circuit includes the It may belong to a switch group different from the corresponding switch of the first circuit.

In the switched-capacitor converter, the first state and the second state may have substantially the same length of time, and a dead time interval may exist between the first state and the second state.

Another aspect of the present invention is a first circuit including at least one capacitor and at least one switch; and a second circuit including substantially the same circuit as the first circuit, wherein the first circuit and the second circuit each include: a first switch having a drain terminal connected to an input voltage; a first capacitor having one end connected to the source terminal of the first switch; a second switch having a drain terminal connected to the other end of the first capacitor and a source terminal connected to a reference potential; a third switch having a source terminal connected to the other end of the first capacitor; a fourth switch having a drain terminal connected to the drain terminal of the third switch; a fifth switch having a drain terminal connected to a source terminal of the fourth switch; a sixth switch having a drain terminal connected to the source terminal of the fifth switch and a source terminal connected to a reference potential; a seventh switch having a source terminal connected to the drain terminal of the fourth switch; and a second capacitor having one end connected to the drain terminal of the fourth switch and the other end connected to the drain terminal of the sixth switch, wherein the drain terminal of the seventh switch of the first circuit is connected to the drain terminal of the second circuit. is connected to one end of the first capacitor, and a drain terminal of the seventh switch of the second circuit is connected to one end of the first capacitor of the first circuit.

In the switched capacitor converter, a connection node of a source terminal of the fourth switch and a drain terminal of the fifth switch may be connected to an output voltage.

The switch capacitor converter includes at least one of a first charge sharing switch and a second charge sharing switch, wherein the first charge sharing switch includes one end of the first capacitor of the first circuit and the first charge sharing switch of the second circuit. connected between one end of a capacitor and/or connected between the other end of the first capacitor in the first circuit and the other end of the first capacitor in the second circuit, wherein the second charge sharing switch is It may be connected between one end of the second capacitor and one end of the second capacitor of the second circuit and/or between the other end of the second capacitor of the first circuit and the other end of the second capacitor of the second circuit. there is.

In the switched-capacitor converter, the first charge sharing switch and/or the second charge sharing switch may be semiconductor switching elements capable of bi-directional on/off control.

In the switched-capacitor converter, the first, third, fifth, and seventh switches of the first circuit and the second, fourth, and sixth switches of the second circuit belong to a first switch group that is turned on in a first state, The first, third, fifth, and seventh switches of the second circuit and the second, fourth, and sixth switches of the first circuit belong to a second switch group that is turned on in a second state, and the first charge sharing switch and Alternatively, the second charge sharing switch may be turned on during a dead time interval in which switches belonging to the first switch group and the second switch group are all turned off.

In the switched-capacitor converter, the first state and the second state may have substantially the same length of time, and the dead time interval may exist between the first state and the second state.

Another aspect of the present invention, the first switch (S31) to which the drain terminal is connected to the input voltage; a first capacitor C31 having one end connected to the source terminal of the first switch; a second switch (S32) having a drain terminal connected to the other end of the first capacitor and a source terminal connected to a reference potential; a third switch (S33) having a source terminal connected to the other end of the first capacitor; a fourth switch (S34) having a drain terminal connected to the drain terminal of the third switch; a fifth switch (S35) having a drain terminal connected to a source terminal of the fourth switch; a sixth switch (S36) having a drain terminal connected to the source terminal of the fifth switch and a source terminal connected to a reference potential; a second capacitor C32 having one end connected to the drain terminal of the fourth switch and the other end connected to the drain terminal of the sixth switch; a seventh switch (S37) having a drain terminal connected to one end of the first capacitor; a third capacitor (C33) having one end connected to the source terminal of the seventh switch; an eighth switch (S38) having a drain terminal connected to one end of the third capacitor; a ninth switch (S39) having a drain terminal connected to the source terminal of the eighth switch and a source terminal connected to the other terminal of the third capacitor; and a tenth switch (S40) having a drain terminal connected to the source terminal of the ninth switch and a source terminal connected to a reference potential, between one end of the second capacitor and one end of the third capacitor and/or A switched capacitor converter characterized in that a charge sharing switch (SC3) is connected between the other end of the second capacitor and the other end of the third capacitor.

In the switched capacitor converter, a source terminal of the fourth switch and a source terminal of the eighth switch may be connected to an output voltage.

In the switched-capacitor converter, the charge sharing switch may be a semiconductor switching element capable of bi-directional on/off control.

In the switched-capacitor converter, the first, third, fifth, eighth and tenth switches belong to a first switch group that is turned on in a first state and the second, fourth, sixth, seventh and ninth switches are in a second state. The charge sharing switch, which belongs to a second switch group that is turned on, may be turned on during a dead time period in which both switches belonging to the first switch group and the second switch group are turned off.

In the switched-capacitor converter, the first state and the second state may have substantially the same length of time, and the dead time interval may exist between the first state and the second state.

According to the present invention, it is possible to provide a switched capacitor converter that can operate with high efficiency at a high voltage conversion ratio exceeding 2:1 (eg, 4:1).

In addition, according to the present invention, it is possible to provide a switched capacitor converter capable of reducing switching loss.

The effects of the present invention are not limited to the above effects, and various effects not mentioned herein may be included in the present specification.

1 is a block diagram illustrating a switched capacitor converter according to an embodiment of the present invention.

2 is a circuit diagram example of a switched capacitor converter to which the embodiment of FIG. 1 is applied.

FIG. 3 is a diagram illustrating an operating waveform of the switched-capacitor converter of FIG. 2 by way of example.

FIG. 4 is a diagram illustrating a switch on/off operation of the switched capacitor converter of FIG. 2 by way of example.

5 and 6 are diagrams illustrating a first state (phase 1) of the switched-capacitor converter of FIG. 2 by way of example.

7 and 8 are diagrams illustrating a second state (phase 2) of the switched capacitor converter of FIG. 2 by way of example.

FIG. 9 is a diagram explaining switching loss of the switched capacitor converter of FIG. 2 .

10 is a block diagram illustrating a switched capacitor converter according to another embodiment of the present invention.

11 is a circuit diagram example of a switched capacitor converter to which the embodiment of FIG. 10 is applied.

FIG. 12 is a diagram illustrating an operating waveform of the switched-capacitor converter of FIG. 11 by way of example.

13 is a diagram illustrating a switch on/off operation of the switched capacitor converter of FIG. 11 by way of example.

FIG. 14 is a diagram explaining a principle of reducing switching loss by the charge sharing switch of the switched-capacitor converter of FIG. 11 .

15 illustrates a switch capable of bi-directional on/off control that can be used for the first charge sharing switch SC1 and/or the second charge sharing switch SC2.

16 is a circuit diagram illustration of a switched capacitor converter according to another embodiment of the present invention.

FIG. 17 is a diagram illustrating an operating waveform of the switched-capacitor converter of FIG. 16 by way of example.

FIG. 18 is a diagram illustrating a first state (phase 1) of the switched-capacitor converter of FIG. 16 by way of example.

FIG. 19 is a diagram illustrating a second state (phase 2) of the switched-capacitor converter of FIG. 16 by way of example.

FIG. 20 is a circuit diagram in which a charge sharing switch is added to the switched capacitor converter of FIG. 16 as another embodiment of the present invention.

Hereinafter, some embodiments of the present invention will be described in detail through exemplary drawings. In adding reference numerals to components of each drawing, it should be noted that the same components have the same numerals as much as possible even if they are displayed on different drawings. In addition, in describing the present invention, if it is determined that a detailed description of a related known configuration or function may obscure the gist of the present invention, the detailed description will be omitted.

Also, terms such as first, second, A, B, (a), and (b) may be used in describing the components of the present invention. These terms are only used to distinguish the component from other components, and the nature, order, or order of the corresponding component is not limited by the term. When an element is described as being “connected,” “coupled to,” or “connected” to another element, that element is directly connected or connectable to the other element, but there is another element between the elements. It will be understood that elements may be “connected”, “coupled” or “connected”.

1 is a block diagram illustrating a switched capacitor converter 100 according to an embodiment of the present invention.

The switched capacitor converter 100 may include a first circuit 110 and a second circuit 120 . The switched capacitor converter 100 may receive an input voltage Vin from a power source through an input terminal, convert the voltage, and then provide an output voltage Vo to a load through an output terminal. The switched capacitor converter 100 according to the present embodiment may selectively operate at a ratio of the input voltage Vin to the output voltage Vo of 2:1, 3:1, or 4:1.

The switched capacitor converter 100 may be illustratively used for ultra-fast charging of a mobile system (smart phone, tablet, etc.). The switch capacitor converter 100 is a circuit in which a semiconductor switching element (hereinafter simply referred to as a 'switch') and a capacitor are combined without using an inductor, and the input voltage is changed by changing the connection of the capacitor through the on/off operation of the switch. The relationship between (Vin) and the output voltage (Vin) can be changed. However, according to embodiments, the switched capacitor converter 100 may include a small-sized inductor.

The first circuit 110 may include at least one capacitor and at least one switch. The second circuit 120 may be configured with substantially the same circuit as the first circuit 110 . In this case, corresponding switches at positions corresponding to each other of the first circuit 110 and the second circuit 120 may be turned on/off complementary to each other. In addition, at least some of the corresponding nodes of the first circuit 110 and the second circuit 120 corresponding to each other may have voltage states complementary to each other.

Here, the corresponding switches in the positions corresponding to each other in the first circuit 110 and the second circuit 120 are located in the same position in the first circuit 110 and the second circuit 120 composed of substantially the same circuits. It means two switches placed. For example, in FIG. 2 , the first switch S11 of the first circuit 110 and the first switch S21 of the second circuit 120 may be understood as corresponding switches. At this time, when the first switch S11 of the first circuit 110 is ON, the first switch S21 of the second circuit 120 is OFF, and the When the first switch S11 is OFF, the first switch S21 of the second circuit 120 may operate in such a way that it is turned ON. For this operation, the corresponding switches are complementary to each other. It can be expressed as on/off.

Corresponding nodes of the first circuit 110 and the second circuit 120 at positions corresponding to each other are two nodes at the same position in the first circuit 110 and the second circuit 120 composed of circuits substantially identical to each other. means node. For example, in FIG. 2 , the second node N12 of the first circuit 110 and the second node N22 of the second circuit 120 may be understood as corresponding nodes. At least some of the corresponding nodes of the first circuit 110 and the second circuit 120 corresponding to each other may have complementary voltage states, which will be described in detail below.

The first circuit 110 and the second circuit 120 may include a connection wire 130 for electrical connection to each other as needed. Although only one connection wire 130 is shown in FIG. 1 , a plurality of connection wires 130 may or may not be used as needed.

2 is a circuit diagram example of a switched capacitor converter 200 to which the embodiment of FIG. 1 is applied.

The switched capacitor converter 200 may include a first circuit 110 including at least one capacitor and at least one switch and a second circuit 120 composed of substantially the same circuit as the first circuit 110. there is.

The first circuit 110 includes a first switch (S11), a second switch (S12), a third switch (S13), a fourth switch (S14), a fifth switch (S15), a sixth switch (S16), 7 switch S17, a first capacitor C11 and a second capacitor C12 may be included. It is obvious that additional elements such as a voltage stabilization capacitor and a filter may be further included, but the basic operation of the circuit is the first switch S11 to the seventh switch S17, the first capacitor C11 and the second capacitor. Since it is determined by (C12), these elements will be mainly described.

A drain terminal of the first switch S11 of the first circuit 110 may be connected to the input voltage Vin through the first node N11.

One end (upper terminal in the drawing) of the first capacitor C11 may be connected to the source terminal of the first switch S11 through the second node N12.

The drain terminal of the second switch S12 is connected to the other terminal (lower terminal in the drawing) of the first capacitor C11 through the third node N13, and the source terminal of the second switch S12 is connected to the reference potential (GND). can be connected to

A source terminal of the third switch S13 may be connected to the other end of the first capacitor C11 through the third node N13.

A drain terminal of the fourth switch S14 may be connected to a drain terminal of the third switch S13 through the fourth node N14.

A drain terminal of the fifth switch S15 may be connected to a source terminal of the fourth switch S14 through the fifth node N15.

The drain terminal of the sixth switch S16 may be connected to the source terminal of the fifth switch S15 through the sixth node N16, and the source terminal of the sixth switch S16 may be connected to the reference potential GND.

A source terminal of the seventh switch S17 may be connected to a drain terminal of the fourth switch S14 through a fourth node N14.

One end of the second capacitor C12 (upper terminal in the drawing) is connected to the drain terminal of the fourth switch S14 through the fourth node N14, and the other end of the second capacitor C12 (lower terminal in the drawing) may be connected to the drain terminal of the sixth switch S16 through the sixth node N16.

A connection node N15 of the source terminal of the fourth switch S14 and the drain terminal of the fifth switch S15 may be connected to the output voltage Vo.

The second circuit 120 may be configured with substantially the same circuit as the first circuit 110 . The second circuit 120 includes a first switch (S21), a second switch (S22), a third switch (S23), a fourth switch (S24), a fifth switch (S25), a sixth switch (S26), It may include 7 switches S27, a first capacitor C21 and a second capacitor C22. In addition, it is obvious that additional elements such as a voltage stabilization capacitor and a filter may be further included.

A drain terminal of the first switch S21 of the second circuit 120 may be connected to the input voltage Vin through the first node N21.

One end (upper terminal in the drawing) of the first capacitor C21 may be connected to the source terminal of the first switch S21 through the second node N22.

The drain terminal of the second switch S22 is connected to the other terminal (lower terminal in the drawing) of the first capacitor C21 through the third node N23, and the source terminal of the second switch S22 is connected to the reference potential (GND). can be connected to

A source terminal of the third switch S23 may be connected to the other end of the first capacitor C21 through the third node N23.

A drain terminal of the fourth switch S24 may be connected to a drain terminal of the third switch S23 through the fourth node N24.

A drain terminal of the fifth switch S25 may be connected to a source terminal of the fourth switch S24 through a fifth node N25.

The drain terminal of the sixth switch S26 may be connected to the source terminal of the fifth switch S25 through the sixth node N26, and the source terminal of the sixth switch S26 may be connected to the reference potential GND.

A source terminal of the seventh switch S27 may be connected to a drain terminal of the fourth switch S24 through a fourth node N24.

One end (upper terminal in the drawing) of the second capacitor C22 is connected to the drain terminal of the fourth switch S24 through the fourth node N24, and the other end (lower terminal in the drawing) of the second capacitor C22 is It may be connected to the drain terminal of the sixth switch S26 through the sixth node N26.

A connection node N25 of the source terminal of the fourth switch S24 and the drain terminal of the fifth switch S25 may be connected to the output voltage Vo.

The drain terminal of the seventh switch S17 of the first circuit 110 is connected to one end of the first capacitor C21 through the second node N22 of the second circuit 120, and the second circuit 120 The drain terminal of the seventh switch S27 of may be connected to one end of the first capacitor C11 through the second node N12 of the first circuit 110 .

A switch used in the switch capacitor converter 200 may be a semiconductor switching element having an on/off control function. Although a MOSFET is illustrated in FIG. 2 as being used for a switch, a known semiconductor switching device such as an IGBT, MCT, or BJT may be used in addition to the MOSFET.

FIG. 3 is a diagram illustratively illustrating an operating waveform when the switched capacitor converter 200 of FIG. 2 operates at a voltage conversion ratio of 4:1, and FIG. 4 is a diagram of a switch of the switched capacitor converter 200 of FIG. 2 It is a diagram illustrating an on/off sequence by way of example.

2 to 4, the switched capacitor converter 200 repeats a first state (phase 1), a dead time (DT), a second state (phase 2), and a dead time (DT) can work as

As illustrated in FIG. 4 , the switches of the first circuit 110 and the second circuit 120 may belong to either one of the first switch group SG1 and the second switch group SG2 , respectively. Switches belonging to the same switch group can perform the same on/off operation.

Illustratively, the first switch S11, the third switch S13, the fifth switch S15, the seventh switch S17 of the first circuit 110, and the second switch of the second circuit 120 ( S22), the fourth switch S24, and the sixth switch S26 belong to the first switch group SG1, and the second switch S12, the fourth switch S14, and the second switch S14 of the first circuit 110 The six switches S16, the first switch S21, the third switch S23, the fifth switch S25, and the seventh switch S27 of the second circuit 120 belong to the second switch group SG2. can

The first switch group SG1 can be turned on in a first state (phase 1) and turned off in a second state (phase 2), and the second switch group SG2 is opposite to the first switch group SG1. It may be turned off in phase 1 and turned on in phase 2. During the dead time DT period, both the first switch group SG1 and the second switch group SG2 may be turned off.

The switch of the first circuit 110 belongs to one of the first switch group SG1 and the second switch group SG2, and the switch of the second circuit 120 is the corresponding switch of the first circuit 110 and It can be understood as belonging to different switch groups. For example, the first switch S11 of the first circuit 110 and the first switch S21 of the second circuit 120 may belong to different switch groups as corresponding switches. In this case, corresponding switches of the first circuit 110 and the second circuit 120 may be turned on/off complementary to each other.

The first state (phase 1) is a period in which the first switch group (SG1) is turned on and the second switch group (SG2) is turned off, and the second state (phase 2) is when the first switch group (SG1) is turned off , it may be a period in which the second switch group SG2 is turned on. The first phase (phase 1) and the second phase (phase 2) may have substantially the same length of time as each other. A dead time (DT) section may exist between the first state (phase 1) and the second state (phase 2).

3 shows the second node voltage VN12, the third node voltage VN13, and the fourth node voltage VN14 of the first circuit 110 in the first state (phase 1) and the second state (phase 2). , the sixth node voltage VN16 and the second node voltage VN22, the third node voltage VN23, the fourth node voltage VN24, and the sixth node voltage VN26 of the second circuit 120 are illustrated. there is.

The second node voltage VN12, the third node voltage VN13, the fourth node voltage VN14, and the sixth node voltage VN16 of the first circuit 110 are relatively high voltages in the first phase. state and may be in a relatively low voltage state in the second state (phase 2). Conversely, the second node voltage VN22, the third node voltage VN23, the fourth node voltage VN24, and the sixth node voltage VN26 of the second circuit 120 are relative in the first phase. It becomes a low voltage state and can become a relatively high voltage state in the second state (phase 2). Here, the relatively high voltage state or the relatively low voltage state means whether the voltage is relatively high or low when comparing the voltage in the first phase (phase 1) and the voltage in the second phase (phase 2) for the same node. can be understood as

As such, corresponding nodes (VN12 and VN22, VN13 and VN23, VN14 and VN24, and VN16 and VN26) at positions corresponding to each other of the first circuit 110 and the second circuit 120 may have voltage states complementary to each other. there is. Here, the fact that the corresponding nodes have voltage states complementary to each other means that when one node (eg, VN12) is in a relatively high voltage state, another node (eg, VN22) has a relatively low voltage state, and one node (eg, VN12) has a relatively high voltage state. When in the low voltage state, the other node (eg VN22) has a relatively high voltage state, and the voltage magnitude of the high voltage state of the two nodes (eg VN12 and VN22) is substantially the same as that of the two nodes (eg VN12 and VN22). It means that the voltage magnitudes of the low voltage state are substantially equal to each other.

However, since the first node N11 of the first circuit 110 and the first node N21 of the second circuit 120 are equally connected to the input voltage Vin, they do not have complementary voltage states. Also, since the fifth node N15 of the first circuit 110 and the fifth node N25 of the second circuit 120 are equally connected to the output voltage Vo, they do not have complementary voltage states. As such, it should be understood that not all corresponding nodes of the first circuit 110 and the second circuit 120 at positions corresponding to each other should have voltage states complementary to each other.

As illustrated in FIGS. 3 and 4 , all switches of the first circuit 110 and the second circuit 120 may be turned off during the dead time (DT) period. When switching between the first state (phase 1) and the second state (phase 2), switches belonging to the first switch group SG1 and the second switch group SG2 due to an error in the on/off timing of each switch Since a short may occur when turned on at the same time, a dead time DT period in which all switches of the first circuit 110 and the second circuit 120 are turned off may be set to prevent this.

5 and 6 are diagrams illustrating a first state (phase 1) of the switched-capacitor converter 200 of FIG. 2 by way of example.

The first switch S11, the third switch S13, the fifth switch S15, and the seventh switch of the first circuit 110 belonging to the first switch group SG1 in the first state (phase 1) ( S17), the second switch S22, the fourth switch S24, and the sixth switch S26 of the second circuit 120 are turned on, and the first circuit 110 belonging to the second switch group SG2 The second switch (S12), the fourth switch (S14), the sixth switch (S16), the first switch (S21), the third switch (S23), the fifth switch (S25) of the second circuit 120, 7 switch (S27) can be off. 5 exemplarily shows a connection state of the switched capacitor converter 200 in this case.

Considering the connection state of the switch of FIG. 5 , the switch is not shown and the connection relationship between the capacitors can be briefly shown as shown in FIG. 6 . The first capacitor C11 and the second capacitor C12 of the first circuit 110 are sequentially connected in series between the input voltage Vin and the output voltage Vo (here, the output voltage Vo has an output terminal It is shown that there is a capacitor Co, and the output capacitor Co is used in most applications), the second capacitor C22 of the second circuit 120 is connected in parallel to the output capacitor Co, The first capacitor C21 of the second circuit 120 may be connected to a connection node of the first capacitor C11 and the second capacitor C12 of the first circuit 110 .

Referring to FIG. 6 , relational expressions of voltages in the first state (phase 1) may be expressed as Equations 1 to 3 below.

Next, FIGS. 7 and 8 are diagrams illustrating a second state (phase 2) of the switched-capacitor converter 200 of FIG. 2 by way of example.

In the second state (phase 2), the first switch S11, the third switch S13, the fifth switch S15, and the seventh switch S17 of the first circuit 110 belonging to the first switch group SG1 ), the second switch S22, the fourth switch S24, and the sixth switch S26 of the second circuit 120 are turned off, and the first circuit 110 belonging to the second switch group SG2 2 switch (S12), 4th switch (S14), 6th switch (S16), 1st switch (S21), 3rd switch (S23), 5th switch (S25), 7th switch of the second circuit 120 Switch S27 may be turned on. 7 exemplarily shows a connection state of the switched capacitor converter 200 in this case.

Considering the switch connection state of FIG. 7 , the connection relationship between the capacitors can be briefly shown as shown in FIG. 8 . The first capacitor C21 and the second capacitor C22 of the second circuit 120 are sequentially connected in series between the input voltage Vin and the output voltage Vo, and the second capacitor C21 of the first circuit 110 The capacitor C12 is connected in parallel to the output capacitor Co, and the first capacitor C11 of the first circuit 110 is connected to the first capacitor C21 and the second capacitor C22 of the second circuit 120. It can be connected to the connection node of

Referring to FIG. 8 , relational expressions of voltages in the second state (phase 2) may be expressed as Equations 4 to 6 below.

By solving Equations 1 to 6, the voltage of each capacitor and the relationship between the input voltage Vin and the output voltage Vo can be obtained as in Equations 7 to 9.

As such, the switched-capacitor converter 200 of the present embodiment operates so that the input voltage Vin is four times the output voltage Vo, that is, the ratio of the input voltage Vin to the output voltage Vo is 4:1. However, the withstand voltage of the capacitor may not exceed twice Vo. That is, since a voltage conversion ratio of 4:1 can be implemented without using a capacitor with a high withstand voltage (eg, three or four times Vo), excellent performance in terms of size and efficiency can be exhibited.

When the switched-capacitor converter 200 of this embodiment operates in the manner illustrated in FIGS. 3 to 8, a voltage conversion ratio of 4:1 can be implemented, but when the on/off sequence of the switches is changed, the switched-capacitor converter 200 can operate with a voltage conversion ratio of 2:1 or 3:1.

FIG. 9 is a diagram illustrating switching loss of the switched capacitor converter 200 of FIG. 2 .

Referring to FIG. 3, each node voltage (VN12, VN22, VN13, VN23, VN14, VN24, VN16, VN26) switches between two voltage values in a first state (phase 1) and a second state (phase 2). (0 ↔ Vo for VN16 and VN26, Vo ↔ 2Vo for VN14 and VN24, 0 ↔ 2Vo for VN13 and VN23, 2Vo ↔ 4Vo for VN12 and VN22). In this way, switching loss may occur when the node voltage switches between two voltage values.

FIG. 9 is a diagram for explaining switching loss by way of example. It can be understood that V1 is a voltage value in a first state (phase 1) and V2 is a voltage value in a second state (phase 2). That is, the case where the voltage of a certain node switches between V1 and V2 is exemplified.

When the node voltage rapidly changes from V1 to V2 due to changes in the on/off state of the switches (901), energy loss proportional to the square of the voltage change amount (V2 - V1) may occur as shown in Equation 10.

Here, C can be understood as an equivalent capacitance connected to the corresponding node. An intentionally added capacitor element and/or parasitic capacitance may affect the equivalent capacitance.

Even when the node voltage rapidly changes from V2 to V1 due to changes in the on/off state of the switches (902), the same amount of energy loss as in the case of rapidly changing from V1 to V2 (901) may occur. Therefore, the switching loss due to the two switchings 901 and 902 illustrated in FIG. 9 can be expressed as Equation 11.

In existing mobile systems, switch-capacitor converters are mainly used when they operate at a voltage conversion ratio of 2:1. Switching losses were not much of an issue. However, when operating at a voltage conversion ratio of 4:1, as illustrated in FIG. 3, there are many nodes where the voltage change during switching is twice Vo, and switching loss can occur four times at these nodes (switching loss is proportional to the square of the change), the influence of switching losses can increase. Therefore, a countermeasure to reduce the switching loss is required.

However, it should be understood that this does not mean that the switched capacitor converter 200 illustrated in FIG. 2 itself is a circuit in which a lot of switching loss occurs. As described above, the switched capacitor converter 200 illustrated in FIG. 2 is a circuit that does not require a capacitor of high withstand voltage (3 or 4 times Vo), and only generates a voltage change of 2 Vo during switching, and a voltage change of 3 Vo or 4 Vo It is a circuit with relatively low switching loss compared to circuits that require the use of high voltage capacitors in that voltage variation (switching loss increases by 9 or 16 times) does not occur, but switching loss is accompanied by an increase in voltage conversion ratio. Since the proportion of will increase, it can be understood as the fact that it is desirable to prepare additional measures.

As such, the switched-capacitor converter 200 of FIG. 2 has a great advantage in that it can implement a voltage conversion ratio of 4:1 without using a high-voltage capacitor. However, there is room for improvement in that a sufficient solution to the increase in switching loss accompanying the increase in the voltage conversion ratio cannot be provided. Hereinafter, an embodiment in which switching loss can be reduced while taking advantage of the switched capacitor converter 200 of FIG. 2 will be described.

10 is a block diagram illustrating a switched capacitor converter 1000 according to another embodiment of the present invention.

The switched capacitor converter 1000 of FIG. 10 is different from the switched capacitor converter 100 of FIG. 1 in that it includes a charge sharing switch SC. Accordingly, the description of the switched-capacitor converter 100 of FIG. 1 may also be applied to the switched-capacitor converter 1000 of FIG. 10 unless otherwise described below.

The charge sharing switch SC may be disposed between corresponding nodes that are nodes at the same location in the first circuit 110 and the second circuit 120 . The charge sharing switch SC may be turned on during the dead time period DT so that corresponding nodes of the first circuit 110 and the second circuit 120 have substantially the same voltage value.

That is, as described above with reference to FIGS. 3 and 4, when the corresponding switches of the first circuit 110 and the second circuit 120 change their on/off states, the dead time (DT) in which all of the corresponding switches are turned off. ) period exists, and the charge sharing switch (SC) can be turned on in the dead time (DT) period. When the charge sharing switch SC is turned on during the dead time DT period, corresponding nodes of the first circuit 110 and the second circuit 120 may be in substantially the same voltage state. In this way, by using the charge sharing switch (SC) to ensure that the corresponding nodes have substantially the same voltage as each other during the dead time (DT) period, switching loss when the corresponding switches change their on/off states can be reduced. A principle of reducing switching loss by the charge sharing switch (SC) will be described in detail below.

FIG. 11 is a circuit diagram of a switched capacitor converter 1100 to which the embodiment of FIG. 10 is applied.

The switched capacitor converter 1100 illustrated in FIG. 11 is different from the switched capacitor converter 200 illustrated in FIG. 2 in that it further includes a first charge sharing switch SC1 and a second charge sharing switch SC2. there is. Accordingly, the description with reference to FIG. 2 can also be applied to FIG. 11, unless arranged as described below.

The first charge sharing switch SC1 is the other end of the first capacitor C11 of the first circuit 110 (lower terminal in the drawing) and the other end of the first capacitor C21 of the second circuit 120 (lower terminal in the drawing). terminal) can be connected between them. That is, the first charge sharing switch SC1 may be connected between the third node N13 of the first circuit 110 and the third node N23 of the second circuit 120 . Here, the third node N13 of the first circuit 110 and the third node N23 of the second circuit 120 may be understood as corresponding nodes.

The first charge sharing switch SC1 is turned on during the dead time DT period and connects the third node N13 of the first circuit 110 and the third node N23 of the second circuit 120 (eg, connection through a short circuit or small impedance, etc.) so that the third node N13 of the first circuit 110 and the third node N23 of the second circuit 120 have substantially the same voltage value ( That is, it can perform a charge sharing function). In this case, the first charge sharing switch SC1 is operated by the voltage holding action of the first capacitor C11 of the first circuit 110 and the first capacitor C21 of the second circuit 120. A charge sharing function between the second node N12 of the second circuit 120 and the second node N22 of the second circuit 120 is also performed.

According to an embodiment, the first charge sharing switch SC1 is formed by connecting one end (upper terminal in the drawing) of the first capacitor C11 of the first circuit 110 and the first capacitor C21 of the second circuit 120. It may be connected between one end (upper terminal in the drawing). That is, the first charge sharing switch SC1 may be connected between the second node N12 of the first circuit 110 and the second node N22 of the second circuit 120 . Even in this case, the first charge sharing switch SC1 is operated by the voltage holding action of the first capacitor C11 of the first circuit 110 and the first capacitor C21 of the second circuit 120. Charge sharing between the second node N12 of ) and the second node N22 of the second circuit 120 and the third node N13 of the first circuit 110 and the third node N13 of the second circuit 120 Charge sharing between the nodes N23 may be simultaneously performed.

According to the embodiment, the first charge sharing switch SC1 is between one end of the first capacitor C11 of the first circuit 110 and one end of the first capacitor C21 of the second circuit 120 and the first circuit It may be used together between the other end of the first capacitor C11 of (110) and the other end of the first capacitor C21 of the second circuit 120. That is, two first charge sharing switches SC1 may be used.

As such, the first charge sharing switch SC1 is connected and/or connected between one end of the first capacitor C11 of the first circuit 110 and one end of the first capacitor C21 of the second circuit 120. It may be connected between the other end of the first capacitor C11 of the first circuit 110 and the other end of the first capacitor C21 of the second circuit 120. However, as illustrated in FIG. 11 , a first charge sharing switch SC1 is provided between the other end of the first capacitor C11 of the first circuit 110 and the other end of the first capacitor C21 of the second circuit 120. When is used, the voltage level is relatively low and the driving circuit is easy to implement.

The second charge sharing switch SC2 is the other end of the second capacitor C12 of the first circuit 110 (lower terminal in the drawing) and the other end of the second capacitor C22 of the second circuit 120 (lower terminal in the drawing). terminal) can be connected between them. That is, the second charge sharing switch SC2 may be connected between the sixth node N16 of the first circuit 110 and the sixth node N26 of the second circuit 120 . Here, the sixth node N16 of the first circuit 110 and the sixth node N26 of the second circuit 120 may be understood as corresponding nodes.

The second charge sharing switch SC2 is turned on during the dead time DT period to connect the sixth node N16 of the first circuit 110 and the sixth node N26 of the second circuit 120 (eg, connection through a short circuit or small impedance, etc.) so that the sixth node N16 of the first circuit 110 and the sixth node N26 of the second circuit 120 have substantially the same voltage value ( That is, it can perform a charge sharing function). In this case, the second charge sharing switch SC2 is operated by the voltage holding action of the second capacitor C12 of the first circuit 110 and the second capacitor C22 of the second circuit 120. A charge sharing function is also performed between the fourth node N14 of and the fourth node N24 of the second circuit 120 .

Depending on the embodiment, the second charge sharing switch SC2 is formed between one end (upper terminal in the drawing) of the second capacitor C12 of the first circuit 110 and the second capacitor C22 of the second circuit 120. It may be connected between one end (upper terminal in the drawing). That is, the second charge sharing switch SC2 may be connected between the fourth node N14 of the first circuit 110 and the fourth node N24 of the second circuit 120 . Even in this case, the second charge sharing switch SC2 is operated by the voltage holding action of the second capacitor C12 of the first circuit 110 and the second capacitor C22 of the second circuit 120. Charge sharing between the fourth node N14 of ) and the fourth node N24 of the second circuit 120 and the sixth node N16 of the first circuit 110 and the sixth node N16 of the second circuit 120 The charge sharing function between the nodes N26 can be simultaneously performed.

According to the embodiment, the second charge sharing switch SC2 is between one end of the second capacitor C12 of the first circuit 110 and one end of the second capacitor C22 of the second circuit 120 and the first circuit It may be used together between the other end of the second capacitor C12 of (110) and the other end of the second capacitor C22 of the second circuit 120. That is, two second charge sharing switches SC2 may be used.

As such, the second charge sharing switch SC2 is connected and/or connected between one end of the second capacitor C12 of the first circuit 110 and one end of the second capacitor C22 of the second circuit 120. It may be connected between the other end of the second capacitor C12 of the first circuit 110 and the other end of the second capacitor C22 of the second circuit 120. However, when the second charge sharing switch SC2 is disposed between the other end of the second capacitor C12 of the first circuit 110 and the other end of the second capacitor C22 of the second circuit 120, the voltage level is It has the advantage of being relatively low and easy to implement a driving circuit.

11 illustrates that both the first charge sharing switch SC1 and the second charge sharing switch SC2 are used, but either one of the first charge sharing switch SC1 or the second charge sharing switch SC2 may not be used. That is, at least one of the first charge sharing switch SC1 and the second charge sharing switch SC2 may be used.

The first charge sharing switch SC1 and/or the second charge sharing switch SC2 may reduce switching loss by making voltage values of corresponding nodes substantially equal to each other in the dead time DT period.

The first charge sharing switch SC1 and/or the second charge sharing switch SC2 may be semiconductor switching elements capable of bidirectional on/off control. 11 illustrates that MOSFETs are used for the first charge sharing switch SC1 and the second charge sharing switch SC2, but the first charge sharing switch SC1 and/or the second charge sharing switch SC2 In addition to the MOSFET, a known semiconductor switching element capable of bi-directional on/off control may be used. For example, as illustrated in FIG. 15, a back-gate control MOSFET is used for the first charge sharing switch SC1 and/or the second charge sharing switch SC2, or two MOSFETs may be connected back-to-back.

FIG. 12 is a diagram illustrating an operating waveform of the switched-capacitor converter 1100 of FIG. 11 by way of example.

Compared to the operation waveform illustrated in FIG. 12 , the operation waveform illustrated in FIG. 3 shows the voltage value of each node in the dead time (DT) period in the first phase (phase 1) and the second phase (phase 2). It is different in that it changes to a voltage value (eg, an average value) within a range of voltage values. This is because the first charge sharing switch SC1 and/or the second charge sharing switch SC2 are turned on during the dead time DT period to make voltage values of corresponding nodes substantially equal to each other. For example, when the first charge sharing switch SC1 is turned on during the dead time DT period, the third node N13 of the first circuit 110 and the third node N23 of the second circuit 120 are Since they are connected to each other, the third node voltage VN13 of the first circuit 110 and the third node voltage VN23 of the second circuit 120 are substantially equal to each other. In addition, since the first capacitor C11 of the first circuit 110 and the first capacitor C21 of the second circuit 120 maintain substantially the same voltage (2·Vo) (see Equation 7), When the first charge sharing switch SC1 is turned on, the second node voltage VN12 of the first circuit 110 and the second node voltage VN22 of the second circuit 120 become substantially equal to each other. In the same principle, the fourth node voltage VN14 of the first circuit 110 and the fourth node voltage of the second circuit 120 ( VN24 is substantially equal to each other, and the sixth node voltage VN16 of the first circuit 110 and the sixth node voltage VN26 of the second circuit 120 are substantially equal to each other.

Here, two nodes connected to each other determine what voltage value each node has within the range of high voltage and low voltage in the dead time (DT) period by the first charge sharing switch SC1 and/or the second charge sharing switch SC2. may be affected by the capacitance of For example, when the first charge sharing switch SC1 is turned on, the third node N13 of the first circuit 110 and the third node N23 of the second circuit 120 are connected to each other (eg, short circuit). When the capacitance of the third node N13 of the first circuit 110 and the capacitance of the third node N23 of the second circuit 120 are the same, they have an average value of the voltages of the two nodes, but When the capacitances are different from each other, a voltage value determined according to the size of the capacitance of the two nodes may be formed. In FIG. 12 , it is assumed that the capacitances of the corresponding nodes are the same, and as a result, the voltage value in the dead time (DT) section is illustrated as an average value of the two node voltages.

As such, since the first charge sharing switch SC1 and/or the second charge sharing switch SC2 operate only in the dead time DT period to reduce switching loss, the first state (phase 1) and the second charge sharing switch (phase 1) Operation in phase 2 is not substantially affected. Therefore, it can be considered that there is no practical effect on the basic operation of the switched-capacitor converter 1100, such as a voltage conversion ratio.

FIG. 13 is a diagram illustrating an on/off operation of switches of the switched capacitor converter 1100 of FIG. 11 by way of example.

Referring to FIG. 13 , the switching sequence of the switches belonging to the first switch group SG1 and the second switch group SG2 is the same as that described with reference to FIG. 4 . Accordingly, the description with reference to FIG. 4 can also be applied to FIG. 13 unless otherwise arranged as will be described below.

That is, the first, third, fifth, and seventh switches S11, S13, S15, and S17 of the first circuit 110 and the second, fourth, and sixth switches S22, S24, and S26 of the second circuit 120 are The first, third, fifth, and seventh switches S21, S23, S25, and S27 of the second circuit 120 belong to the first switch group SG1 turned on in the first state (phase 1) and the first circuit ( The second, fourth, and sixth switches S12, S14, and S16 of 110) belong to the second switch group SG2 turned on in the second state (phase 2), and are the first charge sharing switch SC1 and/or the second switch group SG2. The second charge sharing switch SC2 may be turned on during the dead time DT period in which both switches of the first circuit 110 and the second circuit 120 are turned off.

The first phase (phase 1) and the second phase (phase 2) have substantially the same time length, and there is a dead time (DT) section between the first phase (phase 1) and the second phase (phase 1). can

When the switched capacitor converter 1100 operates in the switching sequence illustrated in FIG. 13 , as described with reference to FIG. 4 , the switched capacitor converter 1100 may operate with a voltage conversion ratio of 4:1.

FIG. 14 is a diagram explaining a principle of reducing switching loss by the charge sharing switches SC1 and/or SC2 of the switched capacitor converter 1100 of FIG. 11 .

As described above, when the first charge sharing switch SC1 and/or the second charge sharing switch SC2 are turned on in the dead time DT period, the voltages of each node are the first voltage V1 and the second voltage ( V2) can be changed to a voltage value (intermediate voltage, VM) between. In FIG. 14 , for convenience of explanation, it is assumed that the capacitances of the corresponding nodes are the same and the intermediate voltage VM is the average value of the first voltage V1 and the second voltage V2 in the dead time DT period. However, even if the intermediate voltage VM is not the average of the first voltage V1 and the second voltage V2, there is only a difference in the degree, and the charge sharing switch can reduce switching loss.

Referring to FIG. 14, when transitioning from the first state (phase 1) to the second state (phase 2), a first change 1401 and a second change 1402 occur, and in the second state (phase 2) When switching to the first state (phase 1), a third change 1403 and a fourth change 1404 may occur.

First, looking at the first change 1401 and the third change 1403, in the first change 1401, the corresponding node (voltage V1) receives charge from the corresponding node (voltage V2) and is charged so that the voltage becomes the intermediate voltage. (VM), and the third change (1403) is a change in which the corresponding node (voltage V2) provides charge to the corresponding node (voltage V1) and is partially discharged, thereby lowering the voltage to the intermediate voltage (VM). , the first change 1401 and the third change 1403 are charge sharing processes by the charge sharing switch.

The energy charged to the corresponding node by the first change 1401, that is, the energy change ΔE (1401) corresponds to the difference between the energy when the voltage is VM and the energy when the voltage is V1, so as shown in Equation 12 can indicate

Here, C can be understood as the equivalent capacitance of the corresponding node.

In addition, since the energy discharged from the corresponding node by the third change 1403, that is, the energy change ΔE 1403 corresponds to the difference between the energy in the state where the voltage is V2 and the energy in the state where the voltage is VM, Equation 13 can be expressed as

The loss (charge sharing loss) caused by the first change 1401 and the third change 1403 is the energy change due to the third change 1403 ΔE (1403) to the energy change due to the first change 1401 ΔE Since it is a value obtained by subtracting (1401) (that is, the difference between energy provided by a node with a high voltage and energy stored by a corresponding node with a low voltage), the equation can be expressed as Equation 14. In the derivation of Equation 14, the assumption that the intermediate voltage VM is the average value of the first voltage V1 and the second voltage V2 is applied.

Here, the loss expressed by Equation 14 may be referred to as a charge sharing loss because it is a loss caused by charge sharing through a charge sharing switch.

Next, as described with reference to FIG. 9 , the second change 1402 and the fourth change 1404 are hard-switching phenomena in which switching loss occurs, and the voltage rapidly changes. However, in FIG. 14, since the rapid voltage changes 1402 and 1404 occur after the node voltage is changed to the intermediate voltage VM by the charge sharing switch SC1 and/or SC2, the rapidly changing voltage change amount is reduced by half. There is a difference from the example of FIG. 9 in . Therefore, the switching loss due to the second change 1402 and the fourth change 1404 can be expressed as Equations 15 and 16.

Since the second change 1402 can be understood as a loss due to turn-on and the fourth change 1404 can be understood as a loss due to turn-off, the second change The sum of losses due to 1402 and the fourth change 1404 can be expressed as turn on and off loss. Assuming that VM is the average value of V1 and V2 and calculating turn on and off loss, it can be expressed as in Equation 17.

Since the switching loss due to the first change 1401 to the fourth change 1404 illustrated in FIG. 14 is the sum of Equations 14 and 17, it can be expressed as Equation 18.

In the case of the embodiment of FIG. 2 without using the charge sharing switch, the switching loss of Equation 11 occurs as described with reference to FIG. 9, whereas when using the charge sharing switch, the switching loss of Equation 18 occurs. Switching losses can be halved if a charge-sharing switch is used.

To summarize the reason, before the second change 1402 and the fourth change 1404 in which a loss proportional to the square of the voltage change occurs, the charge sharing switches SC1 and SC2 are turned on, and the node voltage is converted to the intermediate voltage. (VM) can be understood as an effect of reducing the amount of voltage change in the second change 1402 and the fourth change 1404.

As such, the switched-capacitor converter 1100 illustrated in FIG. 11 maintains the advantage of being able to implement a voltage conversion ratio of 4: 1 without using a high withstand voltage capacitor, and the accompanying increase in voltage conversion ratio It also has the advantage that an increase in switching loss can be suppressed.

16 is a circuit diagram of a switched capacitor converter 1600 according to another embodiment of the present invention.

The switched capacitor converter 1600 of FIG. 16 includes the seventh switch S17 of the first circuit 110, the first switch S21 of the second circuit 120 in the switched capacitor converter 200 illustrated in FIG. It can be understood as a state in which the first capacitor C21, the second switch S22, and the third switch S23 are removed.

Specifically, the switched capacitor converter 1600 includes a first switch S31 having a drain terminal connected to the input voltage Vin, a first capacitor C31 having one end connected to the source terminal of the first switch S31, A second switch S32 having a drain terminal connected to the other end of the first capacitor C31 and having a source terminal connected to a reference potential, a third switch S33 having a source terminal connected to the other end of the first capacitor C31, A fourth switch S34 having a drain terminal connected to the drain terminal of the third switch S33, a fifth switch S35 having a drain terminal connected to the source terminal of the fourth switch S34, and a fifth switch S35 A drain terminal is connected to the source terminal of the source terminal, and one end is connected to the drain terminals of the sixth switch S36 and the fourth switch S34 connected to the reference potential, and the other end is connected to the drain terminal of the sixth switch S36. A second capacitor C32 connected thereto, a seventh switch S37 having a drain terminal connected to one end of the first capacitor C31, and a third capacitor C33 having one end connected to the source terminal of the seventh switch S37. , the eighth switch S38 having a drain terminal connected to one end of the third capacitor C33, a drain terminal connected to a source terminal of the eighth switch S38, and a source terminal connected to the other end of the third capacitor C33. It may include a ninth switch S39, and a 10th switch S40 having a drain terminal connected to a source terminal of the ninth switch S39 and a source terminal connected to a reference potential.

Here, the source terminal of the fourth switch S34 and the source terminal of the eighth switch S38 may be connected to the output voltage Vo.

The switch-capacitor converter 1600 configured as described above can selectively operate among voltage conversion ratios of 2:1, 3:1, and 4:1. Explain.

FIG. 17 is a diagram illustrating an operating waveform of the switched-capacitor converter 1600 of FIG. 16 by way of example.

As an embodiment, the 1st, 3rd, 5th, 8th, and 10th switches S31, S33, S35, S38, and S40 belong to the first switch group SG1 turned on in the first state (phase 1) and the second , 4, 6, 7, and 9 switches (S32, S34, S36, S37, S39) may belong to the second switch group (SG2) turned on in the second state (phase 2). The first phase (phase 1) and the second phase (phase 2) have substantially the same time length, and there is a dead time period (DT) between the first phase (phase 1) and the second phase (phase 2). can

FIG. 18 is a diagram illustrating a first state (phase 1) of the switched-capacitor converter 1600 of FIG. 16 by way of example. Referring to FIG. 18, the first capacitor C31 and the second capacitor C32 are sequentially connected in series between the input voltage Vin and the output voltage Vo, and the third capacitor C33 has an output voltage ( Vo) can be connected in parallel.

FIG. 19 is a diagram illustrating a second state (phase 2) of the switched-capacitor converter of FIG. 16 by way of example. Referring to FIG. 19 , one end of the first capacitor C31 is connected to one end of the third capacitor C33, the other end of the first capacitor C31 is connected to the reference potential GND, and the second capacitor C32 ) may be connected in parallel to the output voltage Vo, and the other end of the third capacitor C33 may be connected to the output voltage Vo.

For the case where the first state (phase 1) and the second state (phase 2) have a connection relationship as illustrated in FIGS. 18 and 19, respectively, the voltage conversion ratio in the manner described above with reference to FIGS. 6 and 8 When calculating , it can be seen that the switched-capacitor converter 1600 of FIG. 16 has a voltage conversion ratio of 4:1. When the switching sequence of the first switch S31 to the tenth switch S40 is different from that illustrated in FIG. 17 , the switch-capacitor converter 1600 may operate with a voltage conversion ratio of 2:1 or 3:1.

FIG. 20 is a circuit diagram of a switched capacitor converter 2000 according to another embodiment of the present invention in which a charge sharing switch SC3 is added to the switched capacitor converter 1600 of FIG. 16 .

Referring to FIG. 17 , it can be seen that the sixth node voltage VN36 and the ninth node voltage VN39 have complementary voltage states. Accordingly, the charge sharing switch SC3 may be connected between the sixth node N36 and the ninth node N39. That is, the charge sharing switch SC3 may be connected between the other end of the second capacitor C32 and the other end of the third capacitor C33. In this case, the charge sharing switch SC3 simultaneously performs a charge sharing function between the fourth node N34 and the seventh node N37 as well as between the sixth node N36 and the ninth node N39. can do. As described above, the charge sharing switch SC3 can reduce switching loss by being turned on during a dead time period in which all switches belonging to the first switch group SG1 and the second switch group SG2 are turned off.

Depending on the embodiment, the charge sharing switch SC3 may be changed to be connected between one end of the second capacitor C32 and one end of the third capacitor C33. Alternatively, the charge sharing switch SC3 may be used together between one end of the second capacitor C32 and one end of the third capacitor C33 and between the other end of the second capacitor C32 and the other end of the third capacitor C33. .

As such, the charge sharing switch SC3 is provided between one end of the second capacitor C32 and one end of the third capacitor C33 and/or between the other end of the second capacitor C32 and the other end of the third capacitor C33. Although the charge sharing switch SC3 is used for only one of the two, the sixth node N36 and the ninth node N39 are connected by the voltage holding action of the second capacitor C32 and the third capacitor C33. The charge sharing between the terminals and the charge sharing between the fourth node N34 and the seventh node N37 may be simultaneously performed. However, when the charge sharing switch SC3 is disposed between the other end of the second capacitor C32 and the other end of the third capacitor C33, the voltage level is relatively low and the driving circuit is easy to implement.

The charge sharing switch may be a semiconductor switching device capable of bi-directional on/off control. Illustratively, as illustrated in FIG. 15, a back-gate control MOSFET may be used or two MOSFETs may be used in a back-to-back connection. .

Terms such as "comprise", "comprise" or "having" described above mean that the corresponding component may be inherent unless otherwise stated, and therefore do not exclude other components. It should be construed that it may further include other components. All terms, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which the present invention belongs, unless defined otherwise. Commonly used terms, such as terms defined in a dictionary, should be interpreted as consistent with the meaning in the context of the related art, and unless explicitly defined in the present invention, they are not interpreted in an ideal or excessively formal meaning.

The above description is merely an example of the technical idea of the present invention, and various modifications and variations can be made to those skilled in the art 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 idea of the present invention, but to explain, and the scope of the technical idea of the present invention is not limited by these embodiments. The protection scope of the present invention should be construed according to the claims below, and all technical ideas within the equivalent range should be construed as being included in the scope of the present invention.

Claims (17)

a first circuit comprising at least one capacitor and at least one switch; and A second circuit composed of substantially the same circuit as the first circuit, Corresponding switches at positions corresponding to each other of the first circuit and the second circuit are turned on/off complementary to each other, At least some of the corresponding nodes of the first circuit and the second circuit at positions corresponding to each other have voltage states complementary to each other, At least a portion of the corresponding node, a charge sharing switch is disposed, the switched capacitor converter. The method of claim 1, Switched-capacitor converter, characterized in that when the corresponding switches change their on / off state with each other, there is a dead time interval in which all of the corresponding switches are turned off, and the charge sharing switch is turned on in the dead time interval. The method of claim 2, When the charge sharing switch is turned on in the dead time period, the corresponding nodes have substantially the same voltage value as each other. The method of claim 3, A switched capacitor converter, characterized in that switching loss when the corresponding switch changes on / off state is reduced by using the charge sharing switch so that the corresponding nodes have substantially the same voltage value as each other in the dead time period. The method of claim 1, The switch of the first circuit belongs to one of a first switch group turned on in a first state and a second switch group turned on in a second state, The switch of the second circuit belongs to a different switch group from the corresponding switch of the first circuit. The method of claim 5, The switched-capacitor converter, characterized in that the first state and the second state have substantially the same time length, and a dead time interval exists between the first state and the second state. a first circuit comprising at least one capacitor and at least one switch; and A second circuit composed of substantially the same circuit as the first circuit, The first circuit and the second circuit, respectively, a first switch having a drain terminal connected to an input voltage; a first capacitor having one end connected to the source terminal of the first switch; a second switch having a drain terminal connected to the other end of the first capacitor and a source terminal connected to a reference potential; a third switch having a source terminal connected to the other end of the first capacitor; a fourth switch having a drain terminal connected to the drain terminal of the third switch; a fifth switch having a drain terminal connected to a source terminal of the fourth switch; a sixth switch having a drain terminal connected to the source terminal of the fifth switch and a source terminal connected to a reference potential; a seventh switch having a source terminal connected to the drain terminal of the fourth switch; and A second capacitor having one end connected to the drain terminal of the fourth switch and the other end connected to the drain terminal of the sixth switch; A drain terminal of the seventh switch of the first circuit is connected to one end of the first capacitor of the second circuit, and a drain terminal of the seventh switch of the second circuit is connected to the first capacitor of the first circuit. A switched capacitor converter, characterized in that connected to one end of. The method of claim 7, The switch capacitor converter, characterized in that the connection node of the source terminal of the fourth switch and the drain terminal of the fifth switch is connected to the output voltage. The method of claim 7, The switch capacitor converter includes at least one of a first charge sharing switch and a second charge sharing switch, The first charge sharing switch is connected between one end of the first capacitor of the first circuit and one end of the first capacitor of the second circuit and/or between the other end of the first capacitor of the first circuit and the second circuit. 2 connected between the other ends of the first capacitor of the circuit, The second charge sharing switch is connected between one end of the second capacitor of the first circuit and one end of the second capacitor of the second circuit and/or between the other end of the second capacitor of the first circuit and the second charge sharing switch. Switched capacitor converter, characterized in that connected between the other end of the second capacitor of the second circuit. The method of claim 9, The first charge sharing switch and / or the second charge sharing switch is a switched capacitor converter, characterized in that the semiconductor switching element capable of bi-directional on / off control. The method of claim 9, The first, third, fifth, and seventh switches of the first circuit and the second, fourth, and sixth switches of the second circuit belong to a first switch group that is turned on in a first state, and the second switch of the second circuit Switches 1, 3, 5, and 7 and the switches 2, 4, and 6 of the first circuit belong to a second switch group that is turned on in a second state, The first charge sharing switch and / or the second charge sharing switch is turned on in a dead time period in which all switches belonging to the first switch group and the second switch group are turned off. The method of claim 11, The switched-capacitor converter, characterized in that the first state and the second state have substantially the same length of time, and the dead time interval exists between the first state and the second state. A first switch (S31) having a drain terminal connected to the input voltage; a first capacitor C31 having one end connected to the source terminal of the first switch; a second switch (S32) having a drain terminal connected to the other end of the first capacitor and a source terminal connected to a reference potential; a third switch (S33) having a source terminal connected to the other end of the first capacitor; a fourth switch (S34) having a drain terminal connected to the drain terminal of the third switch; a fifth switch (S35) having a drain terminal connected to the source terminal of the fourth switch; a sixth switch (S36) having a drain terminal connected to the source terminal of the fifth switch and a source terminal connected to a reference potential; a second capacitor C32 having one end connected to the drain terminal of the fourth switch and the other end connected to the drain terminal of the sixth switch; a seventh switch (S37) having a drain terminal connected to one end of the first capacitor; a third capacitor (C33) having one end connected to the source terminal of the seventh switch; an eighth switch (S38) having a drain terminal connected to one end of the third capacitor; a ninth switch (S39) having a drain terminal connected to the source terminal of the eighth switch and a source terminal connected to the other terminal of the third capacitor; and A tenth switch (S40) having a drain terminal connected to the source terminal of the ninth switch and a source terminal connected to a reference potential; including, A switched capacitor converter, characterized in that a charge sharing switch (SC3) is connected between one end of the second capacitor and one end of the third capacitor and / or between the other end of the second capacitor and the other end of the third capacitor. The method of claim 13, A source terminal of the fourth switch and a source terminal of the eighth switch are connected to an output voltage. The method of claim 13, The charge sharing switch is a switched capacitor converter, characterized in that the semiconductor switching element capable of bi-directional on / off control. The method of claim 13, The switches 1, 3, 5, 8, and 10 belong to a first switch group turned on in a first state, and the switches 2, 4, 6, 7, and 9 belong to a second switch group turned on in a second state. belong to, The charge sharing switch is switched-capacitor converter, characterized in that turned on in a dead time period in which all switches belonging to the first switch group and the second switch group are turned off. The method of claim 16 The switched-capacitor converter, characterized in that the first state and the second state have substantially the same length of time, and the dead time interval exists between the first state and the second state.

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