Resonant switched capacitor dc / dc converter and power supply system

Abstract

The application discloses a resonant switched capacitor DC / DC converter and a power supply system, comprising: N resonant switched capacitor groups, M capacitors and at least one LC series circuit; N is an integer greater than or equal to 2; M is an integer less than or equal to N; each resonant switched capacitor group comprises: a switch and a resonant circuit; the resonant circuit comprises a resonant inductor and a resonant capacitor; the LC series circuit is connected between any two resonant switched capacitor groups, that is, a circuit in which an inductor and a capacitor are connected in series. Since the resonant inductor is not sufficient to completely discharge the charge on the junction capacitor of the switch at the moment when the switch is turned off, the charge on the junction capacitor of the switch is completely discharged by increasing the inductor, that is, the current is drawn away, so that the switch realizes soft switching. When each switch truly realizes soft switching, the power consumption of the whole resonant switched capacitor DC / DC converter can be reduced, and the power conversion efficiency of the resonant switched capacitor DC / DC converter is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of power electronics, and particularly relates to a resonant switched capacitor DC / DC converter and a power supply system. BACKGROUND

[0002] At present, switching power supplies are widely used in various electrical equipment to provide power supply meeting requirements for electrical equipment.

[0003] For example, when the application scene is artificial intelligence (AI) and a data center, the power supply voltage of a service single board is generally 48V. The power supply voltage of chips and various loads inside the service single board needs to be lower than 48V, that is, the power supply voltage 48V of the service single board cannot directly supply power to the chips and various loads, and generally needs to be reduced to 5V, 3.3V and 1.8V to supply power to the chips and various loads.

[0004] At present, the DC (Direct Current) / DC converter used for voltage reduction generally adopts an isolated topology, for example, an LLC resonant DC / DC converter.

[0005] The main disadvantage of the LLC resonant DC / DC converter is that it includes a transformer. Since the transformer generally includes a primary winding, a secondary winding and a magnetic core, the volume is large, thus leading to a large volume of the power supply and difficulty in thinning the thickness. In order to reduce the volume, only the switching frequency can be increased, but the increase of the switching frequency will increase the power consumption, leading to the reduction of the power supply efficiency.

[0006] Application Content

[0007] The present application provides a resonant switched capacitor DC / DC converter and a power supply system, which can reduce the volume of the DC / DC converter and improve the power conversion efficiency.

[0008] Embodiments of the present application provide a resonant switched capacitor DC / DC converter, which can be applied to any scenario of a switching power supply, such as power supply of an AI chip or a power supply board of a data center, and can be used as a step-down converter, and then connected to a one-stage voltage stabilizing circuit to output a stable voltage of a load output. It should be understood that embodiments of the present application do not limit the specific application scenario of the DC / DC converter, and the DC / DC converter can be a bidirectional converter, which can be used as a step-up converter and a step-down converter. In order to reduce the area occupied by the circuit and reduce the cost, the LC series circuit can also only include one LC series circuit, and the connection position of the LC series circuit is not specifically limited, and the LC series circuit can be connected between any two resonant cavities. In a possible implementation manner, the LC series circuit can be connected between two resonant cavities with higher voltage, that is, connected between two resonant cavities close to the high-voltage side. Since the reverse voltage borne by the resonant inductor in the resonant cavity on the high-voltage side is higher, the corresponding junction capacitance of the switch is easy to be not fully charged or not fully discharged when charging and discharging.

[0009] The DC / DC converter includes N resonant switched capacitor groups, M capacitors, and at least one LC series circuit; N is an integer greater than or equal to 2; M is an integer less than or equal to N; the LC series circuit includes a first inductor and a first capacitor in series; each resonant switched capacitor group includes a switch and a resonant circuit; the resonant circuit includes at least a resonant inductor and a resonant capacitor; and the two ends of the LC series circuit are respectively connected to resonant circuits in two different resonant switched capacitor groups. Generally, the resonant inductor and the resonant capacitor are connected in series to form a series resonant circuit. The first capacitor in the LC series circuit is used to balance the voltage to prevent the first inductor from being magnetically saturated and unable to work normally during the charging and discharging processes. Embodiments of the present application do not limit the number of LC series circuits connected to the resonant cavities, and one LC series circuit can be connected between any two resonant cavities.

[0010] The function of the resonant inductor in each resonant switch capacitor group is to reduce the current impact of the charging and discharging current on the resonant capacitor, and to reduce the impact of the charging and discharging current on the switch, reduce the loss, and improve the power conversion efficiency of the converter. The embodiment of the present application provides a resonant switch capacitor DC / DC converter, and an LC series circuit is connected between any two resonant switch capacitor groups, that is, a circuit in which an inductor and a capacitor are connected in series. Because the MOS tube is in the instant of turn-off, the resonant inductor is not enough to completely discharge the charge on the junction capacitor of the MOS tube, therefore, by increasing the inductor, the charge on the junction capacitor of the MOS tube is completely discharged, that is, the current is drawn away, so as to realize the soft switching of the MOS tube. When each switch truly realizes soft switching, the power consumption of the entire resonant switch capacitor DC / DC converter can be reduced, thereby improving the power conversion efficiency of the resonant switch capacitor DC / DC converter. In addition, because the direct current / direct current converter does not include a transformer, the size of the converter can be reduced. When the LC series circuit is connected between two resonant switch capacitor groups with higher voltage, the soft switching effect is better.

[0011] In a possible implementation manner, M is equal to N, and the N resonant switch capacitor groups are respectively in one-to-one correspondence with the M capacitors; that is, one resonant switch capacitor group corresponds to one of the M capacitors. Two input ends of each resonant switch capacitor group are respectively connected to two ends of the corresponding capacitor, and two output ends of each resonant switch capacitor group are respectively connected to two ends of the output capacitor.

[0012] The embodiment of the present application adds an LC series circuit to the resonant cavity, mainly uses the first inductor in the LC series circuit to forcibly charge and discharge the junction capacitor of the switch in the resonant cavity, and further ensures that the switch realizes soft switching when the switch is in action. Moreover, the turn-off angle of each resonant switch capacitor group can be reduced, and the turn-off damage of each switch in each resonant switch capacitor group and the equivalent current effective value can be reduced. Because the greater the equivalent current effective value is, the higher the switching loss of the corresponding switch is. The technical scheme provided by the embodiment can make each resonant switch capacitor group closer to the turn-off angle of 180 degrees, thereby improving the load regulation rate of the resonant switch capacitor DC / DC converter.

[0013] In a possible implementation manner, the N resonant switch capacitor groups at least include a first type of resonant capacitor group and a second type of resonant switch capacitor group; the first type of resonant switch capacitor group corresponds to at least two capacitors connected in series in the M capacitors; two input ends of the first type of resonant switch capacitor group are respectively connected to two ends of the at least two capacitors connected in series; the second type of resonant switch capacitor group corresponds to one capacitor in the M capacitors, and two input ends of the second type of resonant switch capacitor group are respectively connected to two ends of the one capacitor in the M capacitors.

[0014] In the case where at least one resonant switched capacitor bank corresponds to multiple capacitors connected in series, this situation differs from the one described above. By changing the connection relationship between the resonant switched capacitor bank and its corresponding capacitors, the voltage transformation ratio of the converter can be altered. For example, the voltage transformation ratio can be increased without increasing the number of resonant switched capacitor banks, thereby saving hardware circuitry, reducing the circuit board area occupied by the entire converter, and saving costs.

[0015] In one possible implementation, the output capacitor and the N capacitors are connected in series between the two input terminals of the converter, and the output capacitor is connected between the two output terminals of the converter; the two input terminals of the converter are connected to the two ends of a DC power supply; the converter is used to step down the voltage of the DC power supply and output it.

[0016] In one possible implementation, the output capacitor and the N capacitors are connected in series between the two output terminals of the converter, and the output capacitor is connected between the two input terminals of the converter; the two input terminals of the converter are connected to the two ends of a DC power supply; the converter is used to boost the voltage of the DC power supply and output it.

[0017] In one possible implementation, each of the resonant switched capacitor groups includes at least four switches: a first switch, a second switch, a third switch, and a fourth switch; the first terminal of the first switch is connected to the first terminal of the capacitor corresponding to the resonant switched capacitor group, and the first terminal of the second switch is connected to the second terminal of the capacitor corresponding to the resonant switched capacitor group; the second terminal of the first switch is connected to the first terminal of the third switch, and the second terminal of the second switch is connected to the first terminal of the fourth switch; the resonant capacitor and the resonant inductor are connected in series to the second terminals of the first switch and the second terminal of the second switch; the second terminal of the third switch is connected to the second terminal of the output capacitor, and the second terminal of the fourth switch is connected to the first terminal of the output capacitor.

[0018] In one possible implementation, the first terminal of the LC series circuit is connected to the second terminal of the first switching transistor in one of the resonant switched capacitor groups, and the second terminal of the LC series circuit is connected to the second terminal of the first switching transistor in the other resonant switched capacitor group.

[0019] In one possible implementation, the first terminal of the LC series circuit is connected to the second terminal of the second switch in one of the resonant switched capacitor groups, and the second terminal of the LC series circuit is connected to the second terminal of the second switch in the other resonant switched capacitor group.

[0020] In one possible implementation, the first switch and the second switch operate synchronously, and the third switch and the fourth switch operate synchronously. Synchronous operation of the two switches means that the timing of the drive signals corresponding to the two switches is in phase. This application does not limit the implementation form of each switch; any controllable switching transistor can be used. The drive signal is applied to the control terminal of the controllable switching transistor, such as the gate or the controllable switch terminal, to control the turn-off and turn-on of the controllable switching transistor.

[0021] In one possible implementation, the phase of the drive signal corresponding to each of the resonant switched capacitor groups is the same. That is, the timing of the drive signals for all resonant switched capacitor groups is the same, and the switches at corresponding positions operate synchronously. The advantage of this is that the timing of the drive signals is relatively easy to implement, requiring only one type of timing drive signal to be generated.

[0022] In one possible implementation, the phase misalignment of the drive signal corresponding to each of the resonant switched capacitor groups is preset by an angle. In some cases, for more flexible control, better soft switching, or reduced power loss, the drive signals of the switches at corresponding positions in different resonant switched capacitor groups can be controlled to have a slight phase misalignment, i.e., a phase difference exists.

[0023] In one possible implementation, the inductance value of the first inductor is greater than that of the resonant inductor. A greater inductance value in the first inductor can provide a better soft-switching effect and enhance the charging and discharging of the MOSFET junction capacitance. In the embodiments of this application, "greater than" generally means that the first inductor is at least 10 times the size of the resonant inductor.

[0024] In one possible implementation, the capacitance of the first capacitor is greater than the capacitance of the resonant capacitor.

[0025] In one possible implementation, when N equals M, the voltage transformation ratio of the converter is N+1. For example, when M=N=3, the voltage transformation ratio of the DC / DC converter is 4, which achieves a 4x buck or 4x boost.

[0026] This application embodiment also provides a power supply system. The advantages of the power supply system can be compared with the advantages of DC / DC described above. The power supply system includes: a rectifier and the resonant switched capacitor DC / DC converter described above; the input terminal of the rectifier is used to connect to an AC power source and to convert the AC voltage output by the AC power source into a DC voltage; the input terminal of the resonant switched capacitor DC / DC converter is connected to the output terminal of the rectifier and to transform the DC voltage output by the rectifier before outputting it.

[0027] In one possible implementation, the circuit further includes a step-down voltage regulator circuit; the input terminal of the step-down voltage regulator circuit is connected to the output terminal of the resonant switched capacitor DC / DC converter, and is used to step down the voltage output by the resonant switched capacitor DC / DC converter to output a stable voltage.

[0028] In one possible implementation, the circuit further includes a voltage regulator circuit connected between the rectifier and the resonant switched capacitor DC / DC converter, used to regulate the DC voltage output by the rectifier and provide it to the resonant switched capacitor DC / DC converter.

[0029] As can be seen from the above technical solutions, the embodiments of this application have the following advantages:

[0030] This application discloses a resonant switched-capacitor DC / DC converter, which adds at least one LC series circuit (the number of LC series circuits is not limited) connected between any two resonant switched-capacitor groups. The LC series circuit includes a first inductor and a first capacitor connected in series. Since the resonant inductance in the resonant switched-capacitor group is insufficient to completely discharge the charge on the junction capacitance of the switch at the moment of turn-off, the inductor in the added LC series circuit completely discharges the charge on the junction capacitance of the switch, effectively removing the current from the junction capacitance. This achieves true soft switching, reducing the turn-off angle of each resonant switched-capacitor group and improving the load regulation of the converter. When each switch achieves true soft switching, the power consumption generated during the switching process can be reduced, thereby reducing the power consumption of the entire resonant switched-capacitor DC / DC converter and improving its power conversion efficiency. Attached Figure Description

[0031] Figure 1 A schematic diagram of a switching power supply provided for an embodiment of this application;

[0032] Figure 2 A schematic diagram of a resonant switched capacitor DC / DC converter provided in an embodiment of this application;

[0033] Figure 3 A schematic diagram of another resonant switched capacitor DC / DC converter provided in the embodiments of this application;

[0034] Figure 4 A schematic diagram of a resonant switched capacitor DC / DC converter provided in an embodiment of this application;

[0035] Figure 5 A schematic diagram of another resonant switched capacitor DC / DC converter provided in the embodiments of this application;

[0036] Figure 6 A schematic diagram of another resonant switched capacitor DC / DC converter provided in the embodiments of this application;

[0037] Figure 7 A schematic diagram of another resonant switched capacitor DC / DC converter provided in the embodiments of this application;

[0038] Figure 8 A schematic diagram of another resonant switched capacitor DC / DC converter provided in the embodiments of this application;

[0039] Figure 9 A schematic diagram of another resonant switched capacitor DC / DC converter provided in the embodiments of this application;

[0040] Figure 10 This is a schematic diagram of a hybrid connection of an LC series circuit provided in an embodiment of this application;

[0041] Figure 11 A schematic diagram of another hybrid connection of LC series circuits provided in the embodiments of this application;

[0042] Figure 12 A schematic diagram of another resonant switched capacitor DC / DC converter provided in the embodiments of this application;

[0043] Figure 13 A schematic diagram of another resonant switched capacitor DC / DC converter provided in the embodiments of this application;

[0044] Figure 14 A schematic diagram of another resonant switched capacitor DC / DC converter provided in the embodiments of this application;

[0045] Figure 15 A schematic diagram of another resonant switched capacitor DC / DC converter provided in the embodiments of this application;

[0046] Figure 16 A schematic diagram of a power supply system provided in an embodiment of this application;

[0047] Figure 17 A schematic diagram of another power supply system provided in an embodiment of this application;

[0048] Figure 18 This is a schematic diagram of another power supply system provided in an embodiment of this application. Detailed Implementation

[0049] To enable those skilled in the art to better understand the technical solutions provided in the embodiments of this application, the application scenarios of the resonant switched capacitor converter and the principle of realizing DC / DC voltage conversion are introduced below.

[0050] The resonant switched-capacitor DC / DC converter provided in this application embodiment is a type of DC / DC converter. As the name suggests, the input of the DC / DC converter is a DC voltage, and its output is also a DC voltage. The resonant switched-capacitor DC / DC converter provided in this application embodiment can be used as a bidirectional DC / DC converter, which can achieve voltage reduction from left to right and voltage boost from right to left, that is, the input and output terminals can be interchanged.

[0051] For example, the resonant switched-capacitor DC / DC converter provided in this application embodiment can be applied in a switching power supply, that is, it is a DC / DC converter inside the switching power supply. This switching power supply is part of a power system, which may also include a rectifier to rectify the AC voltage of the AC power supply into a DC voltage. This power system can power AI chips, that is, integrated on an AI board, or it can serve as a power system for a data center board.

[0052] This application does not specifically limit the application scenario of the converter. The resonant switched capacitor DC / DC converter provided in this application can be applied to various application scenarios that require switching power supplies, such as servers, communication base stations, and photovoltaic equipment. The switching power supply can ultimately output the voltage required by loads such as chips or control circuits.

[0053] The following section uses a switched capacitor DC / DC converter as an example of a buck converter.

[0054] See Figure 1 The figure is a schematic diagram of a switching power supply provided in an embodiment of this application.

[0055] The switching power supply provided in this application embodiment can be applied to AI or data centers, as well as to communication power supplies. There are no restrictions on the specific application scenarios of the switching power supply.

[0056] The switching power supply includes a buck converter 100 and a voltage regulator circuit 200;

[0057] The buck converter 100 can be the resonant switched capacitor DC / DC converter provided in the embodiments of this application. The specific implementation of the resonant switched capacitor DC / DC converter will be described in detail in subsequent embodiments.

[0058] The output of the buck converter 100 is used to connect to the input of the voltage regulator circuit 200;

[0059] The output terminal of the voltage regulator circuit 200 is used to connect to the load and supply power to the load. The voltage regulator circuit 200 has both voltage reduction and voltage regulation functions, so that its output voltage is stable and controllable.

[0060] One possible implementation is that the input voltage of the buck converter 100 is 48V, the output voltage of the buck converter 100 is 12V, and the voltage regulator circuit 200 is used to further step down the 12V input voltage to voltages such as 5V, 3.3V and 1.8V to power the chip and various loads.

[0061] Since the buck converter 100 is used to step down the input 48V to 12V, the resulting 12V voltage will not directly power the chip. Instead, it will be further stepped down and regulated by the voltage regulator circuit 200. That is, the voltage regulator circuit 200 needs to output an accurate voltage to meet the power supply requirements of the load.

[0062] Therefore, for the buck converter 100, its output 12V voltage can be controlled in an open-loop manner, allowing the output voltage to fluctuate within a certain range, as long as it meets the input voltage range of the voltage regulator circuit 200. Thus, for a buck converter corresponding to a 48V voltage being stepped down to 12V, in AI and data center applications, it can be designed as an open-loop power supply. An open-loop power supply refers to a power supply whose output voltage changes with the input voltage; it does not have independent output voltage regulation. For example, the ratio of the input voltage Vin to the output voltage of the buck converter 100 can be 4:1 or 5:1. Simultaneously, since there is no insulation withstand voltage requirement between the output and input voltages, an isolation topology is not mandatory, i.e., a transformer is unnecessary. Therefore, the buck converter in the power supply system provided in this application embodiment can be implemented using a resonant switched capacitor DC / DC converter, without the need for transformer isolation. This reduces the converter's size, making it thinner and smaller, thereby reducing the overall size of the power supply system. For example, the board area and volume occupied by the power supply system can be reduced, meeting miniaturization requirements.

[0063] The working principle of a resonant switched capacitor DC / DC converter is explained below with reference to a schematic diagram.

[0064] See Figure 2 The figure is a schematic diagram of a resonant switched capacitor DC / DC converter provided in an embodiment of this application.

[0065] Figure 2 Taking the left side as the input and the right side as the output as an example, where the input is connected to a DC power supply Vin and the output is Vout, this converter is a buck converter, meaning it steps down Vin before outputting the voltage. The buck ratio varies depending on the number of resonant switched capacitors. Alternatively, the right side can also be the input and the left side the output, in which case it becomes a boost converter.

[0066] For ease of description and understanding, the following example uses a three-cell resonant switched capacitor bank, corresponding to a step-down ratio of 4:1. This means Vin is stepped down by a factor of four, for example, Vin is 48V and Vout is 12V. This embodiment does not specifically limit the exact value of the voltage ratio; it can be set according to the needs of the actual application scenario. The required voltage ratio can be obtained by changing the number or connection relationship of the resonant switched capacitor banks.

[0067] like Figure 2 As shown in this embodiment, one resonant switched capacitor group corresponds to one capacitor, meaning there is a one-to-one correspondence between the resonant switched capacitor group and the capacitor. Three resonant switched capacitor groups correspond to three capacitors: the first capacitor C1, the second capacitor C2, and the third capacitor C3. C1, C2, and C3 are connected in series, and also in series with the output capacitor COUT. That is, C1-COUT are connected in series and then connected across Vin. COUT is connected across Vout. When energy is transferred from Vin to Vout, COUT acts as the output capacitor, and the series connection of C1-COUT acts as the input capacitor. The letters in the diagram are for ease of description and do not have any special meaning.

[0068] For ease of understanding, the four switches in each resonant switched capacitor group are referred to as the first to the fourth switches.

[0069] Figure 2 The dashed box in the middle corresponds to the first resonant switched capacitor group. Each resonant switched capacitor group has the same structure, which will be described below.

[0070] First, let's introduce the first resonant switched capacitor group, which includes four switches and a resonant circuit. The four switches are: first switch Q1_1, second switch Q1_2, third switch Q1_3, and fourth switch Q1_4. The first terminal of Q1_1 is connected to the first terminal of C1, the first terminal of Q1_2 is connected to the second terminal of C1, the first terminal of Q1_3 is connected to the second terminal of Q1_1, the first terminal of Q1_4 is connected to the second terminal of Q1_2, the second terminal of Q1_3 is connected to Vout, and the second terminal of Q1_4 is grounded.

[0071] The second resonant switched capacitor bank is described below. For ease of understanding, the four switches in each resonant switched capacitor bank are referred to as the first to the fourth switches. The four switches are: first switch Q2_1, second switch Q2_2, third switch Q2_3, and fourth switch Q2_4. The first terminal of Q2_1 is connected to the first terminal of C2, the first terminal of Q2_2 is connected to the second terminal of C2, the first terminal of Q2_3 is connected to the second terminal of Q2_1, the first terminal of Q2_4 is connected to the second terminal of Q2_2, the second terminal of Q2_3 is connected to Vout, and the second terminal of Q2_4 is grounded.

[0072] The second resonant switched capacitor bank is described below, in which the four switches are: first switch Q2_1, second switch Q2_2, third switch Q2_3, and fourth switch Q2_4; wherein, the first terminal of Q2_1 is connected to the first terminal of C2, the first terminal of Q2_2 is connected to the second terminal of C2, the first terminal of Q2_3 is connected to the second terminal of Q2_1, the first terminal of Q2_4 is connected to the second terminal of Q2_2, the second terminal of Q2_3 is connected to Vout, and the second terminal of Q2_4 is grounded.

[0073] The third resonant switched capacitor group is described below. For ease of understanding, the four switches in each resonant switched capacitor group are referred to as the first to the fourth switches. The four switches are: first switch Q3_1, second switch Q3_2, third switch Q3_3, and fourth switch Q3_4. The first terminal of Q3_1 is connected to the first terminal of C2, the first terminal of Q3_2 is connected to the second terminal of C2, the first terminal of Q3_3 is connected to the second terminal of Q3_1, the first terminal of Q3_4 is connected to the second terminal of Q3_2, the second terminal of Q3_3 is connected to Vout, and the second terminal of Q3_4 is grounded.

[0074] Figure 2 The left side is the input and the right side is the output; the corresponding resonant switched capacitor DC / DC converter is a buck converter.

[0075] Figure 3 The middle section uses the right side as the input and the left side as the output, meaning the corresponding resonant switched capacitor DC / DC converter is a boost converter.

[0076] by Figure 2Taking a buck converter as an example, the working principle of voltage conversion is explained as follows: When Q1_1 and Q1_2 are closed, and Q1_3 and Q1_4 are open, the electrical energy stored in C1 is transferred to Cr1; when Q1_1 and Q1_2 are open, and Q1_3 and Q1_4 are closed, the electrical energy stored in Cr1 is transferred to Cout, thus realizing the transfer of energy from the input to the output. Similarly, when Q2_1 and Q2_2 are closed, and Q2_3 and Q2_4 are open, the electrical energy stored in C2 is transferred to Cr2; when Q2_1 and Q2_2 are open, and Q2_3 and Q2_4 are closed, the electrical energy stored in Cr2 is transferred to Cout, thus realizing the transfer of energy from the input to the output. When Q3_1 and Q3_2 are closed, and Q3_3 and Q3_4 are open, the electrical energy stored in C3 is transferred to Cr3; when Q3_1 and Q3_2 are open, and Q3_3 and Q3_4 are closed, the electrical energy stored in Cr3 is transferred to Cout, thus realizing the transfer of energy from the input to the output. This is because the voltage across Vin is equal to the sum of the voltages across C1, C2, C3, and Cout. Furthermore, since the voltage across C1 is equal to the voltage across Cr1, the voltage across C2 is equal to the voltage across Cr2, the voltage across C3 is equal to the voltage across Cr3, and the voltages across Cr1, Cr2, and Cr3 are all equal to the voltage across Cout, Vin is four times the voltage across Vout, achieving a fourfold voltage reduction.

[0077] Based on the above analysis, whether it is a boost converter or a buck converter, the left side of the resonant switched capacitor DC / DC converter is the high-voltage side and the right side is the low-voltage side. A similar trend exists for the resonant switched capacitor group: the voltage of the resonant switched capacitor group connected to C1 is the highest, the voltage of the resonant switched capacitor group connected to C2 is the second highest, and the voltage of the resonant switched capacitor group connected to C3 is the lowest.

[0078] The resonant inductor in each resonant switched capacitor bank serves to reduce the current surge of the charging and discharging current on the resonant capacitor, as well as the impact of the charging and discharging current on the switch, thereby reducing losses and improving the power conversion efficiency of the converter.

[0079] This application does not specifically limit the type of switch implementation. Specifically, it can be a controllable switching transistor, such as a metal-oxide-semiconductor field-effect transistor (MOS), an insulated-gate bipolar transistor (IGBT), or other types of switching devices, as long as they include a control terminal that allows control of their switching state. The following description uses a MOS switch as an example.

[0080] For ease of description, we will take a MOSFET as an example to illustrate the concept of a resonant switched capacitor bank.

[0081] for Figure 2 In the MOSFETs Q1_1 and Q1_3, Q2_1 and Q2_3, and Q3_1 and Q3_3, to achieve soft switching, these MOSFETs must, at the moment of turn-off, charge and discharge their respective junction capacitances through the residual currents in Lr1, Lr2, and Lr3. However, within the higher-voltage resonant switching capacitor bank, the reverse voltage across Lr1 is higher. For example, the reverse voltage across Lr1 is Vo*2, while the reverse voltage across Lr2 is Vo, meaning the reverse voltage across Lr1 is twice that across Lr2. Therefore, the current in Lr1 decays faster, resulting in insufficient charge to fully charge or discharge the junction capacitance of the corresponding MOSFETs, preventing these MOSFETs from truly achieving soft switching.

[0082] To address the aforementioned technical issues, this application provides a resonant switched-capacitor DC / DC converter. An LC series circuit (i.e., a circuit connecting an inductor and a capacitor in series) is connected between any two resonant switched-capacitor groups. Since the resonant inductor is insufficient to completely discharge the charge on the junction capacitance of the MOSFET at the moment of turn-off, an additional inductor is added to ensure complete discharge of the charge on the junction capacitance, effectively removing current and achieving soft switching of the MOSFET. When each switch truly achieves soft switching, the power consumption of the entire resonant switched-capacitor DC / DC converter can be reduced, thereby improving its power conversion efficiency.

[0083] Converter Example:

[0084] See Figure 4 The figure is a schematic diagram of a resonant switched capacitor DC / DC converter provided in an embodiment of this application.

[0085] The resonant switched capacitor DC / DC converter provided in this application includes: N resonant switched capacitor groups, M capacitors, and at least one LC series circuit; N is an integer greater than or equal to 2; M is an integer less than or equal to N, that is, M can be equal to N or less than N, for example; when N is 3, M can be 2. The number of M can be set according to the connection relationship and number of resonant switched capacitor groups, and this application does not impose a specific limitation.

[0086] Each resonant switched capacitor bank includes a switch and a resonant circuit; the resonant circuit includes a resonant inductor and a resonant capacitor; generally, the resonant inductor and resonant capacitor are connected in series to form a series resonant circuit. The function of the resonant inductor has already been introduced above and will not be repeated here.

[0087] The two ends of the LC series circuit are respectively connected to one end of the resonant circuit in two different resonant switched capacitor groups; the LC series circuit includes a first inductor and a first capacitor connected in series.

[0088] Each resonant switched capacitor bank can be considered as a resonant cavity. Since the switches within the resonant cavity cannot achieve complete soft switching during operation, this embodiment adds an LC series circuit to the resonant cavity to address this issue. The first inductor in the LC series circuit forces the junction capacitance of the switches within the resonant cavity to charge and discharge, thereby ensuring soft switching during operation. Furthermore, this reduces the turn-off angle of each resonant switched capacitor bank, lowering the turn-off damage of each switch and the equivalent effective current value. A higher equivalent effective current value results in higher switching losses. The technical solution provided in this embodiment allows each resonant switched capacitor bank to achieve a turn-off angle closer to 180 degrees, thereby improving the load regulation of the resonant switched capacitor DC / DC converter.

[0089] When the converter's operating frequency equals its resonant frequency (i.e., the converter operates at its resonant point), the gain of each resonant cavity is 1, meaning the output voltage equals the input voltage. At this point, the output voltage is minimally affected by the load, essentially unaffected by it. However, when the converter's operating frequency differs from its resonant frequency, the output voltage of the resonant cavity decreases. The larger the load, the greater the voltage drop, resulting in a voltage droop. Therefore, to ensure the output voltage remains unaffected by load changes—that is, to improve load regulation—the converter needs to operate at its resonant frequency. A turn-off angle of 180 degrees corresponds to 50% of the positive half-cycle and 0% of the negative half-cycle; the fundamental frequency after Fourier decomposition corresponds to the actual operating frequency. However, when the turn-off angle is less than 180 degrees, the fundamental frequency after Fourier decomposition is significantly affected by higher harmonics, leading to a decrease in the resonant cavity's output voltage.

[0090] In the LC series circuit, the first capacitor is used to block DC and balance the voltage to prevent the first inductor from becoming magnetically saturated and failing to work properly during the charging and discharging process.

[0091] This application does not limit the number of LC series circuits connected to the resonant cavities; an LC series circuit can be connected between any two resonant cavities. For example, when N is 3, it can include 2 LC series circuits: one connected between the first and second resonant cavities, and another connected between the second and third resonant cavities. Alternatively, to reduce the circuit area and cost, only one LC series circuit can be included. The connection position of this LC series circuit is not specifically limited; it can be connected between any two resonant cavities. In one possible implementation, the LC series circuit can be connected between the two resonant cavities with higher voltage, i.e., between the two resonant cavities closer to the high-voltage side. Because the resonant inductor in the high-voltage side resonant cavity experiences a higher reverse voltage, the junction capacitance of the corresponding switch is prone to incomplete charging or discharging during charging and discharging.

[0092] For a buck converter, the output capacitor and N capacitors are connected in series between the two input terminals of the converter, and the output capacitor is connected between the two output terminals of the converter; the two input terminals of the converter are connected to the two ends of a DC power supply; the converter is used to step down the voltage of the DC power supply and output it.

[0093] For a boost converter, the output capacitor and the N capacitors are connected in series between the two output terminals of the converter, and the output capacitor is connected between the two input terminals of the converter; the two input terminals of the converter are connected to the two ends of a DC power supply; the converter is used to boost the voltage of the DC power supply and output it.

[0094] The embodiments of this application do not specifically limit whether the resonant switched capacitor DC / DC converter is a boost converter or a buck converter, that is, the input and output terminals can be interchanged, and bidirectional energy flow can also be realized.

[0095] To make it easier to understand, let's first introduce the scenario where M and N are equal.

[0096] like Figure 4 As shown, taking an example where N is 3 and M is 3, that is, M and N are equal, and each of the N resonant switched capacitor groups corresponds one-to-one with one of the M capacitors. For this type of converter, when N equals M, the voltage transformation ratio is N+1, i.e. Figure 4 The corresponding voltage transformation ratio is 4. Those skilled in the art can set the number of resonant capacitor banks and the number of capacitors according to actual needs.

[0097] Specifically, the two input terminals of each resonant switched capacitor group are connected to the two ends of the corresponding capacitor, and the two output terminals of each resonant switched capacitor group are connected to the two ends of the output capacitor.

[0098] Each resonant switched capacitor bank includes at least four switches: a first switch, a second switch, a third switch, and a fourth switch. The first terminal of the first switch is connected to the first terminal of the corresponding capacitor, and the first terminal of the second switch is connected to the second terminal of the corresponding capacitor. The second terminal of the first switch is connected to the first terminal of the third switch, and the second terminal of the second switch is connected to the first terminal of the fourth switch. The resonant capacitor and resonant inductor are connected in series to the second terminals of the first and second switches. The second terminal of the third switch is connected to the second terminal of the output capacitor, and the second terminal of the fourth switch is connected to the first terminal of the output capacitor. See [link to details] for further information. Figure 2 A description of the connection relationships of the various internal components in a corresponding resonant switched capacitor bank.

[0099] This application does not specifically limit the exact location where the LC series circuit is connected between any two resonant switched capacitor groups, and can include at least the following two connection methods:

[0100] The first type:

[0101] The first terminal of the LC series circuit is connected to the second terminal of the first switching transistor in one of the resonant switched capacitor groups, and the second terminal of the LC series circuit is connected to the second terminal of the first switching transistor in another resonant switched capacitor group.

[0102] The second type:

[0103] The first terminal of the LC series circuit is connected to the second terminal of the second switch in one of the resonant switched capacitor groups, and the second terminal of the LC series circuit is connected to the second terminal of the second switch in the other resonant switched capacitor group.

[0104] Figure 4 and Figure 2 The difference is that an LC series circuit is added between the first resonant switched capacitor group and the second resonant switched capacitor group, that is, the first inductor Lz and the first capacitor Cz form an LC series circuit. Figure 3 The connection relationships of other parts and Figure 4 The same applies, so I won't repeat it here.

[0105] The first end of Lz is connected to the second end of the first switch Q1_1 in the first resonant switched capacitor group, the second end of Lz is connected to the first end of Cz, and the second end of Cz is connected to the second end of the first switch Q2_1 in the second resonant switched capacitor group.

[0106] The specific implementation in this application is not limited. Regarding the relationship between Lz and the resonant inductances in each resonant capacitor group, in one possible implementation, the inductance value of the first inductor Lz can be greater than the inductance value of the resonant inductor. For example... Figure 4In this context, Lz is greater than Lr1, and Lz is greater than Lr2. The larger the inductance value of Lz, the better the soft switching effect. The multiple by which Lz is greater than Lr1 can be set as needed. For example, the ratio of Lz to Lr1 can be greater than 10, and similarly, the ratio of Lz to Lr2 can also be greater than 10.

[0107] Furthermore, the embodiments of this application do not specifically limit the relationship between the capacitance value of the first capacitor in the LC series circuit and the capacitance value of the resonant capacitor in each resonant switching capacitor group. In one feasible implementation, the first capacitor Cz can be selected to be greater than the capacitance value of the resonant capacitor, for example, the capacitance value of Cz is greater than the capacitance value of Cr1.

[0108] Figure 4 The Lz and Cz shown are connected in series on the high-voltage side A of the first resonant switched capacitor bank and the high-voltage side C of the second resonant switched capacitor bank, which is more conducive to achieving soft switching of the switches in the resonant switched capacitor bank. As shown in the figure, the voltage at point A of the first resonant switched capacitor bank is higher than that at point B, and similarly, the voltage at point C of the second resonant switched capacitor bank is higher than that at point D. Because the voltage on the high-voltage side is higher, the junction capacitance of the switch needs an external Lz to force it to charge and discharge, thereby achieving soft switching of the switch. That is, Q1_1 and Q1_3 in the first resonant switched capacitor bank, and Q2_1 and Q2_3 in the second resonant switched capacitor bank.

[0109] The working principle of soft switching in an LC series circuit is analyzed below with reference to the diagram.

[0110] When Q1_1 and Q1_2 are on, the potential at point A is higher than that at point C. When Q1_1 is off, the current at point A flows to point C through Lz and Cz. Lz has the function of holding the current; therefore, in order to maintain the current from point A to point C, current is drawn from the junction capacitance of Q1_1 and Q1_3, thereby discharging the junction capacitance of Q1_1 and Q1_3, making Q1_1 and Q1_3 essentially connected in parallel. At this time, the current at point A does not draw current from Cr1 because the current at point A flows to point B. When the potential at point A gradually decreases to be equal to Vout, the voltage across Q1_3 is equal. At this point, Q1_3 is closed, enabling Q1_3 to truly achieve soft switching.

[0111] The above describes the process of closing Q1_3. The following describes the process of closing Q1_1.

[0112] Because the driving pulse signals corresponding to the first and second resonant cavities can be out of phase, when Q2_1 is turned on, the potential at point C is higher than the potential at point A. When Q3_1 is turned off, the current at point C flows to point A through Lz and Cz. At this time, the junction capacitance of Q3_1 is charged, and the voltage at point A increases. When the voltage at point A rises to be equal to Vin, that is, when the voltages across Q1_1 are equal, Q1_1 turns on, thus enabling Q1_1 to truly achieve soft switching.

[0113] In this embodiment, the timing of the drive signals of the switches in each resonant switched capacitor group is not specifically limited. For example, the corresponding switches in each resonant switched capacitor group operate synchronously, that is, the drive signals corresponding to each resonant switched capacitor group are synchronous. That is, for all resonant switched capacitor groups: the first switch and the second switch operate synchronously, and the third switch and the fourth switch operate synchronously. That is, the phase of the drive signal of each resonant switched capacitor group is the same. The above is only an example. For example, for the same resonant switched capacitor group, the drive signal of the first switch and the drive signal of the second switch may have a phase difference. For example, the first switch turns on first, and the second switch turns on later.

[0114] The above describes the situation where the driving signals of the corresponding switches in all resonant switched capacitor groups are in phase. For example, the driving signals of the first switch, the second switch, the third switch, and the fourth switch in the three resonant switched capacitor groups are in phase.

[0115] In another implementation, the phase of the drive signal for each resonant switched capacitor bank can be staggered by a preset angle, for example... Figure 4 The drive signals corresponding to Q1_1, Q2_1 and Q3_1 are sequentially out of phase by a preset angle, that is, the drive signals of the first switch in each resonant switched capacitor group are not in phase.

[0116] Figure 4 The LC series circuit shown is connected to the first and second resonant switched capacitor groups. The following describes the case where the LC series circuit is connected to the second and third resonant switched capacitor groups.

[0117] See Figure 5 This figure is a schematic diagram of another resonant switched capacitor DC / DC converter provided in an embodiment of this application.

[0118] Figure 5 and Figure 4 The difference is, Figure 5 The first end of Lz in the second resonant switched capacitor group is connected to the second end C of the first switch Q2_1 in the second resonant switched capacitor group, the second end of Lz is connected to the first end of Cz, and the second end of Cz is connected to the second end E of the first switch Q3_1 in the third resonant switched capacitor group.

[0119] Figure 5 The connection relationships of other parts and Figure 4 and Figure 2 The same applies, so I won't repeat it here. Among them, Figure 4 The working principles and advantages described in the corresponding sections also apply to... Figure 5 Corresponding implementation examples.

[0120] Figure 5 In the second resonant switched capacitor bank, the voltage at point C is higher than the voltage at point D. Similarly, for the third resonant switched capacitor bank, the voltage at point E is higher than the voltage at point F.

[0121] The following describes the case where an LC series circuit is connected to the first resonant switched capacitor group and the third resonant switched capacitor group.

[0122] See Figure 6 This figure is a schematic diagram of another resonant switched capacitor DC / DC converter provided in the embodiments of this application.

[0123] Figure 6 and Figure 4 The difference is, Figure 6 The first end of Lz is connected to the second end A of the first switch Q1_1 in the first resonant switched capacitor group, the second end of Lz is connected to the first end of Cz, and the second end of Cz is connected to the second end E of the first switch Q3_1 in the third resonant switched capacitor group.

[0124] Figure 6 The connection relationships of other parts and Figure 4 and Figure 2 The same applies, so I won't repeat it here. Among them, Figure 4 The working principles and advantages described in the corresponding sections also apply to... Figure 6 Corresponding implementation examples.

[0125] Figure 6 In the first resonant switched capacitor bank, the voltage at point A is higher than the voltage at point B. Similarly, for the third resonant switched capacitor bank, the voltage at point E is higher than the voltage at point F.

[0126] above Figures 4-6 The LC series circuits in the above circuits are all connected to the high-voltage side of any two resonant switched capacitor groups. The following describes how to implement the LC series circuit connected to the low-voltage side of any two resonant switched capacitor groups.

[0127] See Figure 7 This figure is a schematic diagram of another resonant switched capacitor DC / DC converter provided in an embodiment of this application.

[0128] Figure 7 In the converter shown, the LC series circuit is connected to the low-voltage side of the first resonant switched capacitor group and the low-voltage side of the second resonant switched capacitor group. Wherein, Figure 7 The first end of Lz is connected to the second end B of the second switch Q1_2 in the first resonant switched capacitor group, the second end of Lz is connected to the first end of Cz, and the second end of Cz is connected to the second end D of the second switch Q2_2 in the second resonant switched capacitor group.

[0129] The following describes the case where an LC series circuit is connected to the low-voltage side of the first resonant switched capacitor group and the low-voltage side of the third resonant switched capacitor group. See [link / reference] Figure 8 This figure is a schematic diagram of another resonant switched capacitor DC / DC converter provided in the embodiments of this application.

[0130] in, Figure 8 The first end of Lz is connected to the second end B of the second switch Q1_2 in the first resonant switched capacitor group, the second end of Lz is connected to the first end of Cz, and the second end of Cz is connected to the second end F of the second switch Q3_2 in the third resonant switched capacitor group.

[0131] The following describes the connection of an LC series circuit between the low-voltage sides of the second and third resonant switched capacitor banks. (See also...) Figure 9 This figure is a schematic diagram of another resonant switched capacitor DC / DC converter provided in the embodiments of this application.

[0132] in, Figure 9 The first end of Lz is connected to the second end D of the second switch Q2_2 in the second resonant switched capacitor group. The second end of Lz is connected to the first end of Cz. The second end of Cz is connected to the second end F of the second switch Q3_2 in the third resonant switched capacitor group.

[0133] above Figures 7-9 This section describes the case where an LC series circuit is connected to the low-voltage side of any two resonant switched capacitor groups. In addition, one end of the LC series circuit can be connected to the high-voltage side of one of the resonant switched capacitor groups, and the other end of the LC series circuit can be connected to the low-voltage side of another resonant switched capacitor group, i.e., a mixed connection. The following is a detailed description with reference to the accompanying drawings.

[0134] See Figure 10 This figure is a schematic diagram of another resonant switched capacitor DC / DC converter provided in an embodiment of this application.

[0135] Figure 10 The diagram shows an LC series circuit connected between the first and second resonant switched capacitor groups. Specifically, the first terminal of Lz is connected to the second terminal A of the first switch Q1_1 in the first resonant switched capacitor group, and the second terminal of Cz is connected to the second terminal D of the second switch Q2_2 in the second resonant switched capacitor group. That is, the LC series circuit connects the high-voltage side of the first resonant switched capacitor group and the low-voltage side of the second resonant switched capacitor group. Alternatively, the circuit can be reversed, connecting the low-voltage side of the first resonant switched capacitor group and the high-voltage side of the second resonant switched capacitor group.

[0136] The following is combined Figure 11 This section introduces another implementation method for hybrid connections.

[0137] See Figure 11 This figure is a schematic diagram of another resonant switched capacitor DC / DC converter provided in an embodiment of this application.

[0138] Figure 11 The diagram shows an LC series circuit connected between the first and third resonant switched capacitor groups. Specifically, the first terminal of Lz is connected to the second terminal A of the first switch Q1_1 in the first resonant switched capacitor group, and the second terminal of Cz is connected to the second terminal F of the second switch Q3_2 in the third resonant switched capacitor group. That is, the LC series circuit connects the high-voltage side of the first resonant switched capacitor group and the low-voltage side of the third resonant switched capacitor group. Alternatively, the connection can be reversed, meaning the LC series circuit connects the low-voltage side of the first resonant switched capacitor group and the high-voltage side of the third resonant switched capacitor group.

[0139] It should be understood that an LC series circuit can also be connected between the low-voltage side of the second resonant switched capacitor group and the high-voltage side of the third switched capacitor group. Similarly, it can also be connected between the high-voltage side of the second resonant switched capacitor group and the low-voltage side of the third switched capacitor group. Examples will not be given here.

[0140] The above diagrams are all based on a three-cell resonant switched capacitor bank, where N is 3. N can also be any other integer. The case where N is 2 will be discussed below.

[0141] See Figure 12 This figure is a schematic diagram of another resonant switched capacitor DC / DC converter provided in the embodiments of this application.

[0142] from Figure 12 It can be seen that the resonant switched capacitor DC / DC converter includes two resonant switched capacitor groups, where the first resonant switched capacitor group corresponds to the first capacitor C1 and the second resonant switched capacitor group corresponds to the second capacitor C2.

[0143] Figure 12 The diagram shows an LC series circuit connected between the first and second resonant switched capacitor groups. Specifically, the first terminal of Lz is connected to the second terminal A of the first switch Q1_1 in the first resonant switched capacitor group, and the second terminal of Cz is connected to the second terminal C of the first switch Q2_1 in the second resonant switched capacitor group. That is, the two ends of the LC series circuit are connected to the high-voltage side of the first and second resonant switched capacitor groups, respectively.

[0144] Figure 12 For an explanation of its working principle, please refer to [link / reference]. Figure 4 The corresponding text descriptions differ only in that Figure 12 Compare Figure 4 Without one resonant switched capacitor bank, the voltage transformation ratio is 3:1, while Figure 4The ratio is 4:1. Everything else is the same, so I will not repeat it here.

[0145] It should be noted that the first inductor in the LC series circuit of this application can be one or more in the actual product, and the number is not limited. Similarly, the first capacitor in the LC series circuit can also be one or more in the actual product, and the number is not limited.

[0146] The above diagrams are all based on the example of one resonant switching capacitor bank corresponding to one capacitor, that is, M and N are equal, the resonant switching capacitor bank and the capacitor have a one-to-one correspondence, and the voltage transformation ratio corresponding to this case is N+1.

[0147] The following describes the case where at least one resonant switched capacitor bank corresponds to multiple capacitors connected in series. This case differs from the previous ones. By changing the connection relationship between the resonant switched capacitor bank and its corresponding capacitors, the voltage transformation ratio of the converter can be altered. For example, the voltage transformation ratio can be increased without increasing the number of resonant switched capacitor banks, thereby saving hardware circuitry, reducing the circuit board area occupied by the entire converter, and saving costs.

[0148] The following section will continue using three resonant switched capacitor banks as an example, but the voltage ratio of the corresponding converter is no longer 4:1.

[0149] See Figure 13 This figure is a schematic diagram of another resonant switched capacitor DC / DC converter provided in an embodiment of this application.

[0150] The N resonant switched capacitor groups include at least a first type of resonant capacitor group and a second type of resonant switched capacitor group.

[0151] The first type of resonant switched capacitor group corresponds to at least two capacitors connected in series among the M capacitors; the two input terminals of the first type of resonant switched capacitor group are respectively connected to the two ends of the at least two capacitors connected in series; that is, the capacitors corresponding to the first type of resonant switched capacitor group are multiple capacitors connected in series, and the number of capacitors connected in series is not specifically limited.

[0152] The second type of resonant switched capacitor group corresponds to one of the M capacitors, and the two input terminals of the second type of resonant switched capacitor group are respectively connected to the two ends of the corresponding one of the M capacitors. That is, each resonant switched capacitor group in the second type of resonant switched capacitor group still corresponds one-to-one with a capacitor.

[0153] A converter may include multiple first-type resonant switched capacitor groups or multiple second-type resonant switched capacitor groups, and there is no specific limit to the specific number.

[0154] Figure 13The voltage ratio of the resonant switched capacitor DC / DC converter shown is 5:1.

[0155] Figure 13 In the first resonant switched capacitor group, the second terminal of the third switch Q1_3 is not connected to the first terminal of Cout, but to the first terminal of C3.

[0156] Alternatively, the connection position of the second terminal of the third switch in other resonant switched capacitor banks can be changed, as described below. Figure 14 Introducing another implementation method.

[0157] See Figure 14 This figure is a schematic diagram of another resonant switched capacitor DC / DC converter provided in an embodiment of this application.

[0158] Figure 14 The voltage ratio of the resonant switched capacitor DC / DC converter shown is 5:1.

[0159] Figure 14 In the second resonant switched capacitor group, the second terminal of the third switch Q2_3 is not connected to the first terminal of Cout, but to the first terminal of C3.

[0160] The above embodiments describe the implementation of a resonant switched capacitor DC / DC converter including one LC series circuit. This application does not specifically limit the number of LC series circuits included in a resonant switched capacitor DC / DC converter. The following describes, with reference to the accompanying drawings, the implementation of a resonant switched capacitor DC / DC converter including two LC series circuits.

[0161] See Figure 15 This figure is a schematic diagram of another resonant switched capacitor DC / DC converter provided in the embodiments of this application.

[0162] In this embodiment, we will continue to use a resonant switched capacitor DC / DC converter with three resonant switched capacitor groups as an example.

[0163] The resonant switched capacitor DC / DC converter provided in this embodiment includes at least two LC series circuits, wherein the first LC series circuit (Lz1 and Cz1) is connected between the high voltage side of the first resonant switched capacitor group and the high voltage side of the second resonant switched capacitor group, and the second LC series circuit (Lz2 and Cz2) is connected between the high voltage side of the second resonant switched capacitor group and the high voltage side of the third resonant switched capacitor group.

[0164] like Figure 15As shown, the first end of Lz1 is connected to the second end A of the first switch Q1_1 in the first resonant switched capacitor group, the second end of Lz1 is connected to the first end of Cz1, and the second end of Cz1 is connected to the second end C of the first switch Q2_1 in the second resonant switched capacitor group.

[0165] The first end of Lz2 is connected to the second end C of the first switch Q2_1 in the second resonant switched capacitor group. The second end of Lz2 is connected to the first end of Cz2. The second end of Cz2 is connected to the second end E of the first switch Q3_1 in the third resonant switched capacitor group.

[0166] Figure 15 The diagram only illustrates the connection position of the two LC series circuits; other connection relationships are also possible. For example, the second LC series circuit can also be connected between the first resonant switched capacitor group and the third resonant switched capacitor group.

[0167] Alternatively, a resonant switched capacitor DC / DC converter may also include three LC series circuits. For example, an LC series circuit can be connected between the first and second resonant switched capacitor groups, an LC series circuit can be connected between the first and third resonant switched capacitor groups, and an LC series circuit can be connected between the second and third resonant switched capacitor groups.

[0168] Based on the resonant switched capacitor DC / DC converter provided in the above embodiments, this application also provides a power supply system, which will be described in detail below with reference to the accompanying drawings.

[0169] See Figure 16 The figure is a schematic diagram of a power supply system provided in an embodiment of this application.

[0170] The power system provided in this application includes: a rectifier 1601 and a resonant switched capacitor DC / DC converter 1602 as described in the above embodiments.

[0171] The input terminal of rectifier 1601 is used to connect to an AC power source and to convert the AC voltage output by the AC power source into a DC voltage.

[0172] The input terminal of the resonant switched capacitor DC / DC converter 1602 is connected to the output terminal of the rectifier 1601, and is used to transform the DC voltage output by the rectifier 1601 before outputting it.

[0173] Other step-down circuits may also be included between rectifier 1601 and resonant switched capacitor DC / DC converter 1602, which step down the output voltage of rectifier 1601 to the range of input voltage that resonant switched capacitor DC / DC converter 1602 can withstand.

[0174] It is understandable that the resonant switched capacitor DC / DC converter 1602 can be a boost converter or a buck converter. For example, it can be used as a buck converter to reduce 48V to 12V to supply subsequent circuits or loads.

[0175] Since the power system provided in this application includes the resonant switched capacitor DC / DC converter 1602 described in the above embodiments, the switches in the resonant switched capacitor DC / DC converter 1602 can truly achieve soft switching, thereby reducing switching losses during operation, reducing the power consumption of the entire converter, improving the power conversion efficiency of the converter, and thus improving the power supply efficiency of the power system.

[0176] See Figure 17 This figure is a schematic diagram of another power supply system provided in an embodiment of this application.

[0177] The power supply system provided in this embodiment may also include a step-down voltage regulator circuit 1701 after the resonant switched capacitor DC / DC converter 1602.

[0178] The input terminal of the step-down regulator circuit 1701 is connected to the output terminal of the resonant switched capacitor DC / DC converter 1602, and is used to step down the voltage output by the resonant switched capacitor DC / DC converter to output a stable voltage.

[0179] For example, the resonant switched-capacitor DC / DC converter 1602 reduces a 48V DC voltage to a 12V DC voltage, and the buck regulator circuit 1701 further reduces and regulates the 12V DC voltage, for example, to output a stable 5V or 3.3V. In one possible implementation, the buck regulator circuit 1701 can be implemented using a closed-loop buck circuit. Because its output voltage can be controlled in a closed loop, a stable output voltage can be achieved, making the output voltage controllable.

[0180] Figure 17 The power supply system described here connects a voltage regulator circuit after the resonant switched-capacitor DC / DC converter 1602. Because the resonant switched-capacitor DC / DC converter 1602 is an open-loop converter, the stability of the output voltage cannot be guaranteed. Besides... Figure 17 Besides the proposed solution, a voltage regulation circuit can be added to the stage before the resonant switched capacitor DC / DC converter 1602. This will be discussed below. Figure 18 A detailed introduction will be provided.

[0181] See Figure 18 This figure is a schematic diagram of another power supply system provided in an embodiment of this application.

[0182] The power supply system provided in this embodiment also includes: a voltage regulator circuit 1801;

[0183] The voltage regulator circuit 1801 is connected between the rectifier 1601 and the resonant switched capacitor DC / DC converter 1602. It is used to regulate the DC voltage output by the rectifier 1601 and provide it to the input terminal of the resonant switched capacitor DC / DC converter 1602.

[0184] Since the voltage regulator circuit 1801 has a voltage regulation function, its output voltage is a very stable voltage, which is equivalent to the input voltage of the resonant switched capacitor DC / DC converter 1602 being very stable. Therefore, this power supply system can ensure that the output voltage of the resonant switched capacitor DC / DC converter 1602 is also very stable, directly providing power to the load.

[0185] It should be understood that in this application, "at least one (item)" means one or more, and "more than" means two or more. "And / or" is used to describe the relationship between related objects, indicating that three relationships can exist. For example, "A and / or B" can represent three cases: only A exists, only B exists, and both A and B exist simultaneously, where A and B can be singular or plural. The character " / " generally indicates that the preceding and following related objects are in an "or" relationship. "At least one (item) of the following" or similar expressions refer to any combination of these items, including any combination of single or plural items. For example, at least one (item) of a, b, or c can represent: a, b, c, "a and b", "a and c", "b and c", or "a and b and c", where a, b, and c can be single or multiple.

[0186] The above-described embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.

Claims

1. A resonant switched capacitor DC / DC converter, characterized in that, include: The system comprises N resonant switched capacitor groups, M capacitors, an output capacitor, and at least one LC series circuit; where N is an integer greater than or equal to 2; and M is an integer less than or equal to N; the LC series circuit includes a first inductor and a first capacitor connected in series; the output capacitor and the M capacitors are connected in series between the two input terminals of the converter; the output capacitor is connected between the two output terminals of the converter; and each resonant switched capacitor group is connected to at least one of the M capacitors. Each of the resonant switched capacitor banks includes: a switch and a resonant circuit; the resonant circuit includes at least a resonant inductor and a resonant capacitor; The two ends of the LC series circuit are respectively connected to the resonant circuits in two different resonant switched capacitor groups.

2. The converter according to claim 1, characterized in that, M is equal to N, and the N resonant switched capacitor groups correspond one-to-one with the M capacitors. Each resonant switched capacitor group includes at least four switches: a first switch, a second switch, a third switch, and a fourth switch. The first terminal of the first switch and the first terminal of the second switch of each of the resonant switched capacitor groups are respectively connected to the two ends of one of the corresponding M capacitors, and the second terminal of the third switch and the second terminal of the fourth switch of each of the resonant switched capacitor groups are respectively connected to the two ends of the output capacitor.

3. The converter according to claim 1, characterized in that, The N resonant switched capacitor groups include at least a first type of resonant switched capacitor group and a second type of resonant switched capacitor group, and each of the resonant switched capacitor groups includes at least four switches: a first switch, a second switch, a third switch, and a fourth switch; The first type of resonant switched capacitor group corresponds to at least two capacitors connected in series among the M capacitors; the first terminal of the first switch and the second terminal of the third switch of the first type of resonant switched capacitor group are respectively connected to the two ends of the at least two capacitors connected in series; The second type of resonant switched capacitor group corresponds to one of the M capacitors, and the first end of the first switch and the first end of the second switch of the second type of resonant switched capacitor group are respectively connected to the two ends of the corresponding one of the M capacitors.

4. The converter according to claim 2 or 3, characterized in that, The two input terminals of the converter are connected to the two ends of a DC power supply; The converter is used to step down the voltage of the DC power supply before outputting it.

5. The converter according to claim 2 or 3, characterized in that, The two input terminals of the converter are connected to the two ends of a DC power supply; The converter is used to boost the voltage of the DC power supply before outputting it.

6. The converter according to claim 2, characterized in that, The first terminal of the first switch is connected to the first terminal of one of the M capacitors corresponding to the resonant switching capacitor group, and the first terminal of the second switch is connected to the second terminal of one of the M capacitors corresponding to the resonant switching capacitor group. The second end of the first switch is connected to the first end of the third switch, and the second end of the second switch is connected to the first end of the fourth switch; The resonant capacitor and the resonant inductor are connected in series to the second terminal of the first switch and the second terminal of the second switch; The second terminal of the third switch is connected to the second terminal of the output capacitor, and the second terminal of the fourth switch is connected to the first terminal of the output capacitor.

7. The converter according to claim 6, characterized in that, The first end of the LC series circuit is connected to the second end of the first switching transistor in one of the resonant switched capacitor groups, and the second end of the LC series circuit is connected to the second end of the first switching transistor in the other resonant switched capacitor group.

8. The converter according to claim 6, characterized in that, The first end of the LC series circuit is connected to the second end of the second switch in one of the resonant switched capacitor groups, and the second end of the LC series circuit is connected to the second end of the second switch in the other resonant switched capacitor group.

9. The converter according to any one of claims 6-8, characterized in that, The first switch and the second switch operate synchronously, and the third switch and the fourth switch operate synchronously.

10. The converter according to any one of claims 1-3, characterized in that, The phases of the driving signals corresponding to each of the resonant switched capacitor groups are the same.

11. The converter according to any one of claims 1-3, characterized in that, The phase misalignment angle of the driving signal corresponding to each of the resonant switched capacitor groups is preset.

12. The converter according to any one of claims 1-3, characterized in that, The inductance of the first inductor is greater than the inductance of the resonant inductor.

13. The converter according to claim 12, characterized in that, The capacitance of the first capacitor is greater than the capacitance of the resonant capacitor.

14. The converter according to claim 2, characterized in that, When N equals M, the voltage transformation ratio of the converter is N+1.

15. A power supply system, characterized in that, include: The rectifier and the resonant switched capacitor DC / DC converter according to any one of claims 1-14; The input terminal of the rectifier is used to connect to an AC power source and to convert the AC voltage output by the AC power source into a DC voltage. The input terminal of the resonant switched capacitor DC / DC converter is connected to the output terminal of the rectifier, and is used to transform the DC voltage output by the rectifier before outputting it.

16. The power supply system according to claim 15, characterized in that, Also includes: Step-down regulator circuit; The input terminal of the buck regulator circuit is connected to the output terminal of the resonant switched capacitor DC / DC converter, and is used to step down the voltage output by the resonant switched capacitor DC / DC converter to output a stable voltage.

17. The power supply system according to claim 15, characterized in that, Also includes: Voltage regulator circuit; The voltage regulator circuit is connected between the rectifier and the resonant switched capacitor DC / DC converter, and is used to regulate the DC voltage output by the rectifier and provide it to the resonant switched capacitor DC / DC converter.

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