Voltage conversion circuit, conversion circuit, device, and conversion method

Abstract

This application provides a voltage conversion circuit, a conversion device, and a conversion method, which can be applied in the field of voltage conversion technology. The voltage conversion circuit includes: a first terminal of a switching circuit of a step-down module electrically connected to a power supply, and a second terminal of the switching circuit electrically connected to multiple capacitors; the switching circuit is configured to control the multiple capacitors to switch between a series connection and a parallel connection under the control of a first control signal from a controller; in the series connection state, the multiple capacitors are charged by the power supply; in the parallel connection state, at least one of the multiple capacitors is discharged to output a discharge voltage; a conversion module converts the discharge voltage into an alternating voltage and outputs the alternating voltage; a transformer module transforms the alternating voltage to obtain and outputs a processed voltage; and a rectifier module rectifies the processed voltage to obtain a target voltage.

Description

Technical Field

[0001] This application relates to the field of voltage conversion technology, and more specifically to a voltage conversion circuit, conversion circuit, device and conversion method. Background Technology

[0002] High-voltage industrial equipment typically has high requirements for voltage levels, adjustment flexibility, and output stability in power transmission. Therefore, ultra-high voltage DC-DC conversion technology, which controls the input voltage of high-voltage industrial equipment to be ultra-high voltage (≥1kV) and allows for precise adjustment of the output voltage over a wide range (e.g., from several hundred volts to several thousand volts), has become an important research direction. However, due to limitations in existing manufacturing processes and materials, the conversion circuit is prone to problems such as high circuit losses, difficulty in voltage and current equalization, and low conversion efficiency during the ultra-high voltage DC-DC conversion process. Summary of the Invention

[0003] In view of the above problems, this application provides a voltage conversion circuit, a conversion circuit, an apparatus, and a conversion method.

[0004] According to a first aspect of this application, a voltage conversion circuit is provided, comprising: a step-down module, including a switching circuit and a plurality of capacitors, a first terminal of the switching circuit being electrically connected to a power supply, and a second terminal of the switching circuit being electrically connected to the plurality of capacitors; the switching circuit being configured to control the plurality of capacitors to switch between a series state and a parallel state under the control of a first control signal from a controller, wherein in the series state, the plurality of capacitors are charged by the power supply, and in the parallel state, at least one of the plurality of capacitors is discharged to output a discharge voltage; a conversion module being electrically connected to the output terminal of the step-down module, configured to convert the discharge voltage into an alternating voltage and output the alternating voltage at the output terminal; a transformer module being electrically connected to the output terminal of the conversion module, configured to transform the alternating voltage to obtain and output a processed voltage at the output terminal; and a rectifier module being electrically connected to the output terminal of the transformer module, configured to rectify the processed voltage to obtain a target voltage.

[0005] A second aspect of this application provides a conversion circuit, comprising: multiple cascaded buck modules, the input terminal of a first-stage buck module being electrically connected to a power supply; each buck module including a switching circuit and multiple capacitors; a first terminal of the switching circuit being electrically connected to the power supply; and a second terminal of the switching circuit being electrically connected to the multiple capacitors; the switching circuit being configured to control the multiple capacitors to switch between a series state and a parallel state under the control of a first control signal from a controller; in the series state, the multiple capacitors being charged by the power supply; and in the parallel state, at least one of the multiple capacitors being discharged, so as to output a discharge voltage through the output terminal of the last-stage buck module; a conversion module electrically connected to the output terminal of the last-stage buck module, the conversion module being configured to convert the discharge voltage into an alternating voltage and output the alternating voltage at the output terminal; a transformer module electrically connected to the output terminal of the conversion module, the buck module being configured to transform the alternating voltage to obtain and output a processed voltage at the output terminal; and a rectifier module electrically connected to the output terminal of the transformer module, the rectifier module being configured to rectify the processed voltage to obtain a target voltage.

[0006] A third aspect of this application provides an electronic device, including the voltage conversion circuit or the conversion circuit described above.

[0007] A fourth aspect of this application provides a voltage conversion method, comprising: controlling multiple capacitors to switch between a series state and a parallel state under the control of a first control signal from a controller; charging the multiple capacitors with a power supply in the series state; discharging through at least one of the multiple capacitors in the parallel state to output a discharge voltage; a conversion module converting the discharge voltage into an alternating voltage and outputting the alternating voltage through the output terminal of the conversion module; a transformer module performing transformer processing on the alternating voltage to obtain and outputting a processed voltage at the output terminal; and a rectifier module performing rectifier processing on the processed voltage to obtain a target voltage.

[0008] According to embodiments of this application, by utilizing a switching circuit and multiple capacitors within the buck module, the series-parallel connections between the multiple capacitors are alternately switched during different time periods of the control signal. Combining the core voltage divider concept of series charging and parallel discharging, the input voltage (ultra-high DC voltage (>1200V)) is stably and alternately divided and released under different series and parallel connection states. This achieves efficient voltage reduction of the input voltage without the need for multiple cascaded buck structures, using fewer components to obtain a discharge voltage compatible with the components within the conversion module, and providing the necessary circuit conditions for voltage and current equalization for the conversion module.

[0009] Furthermore, based on topology decoupling design, through the coordinated cooperation between the buck module with high functional independence and other modules, the voltage and current in the conversion module are processed during the process of achieving voltage and current equalization, thereby improving the working efficiency, reliability and robustness of voltage conversion. This avoids the problems of poor voltage and current equalization and thermal management caused by the cascaded structure of strong coupling of multiple modules, thereby increasing the power density of the circuit while reducing the circuit cost. Attached Figure Description

[0010] The above-mentioned contents, other objects, features and advantages of this application will become clearer from the following description of embodiments with reference to the accompanying drawings, in which:

[0011] Figure 1 A schematic diagram of a voltage conversion circuit according to an embodiment of this application is shown;

[0012] Figure 2 A schematic diagram of a step-down module according to an embodiment of this application is shown;

[0013] Figure 3 A schematic diagram of a step-down module according to another embodiment of this application is shown;

[0014] Figure 4 A schematic diagram illustrating the power flow for charging multiple capacitors within a step-down module according to an embodiment of this application is shown.

[0015] Figure 5 A schematic diagram showing the power flow for charging multiple capacitors within a buck module according to another embodiment of this application is shown;

[0016] Figure 6 A schematic diagram showing the power flow of multiple capacitors discharging within a step-down module according to an embodiment of this application is shown;

[0017] Figure 7 A schematic diagram showing the power flow of multiple capacitors discharging within a buck module according to another embodiment of this application is shown;

[0018] Figure 8 A schematic diagram showing the power flow of multiple capacitors discharging within a buck module according to another embodiment of this application is shown;

[0019] Figure 9a A schematic diagram of the control timing of the transistors in a buck module according to an embodiment of this application is shown;

[0020] Figure 9b A schematic diagram of the control timing of a transistor within a buck module according to another embodiment of this application is shown;

[0021] Figure 10A schematic diagram of a step-down module according to another embodiment of this application is shown;

[0022] Figure 11 A schematic diagram is shown of the discharge voltage experienced by the components in the conversion module during discharge according to an embodiment of this application;

[0023] Figure 12 A schematic diagram of a conversion module according to an embodiment of this application is shown;

[0024] Figure 13 A schematic diagram of a conversion module according to another embodiment of this application is shown;

[0025] Figure 14 A schematic diagram of the control timing of the transistors in the conversion module according to an embodiment of this application is shown;

[0026] Figure 15 A schematic diagram of a voltage conversion circuit according to another embodiment of this application is shown;

[0027] Figure 16 A schematic diagram of the conversion voltage and current according to an embodiment of this application is shown;

[0028] Figure 17 A schematic diagram of voltage and current during the steady-state phase according to an embodiment of this application is shown;

[0029] Figure 18 A schematic diagram of a conversion circuit according to an embodiment of this application is shown;

[0030] Figure 19 A flowchart of a voltage conversion method according to an embodiment of this application is shown. Detailed Implementation

[0031] The embodiments of this application will now be described with reference to the accompanying drawings. However, it should be understood that these descriptions are exemplary only and are not intended to limit the scope of this application. In the following detailed description, numerous specific details are set forth to provide a thorough understanding of the embodiments of this application for ease of explanation. However, it will be apparent that one or more embodiments may be implemented without these specific details. Furthermore, descriptions of well-known structures and technologies are omitted in the following description to avoid unnecessarily obscuring the concepts of this application.

[0032] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of this application. The terms “comprising,” “including,” etc., as used herein indicate the presence of the stated features, steps, operations, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, or components.

[0033] All terms used herein (including technical and scientific terms) have the meanings commonly understood by those skilled in the art, unless otherwise defined. It should be noted that the terms used herein are to be interpreted in a manner consistent with the context of this specification, and not in an idealized or overly rigid way.

[0034] When using expressions such as "at least one of A, B and C", they should generally be interpreted in accordance with the meaning that is commonly understood by those skilled in the art (e.g., "a system having at least one of A, B and C" should include, but is not limited to, a system having A alone, a system having B alone, a system having C alone, a system having A and B, a system having A and C, a system having B and C, and / or a system having A, B and C, etc.).

[0035] High-voltage industrial equipment typically demands high voltage levels, flexible regulation, and stable output for power transmission. Therefore, ultra-high voltage DC-DC conversion technology, which allows for precise adjustment of the output voltage over a wide range (e.g., from several hundred volts to several thousand volts), has become a crucial research area. However, limitations in current manufacturing processes and materials lead to problems such as high circuit losses, difficulty in voltage and current equalization, and low conversion efficiency during ultra-high voltage DC-DC conversion.

[0036] Embodiments of this application provide a voltage conversion circuit, including: a step-down module, comprising a switching circuit and multiple capacitors, wherein a first terminal of the switching circuit is electrically connected to a power supply, and a second terminal of the switching circuit is electrically connected to the multiple capacitors; the switching circuit is configured to control the multiple capacitors to switch between a series state and a parallel state under the control of a first control signal from a controller, wherein in the series state, the multiple capacitors are charged by the power supply, and in the parallel state, at least one of the multiple capacitors is discharged to output a discharge voltage; a conversion module, electrically connected to the output terminal of the step-down module, configured to convert the discharge voltage into an alternating voltage and output the alternating voltage at the output terminal; a transformer module, electrically connected to the output terminal of the conversion module, configured to transform the alternating voltage to obtain and output a processed voltage at the output terminal; and a rectifier module, electrically connected to the output terminal of the transformer module, configured to rectify the processed voltage to obtain a target voltage.

[0037] Figure 1 A schematic diagram of a voltage conversion circuit according to an embodiment of this application is shown.

[0038] like Figure 1 As shown, a voltage conversion circuit for DC-DC conversion of ultra-high voltage may include a controller for controlling the components in the circuit. Figure 1(Not shown in the figure) A step-down module for initially stepping down ultra-high input voltage (≥1kV), a conversion module for alternating conversion of the stepped-down voltage, a transformer module for transforming the alternating voltage, and a rectifier module for rectifying and filtering the transformed voltage.

[0039] Specifically, the step-down module may include a switching circuit and multiple capacitors. A first terminal of the switching circuit is electrically connected to a power supply, and a second terminal of the switching circuit is electrically connected to the multiple capacitors. The switching circuit can be configured to control the multiple capacitors to switch between a series connection and a parallel connection under the control of a first control signal from a controller. In the series connection state, the power supply charges the multiple capacitors; in the parallel connection state, at least one of the capacitors discharges to output a discharge voltage.

[0040] The switching circuit may include multiple components for controlling the connection state of capacitors. Under the control of a first control signal, the connection relationship between multiple capacitors is alternately switched by controlling the on and off states of different components within the switching circuit.

[0041] By switching the connection relationships between multiple capacitors, they alternately enter different charging and discharging states. Based on the core idea of ​​series charging (voltage division) and parallel discharging (voltage release), when the power supply is electrically connected to multiple capacitors, the power supply voltage can be used to charge the capacitors, thus achieving voltage division. When the power supply is disconnected from the capacitors, at least one of the capacitors can release the divided voltage to the conversion module, and this voltage is compatible with the components within the conversion module.

[0042] By using only a step-down module to step down the ultra-high input voltage in the voltage conversion circuit, the prerequisite circuit conditions for voltage and current equalization are provided for the conversion module. This avoids the use of multiple sets of redundant voltage conversion circuits when facing ultra-high input voltage, which would result in different voltage and current in each voltage conversion circuit, and thus cause the thermal balance management of the entire voltage conversion circuit to be out of balance.

[0043] The conversion module can be electrically connected to the output of the buck module. The conversion module can be configured to convert the discharge voltage into an alternating voltage and output the alternating voltage at the output terminal.

[0044] When at least one of the multiple capacitors is in a discharged state, the conversion module performs alternating conversion on the received discharge voltage, thereby converting the DC voltage into an alternating AC voltage that can be used for transformer transformation.

[0045] The transformer module can be electrically connected to the output of the conversion module. The transformer module can be configured to transform alternating voltage and output the processed voltage at the output terminal.

[0046] The rectifier module can be electrically connected to the output terminal of the transformer module. The rectifier module can be configured to rectify the processed voltage to obtain the target voltage V0.

[0047] According to embodiments of this application, by utilizing a switching circuit and multiple capacitors within the buck module, the series-parallel connections between the multiple capacitors are alternately switched during different time periods of the control signal. Combining the core voltage divider concept of series charging and parallel discharging, the input voltage (ultra-high DC voltage (>1200V)) is stably and alternately divided and released under different series and parallel connection states. This achieves efficient voltage reduction of the input voltage without the need for multiple cascaded buck structures, using fewer components to obtain a discharge voltage compatible with the components within the conversion module, and providing the necessary circuit conditions for voltage and current equalization for the conversion module.

[0048] Furthermore, based on the functional topology decoupling design, through the coordinated cooperation between the buck module with high functional independence and other modules, the voltage and current in the conversion module are processed during the process of achieving voltage and current equalization, thereby improving the working efficiency, reliability and robustness of voltage conversion. This avoids the problems of difficulty in voltage and current equalization and poor thermal management caused by the cascaded structure of strong coupling of multiple modules, thereby increasing the power density of the circuit while reducing the circuit cost.

[0049] Figure 2 A schematic diagram of a step-down module according to an embodiment of this application is shown.

[0050] like Figure 2 As shown, the switching circuit can be composed of a first bridge arm and a second bridge arm, combined with a first capacitor C1 and a second capacitor C2 cross-connected between the first bridge arm and the second bridge arm, to step down the power supply voltage (i.e., the input voltage) and discharge to the conversion module.

[0051] Specifically, the first ends of both the first bridge arm and the second bridge arm are electrically connected to the power supply, the first end of the first capacitor C1 is electrically connected to the midpoint of the first bridge arm, the second end of the first capacitor C1 is electrically connected to the second end of the second bridge arm, the first end of the second capacitor C2 is electrically connected to the midpoint of the second bridge arm, and the second end of the second capacitor C2 is electrically connected to the second end of the first bridge arm.

[0052] One end of the first bridge arm and the second bridge arm are electrically connected to the power supply, and the other end is electrically connected to the conversion module. Under the control of the first control signal, the on and off states of different components in the first bridge arm and the second bridge arm are controlled to alternately switch the connection relationship of the first capacitor C1 and the second capacitor C2 that are cross-connected in the first bridge arm and the second bridge arm.

[0053] This allows the power supply voltage (ultra-high voltage) to flow into multiple capacitors cross-connected at the other end and midpoint of the bridge arm when the capacitor is charging. When the capacitor is discharging, the discharge voltage can flow into the conversion module through the other end of the first and second bridge arms.

[0054] According to an embodiment of this application, by electrically connecting one end of the first bridge arm and the second bridge arm to an external power supply and the other end to a conversion module, and cross-connecting the first capacitor and the second capacitor between the first bridge arm and the second bridge arm, a front-end topology circuit for voltage division and discharge of the power supply voltage is constructed. Under the control of the first control signal, by controlling the conduction state of different components within the bridge arm, the flow direction of the power supply voltage and the charging and discharging state of the capacitors are controlled. This allows for the stable and orderly efficient reduction of the input voltage to obtain a discharge voltage, while simultaneously maintaining voltage and current equalization within the buck module, thus providing the necessary circuit conditions for voltage and current equalization for the conversion module.

[0055] Figure 3 A schematic diagram of a step-down module according to another embodiment of this application is shown.

[0056] like Figure 3 As shown, the first bridge arm may include a first transistor and a second transistor, and the connection between the first transistor and the second transistor can be as follows.

[0057] Specifically, the first terminal of the first transistor D1 can be electrically connected to the DC power supply, the second terminal of the first transistor D1 can be electrically connected to the first terminal of the first capacitor C1, and the gate of the first transistor D1 can be electrically connected to the controller. The first terminal of the second transistor D2 can be electrically connected to the first terminal of the first capacitor C1, the second terminal of the second transistor D2 can be electrically connected to the second terminal of the second capacitor C2, and the gate of the second transistor D2 can be electrically connected to the controller.

[0058] The first terminal of the first capacitor C1 is electrically connected to the second terminal of the first transistor D1 (that is, equivalent to the first terminal of the first capacitor C1 being electrically connected to the midpoint of the first bridge arm), and the second terminal of the first capacitor C1 is connected to the second terminal of the second bridge arm. At the same time, the first terminal of the second capacitor C2 is electrically connected to the midpoint of the second bridge arm, and the second terminal of the second capacitor C2 is electrically connected to the second terminal of the second transistor D2.

[0059] Through the above connection relationship, combined with the first control signal sent by the controller to the first transistor D1 and the second transistor D2, the power supply voltage can flow into the first capacitor C1 and the second capacitor C2 in series through the conducting first transistor D1 for a certain period of time, so that the power supply can be used to charge the first capacitor C1 and the second capacitor C2 in series together, thereby allowing the first capacitor C1 and the second capacitor C2 to share the power supply voltage.

[0060] like Figure 3 As shown, the second bridge arm may include a third transistor D3 and a fourth transistor D4, and the connection between the third transistor D3 and the fourth transistor D4 can be seen as follows.

[0061] Specifically, the first terminal of the third transistor D3 can be electrically connected to the power supply, the second terminal of the third transistor D3 can be electrically connected to the first terminal of the second capacitor C2, and the gate of the third transistor D3 can be electrically connected to the controller. The first terminal of the fourth transistor D4 can be electrically connected to the first terminal of the second capacitor C2, the second terminal of the fourth transistor D4 can be electrically connected to the second terminal of the first capacitor C1, and the gate of the fourth transistor D4 can be electrically connected to the controller.

[0062] The first terminal of the first capacitor C1 is electrically connected to the second terminal of the first transistor D1, and the second terminal of the first capacitor C1 is connected to the second terminal of the fourth transistor D4. At the same time, the first terminal of the second capacitor C2 is electrically connected to the second terminal of the third transistor D3 (that is, equivalent to the first terminal of the second capacitor C2 being electrically connected to the midpoint of the second bridge arm), and the second terminal of the second capacitor C2 is electrically connected to the second terminal of the second transistor D2.

[0063] Through the aforementioned connection, and in conjunction with the first control signal sent by the controller to the third transistor D3 and the fourth transistor D4, the power supply voltage can flow into the series-connected first capacitor C1 and second capacitor C2 through the conducting third transistor D3 during another time period, so as to charge the first capacitor C1 and second capacitor C2 together using the power supply. Simultaneously, by using the power supply to charge the series-connected first capacitor C1 and second capacitor C2 through the conducting first transistor D1, the power supply voltage can flow into the first capacitor C1 and second capacitor C2 alternately through different transmission paths, thereby maintaining current sharing in the circuit.

[0064] According to embodiments of this application, based on the construction concepts of HSC (Hybrid Switched-Capacitor) topology and full-bridge topology circuits, a first bridge arm is constructed using a first transistor and a second transistor, and a second bridge arm is constructed using a third transistor and a fourth transistor. Combined with a first capacitor and a second capacitor cross-connected on both sides of the second and fourth transistors, under the control of a first control signal, the series-parallel connections and charging / discharging states of multiple capacitors are alternately switched by controlling the on / off state of the corresponding transistors. By considering the frequency requirements of the buck converter for charging / discharging conversion, a discharge voltage compatible with the components within the conversion module can be obtained efficiently and stably using a high-power-density buck converter, thereby improving the working efficiency, reliability, and robustness of the voltage conversion.

[0065] like Figure 3 As shown, the step-down module may also include a fifth transistor D5. The first terminal of the fifth transistor D5 can be electrically connected to the second terminal of the second capacitor C2, the second terminal of the fifth transistor D5 can be grounded, and the gate of the fifth transistor D5 can be electrically connected to the controller.

[0066] When charging the first capacitor C1 and the second capacitor C2 is required, a complete charging circuit needs to be constructed. A fifth transistor D5 for grounding is provided near the first bridge arm so that when the power supply voltage is transmitted through the corresponding conduction path to charge the series-connected first capacitor C1 and the second capacitor C2, it can be grounded via the conducting fifth transistor D5, forming a complete charging circuit. Simultaneously, when at least one of the first capacitor C1 and the second capacitor C2 is discharging, the fifth transistor D5 can be turned off to prevent the discharge voltage from flowing out of the circuit through the ground terminal.

[0067] refer to Figure 3 The step-down module shown uses a controller to send a first control signal to the control terminals (i.e., the gates) of the first transistor D1, second transistor D2, third transistor D3, fourth transistor D4, and fifth transistor D5 to control the on / off states of the transistors, thereby changing the series and parallel connection states between the first capacitor C1 and the second capacitor C2. This allows the capacitors in different charging or discharging states to perform corresponding charging or discharging operations under different timing stages of the control signal, thus stepping down the ultra-high input voltage to obtain a voltage compatible with the withstand voltage values ​​of the components in the conversion module.

[0068] Among them, the first transistor, the second transistor, the third transistor, the fourth transistor, and the fifth transistor D5 can be NMOS transistors (N-Channel Metal-Oxide-Semiconductor Field-Effect Transistors) or PMOS transistors (P-Channel Metal-Oxide-Semiconductor Field-Effect Transistors). Figure 3 The transistors shown are all NMOS transistors.

[0069] According to an embodiment of this application, in the process of charging the first and second capacitors connected in series using the power supply voltage, it is necessary to construct a complete power supply-ground charging circuit. By setting a fifth transistor connected to ground on one side of the first bridge arm, the conduction and cutoff of the fifth transistor are controlled to switch the circuit to form different charging and discharging stages.

[0070] Figure 4 A schematic diagram showing the power flow for charging multiple capacitors within a step-down module according to an embodiment of this application is provided.

[0071] like Figure 4 As shown, the first transistor D1, the fourth transistor D4, and the fifth transistor D5 are configured to be turned on under the control of the first control signal, so that the first capacitor C1 and the second capacitor C2 are connected in series, and the power supply is configured to charge the first capacitor C1 and the second capacitor C2.

[0072] Under the control of the first control signal, the first transistor D1, the fourth transistor D4, and the fifth transistor D5 turn on in response to the effective level, connecting the first capacitor C1 and the second capacitor C2 in series. The power supply voltage flows through the first transistor D1 on the first bridge arm into the first capacitor C1 and the second capacitor C2, and then through the conducting fifth transistor D5 to form a complete circuit, thereby charging the first capacitor C1 and the second capacitor C2.

[0073] like Figure 4 As shown, when the first transistor D1, the fourth transistor D4, and the fifth transistor D5 are all turned on, the voltage and current first flow into the first capacitor C1 through the first transistor D1, then into the second capacitor C2 through the fourth transistor D4, and then flow out to ground through the fifth transistor D5.

[0074] According to an embodiment of this application, by controlling the first transistor, the fourth transistor, and the fifth transistor to be turned on, in the case of the first capacitor and the second capacitor being connected in series, the power supply voltage flows into the first capacitor and the second capacitor connected in series via the first bridge arm, thereby charging the first capacitor and the second capacitor.

[0075] Figure 5 A schematic diagram of the power flow for charging multiple capacitors within a step-down module according to another embodiment of this application is shown.

[0076] like Figure 5 As shown, the second transistor D2 and the third transistor D3 are configured to be turned on under the control of the first control signal, so that the first capacitor C1 and the second capacitor C2 are connected in series, and the power supply is configured to charge the first capacitor C1 and the second capacitor C2.

[0077] Under the control of the first control signal, the second transistor D2 and the third transistor D3 turn on in response to the effective level, connecting the first capacitor C1 and the second capacitor C2 in series. The power supply voltage flows through the third transistor D3 on the second bridge arm into the first capacitor C1 and the second capacitor C2, and then through the second terminal of the first capacitor C1 to ground, forming a complete circuit to charge the first capacitor C1 and the second capacitor C2.

[0078] like Figure 5 As shown, when the second transistor D2 and the third transistor D3 are turned on, the voltage and current first flow into the second capacitor C2 through the third transistor D3, then into the first capacitor C1 through the second transistor D2, and then flow out through the second terminal of the first capacitor C1 to ground.

[0079] According to an embodiment of this application, by controlling the second transistor and the third transistor to be turned on, in the case of the first capacitor and the second capacitor being connected in series, the power supply voltage flows into the first capacitor and the second capacitor connected in series via the second bridge arm to charge the first capacitor and the second capacitor.

[0080] The capacitance values ​​of the first and second capacitors in the step-down module can be the same or different. The capacitance values ​​of the first and second capacitors can be determined by the specific circuit structure, the input voltage, and the withstand voltage of the components in the conversion module.

[0081] For example, with a power supply voltage of 1200V and the withstand voltage of the components in the conversion module being 650V (the withstand voltage of 650V is the rated value; usually, the voltage flowing through the components in the conversion module needs to be lower than 650V, and it is generally recommended to be around 400V), if the voltage conversion circuit only includes the first step-down module, an 80μF capacitor and a 40μF capacitor can be used. One capacitor shares the 400V voltage, and the other capacitor shares the 800V voltage, in order to perform voltage division and discharge on the input power supply voltage.

[0082] With a power supply voltage of 800V and the withstand voltage of the components in the conversion module being 650V (the withstand voltage of 650V is the rated value; the voltage flowing through the components in the conversion module usually needs to be lower than 650V, and it is usually recommended to be around 400V), and the voltage conversion circuit only including the first step-down module, two capacitors with a capacitance of 80μF can be used, each capacitor sharing 400V of voltage, to divide and discharge the input power supply voltage.

[0083] With a power supply voltage of 1200V and the withstand voltage of the components in the conversion module being 650V (the withstand voltage of 650V is the rated value; the voltage flowing through the components in the conversion module usually needs to be lower than 650V, and it is usually recommended to be around 400V), and with two step-down modules in the voltage conversion circuit, four capacitors with a capacitance of 80μF can be used, each distributing 300V of voltage to divide and discharge the input power supply voltage.

[0084] The ratio of the capacitance values ​​of the first capacitor and the second capacitor can be 3:1 or 1:3. This ensures that the voltage and current values ​​flowing through the two capacitors are not significantly different, thus keeping the voltage and current in the step-down module relatively balanced or within a tolerable range. This facilitates thermal management of the circuit and prevents damage to circuit components.

[0085] Figure 6 A schematic diagram showing the power flow of multiple capacitors discharging within a step-down module according to an embodiment of this application is shown.

[0086] like Figure 6 As shown, the fourth transistor D4 is configured to be turned on under the control of the first control signal, so that the second capacitor C2 and the conversion module form a circuit, and the second capacitor C2 discharges to the conversion module.

[0087] When the capacitance values ​​of the first capacitor C1 and the second capacitor C2 are different, and the capacitance value of the second capacitor C2 is larger, in response to the control of the first control signal, the fourth transistor D4 turns on in response to the effective level. Both the first capacitor C1 and the second capacitor C2 are disconnected from the power supply, and a complete circuit is formed between the second capacitor C2 and the conversion module. At this time, the second capacitor C2 is in a discharging state, and the discharge voltage generated by the second capacitor C2 during discharge flows into the conversion module for subsequent processing through the transmission path electrically connected to the conversion module.

[0088] like Figure 6 As shown, when the fourth transistor D4 is turned on, the voltage and current flow from the second capacitor C2 into the conversion module, and then flow back to the second capacitor C2 through the fourth transistor D4. With the on and off of the components in the conversion module, the discharge voltage is alternately converted.

[0089] According to an embodiment of this application, when the capacitance values ​​of the first capacitor and the second capacitor are different, and the capacitance value of the second capacitor is larger, by controlling the fourth transistor to turn on, the second capacitor with the larger capacitance value (less voltage division) discharges to the conversion module, outputting a discharge voltage that matches the withstand voltage value of the components in the conversion module. This allows full utilization of the transistor with high withstand voltage (low frequency) characteristics, which is different from the components in the conversion module, to process ultra-high voltage, while making the voltage and current flowing into the conversion module achieve the effect of equal voltage and current as much as possible.

[0090] Figure 7 A schematic diagram showing the power flow of multiple capacitors discharging within a buck module according to another embodiment of this application is shown.

[0091] like Figure 7 As shown, the second transistor D2 is configured to be turned on under the control of the first control signal, so that the first capacitor C1 and the conversion module form a circuit, and the first capacitor C1 discharges to the conversion module.

[0092] When the capacitance values ​​of the first capacitor C1 and the second capacitor C2 are different, and the capacitance value of the first capacitor C1 is larger, in response to the control of the first control signal, the second transistor D2 turns on in response to the effective level. Both the first capacitor C1 and the second capacitor C2 are disconnected from the power supply, and a complete circuit is formed between the first capacitor C1 and the conversion module. At this time, the first capacitor C1 is in a discharging state, and the discharge voltage generated when the first capacitor C1 discharges flows into the conversion module for subsequent processing through the transmission path electrically connected to the conversion module.

[0093] like Figure 7 As shown, when the second transistor D2 is turned on, the voltage and current flow from the first capacitor C1 through the second transistor D2 into the conversion module, and then flow directly back to the first capacitor C1. With the switching on and off of the components in the conversion module, the discharge voltage is alternately converted.

[0094] According to the embodiments of this application, when the capacitance values ​​of the first capacitor and the second capacitor are different, and the capacitance value of the first capacitor is larger, by controlling the second transistor to conduct, the first capacitor with the larger capacitance value (less voltage division) discharges to the conversion module, and outputs a discharge voltage that matches the withstand voltage value of the components in the conversion module. Compared with the embodiment where only the fourth transistor is conducted to discharge from the second capacitor, the ultra-high voltage can be processed fully and in a targeted manner, while making the voltage and current flowing into the conversion module achieve the effect of equalizing voltage and current as much as possible.

[0095] Figure 8 A schematic diagram showing the power flow of multiple capacitors discharging within a step-down module according to yet another embodiment of this application is shown.

[0096] like Figure 8As shown, the second transistor D2 and the fourth transistor D4 are configured to be turned on under the control of the first control signal, so that the first capacitor C1 and the second capacitor C2 connected in parallel form a circuit with the conversion module, and the first capacitor C1 and the second capacitor C2 discharge to the conversion module.

[0097] When the capacitance values ​​of the first capacitor C1 and the second capacitor C2 are the same, in response to the control of the first control signal, the second transistor D2 and the fourth transistor D4 are turned on in response to the effective level. Both the first capacitor C1 and the second capacitor C2 are disconnected from the power supply, and are connected in parallel, forming a complete circuit with the conversion module. At this time, the first capacitor C1 and the second capacitor C2 are in a discharging state. The discharge voltage generated by the discharge of the first capacitor C1 and the second capacitor C2 flows into the conversion module for subsequent processing through the transmission path electrically connected to the conversion module.

[0098] like Figure 8 As shown, when both the second transistor D2 and the fourth transistor D4 are turned on, the voltage and current flow from the first capacitor C1 into the conversion module through the second transistor D2, and then directly back to the first capacitor C1. At the same time, the voltage and current also flow from the second capacitor C2 into the conversion module, and then back to the second capacitor C2 through the fourth transistor D4. With the switching on and off of the components in the conversion module, the discharge voltage is alternately converted.

[0099] According to the embodiments of this application, when the capacitance values ​​of the first capacitor and the second capacitor are the same, by controlling the second transistor and the fourth transistor to conduct, the first capacitor and the second capacitor connected in parallel discharge to the conversion module together, and output a discharge voltage that matches the withstand voltage value of the components in the conversion module. As with the embodiments described above that only conduct the fourth transistor or only conduct the second transistor, the ultra-high voltage can be processed in a sufficient and targeted manner, while making the voltage and current flowing into the conversion module achieve the effect of equal voltage and current as much as possible.

[0100] According to an embodiment of this application, under the control of the first control signal, the series-parallel connection state and charging / discharging state of the first capacitor and the second capacitor can be as follows.

[0101] According to an embodiment of this application, during a first time period of a control cycle of the first control signal, the first transistor, the fourth transistor, and the fifth transistor are configured to be turned on under the control of the first control signal, so that the first capacitor and the second capacitor are connected in series.

[0102] According to an embodiment of this application, during a third time period of a control cycle of the first control signal, the second transistor and the third transistor are configured to be turned on under the control of the first control signal, so that the first capacitor and the second capacitor are connected in series.

[0103] According to an embodiment of this application, during a second and a fourth time period of a control cycle of a first control signal, at least one of the second and fourth transistors is configured to be turned on under the control of the first control signal to discharge at least one of the first and second capacitors.

[0104] Each control cycle of the first control signal can include four different operating periods. During each operating period, different effective signals are applied to different transistors to control their coordinated conduction, thereby alternately switching the charging and discharging states between the first and second capacitors. The charging conduction path in the first and third periods is not fixed. It can be that the first, fourth, and fifth transistors are conducting in the first period, and the second and third transistors are conducting in the third period; alternatively, the second and third transistors can be conducting in the first period, and the first, fourth, and fifth transistors are conducting in the third period.

[0105] According to an embodiment of this application, under the control of a first control signal, the first capacitor and the second capacitor alternately charge and discharge, and in two adjacent charging stages, the power supply voltage flows into the first capacitor and the second capacitor through different transmission paths. This achieves voltage and current equalization as much as possible across different bridge arms through the conduction of different bridge arms, avoiding thermal management imbalance caused by excessive power on one side. Furthermore, by combining the alternating switching between charging and discharging, the ultra-high input voltage is stepped down to obtain a discharge voltage that matches the withstand voltage of the components within the conversion module.

[0106] Figure 9a A schematic diagram of the control timing of the transistors in a buck module according to an embodiment of this application is shown.

[0107] like Figure 9a As shown, the horizontal axis can represent time, and the vertical axis corresponding to the transistor can represent the control level. When using an NMOS transistor (high level conduction), the control timing of the first control signal is as follows: in the first time period, the first transistor D1, the fourth transistor D4, and the fifth transistor D5 are turned on, and the first capacitor C1 and the second capacitor C2 are charged in series; in the third time period, the second transistor D2 and the third transistor D3 are turned on, and the first capacitor C1 and the second capacitor C2 are charged in series; in the second and fourth time periods, the second transistor D2 and the fourth transistor D4 are turned on, and the first capacitor C1 and the second capacitor C2 are discharged in parallel.

[0108] Figure 9b A schematic diagram of the control timing of a transistor in a buck module according to another embodiment of this application is shown.

[0109] like Figure 9bAs shown, the horizontal axis represents time, the vertical axis corresponding to the transistors represents the control level, and the vertical axis corresponding to the transistors represents the voltage value. The control sequence of the first control signal is as follows: in the first time period, the second transistor D2 and the third transistor D3 are turned on, and the first capacitor C1 and the second capacitor C2 are charged in series; in the third time period, the first transistor D1, the fourth transistor D4, and the fifth transistor D5 are turned on, and the first capacitor C1 and the second capacitor C2 are charged in series; in the second and fourth time periods, the second transistor D2 and the fourth transistor D4 are turned on, and the first capacitor C1 and the second capacitor C2 are discharged in parallel. With an input voltage of 1200V, through the orderly control of the first control signal, before reaching charge-discharge balance, the discharge voltage output by the first capacitor C1 and the second capacitor C2 gradually increases and is unstable; when charge-discharge balance is reached, the first capacitor C1 and the second capacitor C2 can output a discharge voltage of approximately 400V and maintain stability.

[0110] Figure 10 A schematic diagram of a step-down module according to another embodiment of this application is shown.

[0111] like Figure 10 As shown, the buck module may also include a sixth transistor located near the second bridge arm.

[0112] Specifically, the first terminal of the sixth transistor D6 is electrically connected to the second terminal of the first capacitor C1, the second terminal of the sixth transistor D6 is grounded, and the gate of the sixth transistor D6 is electrically connected to the controller.

[0113] like Figure 3 As shown, the connections of the other transistors and capacitors in the buck converter module are also illustrated. Figure 10 One end of the sixth transistor D6 is electrically connected to the side near the second bridge arm, and the other end is grounded.

[0114] According to an embodiment of this application, by connecting a sixth transistor at the ground terminal near the second bridge arm, and referring to the conduction coordination of the fifth transistor with other transistors, the sixth transistor and other transistors can be used for coordinated control, thereby improving the symmetry and reliability of the circuit.

[0115] According to an embodiment of this application, the second transistor, the third transistor, and the sixth transistor are configured to be turned on under the control of a first control signal, so that the first capacitor and the second capacitor are connected in series.

[0116] Under the control of the first control signal, the second, third, and sixth transistors turn on in response to the effective level, connecting the first and second capacitors in series. The power supply voltage flows through the third transistor on the second bridge arm into the first and second capacitors, and then through the sixth transistor to ground, forming a complete circuit to charge the first and second capacitors.

[0117] According to an embodiment of this application, by controlling the second transistor, the third transistor and the sixth transistor to be turned on, the power supply voltage flows into the first capacitor and the second capacitor in series via the second bridge arm to charge the first capacitor and the second capacitor, when the first capacitor and the second capacitor are connected in series.

[0118] Figure 11 A schematic diagram is shown of the discharge voltage experienced by the components in the conversion module during discharge according to an embodiment of this application.

[0119] like Figure 11 As shown, Figure 11 The diagram shows that when the first capacitor and / or the second capacitor can stably discharge to the conversion module, the voltage that the components in the conversion module can withstand can be stably maintained at around -400V to 400V, which is lower than the withstand voltage of 650V of the components in the conversion module. The horizontal axis can represent time, and the vertical axis can represent voltage value.

[0120] Figure 12 A schematic diagram of a conversion module according to an embodiment of this application is shown.

[0121] like Figure 12 As shown, the conversion module may include a seventh transistor D7 and an eighth transistor D8 for alternating conversion of DC voltage.

[0122] Specifically, the first terminal of the seventh transistor D7 can be electrically connected to the output terminal of the buck module, the second terminal of the seventh transistor D7 can be electrically connected to the first terminal of the eighth transistor D8, and the gate of the seventh transistor D7 can be electrically connected to the controller. The first terminal of the eighth transistor D8 can be electrically connected to the transformer module, the second terminal of the eighth transistor D8 can be grounded, and the gate of the eighth transistor D8 can be electrically connected to the controller. The seventh transistor D7 and the eighth transistor D8 can be transistors with low withstand voltage, low high-frequency switching loss, and small parasitic parameters.

[0123] A half-bridge topology circuit (rear-stage resonant topology circuit) can be constructed using only the seventh transistor D7 and the eighth transistor D8. Under the control of the second control signal, the seventh transistor D7 and the eighth transistor D8 alternately conduct at a frequency faster than that of the transistors in the buck module, thereby alternating the DC discharge voltage to obtain an alternating voltage.

[0124] According to embodiments of this application, based on the high-frequency characteristics of the resonant topology circuit, a half-bridge resonant topology structure is constructed using a seventh and eighth transistor with high-frequency characteristics to efficiently convert the discharge voltage. Simultaneously, through topological decoupling design between the preceding and following stages, the functional connections of the voltage-resistant step-down module and the high-frequency conversion module are decoupled. This achieves voltage and current balance within the conversion module without requiring a cascaded structure with strong coupling of multiple modules, improving the circuit's thermal management performance. Furthermore, since the partial driving implementation of the conversion module is similar to that of a traditional resonant circuit, it has strong applicability and low cost in implementing the circuit structure.

[0125] Figure 13 A schematic diagram of a conversion module according to another embodiment of this application is shown.

[0126] like Figure 13 As shown, in addition to the seventh transistor D7 and the eighth transistor D8, the conversion module may also include the ninth transistor D9 and the tenth transistor D10.

[0127] Specifically, the first terminal of the ninth transistor D9 can be electrically connected to the first terminal of the seventh transistor D7, the second terminal of the ninth transistor D9 can be electrically connected to the first terminal of the tenth transistor D10, and the gate of the ninth transistor D9 can be electrically connected to the controller. The first terminal of the tenth transistor D10 can be electrically connected to the transformer module, the second terminal of the tenth transistor D10 can be grounded, and the gate of the tenth transistor D10 can be electrically connected to the controller.

[0128] The ninth transistor D9 and the tenth transistor D10 can be transistors with low voltage withstand value, low high-frequency switching loss and small parasitic parameters.

[0129] A full-bridge topology circuit (rear-stage resonant topology circuit) can be constructed using the seventh transistor D7, the eighth transistor D8, the ninth transistor D9, and the tenth transistor D10. Under the control of the second control signal, through the coordinated operation of multiple transistors with low withstand voltage, low high-frequency switching loss, and small parasitic parameters, the DC discharge voltage is alternating to obtain an alternating voltage.

[0130] According to embodiments of this application, based on the high-frequency characteristics of the resonant topology circuit, a full-bridge resonant topology structure is constructed using a seventh, eighth, ninth, and tenth transistor with high-frequency characteristics to efficiently convert the discharge voltage. Meanwhile, referring to the embodiments of the half-bridge resonant topology described above, voltage and current balance within the conversion module is achieved without the need for a cascaded structure with strong coupling of multiple modules, improving the circuit's thermal management performance. Furthermore, since the partial driving implementation of the conversion module is similar to that of a traditional resonant circuit, it has strong applicability and lower costs for circuit structure and control.

[0131] According to an embodiment of this application, the seventh and tenth transistors are configured to alternately conduct under the control of a second control signal to convert the discharge voltage into an alternating voltage.

[0132] During the first time period of a control cycle of the second control signal in the transient phase, the seventh and tenth transistors are configured to be turned on under the control of the second control signal, and during the second time period of a control cycle of the second control signal in the transient phase, the eighth and ninth transistors are configured to be turned on under the control of the second control signal.

[0133] During the first time period of a control cycle of the second control signal in the steady-state phase, the seventh and tenth transistors are configured to be turned on under the control of the second control signal, and during the second time period of a control cycle of the second control signal in the steady-state phase, the eighth and ninth transistors are configured to be turned on under the control of the second control signal.

[0134] The conduction frequencies of the seventh, eighth, ninth, and tenth transistors in the transient and steady-state phases can be different.

[0135] According to embodiments of this application, by alternately controlling the seventh and tenth transistors to be turned on, and the eighth and ninth transistors to be turned on, the discharge voltage is subjected to high-frequency alternating conversion processing to obtain an alternating voltage that can be input into the transformer module for transformer processing.

[0136] Figure 14 A schematic diagram of the control timing of transistors within a conversion module according to an embodiment of this application is shown.

[0137] like Figure 14 As shown, the horizontal axis represents time, and the vertical axis corresponding to the transistors represents the control level. At this point, the conversion module includes a seventh transistor D7 and an eighth transistor D8. During both the transient and steady-state phases, both transistors D7 and D8 are alternately conducting. The transistor switching frequency during the transient phase is lower than the transistor switching frequency during the steady-state phase.

[0138] According to an embodiment of this application, the duration of a control cycle within the first control signal is greater than the duration of a control cycle within the second control signal.

[0139] The fact that the control cycle of the first control signal is longer than that of the second control signal indicates that the transistors in the conversion module typically have high-frequency conduction characteristics, extremely low high-frequency switching losses, and small parasitic parameters, making them suitable for high-frequency operating circuit environments. Conversely, the transistors in the buck converter typically have lower conduction losses, making them suitable for lower switching frequency circuit environments. For example, the control frequency of multiple transistors in a buck converter can be around 25 kHz, while the control frequency of multiple transistors in the conversion module, when reaching steady state, can be around 200 kHz.

[0140] According to the embodiments of this application, based on the core concept of matching the functional design of the topology with the power device characteristics of the components, and according to the withstand voltage characteristics and functional characteristics of the buck module and the conversion module, a first control signal with a lower frequency is adapted to the buck module, and a second control signal with a higher frequency is adapted to the conversion module. The two decoupled topologies are driven separately in a relatively independent and isolated manner, so as to maintain stable charging and discharging independently without interfering with the high-frequency controlled conversion module, further reducing the coupling degree between the buck module and the conversion module, and improving the drive independence and operability.

[0141] According to embodiments of this application, the active layer material of the multiple transistors in the switching circuit is silicon carbide, and the active layer material of the multiple transistors in the conversion module is gallium nitride.

[0142] The multiple transistors in the switching circuit can be silicon carbide field-effect transistors, and the multiple transistors in the conversion module can be gallium nitride field-effect transistors.

[0143] According to embodiments of this application, the breakdown voltage of multiple transistors in the switching circuit is greater than the breakdown voltage of multiple transistors in the conversion module. That is, the breakdown voltage of the silicon carbide field-effect transistor is greater than the breakdown voltage of the gallium nitride field-effect transistor.

[0144] Based on the core concept of matching the functional design of different circuit topologies with the power device characteristics of components, different process components (with different withstand voltage values ​​and frequency characteristics) are used in different modules to match the power device characteristics of the components in different modules with the functional design of their corresponding topologies. This allows for a refined decomposition of the circuit structure, which is currently a jumbled mix of functional structures, resulting in step-down modules (equivalent to the front-end HSC topology circuit) and conversion modules (equivalent to the rear-end LLC topology circuit (LLC Resonant Converter)) with different withstand voltage values, thereby improving the circuit's voltage conversion performance.

[0145] According to embodiments of this application, considering the high voltage withstand capability of the buck module and the high frequency characteristics of the conversion module, silicon carbide field-effect transistors (SFETs) with low switching frequency, high voltage withstand capability, and low conduction loss are specifically selected to construct the buck module, enabling stable voltage reduction of ultra-high input voltages. Simultaneously, gallium nitride (GaN) SFETs with extremely low high-frequency switching loss and small parasitic parameters are selected to construct the conversion module, achieving efficient soft-switching operation. Furthermore, by combining the concepts of topology layering and functional partitioning, a voltage conversion circuit that balances high voltage withstand capability and high frequency operation is constructed, significantly improving the circuit's reliability and operating efficiency.

[0146] Furthermore, although the decoupled topology design, based on high-voltage front-end and high-frequency rear-end, uses transistors with different characteristics to build different circuits, there is still a driving correlation between the front and rear topologies in the timing control of the transistors. When the circuit has not reached steady state, the timing control of the buck module and the conversion module can be in a closed-loop coordinated state, based on the closed-loop feedback between the change in the rear stage and the response of the front stage, to maintain the output stability of the discharge voltage.

[0147] For example, during the transient phase, if the conversion module requires more energy for alternating conversion and transformer output, it may reduce the switching frequency within the conversion module to improve energy transfer efficiency, which could lead to a drop in the bus voltage used to transmit the discharge voltage. Based on the detected bus voltage and target voltage, the controller can dynamically adjust the conduction state of the transistors in the preceding buck module (e.g., increasing the capacitor discharge time and decreasing the series charging time), thereby allowing the capacitor to release more energy to maintain the stability of the output discharge voltage.

[0148] During the transient phase, the conversion module requires less energy for alternating conversion and transformer output, which may increase the switching frequency within the module, reducing energy transfer efficiency and potentially causing an increase in the bus voltage used to transmit the discharge voltage. Based on the detected bus voltage and target voltage, the controller can dynamically adjust the conduction state of the transistors in the preceding buck module (e.g., reducing capacitor discharge time and increasing series charging time) to minimize capacitor energy release and maintain the stability of the output discharge voltage.

[0149] Furthermore, when the multiple switching transistors in the step-down module switch between charging and discharging, the switching of the multiple switching transistors in the conversion module can be kept in a temporary stable state (avoiding simultaneous switching), so as to avoid detuning of the conversion module or damage to components due to fluctuations in discharge voltage, thereby improving circuit reliability and stability.

[0150] Figure 15 A schematic diagram of a voltage conversion circuit according to another embodiment of this application is shown.

[0151] like Figure 15 As shown, the transformer module may include a resonant capacitor C3, a first inductor L1, a second inductor L2, and a transformer. The rectifier module may include a first synchronous rectifier M1, a second synchronous rectifier M2, a third synchronous rectifier M3, a fourth synchronous rectifier M4, and a filter capacitor C4.

[0152] Specifically, the first terminal of resonant capacitor C3 is electrically connected to the second terminal of the seventh transistor D7 in the conversion module, and the second terminal of resonant capacitor C3 is electrically connected to the first terminal of the first inductor L1. The second terminal of the first inductor L1 is electrically connected to the same-name terminal of the primary winding of the transformer. The first terminal of the second inductor L2 is electrically connected to the same-name terminal of the primary winding of the transformer, and the second terminal of the second inductor L2 is electrically connected to the opposite-name terminal of the primary winding of the transformer. The same-name terminal of the secondary winding of the transformer is electrically connected to the second terminal of the first synchronous rectifier tube M1 in the rectifier module, and the opposite-name terminal of the secondary winding of the transformer is electrically connected to the first terminal of the fourth synchronous rectifier tube M4 in the rectifier module.

[0153] The first terminal of the first synchronous rectifier M1 is electrically connected to the positive output terminal. The second terminal of the first synchronous rectifier M1 is electrically connected to the first terminal of the second synchronous rectifier M2. The gate of the first synchronous rectifier M1 is electrically connected to the controller. The second terminal of the second synchronous rectifier M2 is electrically connected to the negative output terminal. The gate of the second synchronous rectifier M2 is electrically connected to the controller. The first terminal of the third synchronous rectifier M3 is electrically connected to the positive output terminal. The second terminal of the third synchronous rectifier M3 is electrically connected to the first terminal of the fourth synchronous rectifier M4. The gate of the third synchronous rectifier M3 is electrically connected to the controller. The second terminal of the fourth synchronous rectifier M4 is electrically connected to the negative output terminal. The gate of the fourth synchronous rectifier M4 is electrically connected to the controller. The first terminal of the filter capacitor C4 is electrically connected to the positive output terminal. The second terminal of the filter capacitor C4 is electrically connected to the negative output terminal.

[0154] Synchronous rectifiers built from MOSFETs can also be used in the rectifier module, which can further improve the rectification efficiency and rectification effect of the circuit.

[0155] Figure 16 A schematic diagram of the conversion voltage and current according to an embodiment of this application is shown.

[0156] like Figure 16 As shown, the input voltage of the power supply can be 1200V. After being stepped down by a high-voltage-resistance buck module, a 400V discharge voltage suitable for the conversion module is obtained. Then, after processing by the transformer and rectifier modules, the output voltage is close to the target 12V after stabilization. Furthermore, it can be seen from the operation of the entire voltage conversion circuit that the seventh transistor D7 and the eighth transistor D8 can fluctuate within a safe voltage range of 400V in both transient and steady-state phases. Moreover, after reaching the steady-state phase, the inductor current in each cycle can pass through zero, facilitating the soft-switching characteristics of the seventh transistor D7 and the eighth transistor D8 through control.

[0157] Figure 17 A schematic diagram of voltage and current during the steady-state phase according to an embodiment of this application is shown.

[0158] like Figure 17 As shown, Figure 17 It can be the above Figure 16 An enlarged diagram of a portion of the data. From Figure 17The diagram clearly shows that the power supply input voltage can be 1200V. After being stepped down by a high-voltage-resistance buck module, it obtains a 400V discharge voltage compatible with the conversion module. Then, after processing by the transformer and rectifier modules, the output voltage reaches a target voltage close to 12V in steady state. During the steady-state phase, the seventh transistor D7 and the eighth transistor D8 can fluctuate within a safe voltage range of 400V. Simultaneously, during the steady-state phase, the inductor current can pass through zero in each cycle, facilitating the soft-switching characteristics of the seventh transistor D7 and the eighth transistor D8 through control.

[0159] Figure 18 A schematic diagram of a conversion circuit according to an embodiment of this application is shown.

[0160] like Figure 18 As shown, the conversion circuit may include a multi-stage buck converter.

[0161] Specifically, multiple cascaded buck modules are used. The input terminal of the first-stage buck module is electrically connected to the power supply. Each buck module includes multiple capacitors and multiple transistors. The buck module is configured to control the conduction and cutoff of multiple transistors under the control of a first control signal from the controller, so that multiple capacitors are connected in series to charge multiple capacitors using the power supply voltage; or to connect multiple capacitors in parallel to discharge using at least one capacitor, and output a discharge voltage at the output terminal of the last-stage buck module.

[0162] The conversion module is electrically connected to the output of the last-stage step-down module. The conversion module is configured to convert the discharge voltage into an alternating voltage and output the alternating voltage at the output.

[0163] The transformer module is electrically connected to the output of the conversion module. The step-down module is configured to transform the alternating voltage and obtain and output the processed voltage at the output terminal.

[0164] The rectifier module is electrically connected to the output terminal of the transformer module. The rectifier module is configured to rectify the processed voltage to obtain the target voltage.

[0165] According to embodiments of this application, the conversion circuit may further include multiple cascaded step-down modules. By connecting multiple step-down modules on the basis of the voltage conversion circuit, effective voltage reduction can be achieved when facing extremely high input voltages, so as to obtain a discharge voltage that is compatible with the conversion module.

[0166] According to embodiments of this application, the voltage conversion circuit described above, or a conversion circuit as described above, can be applied to an electronic device.

[0167] Figure 19 A flowchart of a voltage conversion method according to an embodiment of this application is shown.

[0168] like Figure 19 The voltage conversion method of the embodiment shown includes operations S1910 to S1940.

[0169] In operation S1910, under the control of the first control signal from the controller, multiple capacitors are controlled to switch between series and parallel states. In the series state, the multiple capacitors are charged by the power supply. In the parallel state, at least one of the multiple capacitors is discharged to output a discharge voltage.

[0170] In operation S1920, the conversion module converts the discharge voltage into an alternating voltage and outputs the alternating voltage through the output terminal of the conversion module.

[0171] In operation S1930, the transformer module transforms the alternating voltage and outputs the processed voltage at the output terminal.

[0172] In operation S1940, the rectifier module rectifies the processed voltage to obtain the target voltage.

[0173] The effects of the voltage conversion circuit or voltage conversion method based on the above-mentioned voltage conversion circuit or conversion circuit can be referred to the relevant technical effects of the voltage conversion circuit or conversion circuit, and will not be elaborated here.

[0174] Those skilled in the art will understand that the features described in the various embodiments of this application can be combined and / or combined in various ways, even if such combinations or combinations are not explicitly described in this application. In particular, the features described in the various embodiments of this application can be combined and / or combined in various ways without departing from the spirit and teachings of this application. All such combinations and / or combinations fall within the scope of this application.

[0175] The embodiments of this application have been described above. However, these embodiments are merely illustrative and not intended to limit the scope of this application. Although various embodiments have been described above, this does not mean that the measures in the various embodiments cannot be used advantageously in combination. Without departing from the scope of this application, those skilled in the art can make various substitutions and modifications, all of which should fall within the scope of this application.

Claims

1. A voltage conversion circuit, characterized by, The voltage conversion circuit includes: The step-down module includes a switching circuit and multiple capacitors. The first ends of both the first and second bridge arms in the switching circuit are electrically connected to the power supply. The first end of the first capacitor is electrically connected to the midpoint of the first bridge arm, and the second end of the first capacitor is electrically connected to the second end of the second bridge arm. The first end of the second capacitor is electrically connected to the midpoint of the second bridge arm, and the second end of the second capacitor is electrically connected to the second end of the first bridge arm, and grounded via a fifth transistor. The switching circuit is configured to control the multiple capacitors to switch between a series connection and a parallel connection under the control of a first control signal from a controller. During a first time period of one control cycle of the first control signal, the capacitors located between the power supply and the first bridge arm... The first transistor between the midpoints, the fourth transistor between the midpoint of the second bridge arm and the conversion module, and the fifth transistor are configured to be in the ON state. During the third time period of the control cycle, the second transistor between the midpoint of the first bridge arm and the conversion module and the third transistor between the power supply and the midpoint of the second bridge arm are configured to be in the ON state to charge the plurality of capacitors using the power supply in a series state. During the second and fourth time periods of the control cycle, at least one of the second transistor and the fourth transistor is configured to be in the ON state to discharge through at least one of the plurality of capacitors in a parallel state to output a discharge voltage. The conversion module is electrically connected to the output terminal of the step-down module and is configured to convert the discharge voltage into an alternating voltage and output the alternating voltage at the output terminal. A transformer module is electrically connected to the output terminal of the conversion module and is configured to transform the alternating voltage to obtain and output the processed voltage at the output terminal. The rectifier module is electrically connected to the output terminal of the transformer module and is configured to rectify the processed voltage to obtain the target voltage.

2. The voltage conversion circuit according to claim 1, characterized in that, The first terminal of the first transistor is electrically connected to the power supply, the second terminal of the first transistor is electrically connected to the first terminal of the first capacitor, and the gate of the first transistor is electrically connected to the controller. The first terminal of the second transistor is electrically connected to the first terminal of the first capacitor, the second terminal of the second transistor is electrically connected to the second terminal of the second capacitor, and the gate of the second transistor is electrically connected to the controller.

3. The voltage conversion circuit according to claim 2, characterized in that, The first terminal of the third transistor is electrically connected to the power supply, the second terminal of the third transistor is electrically connected to the first terminal of the second capacitor, and the gate of the third transistor is electrically connected to the controller. The first terminal of the fourth transistor is electrically connected to the first terminal of the second capacitor, the second terminal of the fourth transistor is electrically connected to the second terminal of the first capacitor, and the gate of the fourth transistor is electrically connected to the controller.

4. The voltage conversion circuit according to claim 3, characterized in that, The first terminal of the fifth transistor is electrically connected to the second terminal of the second capacitor, the second terminal of the fifth transistor is grounded, and the gate of the fifth transistor is electrically connected to the controller.

5. The voltage conversion circuit of claim 4, wherein, The first transistor, the fourth transistor, and the fifth transistor are configured to be turned on under the control of the first control signal, so that the first capacitor and the second capacitor are connected in series, and the power supply is configured to charge the first capacitor and the second capacitor.

6. The voltage conversion circuit of claim 4, wherein, The second transistor and the third transistor are configured to be turned on under the control of the first control signal, so that the first capacitor and the second capacitor are connected in series, and the power supply is configured to charge the first capacitor and the second capacitor.

7. The voltage conversion circuit according to claim 4, characterized in that, The fourth transistor is configured to be turned on under the control of the first control signal, so that a circuit is formed between the second capacitor and the conversion module, and the second capacitor discharges to the conversion module.

8. The voltage conversion circuit of claim 4, wherein, The second transistor is configured to be turned on under the control of the first control signal, so that a circuit is formed between the first capacitor and the conversion module, and the first capacitor discharges to the conversion module.

9. The voltage conversion circuit of claim 4, wherein, The second transistor and the fourth transistor are configured to be turned on under the control of the first control signal, so that the first capacitor and the second capacitor connected in parallel form a circuit with the conversion module, and the first capacitor and the second capacitor discharge to the conversion module.

10. The voltage conversion circuit of claim 4, wherein, The switching circuit also includes a sixth transistor; The first terminal of the sixth transistor is electrically connected to the second terminal of the first capacitor, the second terminal of the sixth transistor is grounded, and the gate of the sixth transistor is electrically connected to the controller.

11. The voltage conversion circuit of claim 10, wherein, The second transistor, the third transistor, and the sixth transistor are configured to be turned on under the control of the first control signal, so that the first capacitor and the second capacitor are connected in series.

12. The voltage conversion circuit of claim 1, wherein, The conversion module includes a seventh transistor and an eighth transistor; The first terminal of the seventh transistor is electrically connected to the output terminal of the buck module, the second terminal of the seventh transistor is electrically connected to the first terminal of the eighth transistor, and the gate of the seventh transistor is electrically connected to the controller. The first terminal of the eighth transistor is electrically connected to the transformer module, the second terminal of the eighth transistor is grounded, and the gate of the eighth transistor is electrically connected to the controller.

13. The voltage conversion circuit of claim 12, wherein, The conversion module also includes a ninth transistor and a tenth transistor; The first terminal of the ninth transistor is electrically connected to the first terminal of the seventh transistor, the second terminal of the ninth transistor is electrically connected to the first terminal of the tenth transistor, and the gate of the ninth transistor is electrically connected to the controller. The first terminal of the tenth transistor is electrically connected to the transformer module, the second terminal of the tenth transistor is grounded, and the gate of the tenth transistor is electrically connected to the controller.

14. The voltage conversion circuit of claim 13, wherein, The seventh and tenth transistors are configured to alternately conduct under the control of a second control signal to convert the discharge voltage into the alternating voltage.

15. The voltage conversion circuit of claim 14, wherein, The duration of a control cycle within the first control signal is greater than the duration of a control cycle within the second control signal.

16. The voltage conversion circuit of claim 1, wherein The active layer of the multiple transistors in the switching circuit is made of silicon carbide, and the active layer of the multiple transistors in the conversion module is made of gallium nitride.

17. The voltage conversion circuit of claim 16, wherein, The withstand voltage of the transistors in the switching circuit is greater than that of the transistors in the conversion module.

18. A conversion circuit, characterized by The conversion circuit includes: Multiple cascaded buck converter modules are used. The input terminal of the first-stage buck converter module is electrically connected to the power supply. Each buck converter module includes a switching circuit and multiple capacitors. The first ends of the first and second bridge arms in the switching circuit are both electrically connected to the power supply. The first end of the first capacitor is electrically connected to the midpoint of the first bridge arm, and the second end of the first capacitor is electrically connected to the second end of the second bridge arm. The first end of the second capacitor is electrically connected to the midpoint of the second bridge arm, and the second end of the second capacitor is electrically connected to the second end of the first bridge arm, and grounded via a fifth transistor. The switching circuit is configured to control the multiple capacitors to switch between a series connection and a parallel connection under the control of a first control signal from the controller. During a first time period of one control cycle of the first control signal, the capacitors located in... The first transistor between the power supply and the midpoint of the first bridge arm, the fourth transistor between the midpoint of the second bridge arm and the conversion module, and the fifth transistor are configured to be in the ON state. During the third time period of the control cycle, the second transistor between the midpoint of the first bridge arm and the conversion module and the third transistor between the power supply and the second bridge arm are configured to be in the ON state to charge the plurality of capacitors using the power supply in a series state. During the second and fourth time periods of the control cycle, at least one of the second transistor and the fourth transistor is configured to be in the ON state to discharge through at least one of the plurality of capacitors in a parallel state to output a discharge voltage through the output terminal of the last stage buck module. A conversion module is electrically connected to the output terminal of the last-stage step-down module. The conversion module is configured to convert the discharge voltage into an alternating voltage and output the alternating voltage at its output terminal. A transformer module is electrically connected to the output terminal of the conversion module. The step-down module is configured to transform the alternating voltage to obtain and output the processed voltage at the output terminal. A rectifier module is electrically connected to the output terminal of the transformer module. The rectifier module is configured to rectify the processed voltage to obtain the target voltage.

19. An electronic device, comprising: It includes the voltage conversion circuit as described in any one of claims 1-17 or the conversion circuit as described in claim 18.

20. A voltage conversion method applied to the voltage conversion circuit according to any one of claims 1 to 17 or the conversion circuit according to claim 18, characterized by, The method includes: Under the control of the first control signal from the controller, multiple capacitors are controlled to switch between series and parallel states. In the series state, the multiple capacitors are charged by the power supply, and in the parallel state, they are discharged through at least one of the multiple capacitors to output a discharge voltage. The conversion module converts the discharge voltage into an alternating voltage and outputs the alternating voltage through the output terminal of the conversion module; The transformer module transforms the alternating voltage and outputs the processed voltage at the output terminal. The rectification module rectifies the processing voltage to obtain a target voltage.

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