Voltage conversion circuit, power management chip and electronic device

Abstract

This application discloses a voltage conversion circuit, a power management chip, and an electronic device. The voltage conversion circuit includes a multi-phase input circuit, an output circuit, and a logic control module. The output terminal of the previous phase input circuit is coupled to the next phase input circuit. Except for the first phase input circuit, each of the other phase input circuits is equipped with a flying capacitor. The output circuit is connected to the output terminal of the last phase input circuit. The logic control module is connected to each phase input circuit and is used to control the multi-phase input circuits to perform soft-start operations sequentially, thereby achieving a smooth rise in the flying capacitor voltage. Through this method, the voltage conversion circuit of this application can effectively isolate the DC bus from the direct current surge to the flying capacitor at startup, limiting the surge current to a safe threshold. Simultaneously, it ensures that the flying capacitor voltage in each phase input circuit rises smoothly and evenly in stages, thus avoiding the risks caused by uneven voltage stress distribution.

Description

Technical Field

[0001] This application relates to the field of power electronics technology, specifically to a voltage conversion circuit, a power management chip, and an electronic device. Background Technology

[0002] The Input-Parallel Output-Series (IPOS) boost converter is a high-gain topology capable of achieving a wide range of voltage conversion from low input voltage to high output voltage. In practical applications, especially during startup, a key technical challenge exists: the pre-charging of the flying capacitors. When the system powers on, all flying capacitors and output capacitors have an initial voltage of zero. If the converter is started directly at its rated duty cycle, the power supply will instantaneously charge these capacitors, generating a very large inrush current. This inrush current can lead to a series of serious consequences, including damage to power devices, capacitor failure, voltage stress imbalance, and system oscillation and instability. Summary of the Invention

[0003] This application proposes a voltage conversion circuit, a power management chip, and an electronic device, aiming to solve the above-mentioned problems.

[0004] To solve the above-mentioned technical problems, one technical solution adopted in this application is: to provide a voltage conversion circuit, which includes a multi-phase input circuit, an output circuit, and a logic control module. The output terminal of the previous phase input circuit is coupled to the next phase input circuit. Except for the first phase input circuit, each of the other phase input circuits is provided with a flying capacitor. The output circuit is connected to the output terminal of the last phase input circuit. The logic control module is connected to each phase input circuit and is used to control the multi-phase input circuit to perform soft-start operation in sequence to achieve a smooth rise in the voltage of the flying capacitor.

[0005] Each phase input circuit includes a main switch, a synchronization switch, and an inductor. Except for the first phase input circuit, all other phase input circuits include a flying capacitor. In the first phase input circuit, the first end of the inductor is connected to the power supply, and the second end of the inductor is connected to the first pass terminal of the main switch and the first pass terminal of the synchronization switch, respectively. The second pass terminal of the main switch is grounded. In all other phase input circuits, except for the first phase input circuit, the first end of the inductor is connected to the power supply, and the second end of the inductor is connected to the first pass terminal of the main switch and the first pass terminal of the flying capacitor, respectively. The second pass terminal of the main switch is grounded. The second pass terminal of the flying capacitor is connected to the first end of the synchronization switch. The second end of the synchronization switch of the previous phase input circuit is coupled to the connection point between the second pass terminal of the flying capacitor and the first end of the synchronization switch of the next phase input circuit.

[0006] The output circuit includes an output capacitor. The first end of the output capacitor is connected to the second end of the synchronization switch of the last phase input circuit. The second end of the output capacitor is grounded. The first end of the output capacitor and the second end of the synchronization switch of the last phase input circuit serve as the output terminal of the output circuit to provide voltage to the load.

[0007] The logic control module includes a grouping unit and a control unit. The grouping unit is configured to divide the multiphase input circuit into multiple pre-charge circuits, wherein each pre-charge circuit includes at least one phase of input circuit. The control unit is connected to the control terminal of the grouping unit and the control terminal of the main switch and the control terminal of the synchronous switch in each pre-charge circuit, and is configured to control the multiple pre-charge circuits to perform soft-start operations in sequence to achieve a smooth rise in the voltage of the flyover capacitor.

[0008] During the voltage conversion circuit startup phase, the control unit controls the synchronous switches of all pre-charging circuits except the first pre-charging circuit to be turned on, controls the main switches and synchronous switches of the same phase in the first pre-charging circuit to work in a complementary manner, and controls the duty cycle of the main switches in the first pre-charging circuit to increase from zero according to a preset increment function.

[0009] In response to the duty cycle of the main switch in the current pre-charging circuit reaching the preset duty cycle, the control unit controls the main switch and synchronous switch of the same phase in the next pre-charging circuit to work in a complementary manner, and controls the duty cycle of the main switch in the next pre-charging circuit to increase from zero according to a preset increment function until the duty cycle of the main switch in all pre-charging circuits reaches the preset duty cycle.

[0010] In response to the voltage value of the flying capacitor corresponding to the current pre-charging circuit reaching the preset voltage value, the control unit controls the main switch and synchronous switch of the same phase in the next pre-charging circuit to work in a complementary manner, and controls the duty cycle of the main switch in the next pre-charging circuit to increase from zero according to a preset increment function until the voltage values ​​of all flying capacitors reach the preset voltage value.

[0011] The preset increasing functions include exponential increasing functions, linear increasing functions, piecewise linear increasing functions, or sinusoidal half-wave increasing functions.

[0012] To solve the above-mentioned technical problems, another technical solution adopted in this application is: to provide a power management chip, which includes the voltage conversion circuit of any one of the above-mentioned components.

[0013] To address the aforementioned technical problem, another technical solution adopted in this application is to provide an electronic device that includes the aforementioned power management chip.

[0014] The beneficial effects of this application are as follows: Unlike existing technologies, the voltage conversion circuit of this application includes a multi-phase input circuit, an output circuit, and a logic control module. The output terminal of the previous phase input circuit is coupled to the next phase input circuit. Except for the first phase input circuit, each of the other phase input circuits is equipped with a flying capacitor. The output circuit is connected to the output terminal of the last phase input circuit. The logic control module is connected to each phase input circuit and is used to control the multi-phase input circuits to perform soft-start operations sequentially, thereby achieving a smooth rise in the flying capacitor voltage. Through the above method, the voltage conversion circuit of this application can effectively isolate the DC bus from the direct current surge to the flying capacitor at startup, limiting the surge current to within a safe threshold. Simultaneously, it ensures that the flying capacitor voltage in each phase input circuit rises smoothly and evenly in stages, thus avoiding the risks caused by uneven voltage stress distribution. Attached Figure Description

[0015] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with this application and, together with the specification, serve to explain the technical solutions of this application.

[0016] Figure 1 This is a schematic block diagram of the first embodiment of the voltage conversion circuit provided in this application; Figure 2 This is a schematic diagram of the circuit structure of the second embodiment of the voltage conversion circuit provided in this application; Figure 3 This is a schematic diagram of the charging mode of an embodiment of the flying capacitor provided in this application; Figure 4 This is a schematic diagram of the structure of an embodiment of the power management chip of this application; Figure 5 This is a schematic diagram of the structure of an embodiment of the electronic device of this application. Detailed Implementation

[0017] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0018] The Input-Parallel Output-Series (IPOS) boost converter is a high-gain topology capable of achieving a wide range of voltage conversion from low input voltage to high output voltage. In practical applications, especially during startup, a key technical challenge exists: the pre-charging of the flying capacitors. When the system powers on, all flying capacitors and output capacitors have an initial voltage of zero. If the converter is started directly at its rated duty cycle, the power supply will instantaneously charge these capacitors, generating a very large inrush current. This inrush current can lead to a series of serious consequences, including damage to power devices, capacitor failure, voltage stress imbalance, and system oscillation and instability.

[0019] To address the aforementioned problems, this application first proposes a voltage conversion circuit, please refer to [link to relevant documentation]. Figure 1 and Figure 2 , Figure 1 This is a schematic block diagram of the first embodiment of the voltage conversion circuit provided in this application; Figure 2 This is a schematic diagram of the circuit structure of the second embodiment of the voltage conversion circuit provided in this application. Figure 1 and Figure 2 As shown, the voltage conversion circuit 100 in this embodiment includes a multi-phase input circuit 10, an output circuit 20, and a logic control module 30. The output terminal of the previous phase input circuit 10 is coupled to the next phase input circuit 10. Except for the first phase input circuit 10, each of the other phase input circuits 10 is provided with a flying capacitor C. n-1,n (n=2, 3, 4, ...); Output circuit 20 is connected to the output terminal of the last phase input circuit 10; Logic control module 30 is connected to each phase input circuit 10 and is used to control the multi-phase input circuits 10 to perform soft-start operations in sequence to realize the flying capacitor C n-1,n The voltage rises steadily.

[0020] The voltage conversion circuit 100 in this embodiment includes a multi-phase input circuit 10, which operates in an interleaved parallel configuration, and its output is ultimately connected in series to the output circuit 20. The logic control module 30 controls the duty cycle of each phase input circuit 10. Specifically, the logic control module 30 first controls the duty cycle of the first phase input circuit to increase slowly from zero, causing the flying capacitor C of each subsequent phase input circuit 10 to... n-1,n Under the action of the power supply, the capacitors are charged. After the voltage of each flying capacitor is established and stabilized, the logic control module 30 controls the duty cycle of the second phase input circuit 10 to slowly increase from zero. The second phase input circuit 10 is charged based on the voltage of the first phase. This process is repeated to start each phase in turn, so that the voltage of the flying capacitor gradually and steadily rises after the voltage of the previous stage is established.

[0021] Furthermore, the voltage conversion circuit 100 in this embodiment is not limited to... Figure 2 The IPOS boost converter circuit shown can also be other DC-DC converter circuits with similar series output stages and flying capacitor structures, such as multi-level boost converter circuits, hybrid circuits of charge pumps and boost converters, etc., which are not limited here.

[0022] Unlike existing technologies, the voltage conversion circuit 100 of this application includes a multi-phase input circuit 10, an output circuit 20, and a logic control module 30. The output of the previous phase input circuit 10 is coupled to the next phase input circuit 10. Except for the first phase input circuit 10, each of the other phase input circuits 10 is equipped with a flying capacitor C. n-1,n Output circuit 20 is connected to the output terminal of the last phase input circuit 10; logic control module 30 is connected to each phase input circuit 10 and is used to control the multi-phase input circuits 10 to perform soft-start operations in sequence to realize the flying capacitor voltage C. n-1,n The voltage rises steadily. Through the above method, the voltage conversion circuit 100 of this application can effectively isolate the DC bus from the flying capacitor C at startup. n-1,n The direct surge current is limited to a safe threshold; at the same time, the flying capacitor C in each phase input circuit 10 is ensured. n-1,n The voltage rises steadily and evenly in stages, thus avoiding the risks caused by uneven voltage stress distribution.

[0023] Optionally, based on the above embodiments, in this embodiment, an IPOS boost converter circuit is taken as an example, such as... Figure 2 As shown, each phase input circuit 10 in this embodiment includes a main switch S. 1i (i=1, 2, 3, ...), synchronous switch S 2i (i=1, 2, 3, ...) and inductance L i (i=1, 2, 3, ...); except for the first phase input circuit 10, each of the other phase input circuits 10 includes a flying capacitor C. n-1,n In the first phase input circuit 10, the first end of inductor L1 is connected to the power supply terminal, and the second end of inductor L1 is connected to the main switch S. 11 First path terminal and synchronous switch S 21 The first path terminal is connected to the main switch S. 11 The second path terminal is grounded; in all other phase input circuits 10 except the first phase input circuit 10, the inductor L i The first terminal of (i=2, 3, 4, ...) is connected to the power supply terminal, and the inductor L i The second terminals of (i=2, 3, 4, ...) are respectively connected to the main switch S 1i The first path terminal (i=2, 3, 4, ...) and the flying capacitor C n-1,n The first path terminal is connected to the main switch S. 1iThe second path terminal of (i=2, 3, 4, ...) is grounded; the flying capacitor C n-1,n The second path terminal and synchronous switch S 2i The first terminal of (i=2, 3, 4, ...) is connected; where the synchronous switch S of the previous phase input circuit 10 is... 2i The second terminal of (i=1, 2, 3, ...) is coupled to the flying capacitor C of the next phase input circuit 10. n-1,n The second path terminal and synchronous switch S 2i The first end of the connection node (i=1, 2, 3, ...).

[0024] In this embodiment, the main switch S in each phase input circuit 10 1i Synchronous switch S is used to control the on / off state of the input current. 2i During the soft-start phase, forced conduction is performed to provide a low-impedance path, wherein, in this embodiment, the main switch S 1i and synchronous switch S 2i Both can be configured as MOSFET transistors or IGBT devices. Inductor L i As an energy storage element, its first end is directly connected to the power supply, and its second end is simultaneously connected to the main switch S. 1i and synchronous switch S 2i Or flying capacitor C n-1,n It is used to smoothly store and release energy when the duty cycle changes; in the other input circuits 10 besides the first phase input circuit 10, the flying capacitor C n-1,n Connected to inductor L i Output terminal and synchronous switch S 2i Between them, it is used to transfer voltage and balance the voltage of each capacitor.

[0025] Optionally, based on the above embodiments, in this embodiment, an IPOS boost converter circuit is taken as an example, such as... Figure 2 As shown, the output circuit 20 in this embodiment includes an output capacitor C. out Output capacitor C out The synchronous switch S of the first and last phase input circuit 10 2i The second terminal is connected to the output capacitor C. out The second terminal is grounded, and the output capacitor C out The synchronous switch S of the first and last phase input circuit 10 2i The second terminal serves as the output terminal of the output circuit 20 to provide voltage to the load.

[0026] Optionally, based on the above embodiments, please refer to Figure 2 ,like Figure 2As shown, the logic control module 30 of this embodiment includes a grouping unit 32 and a control unit 31. The grouping unit 32 is configured to divide the multiphase input circuit 10 into multiple pre-charging circuits, wherein each pre-charging circuit includes at least one phase of input circuit; the control unit 31, the grouping unit 32, and the main switch S in each pre-charging circuit are also included. 1i Control terminal and synchronous switch S 2i The control terminal connection is configured to control multiple pre-charge circuits to perform soft-start operations sequentially, in order to achieve the flying capacitor C n-1,n The voltage rises steadily.

[0027] In this embodiment, the grouping unit 32 is used to divide the multiphase input circuit 10 into several groups of pre-charge circuits, each group may contain a single-phase or multiphase input circuit 10. After grouping is completed, the control unit 31 receives the instruction from the grouping unit 32 and controls each group of pre-charge circuits to perform a soft-start operation in sequence.

[0028] Specifically, the grouping unit 32 can group the multi-phase input circuits 10 based on a preset grouping strategy. For example, each phase input circuit 10 can be set up as an independent group, or every two phase input circuits 10 can be combined into one group. When grouping, care should be taken not to include too many phases in each pre-charge circuit group, otherwise it may cause damage to power devices or capacitors.

[0029] Furthermore, in this embodiment, the logic control module 30 can be configured as a digital signal processor, a microcontroller, a field-programmable gate array, or even an application-specific integrated circuit or a pure analog control circuit containing corresponding logic, without limitation.

[0030] In this embodiment, the grouping unit 32 enables flexible grouping of the multiphase input circuit 10, allowing the startup sequence to be customized according to load characteristics, thereby improving system startup efficiency.

[0031] Optionally, based on all the above embodiments, in this embodiment, during the startup phase of the voltage conversion circuit 100, the control unit 31 controls the synchronous switches of all pre-charging circuits except the first group of pre-charging circuits to be turned on, and controls the main switch S of the same phase in the first group of pre-charging circuits to be turned on. 1i and synchronous switch S 2i Perform complementary operations and control the main switch S in the first pre-charging circuit. 1i The duty cycle starts from zero and increases according to a preset increment function.

[0032] In this embodiment, taking an example where each pre-charging circuit includes only one phase input circuit 10, during the startup phase of the voltage conversion circuit 100, the control unit 31 controls the synchronous switching S of all input circuits 10 except the first phase input circuit 10. 2i When the circuit is turned on, the synchronous switches S of all input circuits 10 are activated.2i This creates a low-impedance path. Furthermore, this embodiment also controls the main switch S of the first phase input circuit 10. 11 and synchronous switch S 21 Perform complementary operation and control the main switch S of the first phase input circuit 10. 11 The duty cycle starts from zero and increases according to a preset increment function.

[0033] Please see Figure 3 , Figure 3 This is a schematic diagram of the charging mode of an embodiment of the flying capacitor provided in this application. Wherein, Figure 3 The grayscale value in the image indicates a break at that point. For example... Figure 3 As shown in the figure above, when the main switch S 11 On synchronous switch S 21 When turned off, the power supply terminal is connected to all inductors L i During charging, inductor L1 stores energy; such as Figure 3 As shown in the figure below, when the synchronous switch S 21 Turn on main switch S 11 When turned off, all inductors Li cross the flying capacitor C. n-1,n Charging is performed. This alternation causes the first phase input circuit 10 to operate as a boost circuit, using the energy stored in inductor L1 and the freewheeling current to power all subsequent flying capacitors C. n-1,n and output capacitor C out Gradually increase the pressure.

[0034] Optionally, based on all the above embodiments, in this embodiment, in response to the main switch S in the current pre-charging circuit 1i When the duty cycle reaches the preset duty cycle, the control unit 31 controls the main switch S of the same phase in the next pre-charging circuit. 1i and synchronous switch S 2i Perform complementary operations and control the main switch S in the next pre-charging circuit. 1i The duty cycle starts from zero and increases according to a preset increment function until all the main switches S in the pre-charge circuits are reached. 1i The duty cycles all reached the preset duty cycles.

[0035] In this embodiment, as mentioned above, each pre-charging circuit includes only one phase input circuit 10 as an example. That is, in this embodiment, if the main switch S of the current phase input circuit 10... 1i When the duty cycle reaches the preset duty cycle, the control unit 31 maintains the already started phase (e.g., the first phase) at its target duty cycle for stable operation and automatically controls the main switch S of the next phase input circuit 10. 1i With synchronous switch S 2i Entering complementary operating state; simultaneously, the control unit switches the main switch S of the next phase input circuit 10. 1iThe duty cycle is initialized to zero and then smoothly increased according to a preset increment function. At this time, the input of the next phase input circuit 10 is the output node of its previous phase input circuit 10. The next phase input circuit will further boost the voltage based on the previous stage voltage, affecting the subsequent flying capacitor C. n-1,n and output capacitor C out Perform boost charging, repeat this process, and flyback capacitor C n-1,n The voltage can be increased in stages, smoothly and evenly, avoiding the risk of uneven voltage stress.

[0036] Through the above method, this embodiment can enable the flying capacitor C n-1,n The voltage is gradually charged after the preceding voltage is established, thus achieving a smooth voltage rise; by controlling the duty cycle to slowly increase from zero, the inrush current is effectively suppressed.

[0037] Optionally, based on all the above embodiments, in other embodiments, in response to the flying capacitor C corresponding to the current pre-charge circuit n-1,n When the voltage value reaches the preset voltage value, the control unit 31 controls the main switch S of the same phase in the next pre-charging circuit. 1i and synchronous switch S 2i Perform complementary operations and control the main switch S in the next pre-charging circuit. 1i The duty cycle starts from zero and increases according to a preset increment function until all flying capacitors C are exhausted. n-1,n The voltage values ​​all reached the preset voltage values.

[0038] In this embodiment, during each stage of soft-start in each phase input circuit 10, open-loop time control can be avoided, and closed-loop feedback can be introduced instead. For example, during soft-start in the first phase input circuit 10, the flying capacitor C is monitored in real time. 1,2 The voltage is set, and when the voltage value reaches the preset voltage value, a soft-start operation is performed on the second phase input circuit 10. In this embodiment, a closed-loop control method based on voltage feedback is adopted, which can make the startup process more precise.

[0039] Optionally, based on all the above embodiments, in this embodiment, the preset increasing function mentioned above includes, but is not limited to, an exponential increasing function, a linear increasing function, a piecewise linear increasing function, or a sinusoidal half-wave increasing function. That is, any other non-abrupt function that can achieve a smooth start can be used as the preset increasing function in this embodiment.

[0040] In one application scenario, taking an example where each pre-charging circuit includes only one phase input circuit 10, the voltage conversion circuit 100 of this embodiment performs pre-charging specifically including the following steps: Step 1: During the startup phase of the voltage conversion circuit 100, turn on the main switches S of all input circuits 10.1i All are placed in the off state, and at the same time, the synchronous switches S of all input circuits 10 except the first phase input circuit 10 are turned off. 2i Forced into the on state, the synchronous switch S of the first phase input circuit 10 21 With main switch S 11 To perform complementary work.

[0041] Step 2: Synchronization switch S of the first phase input circuit 10 21 With main switch S 11 Apply a complementary pulse width modulation drive signal to activate the main switch S of the first phase input circuit 10. 11 The duty cycle starts from a minimum value (e.g., 0) and increases according to a preset increment function; during this process, the first phase input circuit 10 operates as a basic boost circuit, using the energy stored in inductor L1 and freewheeling current to power the flying capacitor C. 1,2 And through the subsequent conduction of the synchronous switch S 2i The subsequent flying capacitor C is connected n-1,n and output capacitor C out Charging is initiated; when the main switch S of the first phase input circuit 10 is activated... 11 Once the duty cycle reaches the preset duty cycle and the relevant capacitor voltages stabilize, this stage is complete.

[0042] Step 3: Maintain the already started input circuit 10 (e.g., the first phase) operating stably at its preset duty cycle; select the next input circuit 10 to be started (e.g., the second phase) and synchronize its switch S. 22 Switching from forced conduction state to connection with main switch S 12 The complementary operation state; for the main switch S of the second phase input circuit 10 12 A pulse width modulation drive signal is applied, causing its duty cycle to increase from 0 according to a preset increment function. At this time, the input of the second phase input circuit 10 is the output node of its predecessor (the first phase input circuit 10), which will further boost the voltage based on the previous stage, affecting the second flying capacitor C. 2,3 and subsequent flying capacitor C n-1,n and output capacitor C out Charge; and so on, repeat the above process, that is, perform a soft start operation with a duty cycle starting from 0 for each phase input circuit 10 one by one and in sequence.

[0043] Step 4: When the last phase input circuit 10 also completes the soft start and its duty cycle reaches the preset duty cycle, all input circuits 10 enter a stable working state, and the voltage conversion circuit 100 enters the normal high voltage output mode.

[0044] Optionally, this application further proposes a power management chip, please refer to... Figure 4 , Figure 4 This is a schematic diagram of the structure of an embodiment of the power management chip of this application. Figure 4 As shown, the power management chip 200 of this embodiment includes the voltage conversion circuit 100 of any of the above embodiments.

[0045] Optionally, this application further proposes an electronic device, please refer to [link to relevant documentation]. Figure 5 , Figure 5 This is a schematic diagram of the structure of an embodiment of the electronic device of this application. Figure 5 As shown, the electronic device 300 of this embodiment includes the power management chip 200 of the above embodiment.

[0046] The above description is merely an embodiment of this application and does not limit the patent scope of this application. Any equivalent structural or procedural transformations made using the content of this application's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this application.

Claims

1. A voltage conversion circuit, characterized by, include: A multi-phase input circuit, wherein the output terminal of the input circuit of the previous phase is coupled to the input circuit of the next phase, and each input circuit of the other phases except the first phase is provided with a flying capacitor; The output circuit is connected to the output terminal of the input circuit described in the last phase. A logic control module, connected to the input circuit of each phase, is used to control the input circuits of multiple phases to perform soft-start operations in sequence, so as to achieve a smooth rise in the voltage of the flying capacitor.

2. The voltage conversion circuit according to claim 1, characterized by, Each phase of the input circuit includes a main switch, a synchronization switch, and an inductor; except for the input circuit of the first phase, the input circuits of the other phases all include the flying capacitor. In the first phase of the input circuit, the first end of the inductor is connected to the power supply terminal, the second end of the inductor is connected to the first path terminal of the main switch and the first path terminal of the synchronous switch respectively, and the second path terminal of the main switch is grounded. In the input circuits of all phases except the first phase, the first end of the inductor is connected to the power supply terminal, the second end of the inductor is connected to the first path terminal of the main switch and the first path terminal of the flying capacitor, respectively, and the second path terminal of the main switch is grounded; the second path terminal of the flying capacitor is connected to the first end of the synchronous switch. The second terminal of the synchronous switch in the input circuit of the previous phase is coupled to the connection node between the second path terminal of the flying capacitor and the first terminal of the synchronous switch in the input circuit of the next phase.

3. The voltage conversion circuit of claim 2, wherein, The output circuit includes an output capacitor. The first end of the output capacitor is connected to the second end of the synchronization switch of the last phase of the input circuit. The second end of the output capacitor is grounded. The first end of the output capacitor and the second end of the synchronization switch of the last phase of the input circuit serve as the output terminal of the output circuit to provide voltage to the load.

4. The voltage conversion circuit according to claim 2, characterized by The logic control module includes: A grouping unit is configured to divide the multiphase input circuit into multiple groups of pre-charge paths, wherein each group of pre-charge paths includes at least one phase of the input circuit. The control unit, connected to the control terminal of the main switch and the control terminal of the synchronization switch in each group of the pre-charging circuits, is configured to control multiple groups of the pre-charging circuits to perform soft-start operations in sequence, so as to achieve a smooth rise in the voltage of the flying capacitor.

5. The voltage conversion circuit according to claim 4, characterized in that, During the startup phase of the voltage conversion circuit, the control unit controls the synchronous switches of all pre-charging circuits except the first group of pre-charging circuits to be turned on, controls the main switches and synchronous switches of the same phase in the first group of pre-charging circuits to work in a complementary manner, and controls the duty cycle of the main switches in the first group of pre-charging circuits to increase from zero according to a preset increment function.

6. The voltage conversion circuit according to claim 5, characterized in that, In response to the duty cycle of the main switch in the current pre-charging circuit reaching a preset duty cycle, the control unit controls the main switch and the synchronization switch of the same phase in the next pre-charging circuit to work in a complementary manner, and controls the duty cycle of the main switch in the next pre-charging circuit to increase from zero according to a preset increment function until the duty cycle of the main switch in all pre-charging circuits reaches the preset duty cycle.

7. The voltage conversion circuit according to claim 5, characterized in that, In response to the voltage value of the flying capacitor corresponding to the current pre-charging circuit reaching a preset voltage value, the control unit controls the main switch and the synchronous switch of the same phase in the next pre-charging circuit to work in a complementary manner, and controls the duty cycle of the main switch in the next pre-charging circuit to increase from zero according to a preset increment function until the voltage values ​​of all flying capacitors reach the preset voltage value.

8. The voltage conversion circuit according to claim 6 or 7, characterized in that, The preset increasing function includes an exponential increasing function, a linear increasing function, a piecewise linear increasing function, or a sinusoidal half-wave increasing function.

9. A power management chip, characterized in that... Includes the voltage conversion circuit according to any one of claims 1-8.

10. An electronic device, characterized in that, Includes the power management chip as described in claim 9.

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