Hybrid switching power converter and method for the same

Abstract

A hybrid switching power converter performs power conversion between a first voltage and a second voltage using multi-level pulse-width modulation (PWM). The hybrid switching power converter includes an inductor coupled to a switching node, at least one conversion capacitor, at least one balancing capacitor, and plural switches. These components periodically reconfigure their electrical connections in multiple switching states, enabling voltage balance of the at least one converter capacitor. The switching states include distinct first and second states, wherein the at least one conversion capacitor and the at least one balancing capacitor are electrically connected to the switching node in corresponding configurations. In steady-state operation, the voltage across the at least one conversion capacitor is regulated to a voltage division of the second voltage.

Description

Technical Field

[0001] This invention relates to a hybrid switching power converter and its method, and more particularly to a hybrid switching power converter and its method that avoids capacitor voltage offset problems. Prior Technology

[0002] Please refer to Figures 1A and 1B. Figures 1A and 1B illustrate the prior art phase selection mechanism based on flyaway capacitor charge-discharge operation (CF-CDPS) and its corresponding time waveforms. In the circuit shown in Figure 1A, signal generation module 301 uses a voltage divider and a resistor network to generate input differential signals VA and VB. The difference between the input differential signals VA and VB is equal to the cross voltage VCF of the flyaway capacitor. These signals are further passed to comparator 302 for signal amplification and comparison, and finally output to latch-up circuit 303 to determine the final phase selection.

[0003] Figure 1B shows the operating waveform and phase selection process. In the operating waveform, Pch represents the charging phase and Pdch represents the discharging phase. Comparator 302 compares the voltage across the VCF and the reference voltage Vo / 2. If the voltage across the VCF is consistently less than Vo / 2, the control circuit will continuously trigger the charging phase. If the voltage across the VCF is consistently greater than Vo / 2, the control circuit will continuously trigger the discharging phase. This continues until the voltage across the VCF is approximately equal to Vo / 2, at which point the circuit returns to a balanced state of alternating triggering of the charging and discharging phases.

[0004] This approach, when continuously triggering charging or discharging phases, will increase the ripple of the VCF (voltage cross-flow factor) of the flying capacitor due to the continuous charging or discharging of the flying capacitor, thus resulting in larger ripple in the output voltage. Furthermore, even when the VCF is approximately equal to Vo / 2, it may still require triggering two charging phases or two discharging phases consecutively to increase the ripple in both the VCF and the output voltage. Summary of the Invention

[0005] In one viewpoint, the present invention provides a hybrid switching power converter for power conversion between a first voltage and a second voltage. The hybrid switching power converter includes: an inductor coupled to an inductor switching node; at least one switching capacitor; at least one balancing capacitor; and a plurality of switches for periodically switching the electrical connections of the inductor, the at least one switching capacitor, the at least one balancing capacitor, the first voltage, and the second voltage in multiple switching states, thereby performing power conversion between the first voltage and the second voltage using multi-stage pulse width modulation. The multiple switching states include a first switching state and a second switching state that are distinct from each other. The plurality of switches control the at least one switching capacitor and the at least one balancing capacitor, which are electrically connected to the inductor switching node in the first switching state and the second switching state, respectively, to achieve voltage balance. In steady state, the voltage across the at least one switching capacitor is regulated and stabilized as a division voltage of the second voltage.

[0006] In a preferred embodiment, the at least one balancing capacitor includes a first balancing capacitor, wherein in the first switching state, the first balancing capacitor is connected in parallel to at least a portion of the at least one switching capacitor, and wherein in the second switching state, the first balancing capacitor is connected in series to at least a portion of the at least one switching capacitor between the second voltage and a ground potential.

[0007] In a preferred embodiment, the hybrid switching power converter further includes a current sensing circuit for sensing the current of a corresponding switch among the plurality of switches in the first or second switching state to generate a current sensing signal to indicate an inductor current, wherein the current flowing through the corresponding switch is equal to the inductor current.

[0008] In a preferred embodiment, the current flowing through the corresponding switch does not include a balancing current flowing from or to the at least one switching capacitor.

[0009] In a preferred embodiment, when the multiple switches control the inductor switching node to be electrically connected to the second voltage or a ground potential, the at least one switching capacitor and the at least one balancing capacitor are electrically disconnected from each other.

[0010] In a preferred embodiment, the at least one switching capacitor includes a first switching capacitor, and the at least one balancing capacitor includes a first balancing capacitor, configured as one of the following: a first configuration: the multiple switches include a first balancing switch coupled between the first balancing capacitor and the inductor switching node; or a second configuration: the multiple switches include a first balancing switch coupled between the first balancing capacitor and a first switchable terminal; and a second balancing switch coupled between the first balancing capacitor and a second switchable terminal; wherein the first switchable terminal and the second switchable terminal correspond to two of the following options: the inductor switching node; the upper end of the first switching capacitor; and the lower end of the first switching capacitor.

[0011] In a preferred embodiment, the at least one switching capacitor includes a first switching capacitor, the plurality of switches includes a plurality of upper bridge switches, the plurality of upper bridge switches includes a first and a second upper bridge switch connected in series between the inductor switching node and the second voltage, which are coupled to each other at the upper end of the first switching capacitor, and includes a first and a second lower bridge switch connected in series between the inductor switching node and a ground potential, which are coupled to each other at the lower end of the first switching capacitor.

[0012] In a preferred embodiment, the hybrid switching power converter further includes a current sensing circuit for sensing a switching current flowing through one of the first upper bridge switch or the first lower bridge switch in the first or second switching state to generate a current sensing signal to indicate an inductor current of the inductor, wherein the switching current is equal to the inductor current and does not include a balancing current between the first balancing capacitor and the first switching capacitor; wherein the configuration of the multiple switches does not include the first configuration.

[0013] In a preferred embodiment, the at least one switching capacitor includes a first switching capacitor and a second switching capacitor, and the at least one balancing capacitor includes a first balancing capacitor and a second balancing capacitor; wherein the first balancing capacitor is configured as one of the following: a first configuration: the multiple switches include a first balancing switch coupled between the first balancing capacitor and the inductor switching node; or a second configuration: the multiple switches include a first balancing switch coupled between the first balancing capacitor and a first switchable terminal; and a second balancing switch coupled between the first balancing capacitor and a second switchable terminal; wherein the first switchable terminal and the second switchable terminal respectively correspond to two of the following options: the inductor The switching node; the upper or lower end of the first switching capacitor; the upper or lower end of the second switching capacitor; wherein the second balancing capacitor is configured as one of the following: a third configuration: the plural switch includes a third balancing switch coupled between the second balancing capacitor and the inductor switching node; or a fourth configuration: the plural switch includes a third balancing switch coupled between the second balancing capacitor and a third switchable terminal; and a fourth balancing switch coupled between the second balancing capacitor and a fourth switchable terminal; wherein the third switchable terminal and the fourth switchable terminal correspond to two of the following options: the inductor switching node; the upper or lower end of the first switching capacitor; the upper or lower end of the second switching capacitor.

[0014] In a preferred embodiment, the plurality of switches includes first to third upper bridge switches and first to third lower bridge switches, wherein the first upper bridge switch is coupled between the inductor switching node and the upper end of the first conversion capacitor; the second upper bridge switch is coupled between the upper end of the first conversion capacitor and the upper end of the second conversion capacitor; the third upper bridge switch is coupled between the upper end of the second conversion capacitor and the second voltage; the first lower bridge switch is coupled between the inductor switching node and the lower end of the first conversion capacitor; the second lower bridge switch is coupled between the lower end of the first conversion capacitor and the lower end of the second conversion capacitor; and the third lower bridge switch is coupled between the lower end of the second conversion capacitor and the ground. Between potentials; wherein, the first switchable terminal and the second switchable terminal respectively correspond to two of the following options: the inductor switching node; the upper end of the first conversion capacitor; the lower end of the first conversion capacitor; the lower end of the second conversion capacitor; wherein, the third switchable terminal and the fourth switchable terminal respectively correspond to two of the following options: the inductor switching node; the upper end of the first conversion capacitor; the lower end of the first conversion capacitor; the upper end of the second conversion capacitor; wherein, in steady state, the voltage across the first conversion capacitor and the first balancing capacitor is 1 / 3 of the second voltage, and the voltage across the second conversion capacitor and the second balancing capacitor is 2 / 3 of the second voltage.

[0015] In another viewpoint, the present invention provides a hybrid switching power conversion method for switching power between a first voltage and a second voltage. The hybrid switching power conversion method includes: periodically switching at least one inductive element, at least one switching capacitor, and at least one balancing capacitor in multiple switching states, and combining them with different electrical connections between the first voltage and the second voltage; wherein the multiple switching states include at least a first switching state and a second switching state, and the step of combining different electrical connections between the first voltage and the second voltage includes: electrically connecting the at least one switching capacitor and the at least one balancing capacitor with different electrical connection combinations in the first switching state and the second switching state to an inductive switching node, thereby adjusting the voltage across the at least one switching capacitor to a division of the second voltage in a steady state to achieve multi-step pulse width modulation power conversion, wherein one end of the at least one inductive element is coupled to the inductive switching node.

[0016] In a preferred embodiment, the at least one balancing capacitor includes a first balancing capacitor, and the method further includes: in the first switching state, controlling the first balancing capacitor to be connected in parallel with at least a portion of the at least one switching capacitor to output its voltage to the inductor switching node; in the second switching state, controlling the first balancing capacitor to be connected in series with at least a portion of the at least one switching capacitor and distributing it between the second voltage and a ground potential; wherein, by switching between the parallel and series connections, in a steady state, the first balancing capacitor helps stabilize the voltage across the at least one switching capacitor as the voltage division of the second voltage.

[0017] In a preferred embodiment, the method further includes: sensing a current in a switch to generate a current sensing signal in the first switching state or the second switching state, the switch current corresponding to an inductor current in the inductive element, wherein the switch is used to switch the switching capacitor to the corresponding first switching state or the second switching state.

[0018] In a preferred embodiment, the current flowing through the switch does not include a balancing current flowing from or to the at least one switching capacitor.

[0019] In a preferred embodiment, in another part of the multiple switching states, the inductor switching node is electrically connected to the second voltage or a ground potential, and there is an electrical disconnect between the at least one switching capacitor and the at least one balancing capacitor.

[0020] In a preferred embodiment, the at least one switching capacitor includes a first switching capacitor, and the at least one balancing capacitor includes a first balancing capacitor. The method further includes controlling the first balancing capacitor in one of the following ways: a first configuration: turning on or off the electrical connection of the first balancing capacitor to the inductor switching node under different switching states; or a second configuration: turning on or off the electrical connection between the first balancing capacitor and a first switchable terminal and a second switchable terminal under different switching states; wherein the first switchable terminal and the second switchable terminal correspond to the inductor switching node, the upper end or the lower end of the first switching capacitor.

[0021] This invention proposes a hybrid switching power converter to effectively achieve voltage balance of the switching capacitor.

[0022] The following detailed description through specific embodiments will make it easier to understand the purpose, technical content, features and effects achieved by this invention. Simple Explanation of the Diagram

[0023] Figures 1A and 1B show the prior art phase selection mechanism based on fly-through capacitor charge-discharge operation (CF-CDPS) and its corresponding time waveforms.

[0024] Figure 2 is a schematic diagram of the upper-level architecture of a hybrid switching power converter according to one embodiment of the present invention.

[0025] Figure 3 is a circuit diagram showing a specific hybrid switching power converter according to one embodiment of the present invention.

[0026] Figures 4A to 4D illustrate the specific conduction paths of a hybrid switching power converter under different switching states according to an embodiment of the present invention.

[0027] Figure 5 is a table showing the voltage of the on / off switch and inductor switching node of a hybrid switching power converter under different switching states according to one embodiment of the present invention.

[0028] Figure 6 is a simplified schematic diagram showing a hybrid switching power converter in different operating states according to one embodiment of the present invention.

[0029] Figure 7 shows a circuit diagram of one specific embodiment of the hybrid switching power converter of the present invention.

[0030] Figure 8 shows a circuit diagram of another specific embodiment of the hybrid switching power converter of the present invention.

[0031] Figures 9A and 9B show schematic diagrams of the state after adding a balancing capacitor to the hybrid switching power converter in an embodiment of the present invention.

[0032] Figure 10 is a circuit diagram according to the present invention, corresponding to a more specific embodiment of one of Figures 7.

[0033] Figure 11 shows a hybrid switching power converter according to one embodiment of the present invention.

[0034] Figures 12A to 12D show the four main operating states of the hybrid switching power converter.

[0035] Figure 13 is a circuit diagram of a hybrid switching power converter according to another embodiment of the present invention.

[0036] Figures 14A and 14B illustrate the operational behavior of a hybrid switching power converter in state I and state II, respectively, according to an embodiment of the present invention.

[0037] Figure 15 shows a circuit diagram of a hybrid switching power converter and a balancing capacitor according to another embodiment of the present invention.

[0038] Figures 16A and 16B are waveform diagrams showing a hybrid switching power converter during balanced operation according to one embodiment of the present invention.

[0039] Figure 17 shows a schematic diagram of a fourth-order hybrid switching power converter circuit according to one embodiment of the present invention.

[0040] Figures 18A and 18B show various switching configurations for the balancing capacitor CC1.

[0041] Figures 19A and 19B show the switching configurations of the balancing capacitor CC2, respectively.

[0042] Figures 20A to 20D are simplified schematic diagrams showing a hybrid switching power converter in different operating states according to an embodiment of the present invention.

[0043] Figure 21 shows a circuit diagram of a hybrid switching power converter according to one embodiment of the present invention.

[0044] Figure 22 shows a circuit diagram of a multi-stage pulse width modulation hybrid switching power converter according to one embodiment of the present invention. Implementation

[0045] The diagrams in this invention are all schematic and are mainly intended to show the coupling relationship between circuits and the relationship between signal waveforms. The circuits, signal waveforms and frequencies are not drawn to scale.

[0046] Please refer to Figure 2. Figure 2 is a schematic diagram of the upper-level architecture of a hybrid switching power converter according to one embodiment of the present invention. As shown in Figure 2, the hybrid switching power converter 111 includes an inductor L, switching capacitors CF1~CFm, multiple switches Q1~Qk, at least one balancing capacitor CC1~CCm, and a current sensing circuit 20, where m is an integer greater than or equal to 1. The multiple switches Q1~Qk are used to periodically control the electrical connection between the inductor L, switching capacitors CF1~CFm, balancing capacitors CC1~CCm, and the first voltage V1 and the second voltage V2 in a multiple switching state, thereby performing multi-stage pulse width modulation power conversion between the first voltage V1 and the second voltage V2. In one embodiment, the number of balancing capacitors CC1~CCm corresponds to the number of switching capacitors CF1~CFm, and is used to balance the voltage of the switching capacitors CF1~CFm.

[0047] It should be noted that the voltage balance mentioned here refers to the following: under steady state, the voltage across the switching capacitors CF1~CFm is approximately equal and balanced to a predetermined equilibrium voltage, such as a division of the second voltage, in the complex switching states, without any voltage being higher than the predetermined equilibrium voltage in one switching state and lower than that equilibrium voltage in another state. Furthermore, one of the first voltage V1 and the second voltage V2 corresponds to the input voltage, while the other corresponds to the output voltage.

[0048] In addition, the current sensing circuit 20 is used to sense the current of at least one of the switches Q1 to Qk to generate a current sensing signal SCS. Preferably, it does not include the balancing current that occurs between the balancing capacitor and the switching capacitor during the balancing voltage process, so that the current sensing signal SCS can more accurately reflect the inductor current.

[0049] Please refer to Figure 3. Figure 3 is a circuit diagram showing a specific hybrid switching power converter according to one embodiment of the present invention. As shown in Figure 3, the hybrid switching power converter 111 includes an inductor L, multiple switches QU1~QU2, QL1~QL2, and a switching capacitor CF1. In one embodiment, the inductor L is coupled between a first voltage V1 and an inductor switching node LX. Switches QU1 and QU2 are connected in series between the inductor switching node LX and a second voltage V2, and are coupled to each other at the upper end T_CF1 of the switching capacitor CF1. Switches QL1 and QL2 are connected in series between the inductor switching node LX and ground potential, and are coupled to each other at the lower end B_CF1 of the switching capacitor CF1. Switches QU1 and QU2 control the electrical connection between the inductor switching node LX and the upper end T_CF1 of the switching capacitor CF1, while switches QL1 and QL2 control the electrical connection between the inductor switching node LX and the lower end B_CF1 of the switching capacitor CF1.

[0050] In a specific operating mode, by adjusting the on and off states of switches QU1~QU2 and QL1~QL2, the voltage at the inductor switching node LX can be switched between 0, the voltage across capacitor CF1 VCF1, and the second voltage V2. For example, when switches QU1 and QL2 are on, the voltage VLX at the inductor switching node LX is fixed at the voltage across VCF1; while when switches QU2 and QL1 are on, the voltage VLX at the inductor switching node LX is equal to the second voltage V2 minus the voltage across VCF1. By controlling the switch configuration, the hybrid switching power converter 111 can simultaneously achieve boost and buck functions, possessing high efficiency and high voltage regulation performance, making it suitable for power management and load voltage regulation applications.

[0051] Please refer to Figures 4A-4D. Figures 4A-4D illustrate the specific conduction paths of the hybrid switching power converter under different switching states (states I, II, III, and IV) according to embodiments of the present invention. In one embodiment, the four states respectively show the changes between the inductor switching node LX at ground (GND), the second voltage V2, the upper terminal T_CF1 of the switching capacitor CF1, and the second voltage V2 minus the voltage across the switching capacitor CF1 VCF1.

[0052] Referring to Figures 4A and 5 simultaneously, in state I, switches QL2 and QU1 are switched on, and the inductor switching node LX is electrically connected to the upper end T_CF1 of the switching capacitor CF1. The voltage VLX at the inductor switching node LX is equal to the cross voltage VCF1. Referring to Figures 4B and 5 simultaneously, in state II, switches QL1 and QU2 are switched on, and the inductor switching node LX is electrically connected to the lower end B_CF1 of the switching capacitor CF1. At this time, the voltage VLX at the inductor switching node LX is the second voltage V2 minus the cross voltage VCF1. Referring to Figures 4C and 5 simultaneously, in state III, switches QL1 and QL2 are switched on, and the inductor switching node LX is electrically connected to the ground potential. The cross voltage VCF1 of the switching capacitor CF1 is determined by the charging in the previous state. Please refer to Figures 4D and 5 simultaneously. In state IV, switches QU1 and QU2 are switched to conduction, and the inductor switching node LX is electrically connected to the second voltage V2, causing the upper end T_CF1 of the switching capacitor CF1 to be charged to a voltage equal to the second voltage V2.

[0053] The black dashed lines in the diagram represent the current conduction path in each state. For example, in state III, the black dashed line shows the complete path of current flowing from the first voltage V1 through the inductor L and back to ground; while in state II, the black dashed line shows the charging path from the second voltage V2 through the switching capacitor CF1 to the inductor switching node LX.

[0054] Please refer to Figure 6, which shows a simplified schematic diagram of the hybrid switching power converter 111 under different operating states. This invention defines four main operating states, I, II, III, and IV, to correspond to different electrical connection configurations between the inductor switching node LX and the switching capacitor CF1 (or the second voltage V2, ground potential). Through the alternating switching of these states, the converter can perform third-order pulse width modulation boost or buck power conversion between the first voltage V1 and the second voltage V2. The switching and node voltage relationships for each state are explained below:

[0055] State I:

[0056] Switches QU1 and QL2 are turned on, and switches QU2 and QL1 are turned off. As a result, the inductor switching node LX is electrically connected to the upper end T_CF1 of the switching capacitor CF1, and the lower end B_CF1 is electrically connected to the ground potential, so that the voltage VLX of the inductor switching node LX is approximately the voltage VCF1 across the switching capacitor CF1.

[0057] State II:

[0058] When switches QU2 and QL1 are turned on and QU1 and QL2 are turned off, the inductor switching node LX is electrically connected to the lower end B_CF1 of the switching capacitor CF1, and the upper end T_CF1 is electrically connected to the second voltage V2, so that the voltage VLX of the inductor switching node LX is approximately V2 – VCF1.

[0059] State III:

[0060] Switches QL1 and QL2 are turned on, and switches QU1 and QU2 are turned off. This directly connects the inductor switching node LX to ground, so the voltage VLX at the inductor switching node LX is approximately 0. In this state, the switching capacitor CF1 may float while maintaining its previously charged voltage VCF1.

[0061] State IV:

[0062] Switches QU1 and QU2 are turned on, and switches QL1 and QL2 are turned off. As a result, the inductor switching node LX is electrically connected to the second voltage V2. Therefore, the voltage VLX at the inductor switching node LX is approximately the second voltage V2.

[0063] It should be noted that under ideal conditions, or when the voltage across capacitor CF1 (VCF1) and the second voltage V2 are in voltage balance, VCF1 may be approximately half of the second voltage V2. In this case, during states I and II, the converter can make the voltage VLX at the inductor switching node LX approximately V2 / 2, respectively. In other words, the converter can switch the voltage VLX at the inductor switching node LX between ground potential, the voltage division of the second voltage V2 (e.g., V2 / 2), and the second voltage V2 itself by switching between these different states, thereby achieving third-order pulse width modulation boost or buck power supply conversion.

[0064] Figure 7 shows a circuit diagram of a specific embodiment of the hybrid switching power converter of the present invention. The difference between this embodiment and the embodiment in Figure 3 is that the hybrid switching power converter 112 adds a balance switch QB1 and a balance capacitor CC1 to balance the voltage of the switching capacitor CF1.

[0065] In this embodiment, the upper end of the balancing capacitor CC1 is coupled to the inductor switching node LX via the balancing switch QB1, and the lower end is coupled to ground potential. In another embodiment, the upper end of the balancing capacitor CC1 can be coupled to the second voltage V2, and the lower end is coupled to the inductor switching node LX via the balancing switch QB1. Voltage balance between the balancing capacitor CC1 and the switching capacitor CF1 can be achieved using a single switch QB1. When the system operates in the corresponding state, the balancing switch QB1 is turned on, thus electrically connecting the balancing capacitor CC1 to the inductor switching node LX.

[0066] Please refer to Figure 8. Figure 8 shows a circuit diagram of another specific embodiment of the hybrid switching power converter of the present invention. The difference between this embodiment and the embodiment in Figure 3 is that the hybrid switching power converter 113 further includes balance switches QB3 and QB4. In this embodiment, the balance capacitor CC1 can have various coupling methods, which are described in detail below.

[0067] In this embodiment, the upper end of the balancing capacitor CC1 is coupled to the switchable terminals A and B respectively through the balancing switches QB3 and QB4, while the lower end is fixedly coupled to the ground potential.

[0068] In other embodiments, the upper end of the balancing capacitor CC1 can be directly coupled to the second voltage V2, while the lower end is coupled to the switchable terminals A and B respectively through balancing switches QB3 and QB4.

[0069] The aforementioned switchable terminals A and B can be selected as either the inductor switching node LX, the upper end T_CF1 of the switching capacitor CF1, or the lower end B_CF1, depending on the actual application requirements. The details will be described later.

[0070] The configurations in Figures 7 and 8 above allow for the parallel or series connection of the balancing capacitor CC1 and the switching capacitor CF1 through different switching states, thereby balancing the voltage of the switching capacitor CF1.

[0071] For example, please refer to Figures 7, 8, and 9A simultaneously. In state I, when the balancing switch QB3 is on and the balancing switch QB4 is off, the upper end of the balancing capacitor CC1 is electrically connected to the inductor switching node LX, forming a parallel connection with the upper end of the switching capacitor CF1. In state II, when the balancing switch QB4 is on and the balancing switch QB3 is off, the upper end of the balancing capacitor CC1 is electrically connected to the lower end of the switching capacitor CF1, forming another voltage balancing mode. This dual-switch structure provides greater operational flexibility, allowing the balancing capacitor CC1 to participate in balancing operations in multiple states.

[0072] Please refer to Figures 7, 8, and 9A-9B simultaneously. Figures 9A-9B show schematic diagrams of the state after adding a balancing capacitor CC1 to the hybrid switching power converter in an embodiment of the present invention.

[0073] In state I, the upper end T_CF1 of the switching capacitor CF1 is switched to be electrically connected to the inductor switching node LX, while the lower end B_CF1 is connected to the ground potential. The balancing capacitor CC1 is switched to be connected in parallel with the switching capacitor CF1. Thus, the voltage across the switching capacitor CF1 VCF1 is equal to the voltage across the balancing capacitor CC1 VCC1, that is: VCF1=VCC1.

[0074] In state II, the upper end T_CF1 of the switching capacitor CF1 is switched to be electrically connected to the second voltage V2, while the lower end B_CF1 is switched to be electrically connected to the inductor switching node LX. The balancing capacitor CC1 is switched to be connected in series with the switching capacitor CF1. Thus, the sum of the voltages across the switching capacitor CF1 VCF1 and the voltage across the balancing capacitor CC1 VCC1 is the second voltage V2, that is: VCF1 + VCC1 = V2.

[0075] When the hybrid switching power converter periodically switches between states I and II, as mentioned above, due to the two equations in states I and II, in steady state, the voltage across the switching capacitor CF1 VCF1 and the voltage across the balancing capacitor CC1 VCC1 will both be equal to V2 / 2. Therefore, the switching capacitor CF1 achieves voltage balance, which in turn enables the hybrid switching power converter to switch stably when performing the aforementioned third-order pulse width modulation, reducing voltage and current ripple.

[0076] In one embodiment, as shown in FIG9B, in state III, the inductor switching node LX is switched to be electrically connected to the ground potential, the upper end T_CF1 of the switching capacitor CF1 is switched to be floating and the lower end B_CF1 is electrically connected to the ground potential, and the balancing capacitor CC1 is also switched to be floating. In state IV, the inductor switching node LX is switched to be electrically connected to the second voltage V2, the upper end T_CF1 of the switching capacitor CF1 is switched to be electrically connected to the second voltage V2 and the lower end B_CF1 is floating, and the balancing capacitor CC1 is also switched to be floating.

[0077] Figure 10 is a circuit diagram according to the present invention, corresponding to a more specific embodiment of Figure 7. This embodiment uses a single balanced switch QB1. Since the balanced switch Q1 is coupled to the inductor switching node LX, in this embodiment, the balanced switch QB1 includes two MOS transistors QBa and QBb with their body diodes reverse-coupled, thereby preventing the body diodes from conducting in the forward direction when the balanced switch QB1 is switched off.

[0078] Figure 11 shows a hybrid switching power converter according to one embodiment of the present invention, specifically illustrating the coupling method of the balance switches QB3 and QB4. This embodiment corresponds to a specific embodiment of the structure shown in Figure 8. Specifically, in this embodiment, the balance switch QB3 is coupled between the upper end T_CF1 of the switching capacitor CF1 and the upper end of the balance capacitor CC1, while the balance switch QB4 is coupled between the lower end B_CF1 of the switching capacitor CF1 and the upper end of the balance capacitor CC1, with the lower end of the balance capacitor CC1 coupled to ground potential.

[0079] In this embodiment, the hybrid switching power converter 115 further includes a current sensing circuit 20, which is coupled to the current path flowing through switches QU1 and / or QL1. This circuit generates a current sensing signal SU1 or SL1 during the corresponding switching state. The current sensing circuit 20 provides a current sensing signal SU1 or SL1 proportional to the inductor current IL by sensing the current flowing through switches QU1 and / or QL1. Since this current sensing design does not include the balancing current between the balancing capacitor CC1 and the switching capacitor CF1 in the sensing, misjudgments in current control can be avoided, improving the accuracy of the system. Details are described below.

[0080] Figures 12A to 12D show the four main operating states of the hybrid switching power converter 115, which are described in sequence below:

[0081] State I (Figure 12A):

[0082] Switches QL2 and QU1, as well as the balancing switch QB3, are turned on, connecting the upper end T_CF1 of the switching capacitor CF1 to the inductor switching node LX and the lower end B_CF1 to ground potential. The balancing capacitor CC1 is connected in parallel with the switching capacitor CF1 through the balancing switch QB3. At this time, the current sensing circuit 20 can sense the current through switch QU1. Since the balancing capacitor CC1 and the switching capacitor CF1 are voltage balanced through the balancing switch QB3, the current flowing through switch QU1 does not include the balancing current between the balancing capacitor CC1 and the switching capacitor CF1. This avoids interference from the balancing current in the measurement of the inductor current IL.

[0083] State II (Figure 12B)

[0084] Switches QL1 and QU2, as well as the balancing switch QB4, are turned on, connecting the upper terminal T_CF1 of the switching capacitor CF1 to the second voltage V2 and the lower terminal B_CF1 to the inductor switching node LX. The balancing capacitor CC1 is connected in series with the switching capacitor CF1 between the ground potential and the second voltage V2. At this time, the current sensing circuit 20 senses the current passing through switch QL1. Similarly, the current sensing signal SL1 generated thereby will not include the aforementioned balancing current.

[0085] State III (Figure 12C): Switches QL1 and QL2 are on, while balancing switches QB3 and QB4 are off, connecting the inductor switching node LX to ground. The upper end T_CF1 of the switching capacitor CF1 is floating, and the lower end B_CF1 is connected to ground. The balancing capacitor CC1 is also floating. At this time, the switching capacitor CF1 and the balancing capacitor CC1 are electrically disconnected from each other. The current sensing circuit 20 can sense the current flowing through switch QL1, which does not include the aforementioned balancing current.

[0086] State IV (Figure 12D)

[0087] Switches QU1 and QU2 are turned on, while balancing switches QB3 and QB4 are turned off, connecting the inductor switching node LX to the second voltage V2. The upper terminal T_CF1 of the switching capacitor CF1 is connected to the second voltage V2, while the lower terminal B_CF1 is floating. The balancing capacitor CC1 is also floating. At this time, the switching capacitor CF1 and the balancing capacitor CC1 are electrically disconnected from each other. The current sensing circuit 20 senses the current passing through switch QU1, which does not include the aforementioned balancing current.

[0088] Please refer to Figure 13. Figure 13 is a circuit diagram of a hybrid switching power converter according to another embodiment of the present invention. This embodiment corresponds to another specific embodiment of Figure 8, wherein the balance switch QB3' is coupled between the inductor switching node LX and the balance capacitor CC1, and the balance switch QB4 is coupled between the lower end B_CF1 of the switching capacitor CF1 and the balance capacitor CC1. In this embodiment, the balance switch QB3' includes two MOS transistors QBa and QBb with their body diodes reverse-coupled.

[0089] Please refer to Figures 14A and 14B. Figures 14A and 14B illustrate the operational behavior of the hybrid switching power converter in states I and II, respectively, according to an embodiment of the present invention. Figure 14A corresponds to state I, where switches QL2, QU1, and the balancing switch QB3' are switched on; the rest is similar to the embodiment of Figure 12A, so its description is omitted. Figure 14B corresponds to state II, where switches QL1, QU2, and the balancing switch QB4 are switched on; the rest is similar to the embodiment of Figure 12B, so its description is omitted. It is worth noting that in state II of Figure 14B, the current sensing circuit 20 can sense the current through switch QL1; similarly, the current sensing signal SL1 generated therefrom will not include the aforementioned balancing current.

[0090] Furthermore, this embodiment can correspond to state III of Figure 6 by switching switches QL1 and QL2 to be on and switching balance switches QB3' and QB4 to be off. This embodiment can also correspond to state IV of Figure 6 by switching switches QU1 and QU2 to be on and switching balance switches QB3' and QB4 to be off.

[0091] Please refer to Figure 15. Figure 15 shows a circuit diagram of a hybrid switching power converter 125 and a balancing capacitor CC1 according to another embodiment of the present invention. This embodiment is similar to the structure shown in Figure 8, but with some differences: In this embodiment, the upper end of the balancing capacitor CC1 is directly coupled to the second voltage V2, and its lower end is connected to the inductor switching node LX and the upper end T_CF1 of the switching capacitor CF1 through balancing switches QB1 and QB4, respectively. With this configuration, the system can switch the balancing capacitor CC1 and the switching capacitor CF1 to be connected in parallel or in series under different operating states to achieve dynamic voltage balance.

[0092] In practical operation, when the inductor switching node LX is adjusted via switch configuration in a certain state so that the balancing capacitor CC1 and the switching capacitor CF1 are connected in parallel, the balancing switch QB1 is turned on and the balancing switch QB4 is turned off, allowing the balancing capacitor CC1 and the switching capacitor CF1 to share the voltage. In the other state, the balancing switch QB4 is turned on and the balancing switch QB1 is turned off, then the balancing capacitor CC1 and the switching capacitor CF1 are connected in series between the second voltage V2 and ground. Under this two-mode switching operation, the switching capacitor CF1 can eventually be adjusted to a balanced state with a voltage across approximately V2 / 2.

[0093] Figures 16A and 16B are waveform diagrams of a hybrid switching power converter during balancing operation according to one embodiment of the present invention. Figures 16A and 16B show the transient waveforms of the voltage VCF1 across the switching capacitor CF1 as it returns to the balancing voltage from above the balancing voltage (i.e., VCC1) and below the balancing voltage, respectively. It takes only a few switching cycles to return to balance, which is much faster than the prior art. Furthermore, in the steady state of balance, there is no periodic continuous charging or discharging phase, thus significantly reducing the ripple of the second voltage V2.

[0094] Please refer to Figure 17. Figure 17 shows a schematic diagram of a four-stage hybrid switching power converter circuit according to one embodiment of the present invention. This embodiment, based on the previous three-stage converter, adds a switching capacitor CF2 and corresponding third upper and lower bridge switches (QU3, QL3). Specifically, the inductor switching node LX is sequentially coupled to the second voltage V2 through the upper bridge switches QU1, QU2, and QU3, and sequentially coupled to ground potential through the lower bridge switches QL1, QL2, and QL3. The upper end T_CF1 of the switching capacitor CF1 is coupled between the upper bridge switches QU1 and QU2, and the lower end B_CF1 is coupled between the lower bridge switches QL1 and QL2. The upper end T_CF2 of the switching capacitor CF2 is coupled between the upper bridge switches QU2 and QU3, and the lower end B_CF2 is coupled between the lower bridge switches QL2 and QL3. This configuration allows for the acquisition of fourth-order voltages, such as V2 / 3 and V2 / 3, at the inductor switching node LX, to achieve fourth-order pulse width modulation.

[0095] To ensure that the switching capacitors CF1 and CF2 maintain the target voltage during dynamic operation, the present invention further includes balancing capacitors CC1 and CC2 and corresponding balancing switches to force each capacitor to reach a stable value of balanced voltage.

[0096] Figures 18A and 18B show various switching configurations for the balancing capacitor CC1. In Figure 18A, the balancing capacitor CC1 can be coupled to the inductor switching node LX via a single balancing switch (such as QB3). When it is necessary to balance the voltage across the balancing capacitor CC1 with the switching capacitor CF1 or CF2, this single switch can be turned on to connect the balancing capacitor CC1 in parallel or in series with the switching capacitor CF1 or CF2 via the inductor switching node LX. This single-switch configuration can significantly reduce hardware complexity.

[0097] In Figure 18B, the balancing capacitor CC1 can be switched to switchable terminals C and D via two balancing switches (such as QB3 and QB4), so that the balancing capacitor CC1 can be turned on to multiple potentials in different states. For example, the switching terminals C and D can correspond to the inductor switching node LX, the upper and lower terminals T_CF1, B_CF1, or the lower terminal B_CF2 of the switching capacitor CF1.

[0098] Figures 19A and 19B show the switching configurations of the balancing capacitor CC2, which are similar in design concept to the balancing capacitor CC1. However, in most cases, the balancing capacitor CC2 is used to help maintain a higher voltage division (e.g., V2*2 / 3). In Figure 19A, the balancing capacitor CC2 can be coupled to the inductor switching node LX through a single balancing switch (e.g., QB5), electrically connecting the balancing capacitor CC2 to the inductor switching node LX under appropriate switching conditions. In Figure 19B, the balancing capacitor CC2 can be connected to different switchable terminals A and B by two balancing switches (QB5 and QB6).

[0099] Please refer to Figures 20A, 20B, 20C, and 20D. The following includes the embodiments shown in Figures 17 and 18A, 18B, 19A, and 19B, illustrating the switching states 1 to 8 corresponding to the switching of these switching and balancing switches. Each state mainly explains the connection relationships between the switching capacitors CF1 and CF2 and the inductor switching node LX, the second voltage V2, and the ground potential, as well as the electrical connection relationships between the balancing capacitors CC1 and CC2 and the switching capacitors CF1 and CF2, thereby achieving voltage balance while achieving multi-stage PWM conversion. Figure 20A illustrates states 1 and 2, Figure 20B illustrates states 3 and 4, Figure 20C illustrates states 5 and 6, and Figure 20D illustrates states 7 and 8.

[0100] In state 1, the lower end (B_CF2) of the switching capacitor CF2 is electrically connected to ground, the upper end (T_CF2) of CF2 is electrically connected to the upper end (T_CF1) of CF1, and the lower end (B_CF1) of CF1 is electrically connected to the inductor switching node LX. The upper end of the balancing capacitor CC1 is electrically connected to the inductor switching node LX. At this time, the voltage VLX of the inductor switching node LX has the following relationship with the voltage across each capacitor:

[0101] VLX = VCC1 = VCF2 - VCF1

[0102] VCC1 is the voltage across the balancing capacitor CC1, and VCF1 and VCF2 are the voltages across the switching capacitors CF1 and CF2, respectively.

[0103] In state 2, the upper ends of CF2 (T_CF2) and CF1 (T_CF1) are electrically connected to the inductor switching node LX, the lower end of CF2 (B_CF2) is electrically connected to ground, and the lower end of CF1 (B_CF1) is floating. Furthermore, CC2 is connected in parallel with CF2 between the inductor switching node LX and ground. At this time, the voltage VLX at the inductor switching node LX has the following relationship with the voltage across each capacitor:

[0104] VLX = VCF2 = VCC2

[0105] VCC2 is the voltage across the balancing capacitor CC2.

[0106] In state 1, the lower end (B_CF2) of the switching capacitor CF2 is electrically connected to ground, the upper end (T_CF2) of the switching capacitor CF2 is electrically connected to the upper end (T_CF1) of the switching capacitor CF1, and the lower end (B_CF1) of the switching capacitor CF1 is electrically connected to the inductor switching node LX. The upper end of the balancing capacitor CC1 is also electrically connected to the inductor switching node LX. At this time, the voltage VLX of the inductor switching node LX has the following relationship with the voltage across each capacitor:

[0107] VLX = VCC1 = VCF2 - VCF1

[0108] VCC1 is the voltage across the balancing capacitor CC1, while VCF1 and VCF2 are the voltages across the switching capacitors CF1 and CF2, respectively.

[0109] In state 2, the upper ends (T_CF2) of switching capacitor CF2 and the upper ends (T_CF1) of switching capacitor CF1 are simultaneously connected to the inductor switching node LX. The lower end (B_CF2) of switching capacitor CF2 is connected to ground potential, while the lower end (B_CF1) of switching capacitor CF1 is in a floating state. Furthermore, the balancing capacitor CC2 is connected in parallel with the switching capacitor CF2 between the inductor switching node LX and the ground potential. At this time, the voltage VLX at the inductor switching node LX has the following relationship with the voltage across each capacitor:

[0110] VLX = VCF2 = VCC2

[0111] VCC2 is the voltage across the balancing capacitor CC2.

[0112] In state 3, the upper end (T_CF1) of the switching capacitor CF1 is electrically connected to the inductor switching node LX, and the lower end (B_CF1) of the switching capacitor CF1 is electrically connected to the ground potential, while the switching capacitor CF2 is in a floating state. In this state, the balancing capacitor CC1 is connected in parallel with the switching capacitor CF2 between the inductor switching node LX and the ground potential, making the following relationship valid:

[0113] VLX = VCF1 = VCC1

[0114] In state 4, switching capacitor CF2 and switching capacitor CF1 are connected in series between the second voltage V2 and the inductor switching node LX, with switching capacitor CF1 connected in reverse. The balancing capacitor CC2 is connected between the inductor switching node LX and ground potential. At this time, the voltage VLX at the inductor switching node LX and the voltage across each capacitor have the following relationship:

[0115] VLX = V2 – VCF2 + VCF1 = VCC2

[0116] In state 5, switching capacitor CF2 is electrically connected between the second voltage V2 and the inductor switching node LX, switching capacitor CF1 is electrically connected to the floating connection and the inductor switching node LX, and balancing capacitor CC1 is electrically connected between the inductor switching node LX and the ground potential, so that the following relationship holds:

[0117] VLX = V2 – VCF2 = VCC1

[0118] In state 6, switching capacitor CF1 is electrically connected between the second voltage V2 and the inductor switching node LX, switching capacitor CF2 is electrically connected between the second voltage V2 and the floating connection, and balancing capacitor CC2 is electrically connected between the inductor switching node LX and the ground potential, so that the following relationship holds:

[0119] VLX = V2 – VCF1 = VCC2

[0120] In state 7, the inductor switching node LX is directly connected to the second voltage V2, and the switching capacitors CF1 and CF2 are both connected between the second voltage V2 and the floating connection. The balancing capacitors CC1 and CC2 are also in the floating connection state and do not participate in the voltage division operation.

[0121] In state 8, the inductor switching node LX is directly connected to the ground potential, and the switching capacitors CF1 and CF2 are both connected between the floating connection and the ground potential. The balancing capacitors CC1 and CC2 are also kept floating.

[0122] By periodically switching between at least two states from state 1 to state 6, the inductor switching node LX can periodically switch between any two adjacent potentials, such as V2, V2*2 / 3, V2*1 / 3 and ground potential, at different time periods to achieve fourth-order PWM power conversion.

[0123] Furthermore, due to the participation of the aforementioned balancing capacitors CC1 and CC2, voltage balancing can be performed periodically in at least two switching states by controlling the voltage VLX of the inductor switching node LX.

[0124] For example, when the periodic switching states of a hybrid switching power converter circuit include state 1, state 5, and state 3, we can obtain VCF2 - VCF1 = VCC1 = V2 - VCF2 (based on state 1 and state 5), and VCF1 = VCC1 (state 3). Therefore, we can conclude that:

[0125] VCF1 = VCC1 = 1 / 3*V2, and VCF2 = 2 / 3*V2

[0126] Under other state transitions, it is ensured that VCC2 = VCF2 = 2 / 3*V2

[0127] In addition, in other embodiments, the fixed terminals of the balancing capacitors CC1 or CC2 may also be coupled to the second voltage V2 as required.

[0128] Please refer to Figure 21. Figure 21 is a circuit diagram of a hybrid switching power converter according to one embodiment of the present invention. As shown in Figure 21, this embodiment corresponds to a specific embodiment combining Figures 17, 18A, and 19A. This embodiment includes balancing switches QB3 and QB5 and balancing capacitors CC1 and CC2. Balancing capacitors CC1 and CC2 are connected to the inductor switching node LX through balancing switches QB3 and QB5, respectively. In this embodiment, voltage balancing for multiple voltage levels can be achieved with a minimum number of switches.

[0129] Please refer to Figure 22. Figure 22 is a circuit diagram of a multi-stage pulse width modulation hybrid switching power converter according to one embodiment of the present invention, wherein the dynamic electrical connection of balancing capacitors CC1 and CC2 is controlled by multiple balancing switches. Specifically, this embodiment corresponds to a specific embodiment combining Figures 17, 18B, and 19B, and this embodiment further includes balancing switches QB3~QB6 and balancing capacitors CC1 and CC2. Balancing capacitor CC1 is coupled to the upper end T_CF1 of switching capacitor CF1 through balancing switch QB3, and to the lower end B_CF1 of switching capacitor CF1 through balancing switch QB4. At the same time, balancing capacitor CC2 is coupled to the upper end T_CF2 of switching capacitor CF2 through balancing switch QB5, and to the lower end B_CF1 of switching capacitor CF1 through balancing switch QB6.

[0130] Furthermore, a more flexible combination design can be considered. For example, balancing capacitor CC1 is connected as shown in Figure 21, while balancing capacitor CC2 is configured as shown in Figure 22. Conversely, the balancing capacitor CC1 configuration of Figure 22 can be combined with the balancing capacitor CC2 configuration of Figure 21. Such combinations allow for flexible configuration of the capacitor and switch connections under different states and requirements. Although these combinations are not shown in detail here, suitable configurations can be derived by those skilled in the art based on the specific requirements.

[0131] Furthermore, it should be noted that in the embodiment of Figure 22, for example, the hybrid switching power converter can be switched to state 5 by turning on switches QU3, QU1, QL1 and QB4. In this state, the current sensing circuit 20 can sense the current through switch QU1 and generate a current sensing signal SU1, which also does not include the aforementioned balancing current (at this time, the balancing current flows through the balancing switch QB4). The current sensing signal SL1 can be obtained by current sensing in another corresponding state.

[0132] In summary, the hybrid switching power converter of the present invention can reduce voltage stress, improve energy utilization efficiency, ensure voltage balance, avoid capacitor voltage deviation problems, improve system stability, allow for various balancing capacitor and switch configurations, adapt to different application scenarios, and avoid interference from balancing current, providing accurate inductor current signals, which helps to stabilize the hybrid switching power converter during startup or transient operation.

[0133] The present invention has been described above with reference to preferred embodiments. However, the above description is only intended to facilitate understanding of the invention by those skilled in the art and is not intended to limit the broadest scope of the invention. The described embodiments are not limited to individual application and can also be combined. For example, two or more embodiments can be used in combination, and a component of one embodiment can replace a corresponding component in another embodiment. Furthermore, within the same spirit of the invention, those skilled in the art can conceive of various equivalent changes and combinations. For example, the phrase "processing or calculating based on a signal or generating an output result" in the present invention is not limited to the signal itself, but also includes, when necessary, performing voltage-to-current conversion, current-to-voltage conversion, and / or proportional conversion on the signal, and then processing or calculating based on the converted signal to generate an output result. Therefore, within the same spirit of the invention, those skilled in the art can conceive of various equivalent changes and combinations, and there are many combinations, which will not be listed here. Therefore, the scope of the present invention should cover the above and all other equivalent changes.

[0134] 20: Current sensing circuit 111, 112, 113, 115, 125: Hybrid Switching Power Converters 301: Signal Generation Module 302: Comparator 303: Latch circuit A, B, C, D: Switchable terminals B_CF1, B_CF2: Lower end CC1~CCm: Balanced capacitors CF1~CFm: Conversion capacitors GND: Grounding potential IL: Inductor current L: Inductor LX: Inductor switching node Pch: Charging phase Pdch: Discharge Phase QB1, QB3~QB6: Balance switch QBa, QBb: MOS transistors QL1, QL2, QL3, QU1, QU2, QU3: Switches Q1~Qk: Complex number switches SCS, SL1, SU1: Current sensing signals T_CF1, T_CF2: Upper end VA, VB: Input differential signals VCF, VCF1, VCF2, VCC1, VCC2: Transvoltage VLX: Voltage Vo: Reference voltage V1: First voltage V2: Second voltage

Claims

1. A hybrid switching power converter for power conversion between a first voltage and a second voltage, the hybrid switching power converter comprising: an inductor coupled to an inductor switching node; at least one switching capacitor; at least one balancing capacitor; and a plurality of switches for periodically switching the electrical connections of the inductor, the at least one switching capacitor, the at least one balancing capacitor, the first voltage, and the second voltage in a plurality of switching states, thereby performing power conversion between the first voltage and the second voltage using multi-step pulse width modulation; wherein the plurality of switching states include a first switching state and a second switching state that are different from each other, wherein the plurality of switches control the at least one switching capacitor and the at least one balancing capacitor to be electrically connected to the inductor switching node in the first switching state and the second switching state, respectively, to achieve voltage balance, thereby adjusting and stabilizing the voltage across the at least one switching capacitor to a division voltage of the second voltage in steady state; wherein the at least one switching capacitor includes a first switching capacitor, and the at least one balancing capacitor includes a first balancing capacitor; The complex switch includes a first balanced switch coupled between a first terminal and a first switchable terminal of the first balanced capacitor; and a second balanced switch coupled between the first terminal and a second switchable terminal of the first balanced capacitor. The first switchable terminal and the second switchable terminal correspond to either of the following options: the inductor switching node; the upper end of the first switching capacitor; the lower end of the first switching capacitor.

2. The hybrid switching power converter as claimed in claim 1, wherein in the first switching state, the first balancing capacitor is connected in parallel to at least a portion of the at least one switching capacitor; wherein in the second switching state, the first balancing capacitor is connected in series to at least a portion of the at least one switching capacitor between the second voltage and a ground potential.

3. The hybrid switching power converter as described in claim 1 further includes a current sensing circuit for sensing the current of a corresponding switch among the plurality of switches in the first or second switching state to generate a current sensing signal to indicate an inductor current, wherein the current flowing through the corresponding switch corresponds to the inductor current.

4. The hybrid switching power converter as claimed in claim 3, wherein the current flowing through the corresponding switch does not include a balancing current flowing from or to the at least one balancing capacitor.

5. The hybrid switching power converter as claimed in claim 1, wherein when the plurality of switches control the inductor switching node to be electrically connected to the second voltage or a ground potential, the at least one switching capacitor and the at least one balancing capacitor are electrically disconnected from each other.

6. The hybrid switching power converter as claimed in claim 4, wherein the multiple switches include multiple upper bridge switches, the multiple upper bridge switches including a first and a second upper bridge switch connected in series between the inductor switching node and the second voltage, which are coupled to each other at the upper end of the first switching capacitor, and including a first and a second lower bridge switch connected in series between the inductor switching node and a ground potential, which are coupled to each other at the lower end of the first switching capacitor.

7. The hybrid switching power converter as described in claim 6, wherein the corresponding switch is the first upper bridge switch or the first lower bridge switch; wherein the current flowing through the corresponding switch does not include a first balancing current between the first balancing capacitor and the first switching capacitor, wherein the first balancing current flows through the first balancing switch or the second balancing switch.

8. The hybrid switching power converter as claimed in claim 4, wherein the at least one switching capacitor further includes a second switching capacitor, and the at least one balancing capacitor further includes a second balancing capacitor; wherein the plurality of switches further includes: A third balance switch is coupled between the second balance capacitor and a third switchable terminal; and a fourth balancing switch coupled between the second balancing capacitor and a fourth switchable terminal; wherein the first switchable terminal and the second switchable terminal respectively correspond to any two of the following options: the inductor switching node; the upper or lower end of the first switching capacitor; the upper or lower end of the second switching capacitor; wherein the third switchable terminal and the fourth switchable terminal respectively correspond to any two of the following options: the inductor switching node; the upper or lower end of the first switching capacitor; the upper or lower end of the second switching capacitor.

9. The hybrid switching power converter as described in claim 8, wherein the plurality of switches includes first to third upper bridge switches and first to third lower bridge switches, wherein, The first upper bridge switch is coupled between the inductor switching node and the upper end of the first conversion capacitor; the second upper bridge switch is coupled between the upper ends of the first and second conversion capacitors; the third upper bridge switch is coupled between the upper end of the second conversion capacitor and the second voltage; the first lower bridge switch is coupled between the inductor switching node and the lower end of the first conversion capacitor; the second lower bridge switch is coupled between the lower ends of the first and second conversion capacitors; the third lower bridge switch is coupled between the lower end of the second conversion capacitor and a ground potential; wherein the first switchable terminal and the second switchable terminal respectively correspond to any two of the following options: the inductor switching node; the upper end of the first conversion capacitor; the lower end of the first conversion capacitor; the lower end of the second conversion capacitor; wherein the third switchable terminal and the fourth switchable terminal respectively correspond to any two of the following options: the inductor switching node; the upper end of the first conversion capacitor; the lower end of the first conversion capacitor; the upper end of the second conversion capacitor; In steady state, the voltage across the first switching capacitor and the first balancing capacitor is 1 / 3 of the second voltage, and the voltage across the second switching capacitor and the second balancing capacitor is 2 / 3 of the second voltage.

10. A hybrid switching power conversion method for switching power between a first voltage and a second voltage, the hybrid switching power conversion method comprising: in a plurality of switching states, periodically switching an inductor, at least one switching capacitor, and at least one balancing capacitor by a plurality of switches, and subjecting them to different electrical connections between the first voltage and the second voltage; wherein the plurality of switching states include at least a first switching state and a second switching state, and the step of subjecting the different electrical connections between the first voltage and the second voltage includes: The at least one switching capacitor and the at least one balancing capacitor are electrically connected to an inductor switching node in different electrical connection combinations in the first switching state and the second switching state, respectively, to achieve voltage balance. This allows the voltage across the at least one switching capacitor to be adjusted to a fraction of the second voltage in steady state, thereby achieving multi-step pulse width modulation power conversion. One end of the inductor is coupled to the inductor switching node. The at least one switching capacitor includes a first switching capacitor, and the at least one balancing capacitor includes a first balancing capacitor. The multiple switches include a first balancing switch coupled between a first terminal and a first switchable terminal of the first balancing capacitor; and a second balancing switch coupled between the first terminal and a second switchable terminal of the first balancing capacitor. The first switchable terminal and the second switchable terminal correspond to any two of the following: the inductor switching node; the upper end of the first switching capacitor; and the lower end of the first switching capacitor.

11. The hybrid switching power conversion method as described in claim 10, further comprising: in the first switching state, controlling the first balancing capacitor to be connected in parallel with at least a portion of the at least one switching capacitor to output its voltage to the inductor switching node; in the second switching state, controlling the first balancing capacitor to be connected in series with at least a portion of the at least one switching capacitor, and distributing it between the second voltage and a ground potential; wherein, By switching between parallel and series connections as described above, in steady state, the first balancing capacitor helps stabilize the voltage across the at least one switching capacitor as the voltage division of the second voltage.

12. The hybrid switching power conversion method as described in claim 10 further includes: in the first switching state or the second switching state, sensing the current of a corresponding switch among the plurality of switches to generate a current sensing signal to indicate an inductor current of the inductor, wherein the current of the corresponding switch corresponds to the inductor current.

13. The hybrid switching power conversion method as described in claim 12, wherein the current flowing through the corresponding switch does not include a balancing current flowing from or to the at least one balancing capacitor.

14. The hybrid switching power conversion method as described in claim 10, wherein in another part of the switching states of the plurality of switching states, the inductor switching node is electrically connected to the second voltage or a ground potential, and an electrical disconnect is present between the at least one switching capacitor and the at least one balancing capacitor.

15. The hybrid switching power conversion method as described in claim 13, wherein the step of achieving voltage balance includes: In the first switching state or the second switching state, the inductor current is turned on by the corresponding switch; And turn on the first balance switch or the second balance switch to generate a first balance current between the first balance capacitor and the first switching capacitor, wherein the first balance current flows through the first balance switch or the second balance switch; wherein the current flowing through the corresponding switch does not include the first balance current.

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