Multi-phase power converter

Abstract

A multi-phase power converter is provided. The multi-phase power converter includes a plurality of switch components as a buck high-side switch, a buck low-side switch, a boost high-side switch and a boost low-side switch, and a control circuit. A first terminal of the buck high-side switch is coupled to an input voltage. A first terminal of the buck low-side switch is connected to a second terminal of the buck high-side switch. A first terminal of the boost low-side switch is connected to a second terminal of the boost high-side switch. Second terminals of the buck low-side switches are respectively connected to first terminals of inductors. Second terminals of the boost low-side switches are respectively connected to second terminals of the inductors. The control circuit controls each of these switch components according to a voltage of the boost high-side switch.

Description

[Technical Field]

[0001] This invention relates to power converters, and more particularly to a multiphase power converter. [Previous Technology]

[0002] Power converters are indispensable for electronic devices. They are used to regulate power and supply the regulated power to the electronic devices. Power converters are generally single-phase. In recent years, multi-phase power converters have been developed to meet various other application needs.

[0003] However, the internal configuration and control of existing multiphase power converters remain simplistic, making them unsuitable for various application requirements. In existing multiphase power converters, the control circuit controls multiple switching elements in a manner that fails to ensure that the slopes of multiple bands in each of the multiple waveforms of the current flowing from the multiple switching elements to the inductor are identical to the slopes of multiple bands in the previous waveform. Therefore, the current variation in existing multiphase power converters is unstable. [Summary of the Invention]

[0004] To address the shortcomings of existing technologies, the present invention provides a multiphase power converter, comprising multiple phase switching circuits, a control circuit, and multiple inductors. Each inductor has a first terminal and a second terminal. Each phase switching circuit includes two buck-side switches, serving as a buck-side upper bridge switch and a buck-side lower bridge switch, respectively. The first terminal of the buck-side upper bridge switch is coupled to the input voltage. The first terminal of the buck-side lower bridge switch is connected to the second terminal of the buck-side upper bridge switch. The second terminal of the buck-side lower bridge switch is grounded. The multiple first terminals of the multiple buck-side lower bridge switches of the multiple phase switching circuits are respectively connected to the multiple first terminals of the multiple inductors. Each phase switching circuit further includes two boost-side switches, serving as a boost-side upper bridge switch and a boost-side lower bridge switch, respectively. The first terminal of the boost-side upper bridge switch is connected to an output node. The first terminal of the boost-side lower bridge switch is connected to the second terminal of the boost-side upper bridge switch. The second terminal of the boost-side lower bridge switch is grounded. The multiple first terminals of the multiple boost-side lower bridge switches of the multiple phase switching circuits are respectively connected to the multiple second terminals of the multiple inductors. The control circuit connects to the control terminals of each buck-side switch, the control terminals of each boost-side switch, and the output node. The control circuit is configured to control each buck-side switch and each boost-side switch based on the output voltage of the output node.

[0005] In addition, the present invention provides a multiphase power converter, comprising two phase switching circuits and a control circuit. The two phase switching circuits serve as a first phase switching circuit and a second phase switching circuit, respectively. Each phase switching circuit includes two buck-side switches, serving as a buck-side upper bridge switch and a buck-side lower bridge switch, respectively. The first terminal of the buck-side upper bridge switch is coupled to the input voltage. The first terminal of the buck-side lower bridge switch is connected to the second terminal of the buck-side upper bridge switch. The second terminal of the buck-side lower bridge switch is grounded. The first phase switching circuit further includes two boost-side switches, serving as a boost-side upper bridge switch and a boost-side lower bridge switch, respectively. The first terminal of the boost-side upper bridge switch is connected to an output node. The first terminal of the boost-side lower bridge switch is connected to the second terminal of the boost-side lower bridge switch. The second terminal of the boost-side lower bridge switch is grounded. The first terminal of the buck-side lower bridge switch of the first phase switching circuit is connected to the first terminal of a first inductor. The first terminal of the boost-side lower bridge switch is connected to the second terminal of the first inductor. The second terminal of the first inductor is connected to the first terminal of the second inductor, and the second terminal of the second inductor is connected to the first terminal of the step-down lower bridge switch of the second phase switching circuit. The control circuit is connected to the control terminals of each step-down switch, the control terminals of each boost switch, and the output node. The control circuit is configured to control each step-down switch and each boost switch according to the output voltage of the output node.

[0006] In addition, the present invention provides a multiphase power converter, comprising two phase switching circuits and a control circuit. The two phase switching circuits serve as a first phase switching circuit and a second phase switching circuit, respectively. Each phase switching circuit has two boost-side switches serving as a boost-side upper bridge switch and a boost-side lower bridge switch, respectively. The first terminal of the boost-side upper bridge switch is connected to an output node. The first terminal of the boost-side lower bridge switch is connected to the second terminal of the boost-side lower bridge switch. The second terminal of the boost-side lower bridge switch is grounded. The first phase switching circuit further comprises two buck-side switches serving as a buck-side upper bridge switch and a buck-side lower bridge switch, respectively. The first terminal of the buck-side upper bridge switch is coupled to an input voltage. The first terminal of the buck-side lower bridge switch is connected to the second terminal of the buck-side upper bridge switch. The second terminal of the buck-side lower bridge switch is grounded. The first terminal of the buck-side lower bridge switch is connected to the first terminal of a first inductor. The first terminal of the boost-side lower bridge switch of the first phase switching circuit is connected to the second terminal of the first inductor. The first terminal of the boost-side lower bridge switch of the second phase switching circuit is connected to the first terminal of a second inductor. The second terminal of the second inductor is connected to the first terminal of the first inductor. The control circuit is connected to the control terminals of each boost-side switch, each buck-side switch, and the output node. The control circuit is configured to control each boost-side switch and each buck-side switch based on the output voltage of the output node.

[0007] In addition, the present invention provides a multiphase power converter, comprising multiple phase switching circuits, a control circuit, and multiple inductors. One of the multiple phase switching circuits serves as a first phase switching circuit. Each inductor includes a first terminal and a second terminal. Each phase switching circuit includes two buck-side switches, respectively serving as a buck-side upper bridge switch and a buck-side lower bridge switch. The first terminal of the buck-side upper bridge switch is coupled to the input voltage. The first terminal of the buck-side lower bridge switch is connected to the second terminal of the buck-side upper bridge switch. The second terminal of the buck-side lower bridge switch is grounded. The first phase switching circuit further includes two boost-side switches, respectively serving as a boost-side upper bridge switch and a boost-side lower bridge switch. The first terminal of the boost-side upper bridge switch is connected to an output node. The first terminal of the boost-side lower bridge switch is connected to the second terminal of the boost-side lower bridge switch. The second terminal of the boost-side lower bridge switch is grounded. The multiple first terminals of the multiple inductors are respectively connected to the multiple first terminals of the multiple buck-side lower bridge switches of the multiple phase switching circuits. The second terminal of each inductor is connected to the first terminal of the boost-side lower bridge switch. The control circuit connects to the control terminals of each buck-side switch, the control terminals of each boost-side switch, and the output node. The control circuit is configured to control each buck-side switch and each boost-side switch based on the output voltage of the output node.

[0008] In addition, the present invention provides a multiphase power converter, comprising multiple phase switching circuits, a control circuit, and multiple inductors. One of the multiple phase switching circuits serves as a first phase switching circuit. Each inductor includes a first terminal and a second terminal. Each phase switching circuit includes two boost-side switches, serving as a boost-side upper bridge switch and a boost-side lower bridge switch, respectively. The first terminal of the boost-side upper bridge switch is connected to an output node. The first terminal of the boost-side lower bridge switch is connected to the second terminal of the boost-side lower bridge switch. The second terminal of the boost-side lower bridge switch is grounded. The first phase switching circuit further includes two buck-side switches, serving as a buck-side upper bridge switch and a buck-side lower bridge switch, respectively. The first terminal of the buck-side upper bridge switch is coupled to an input voltage. The first terminal of the buck-side lower bridge switch is connected to the second terminal of the buck-side upper bridge switch. The second terminal of the buck-side lower bridge switch is grounded. The first terminal of each inductor is connected to the first terminal of the buck-side lower bridge switch. The multiple second terminals of the multiple inductors are respectively connected to the multiple first terminals of the multiple boost-side lower bridge switches of the multiple phase switching circuits. The control circuit connects to the control terminals of each boost-side switch, each buck-side switch, and the output node. The control circuit is configured to control each boost-side switch and each buck-side switch based on the output voltage of the output node.

[0009] As described above, the present invention provides a multiphase power converter. The multiphase power converter of the present invention includes multiple phase switching circuits, and a control circuit can perform phase-by-phase control on the multiple phase switching circuits, switching the multiphase power converter between boost mode, buck mode, and buck-boost mode to generate the required voltage. The multiphase power converter of the present invention can include only two phase switching circuits or easily expand to include more phase switching circuits to meet different practical application requirements. Furthermore, the number of buck-side switching circuits and boost-side switching circuits included in each of the multiple phase switching circuits of the multiphase power converter of the present invention can be adjusted depending on whether boost or buck is the primary application requirement.

[0010] To further understand the features and technical content of the present invention, please refer to the following detailed description and drawings of the present invention. However, the drawings provided are for reference and illustration only and are not intended to limit the present invention.

Implementation Method

[0011] The following describes the implementation of the present invention through specific embodiments. Those skilled in the art can understand the advantages and effects of the present invention from the content disclosed in this specification. The present invention can be implemented or applied through other different specific embodiments, and various details in this specification can also be modified and changed based on different viewpoints and applications without departing from the concept of the present invention. In addition, the accompanying drawings of the present invention are only simple illustrations and are not depictions based on actual dimensions, as stated in advance. The following embodiments will further describe the relevant technical content of the present invention in detail, but the disclosed content is not intended to limit the scope of protection of the present invention. In addition, the term "or" used herein should be interpreted as potentially including any or more combinations of the associated listed items, depending on the actual situation.

[0012] The following describes the implementation of the present invention through specific embodiments. Those skilled in the art can understand the advantages and effects of the present invention from the content disclosed in this specification. The present invention can be implemented or applied through other different specific embodiments, and various details in this specification can also be modified and changed based on different viewpoints and applications without departing from the concept of the present invention. In addition, the accompanying drawings of the present invention are only simple illustrations and are not depictions based on actual dimensions, as stated in advance. The following embodiments will further describe the relevant technical content of the present invention in detail, but the disclosed content is not intended to limit the scope of protection of the present invention. In addition, the term "or" used herein should be interpreted as potentially including any or more combinations of the associated listed items, depending on the actual situation.

[0013] Please refer to Figure 1, which is a circuit diagram of a multiphase power converter according to the first embodiment of the present invention.

[0014] The multiphase power converter of the present invention includes multiple phase switching circuits and multiple inductors. As shown in FIG1, in a first embodiment, the multiphase power converter of the present invention includes two phase switching circuits as a first phase switching circuit PHA and a second phase switching circuit PHB, two inductors as a first inductor La and a second inductor Lb, and includes a control circuit 100.

[0015] The multiphase power converter of the first embodiment of the present invention includes two buck-side switching circuits and two boost-side switching circuits.

[0016] In the first embodiment of the present invention, one of the two step-down side switching circuits includes a step-down side upper bridge switch HS1A and a step-down side lower bridge switch LS1A of the first phase switching circuit PHA, and the other includes a step-down side upper bridge switch HS1B and a step-down side lower bridge switch LS1B of the second phase switching circuit PHB.

[0017] In the first embodiment of the present invention, one of the two boost-side switching circuits includes a boost-side upper bridge switch HS2A and a boost-side lower bridge switch LS2A of the first phase switching circuit PHA, and the other includes a boost-side upper bridge switch HS2B and a boost-side lower bridge switch LS2B of the second phase switching circuit PHB.

[0018] If necessary, the multiphase power converter of the present invention may further include one or more buffers, such as, but not limited to, the multiple buffers BH1A, BL1A, BH2A, BL2A, BH1B, BL1B, BH2B, and BL2B shown in FIG1. ​​Each buffer includes an input terminal and an output terminal. The multiple input terminals of the multiple buffers are respectively connected to the multiple output terminals of the control circuit 100. The multiple output terminals of the multiple buffers are respectively connected to the multiple control terminals of the multiple switching elements (including the buck-side upper bridge switch HS1A, the buck-side lower bridge switch LS1A, the boost-side upper bridge switch HS2A, the boost-side lower bridge switch LS2A, the buck-side upper bridge switch HS1B, the buck-side lower bridge switch LS1B, the boost-side upper bridge switch HS2B, and the boost-side lower bridge switch LS2B).

[0019] The first terminal of the buck-side upper bridge switch HS1A is coupled to the input voltage VIN. The first terminal of the buck-side lower bridge switch LS1A is connected to the second terminal of the buck-side upper bridge switch HS1A and the first terminal of the first inductor La. The first terminal of the boost-side upper bridge switch HS2A is connected to an output node NT. The first terminal of the boost-side lower bridge switch LS2A is connected to the second terminal of the boost-side upper bridge switch HS2A and the second terminal of the first inductor La. The second terminals of both the buck-side lower bridge switch LS1A and the boost-side lower bridge switch LS2A are grounded.

[0020] The first terminal of the buck-side upper bridge switch HS1B is coupled to the input voltage VIN. The first terminal of the buck-side lower bridge switch LS1B is connected to the second terminal of the buck-side upper bridge switch HS1B and the second terminal of the second inductor Lb. The first terminal of the boost-side upper bridge switch HS2B is connected to an output node NT. The first terminal of the boost-side lower bridge switch LS2B is connected to the second terminal of the boost-side upper bridge switch HS2B and the first terminal of the second inductor Lb. The second terminals of both the buck-side lower bridge switch LS1B and the boost-side lower bridge switch LS2B are grounded.

[0021] If necessary, the multiphase power converter of the present invention may further include an output circuit connected between the output node NT and ground. This output circuit may include, for example but not limited to, an output capacitor Cout as shown in FIG1, with a first terminal of the output capacitor Cout connected to the output node NT and a second terminal of the output capacitor Cout grounded. In practice, this output circuit may additionally or alternatively include one or more resistors or voltage divider circuits.

[0022] The input terminal of the control circuit 100 is connected to the output node NT (or, in practice, to a voltage divider circuit). The power supply terminal of the control circuit 100 can be coupled to the input voltage VIN. The multiple output terminals of the control circuit 100 are respectively (through multiple buffers) connected to one control terminal of each of the aforementioned multiple switching elements.

[0023] The control circuit 100 can use the input voltage VIN and, based on the output voltage VOUT obtained from the output node NT, output multiple control signals to the multiple control terminals of the multiple switching elements respectively, so as to control these multiple switching elements.

[0024] Please refer to Figures 1 to 6 together. Figure 2 is a circuit diagram of the control circuit of the multiphase power converter of the first embodiment of the present invention. Figure 3 is a waveform diagram of the comparison signal and multiple phase signals of the multiphase power converter of the first embodiment of the present invention. Figures 4 to 6 are waveform diagrams of the signals of the multiphase power converter of the first embodiment of the present invention in buck mode, boost mode and buck-boost mode respectively.

[0025] For example, the control circuit 100 shown in FIG1 may be the same as the control circuit 100 shown in FIG2. As shown in FIG2, the control circuit 100 includes an error amplifier AMP, a comparator CMP, a phase splitter circuit PST, and a buck-boost control circuit CTR.

[0026] The first input terminal of the error amplifier AMP, for example, the non-inverting input terminal, is coupled to a reference voltage VREF. As shown in Figure 2, the second input terminal of the error amplifier AMP, for example, the inverting input terminal, is connected to the output node NT as shown in Figure 1 to receive the output voltage VOUT from the output node NT (or, in practice, a divided voltage of the output voltage VOUT from a voltage divider circuit). The first input terminal of the comparator CMP, for example, the non-inverting input terminal, is connected to the output terminal of the error amplifier AMP. The second input terminal of the comparator CMP, for example, the inverting input terminal, can be coupled to a ramp voltage VRAMP.

[0027] The error amplifier AMP multiplies the difference between the output voltage VOUT (or practically its voltage divider) of the output node NT and the reference voltage VREF by a gain to output an error amplification signal EAO. The comparator CMP compares the voltage of the error amplification signal EAO received from the output of the error amplifier AMP with the ramp voltage VRAMP to output a comparison signal CPO.

[0028] If necessary, the control circuit 100 may further include a first resistor Re, a first capacitor Ce, a ramp signal generating circuit RMG, or any combination thereof. The first terminal of the first resistor Re is connected to the output terminal of the error amplifier AMP. The second terminal of the first resistor Re is connected to the first terminal of the first capacitor Ce. The second terminal of the first capacitor Ce is grounded.

[0029] The input terminal of the ramp signal generating circuit RMG can be connected to the output terminal of the comparator CMP. The output terminal of the ramp signal generating circuit RMG can be connected to the second input terminal of the comparator CMP, such as the inverting input terminal. The ramp signal generating circuit RMG can modulate the voltage value of a ramp voltage VRAMP of a ramp signal based on a comparison signal CPO from the output terminal of the comparator CMP, and output this ramp signal to the second input terminal of the comparator CMP, such as the inverting input terminal.

[0030] It is worth noting that the phase-splitting circuit PST is connected to the output of the comparator CMP. The phase-splitting circuit PST divides a comparison signal CPO received from the output of the comparator CMP into two phase-splitting signals CPO1 and CPO2, wherein multiple phases of multiple waveforms of phase-splitting signal CPO1 are staggered with multiple phases of multiple waveforms of phase-splitting signal CPO2. For example, as shown in Figure 3, the phase-splitting circuit PST distributes multiple waveforms of the comparison signal CPO to the two phase-splitting signals CPO1 and CPO2 in turn, and the multiple waveforms of phase-splitting signal CPO1 are staggered with multiple waveforms of phase-splitting signal CPO2 on the time axis. In this way, the multiphase power converter can stagger the control of the first phase switching circuit PHA and the second phase switching circuit PHB.

[0031] As shown in Figure 2, the buck-boost control circuit CTR is connected to the phase-splitting circuit PST and one control terminal of each of the buck-side upper bridge switch HS1A, buck-side lower bridge switch LS1A, boost-side upper bridge switch HS2A, boost-side lower bridge switch LS2A, buck-side upper bridge switch HS1B, buck-side lower bridge switch LS1B, boost-side upper bridge switch HS2B, and boost-side lower bridge switch LS2B as shown in Figure 1.

[0032] For example, as shown in Figure 2, the buck-boost control circuit CTR includes two phase control circuits, namely the first phase control circuit RPHA and the second phase control circuit RPHB, which are respectively configured to receive phase signals CPO1 and CPO2 from the phase splitting circuit PST.

[0033] The first phase control circuit RPHA includes two switch control circuits W1A and W2A. The second phase control circuit RPHB includes two switch control circuits W1B and W2B. Switch control circuit W1A is the first phase buck-side control circuit. Switch control circuit W2A is the first phase boost-side control circuit. Switch control circuit W1B is the second phase buck-side control circuit. Switch control circuit W2B is the second phase boost-side control circuit.

[0034] Each of the multiple switch control circuits W1A, W2A, W1B, and W2B includes an on-time setting circuit TON, an on-time signal generation circuit FFP, and a drive circuit DRV. For example, the on-time signal generation circuit FFP may be an SR flip-flop or, in practice, other circuits.

[0035] A setting terminal S of the conduction time signal generation circuit FFP of each of the multiple switch control circuits W1A and W2A receives a phase-splitting signal CPO1 from the first output terminal of the connected phase-splitting circuit PST. A setting terminal S of the conduction time signal generation circuit FFP of each of the multiple switch control circuits W1B and W2B receives a phase-splitting signal CPO2 from the second output terminal of the connected phase-splitting circuit PST.

[0036] In each of the multiple switch control circuits W1A, W2A, W1B, and W2B, an output terminal Q of the conduction time signal generation circuit FFP is connected to an input terminal of the conduction time setting circuit TON and an input terminal of the drive circuit DRV, and an output terminal of the conduction time setting circuit TON is connected to a reset terminal R of the conduction time signal generation circuit FFP.

[0037] The conduction time setting circuit TON of each of the multiple switch control circuits W1A, W2A, W1B, and W2B outputs a conduction time setting signal. The conduction time signal generating circuit FFP of each of the multiple switch control circuits W1A and W2A outputs a conduction time signal based on the phase-splitting signal CPO1 and the conduction time setting signal. The conduction time signal generating circuit FFP of each of the multiple switch control circuits W1B and W2B outputs a conduction time signal based on the phase-splitting signal CPO2 and the conduction time setting signal.

[0038] The drive circuit DRV of the switch control circuit W1A outputs two control signals SH1A and SL1A to the control terminals of the upper bridge switch HS1A on the step-down side and the lower bridge switch LS1A on the step-down side, respectively, based on a conduction time signal received from an output terminal Q of the conduction time signal generation circuit FFP.

[0039] The drive circuit DRV of the switch control circuit W2A outputs two control signals SH2A and SL2A to the control terminals of the upper bridge switch HS2A on the boost side and the lower bridge switch LS2A on the boost side, respectively, based on a conduction time signal received from the output terminal Q of the conduction time signal generation circuit FFP.

[0040] The drive circuit DRV of the switch control circuit W1B outputs two control signals SH1B and SL1B to the control terminals of the upper bridge switch HS1B on the step-down side and the lower bridge switch LS1B on the step-down side, respectively, based on a conduction time signal received from the output terminal Q of the conduction time signal generation circuit FFP.

[0041] The drive circuit DRV of the switch control circuit W2B outputs two control signals SH2B and SL2B to the control terminals of the upper bridge switch HS2B and the lower bridge switch LS2B on the boost side, respectively, based on a conduction time signal received from the output terminal Q of the conduction time signal generation circuit FFP.

[0042] The control circuit of the multiphase power converter in the first embodiment of the present invention can operate in buck mode, boost mode, and buck-boost mode.

[0043] As shown in Figure 1, the second phase boost side signal S2B is shown in Figure 4, Figure 5 and Figure 6 in buck mode, boost mode and buck-boost mode respectively.

[0044] As shown in Figure 1, the first phase boost side signal S2A is shown in Figure 4, Figure 5 and Figure 6 in buck mode, boost mode and buck-boost mode respectively.

[0045] As shown in Figure 1, the second phase step-down side signal S1B in step-down mode, step-up mode, and step-down-step-up mode are shown in Figures 4, 5, and 6, respectively.

[0046] As shown in Figure 1, the first phase buck side signal S1A is shown in Figure 4, Figure 5 and Figure 6 in buck mode, boost mode and buck-boost mode respectively.

[0047] The current ILa of the first inductor La in buck mode, boost mode, and buck-boost mode are shown in Figures 4, 5, and 6, respectively. The current ILb of the second inductor Lb in buck mode, boost mode, and buck-boost mode are shown in Figures 4, 5, and 6, respectively.

[0048] It is worth noting that in the multiphase power converter of the first embodiment of the present invention, each of the multiple waveforms of currents ILa and ILb has multiple bands with different slopes, and the multiple slopes of the multiple bands of each of the multiple waveforms of currents ILa and ILb are respectively the same as the multiple slopes of the previous multiple bands. Accordingly, the currents ILa and ILb of the multiphase power converter of the present invention change stably.

[0049] Please refer to Figures 7 to 11, wherein Figure 7 is a circuit diagram of the multiphase power converter of the second embodiment of the present invention, Figure 8 is a circuit diagram of the control circuit of the multiphase power converter of the second embodiment of the present invention, Figure 9 is a waveform diagram of the signal of the multiphase power converter of the second embodiment of the present invention in buck mode, Figure 10 is a waveform diagram of the signal of the multiphase power converter of the second embodiment of the present invention in boost mode, and Figure 11 is a waveform diagram of the signal of the multiphase power converter of the second embodiment of the present invention in buck-boost mode.

[0050] The second embodiment of the present invention is the same as the first embodiment, and will not be repeated herein.

[0051] Compared to the first embodiment of FIG1, the multiphase power converter of the second embodiment of the present invention shown in FIG7 can operate in boost mode and buck-boost mode, but the main requirement is to operate in buck mode to convert the input voltage VIN from a high voltage value to a low voltage value output voltage VOUT.

[0052] As shown in FIG7, in the second embodiment, the multiphase power converter of the present invention includes two buck-side switching circuits, but only one boost-side switching circuit. One buck-side switching circuit includes a buck-side upper bridge switch HS1A and a buck-side lower bridge switch LS1A, the other buck-side switching circuit includes a buck-side upper bridge switch HS1B and a buck-side lower bridge switch LS1B, and the boost-side switching circuit includes a boost-side upper bridge switch HS2A and a boost-side lower bridge switch LS2A.

[0053] Compared to the first embodiment in FIG1, the multiphase power converter of the second embodiment of the present invention shown in FIG7 omits the additional boost-side switching circuit including the boost-side upper bridge switch HS2B and the boost-side lower bridge switch LS2B. Correspondingly, the switch control circuit W2B for controlling the boost-side upper bridge switch HS2B and the boost-side lower bridge switch LS2B as shown in FIG1 is omitted in the buck-boost control circuit CTR in FIG8.

[0054] As shown in Figure 7, the second end of the first inductor La is connected to the first end of the second inductor Lb. The second end of the second inductor Lb is connected to the first end of the step-down bridge switch LS1B.

[0055] As shown in Figure 8, the setting terminal S of the time signal generation circuit FFP of the switch control circuit W2A is connected to the output terminal of the comparator CMP (instead of the phase splitting circuit PST as shown in Figure 2). The time signal generation circuit FFP of the switch control circuit W2A outputs an on-time signal to the drive circuit DRV based on a comparison signal CPO received from the output terminal of the comparator CMP (instead of receiving the phase splitting signal CPO1 as shown in Figure 2) and an on-time setting signal received from the on-time setting circuit TON.

[0056] As shown in Figure 8, the phase-splitting circuit PST divides the comparison signal CPO output by the comparator CMP into two phase-splitting signals CPO1 and CPO2 that are staggered from each other, as shown in Figure 11.

[0057] The working period of the waveform of the conduction time signal is used as one conduction time. As shown in Figure 8, the conduction time of the conduction time signal output by the time signal generation circuit FFP of the switch control circuit W2A is only half of the conduction time of the conduction time signal output by the time signal generation circuit FFP of the switch control circuit W2A as shown in Figure 2.

[0058] As shown in Figure 7, the first phase buck signal S1A in buck mode, boost mode, and buck-boost mode are shown in Figures 9, 10, and 11, respectively. As shown in Figure 7, the second phase buck signal S1B in buck mode, boost mode, and buck-boost mode are shown in Figures 9, 10, and 11, respectively.

[0059] As shown in Figure 7, the first phase boost side signal S2A is shown in Figure 9, Figure 10 and Figure 11 in buck mode, boost mode and buck-boost mode respectively.

[0060] When the multiphase power converter of the present invention includes two buck-side switching circuits and one boost-side switching circuit, the frequency of the first phase boost-side signal S2A is twice the frequency of the first phase buck-side signal S1A and twice the frequency of the second phase buck-side signal S1B.

[0061] As shown in Figure 7, the current ILa of the first inductor La in the buck mode, boost mode, and buck-boost mode are shown in Figures 9, 10, and 11, respectively. The current ILb of the second inductor Lb in the buck mode, boost mode, and buck-boost mode are shown in Figures 9, 10, and 11, respectively.

[0062] It is worth noting that in the multiphase power converter of the second embodiment of the present invention, each of the multiple waveforms of currents ILa and ILb has multiple bands with different slopes, and the multiple slopes of the multiple bands of each of the multiple waveforms of currents ILa and ILb are the same as the multiple slopes of the multiple bands of the previous one. Accordingly, the currents ILa and ILb of the multiphase power converter of the present invention change stably.

[0063] Please refer to Figures 12 to 16, wherein Figure 12 is a circuit diagram of the multiphase power converter of the third embodiment of the present invention, Figure 13 is a circuit diagram of the control circuit of the multiphase power converter of the third embodiment of the present invention, Figure 14 is a waveform diagram of the signal of the multiphase power converter of the third embodiment of the present invention in buck mode, Figure 15 is a waveform diagram of the signal of the multiphase power converter of the third embodiment of the present invention in boost mode, and Figure 16 is a waveform diagram of the signal of the multiphase power converter of the third embodiment of the present invention in buck-boost mode.

[0064] The third embodiment of the present invention is the same as the first embodiment, and will not be repeated here.

[0065] Compared to the first embodiment of FIG1, the multiphase power converter of the third embodiment of the present invention shown in FIG12 can operate in buck mode and buck-boost mode, but the main requirement is to operate in boost mode to convert the input voltage VIN from a low voltage value to a high voltage output voltage VOUT.

[0066] As shown in Figure 12, in the third embodiment, the multiphase power converter of the present invention includes only one buck-side switching circuit and two boost-side switching circuits. One boost-side switching circuit includes a boost-side upper bridge switch HS2A and a boost-side lower bridge switch LS2A, and the other boost-side switching circuit includes a boost-side upper bridge switch HS2B and a boost-side lower bridge switch LS2B. The buck-side switching circuit includes a boost-side upper bridge switch HS2A and a boost-side lower bridge switch LS2A.

[0067] Compared to the first embodiment in FIG1, the multiphase power converter of the third embodiment of the present invention shown in FIG12 omits the additional buck-side switching circuit including the buck-side upper bridge switch HS1B and the buck-side lower bridge switch LS1B. Correspondingly, in the buck-boost control circuit CTR in FIG13, the switch control circuit W1B for controlling the buck-side upper bridge switch HS1B and the buck-side lower bridge switch LS1B as shown in FIG1 is omitted.

[0068] As shown in Figure 12, the first terminal of the second inductor Lb is connected to the first terminal of the boost-side lower bridge switch LS2B. The second terminal of the second inductor Lb is connected to the first terminal of the first inductor La.

[0069] As shown in Figure 13, the setting terminal S of the time signal generation circuit FFP of the switch control circuit W1A is connected to the output terminal of the comparator CMP (instead of the phase splitting circuit PST as shown in Figure 2). The time signal generation circuit FFP of the switch control circuit W1A outputs a conduction time signal to the drive circuit DRV based on a comparison signal CPO (instead of the phase splitting signal CPO1 as shown in Figure 2) received from the output terminal of the comparator CMP and a conduction time setting signal received from the conduction time setting circuit TON.

[0070] The working period of the waveform of the conduction time signal is used as one conduction time. As shown in Figure 13, the conduction time of the conduction time signal output by the time signal generation circuit FFP of the switch control circuit W2A is only half of the conduction time of the conduction time signal output by the time signal generation circuit FFP of the switch control circuit W2A as shown in Figure 2.

[0071] As shown in Figure 12, the first phase boost side signal S2A in buck mode, boost mode, and buck-boost mode are shown in Figures 14, 15, and 16, respectively. As shown in Figure 12, the second phase boost side signal S2B in buck mode, boost mode, and buck-boost mode are shown in Figures 14, 15, and 16, respectively.

[0072] As shown in Figure 12, the first phase step-down side signal S1A is shown in Figure 14, Figure 15 and Figure 16 in step-down mode, step-up mode and step-down-step-up mode respectively.

[0073] When the multiphase power converter of the present invention includes two boost-side switching circuits and one buck-side switching circuit as shown in FIG12, the frequency of the first phase buck-side signal S1A is twice the frequency of the first phase boost-side signal S2A and twice the frequency of the second phase boost-side signal S2B.

[0074] As shown in Figure 12, the current ILa of the first inductor La in the buck mode, boost mode, and buck-boost mode are shown in Figures 14, 15, and 16, respectively. The current ILb of the second inductor Lb in the buck mode, boost mode, and buck-boost mode are shown in Figures 14, 15, and 16, respectively.

[0075] Please refer to Figure 17, which is a circuit diagram of a multiphase power converter according to the fourth embodiment of the present invention.

[0076] As shown in Figure 1, the multiphase power converter of the first embodiment of the present invention includes only two phase switching circuits as the first phase switching circuit PHA and the second phase switching circuit PHB respectively.

[0077] In contrast, as shown in FIG17, the multiphase power converter of the fourth embodiment of the present invention includes three phase switching circuits as the first phase switching circuit PHA, the second phase switching circuit PHB, and the third phase switching circuit PHC, respectively, and includes three inductors as the first inductor La, the second inductor Lb, and the third inductor Lc, respectively. In practice, the multiphase power converter of the present invention may include more than three phase switching circuits, and correspondingly include the same number of inductors.

[0078] The fourth embodiment of the present invention is the same as the first embodiment, and will not be repeated here.

[0079] As shown in Figure 17, the third phase switching circuit PHC includes a buck-side upper bridge switch HS1C, a buck-side lower bridge switch LS1C, a boost-side upper bridge switch HS2C, and a boost-side lower bridge switch LS2C.

[0080] The first terminal of the buck-side upper bridge switch HS1C is coupled to the input voltage VIN. The first terminal of the buck-side lower bridge switch LS1C is connected to the second terminal of the buck-side upper bridge switch HS1C and the first terminal of the third inductor Lc. The first terminal of the boost-side upper bridge switch HS2C is connected to the first terminal of an output node NT or an output capacitor Cout. The first terminal of the boost-side lower bridge switch LS2C is connected to the second terminal of the boost-side upper bridge switch HS2C and the second terminal of the third inductor Lc.

[0081] The control circuit 100 can be coupled to the input voltage VIN. The control circuit 100 is connected to the first terminal of the output node NT or the output capacitor Cout. The control circuit 100 can use the input voltage VIN and, based on an output voltage VOUT at the first terminal of the output node NT or the output capacitor Cout, output multiple control signals to the control terminals of the connected buck-side upper bridge switch HS1C, buck-side lower bridge switch LS1C, boost-side upper bridge switch HS2C, and boost-side lower bridge switch LS2C, respectively.

[0082] If necessary, the multiphase power converter of the present invention may further include one or more buffers, such as, but not limited to, the multiple buffers BH1A, BL1A, BH2A, BL2A, BH1B, BL1B, BH2B, BL2B, BH1C, BL1C, BH2C, and BL2C shown in FIG. 17. Multiple input terminals of the multiple buffers BH1C, BL1C, BH2C, and BL2C are respectively connected to multiple output terminals of the control circuit 100. Multiple output terminals of the multiple buffers BH1C, BL1C, BH2C, and BL2C are respectively connected to one control terminal of each of the buck-side upper bridge switch HS1C, the buck-side lower bridge switch LS1C, the boost-side upper bridge switch HS2C, and the boost-side lower bridge switch LS2C.

[0083] Please refer to Figures 17 to 19 together, wherein Figure 18 is a circuit diagram of the control circuit of the multiphase power converter of the fourth embodiment of the present invention, and Figure 19 is a waveform diagram of the signal of the multiphase power converter of the fourth embodiment of the present invention.

[0084] For example, the control circuit 100 shown in FIG17 may be the same as the control circuit 100 shown in FIG18. The buck-boost control circuit CTR of the control circuit 100 may include multiple phase control circuits, such as, but not limited to, three phase control circuits as the first phase control circuit RPHA, the second phase control circuit RPHB, and the third phase control circuit RPHC, respectively.

[0085] As shown in Figure 18, the phase-splitting circuit PST divides a comparison signal CPO received from the comparator CMP into three phase-splitting signals CPO1, CPO2, and CPO3. For example, as shown in Figure 19, the phase-splitting circuit PST distributes multiple waveforms from the comparator CMP in turn to the first phase control circuit RPHA, the second phase control circuit RPHB, and the third phase control circuit RPHC. In this way, the multiphase power converter can stagger the control of the first phase control circuit RPHA, the second phase control circuit RPHB, and the third phase control circuit RPHC.

[0086] The third phase control circuit RPHC includes two switch control circuits W1C and W2C. Switch control circuit W1C is the buck side control circuit, and switch control circuit W2C is the boost side control circuit.

[0087] In each of the two switch control circuits W1C and W2C, the time signal generation circuit FFP outputs a conduction time signal based on the phase split signal CPO3 received from the phase split circuit PST and a conduction time setting signal received from the conduction time setting circuit TON.

[0088] As shown in Figure 18, the drive circuit DRV of the switch control circuit W1C outputs two control signals SH1C and SL1C to the control terminals of the step-down upper bridge switch HS1C and the step-down lower bridge switch LS1C, respectively, according to this conduction time signal.

[0089] As shown in Figure 18, the drive circuit DRV of the switch control circuit W2C outputs two control signals SH2C and SL2C to the control terminals of the boost-side upper bridge switch HS2C and the boost-side lower bridge switch LS2C, respectively, based on this conduction time signal.

[0090] As shown in Figure 17, the waveforms of the first phase buck side signal S1A, the first phase boost side signal S2A, the second phase buck side signal S1B, the second phase boost side signal S2B, the third phase buck side signal S1C, and the third phase boost side signal S2C can be shown in Figure 19 respectively.

[0091] As shown in Figure 17, the current ILa of the first inductor, the current ILb of the second inductor Lb, and the current ILc of the third inductor Lc can be represented as shown in Figure 19.

[0092] Please refer to Figures 20 to 22, wherein Figure 20 is a circuit diagram of the multiphase power converter of the fifth embodiment of the present invention, Figure 21 is a circuit diagram of the control circuit of the multiphase power converter of the fifth embodiment of the present invention, and Figure 22 is a waveform diagram of the signal of the multiphase power converter of the fifth embodiment of the present invention.

[0093] The similarities between the fifth embodiment of the present invention and the first and fourth embodiments will not be repeated herein. The difference between the fifth embodiment and the fourth embodiment of the present invention is that, as shown in FIG20, in the multiphase power converter of the fifth embodiment of the present invention, the second phase switching circuit PHB only includes the buck-side upper bridge switch HS1B and the buck-side lower bridge switch LS1B, but omits the boost-side upper bridge switch HS2B and the boost-side lower bridge switch LS2B as shown in FIG18, and the third phase switching circuit PHC also only includes the buck-side upper bridge switch HS1C and the buck-side lower bridge switch LS1C, but omits the boost-side upper bridge switch HS2C and the boost-side lower bridge switch LS2C as shown in FIG18.

[0094] Correspondingly, in the control circuit 100 shown in FIG21, the buck-boost control circuit CTR includes only three buck-side control circuits (i.e., switch control circuits W1A, W1B, and W1C) and one boost-side control circuit (i.e., switch control circuit W2A). Compared with the fourth embodiment in FIG18, in the fifth embodiment in FIG21, the two boost-side control circuits (i.e., switch control circuits W2B and W2C) are omitted.

[0095] As shown in Figure 21, the phase-splitting circuit PST divides the comparison signal CPO output by the comparator CMP into three staggered phase signals CPO1, CPO2, and CPO3 as shown in Figure 22.

[0096] As shown in Figure 20, the second end of the second inductor Lb and the second end of the third inductor Lc are connected to the second end of the first inductor La and the first end of the boost side lower bridge switch LS2A.

[0097] The first phase step-down side signal S1A, the first phase step-up side signal S2A, the second phase step-down side signal S1B and the third phase step-down side signal S1C shown in Figure 20 can be respectively shown in Figure 22.

[0098] As shown in Figure 20, the current ILa of the first inductor, the current ILb of the second inductor Lb, and the current ILc of the third inductor Lc are shown in Figure 22.

[0099] Please refer to Figures 23 to 25, wherein Figure 23 is a circuit diagram of the multiphase power converter of the sixth embodiment of the present invention, Figure 24 is a circuit diagram of the control circuit of the multiphase power converter of the sixth embodiment of the present invention, and Figure 25 is a waveform diagram of the signal of the multiphase power converter of the sixth embodiment of the present invention.

[0100] The similarities between the sixth embodiment of the present invention and the first and fourth embodiments will not be repeated herein. The difference between the sixth embodiment and the fourth embodiment of the present invention is that, as shown in FIG20, in the multiphase power converter of the sixth embodiment of the present invention, the second phase switching circuit PHB only includes the boost-side upper bridge switch HS2B and the boost-side lower bridge switch LS2B, but omits the buck-side upper bridge switch HS1B and the buck-side lower bridge switch LS1B as shown in FIG18, and the third phase switching circuit PHC also only includes the boost-side upper bridge switch HS2C and the boost-side lower bridge switch LS2C, but omits the buck-side upper bridge switch HS1C and the buck-side lower bridge switch LS1C as shown in FIG18.

[0101] Correspondingly, in the control circuit 100 shown in FIG24, the buck-boost control circuit CTR includes only one buck-side control circuit (i.e., switch control circuit W1A) and three boost-side control circuits (i.e., switch control circuits W2A, W2B, and W2C). Compared with the fourth embodiment in FIG18, in the sixth embodiment in FIG24, the two buck-side control circuits (i.e., switch control circuits W1B and W1C) are omitted.

[0102] As shown in Figure 24, the phase-splitting circuit PST divides the comparison signal CPO output by the comparator CMP into three staggered phase signals CPO1, CPO2, and CPO3 as shown in Figure 25.

[0103] As shown in Figure 23, the first end of the second inductor Lb and the second end of the third inductor Lc are connected to the first end of the first inductor La and the first end of the step-down bridge switch LS1A.

[0104] The first phase step-down side signal S1A, the first phase step-up side signal S2A, the second phase step-up side signal S2B and the third phase step-up side signal S2C shown in Figure 23 can be respectively shown in Figure 25.

[0105] As shown in Figure 23, the current ILa of the first inductor, the current ILb of the second inductor Lb, and the current ILc of the third inductor Lc are shown in Figure 25.

[0106] Each of the multiple waveforms of the currents ILa, ILb, and ILc has multiple bands with different slopes, and the multiple slopes of the multiple bands of each of the multiple waveforms of the currents ILa, ILb, and ILc are respectively the same as the multiple slopes of the previous waveform. Accordingly, the currents ILa, ILb, and ILc of the multiphase power converter of the present invention are stable.

[0107] In summary, the present invention provides a multiphase power converter. The multiphase power converter of the present invention includes multiple phase switching circuits, and the control circuit can perform phase-by-phase control on the multiple phase switching circuits, switching the multiphase power converter between boost mode, buck mode, and buck-boost mode to generate the required voltage. The multiphase power converter of the present invention can include only two phase switching circuits or can easily expand to include more phase switching circuits to meet different practical application requirements. Furthermore, the number of buck-side switching circuits and boost-side switching circuits included in each of the multiple phase switching circuits of the multiphase power converter of the present invention can be adjusted depending on whether boost or buck is the primary application requirement.

[0108] The content disclosed above is only a preferred and feasible embodiment of the present invention, and is not intended to limit the scope of the patent application of the present invention. Therefore, all equivalent technical changes made using the contents of the present invention specification and drawings are included in the scope of the patent application of the present invention.

[0109] The content disclosed above is only a preferred and feasible embodiment of the present invention, and is not intended to limit the scope of the patent application of the present invention. Therefore, all equivalent technical changes made using the contents of the present invention specification and drawings are included in the scope of the patent application of the present invention. [Simplified Explanation of the Diagram]

[0110] Figure 1 is a circuit diagram of a multiphase power converter according to the first embodiment of the present invention.

[0111] Figure 2 is a circuit diagram of the control circuit of the multiphase power converter according to the first embodiment of the present invention.

[0112] Figure 3 is a waveform diagram of the comparison signal and multiple phase signals of the multiphase power converter of the first embodiment of the present invention.

[0113] Figure 4 is a waveform diagram of the signal of the multiphase power converter in buck mode according to the first embodiment of the present invention.

[0114] Figure 5 is a waveform diagram of the signal of the multiphase power converter in boost mode according to the first embodiment of the present invention.

[0115] Figure 6 is a waveform diagram of the signal of the multiphase power converter in buck-boost mode according to the first embodiment of the present invention.

[0116] Figure 7 is a circuit diagram of a multiphase power converter according to a second embodiment of the present invention.

[0117] Figure 8 is a circuit diagram of the control circuit of the multiphase power converter according to the second embodiment of the present invention.

[0118] Figure 9 is a waveform diagram of the signal of the multiphase power converter in buck mode according to the second embodiment of the present invention.

[0119] Figure 10 is a waveform diagram of the signal of the multiphase power converter in boost mode according to the second embodiment of the present invention.

[0120] Figure 11 is a waveform diagram of the signal of the multiphase power converter in buck-boost mode according to the second embodiment of the present invention.

[0121] Figure 12 is a circuit diagram of a multiphase power converter according to the third embodiment of the present invention.

[0122] Figure 13 is a circuit diagram of the control circuit of the multiphase power converter according to the third embodiment of the present invention.

[0123] Figure 14 is a waveform diagram of the signal of the multiphase power converter in buck mode according to the third embodiment of the present invention.

[0124] Figure 15 is a waveform diagram of the signal of the multiphase power converter in boost mode according to the third embodiment of the present invention.

[0125] Figure 16 is a waveform diagram of the signal of the multiphase power converter in buck-boost mode according to the third embodiment of the present invention.

[0126] Figure 17 is a circuit diagram of a multiphase power converter according to the fourth embodiment of the present invention.

[0127] Figure 18 is a circuit diagram of the control circuit of the multiphase power converter according to the fourth embodiment of the present invention.

[0128] Figure 19 is a waveform diagram of the signal of the multiphase power converter according to the fourth embodiment of the present invention.

[0129] Figure 20 is a circuit diagram of a multiphase power converter according to the fifth embodiment of the present invention.

[0130] Figure 21 is a circuit diagram of the control circuit of the multiphase power converter according to the fifth embodiment of the present invention.

[0131] Figure 22 is a waveform diagram of the signal of the multiphase power converter according to the fifth embodiment of the present invention.

[0132] Figure 23 is a circuit diagram of a multiphase power converter according to the sixth embodiment of the present invention.

[0133] Figure 24 is a circuit diagram of the control circuit of the multiphase power converter according to the sixth embodiment of the present invention.

[0134] Figure 25 is a waveform diagram of the signal of the multiphase power converter according to the sixth embodiment of the present invention.

Claims

1. A multiphase power converter, comprising: a plurality of phase switching circuits; a control circuit; and a plurality of inductors, each inductor having a first terminal and a second terminal; wherein each phase switching circuit comprises two buck-side switches respectively serving as: a buck-side upper bridge switch, the first terminal of the buck-side upper bridge switch being coupled to an input voltage; and a buck-side lower bridge switch, the first terminal of the buck-side lower bridge switch being connected to the second terminal of the buck-side upper bridge switch, the second terminal of the buck-side lower bridge switch being grounded; wherein the plurality of first terminals of the plurality of buck-side lower bridge switches of the plurality of phase switching circuits are respectively connected to the plurality of first terminals of the plurality of inductors; wherein each phase switching circuit further comprises two boost-side switches respectively serving as: a boost-side upper bridge switch, the first terminal of the boost-side upper bridge switch being connected to an output node; and a boost-side lower bridge switch, the first terminal of the boost-side lower bridge switch being connected to the second terminal of the boost-side upper bridge switch, the second terminal of the boost-side lower bridge switch being grounded; The first terminals of the multiple boost-side lower bridge switches of the multiple phase switching circuits are respectively connected to the multiple second terminals of the multiple inductors; wherein the control circuit is connected to the control terminals of each buck-side switch, the control terminals of each boost-side switch and the output node, and is configured to control each buck-side switch and each boost-side switch according to an output voltage of the output node.

2. The multiphase power converter as claimed in claim 1 further includes: an output circuit connected between the output node and ground.

3. The multiphase power converter as claimed in claim 1, wherein the control circuit comprises: an error amplifier, a first input of the error amplifier being coupled to a reference voltage, and a second input of the error amplifier being connected to the output node; and a comparator, a first input of the comparator being connected to the output of the error amplifier, and a second input of the comparator being coupled to a ramp voltage. A phase-splitting circuit is connected to the output of the comparator and configured to split a comparison signal received from the output of the comparator into multiple phase-splitting signals, the multiple phase-splitting signals respectively corresponding to multiple phase-switching circuits; A step-up / step-down control circuit is provided, which is connected to the phase-splitting circuit, the control terminal of each step-down switch, and the control terminal of each step-up switch, and is configured to control the corresponding phase switch circuit according to each phase-splitting signal.

4. The multiphase power converter as claimed in claim 3, wherein the buck-boost control circuit includes a plurality of phase control circuits, each configured to receive a plurality of the phase-splitting signals; wherein each phase control circuit includes two switch control circuits, each switch control circuit including: a conduction time setting circuit configured to output a conduction time setting signal; a conduction time signal generating circuit connected to the phase-splitting circuit and the conduction time setting circuit, configured to output a conduction time signal based on the phase-splitting signal and the conduction time setting signal; and a drive circuit connected to the conduction time signal generating circuit, a control terminal of one buck-side switch and a control terminal of one boost-side switch, configured to control the buck-side switch and the boost-side switch based on the conduction time signal.

5. A multiphase power converter, comprising: two phase switching circuits, respectively serving as a first phase switching circuit and a second phase switching circuit; and a control circuit; wherein each of the phase switching circuits comprises two buck-side switches, respectively serving as: a buck-side upper bridge switch, the first terminal of which is coupled to an input voltage; and a buck-side lower bridge switch, the first terminal of which is connected to the second terminal of the buck-side upper bridge switch, the second terminal of which is grounded; wherein the first phase switching circuit further comprises two boost-side switches, respectively serving as: a boost-side upper bridge switch, the first terminal of which is connected to an output node; and a boost-side lower bridge switch, the first terminal of which is connected to the second terminal of the boost-side lower bridge switch, the second terminal of which is grounded; wherein the first terminal of the buck-side lower bridge switch of the first phase switching circuit is connected to the first terminal of a first inductor, and the first terminal of the boost-side lower bridge switch is connected to the second terminal of the first inductor; The second end of the first inductor is further connected to the first end of a second inductor, and the second end of the second inductor is connected to the first end of the step-down bridge switch of the second phase switching circuit; wherein the control circuit is connected to the control terminals of each step-down switch, the control terminals of each boost switch, and the output node, and is configured to control each step-down switch and each boost switch according to an output voltage of the output node.

6. The multiphase power converter as claimed in claim 5 further includes: an output circuit connected between the output node and ground.

7. The multiphase power converter of claim 5, wherein the control circuitry comprises: an error amplifier having a first input coupled to a reference voltage and a second input connected to the output node; a comparator having a first input connected to the output of the error amplifier and a second input coupled to a ramp voltage; a phase-splitting circuit connected to the output of the comparator and configured to split a comparison signal received from the output of the comparator into a first phase-splitting signal and a second phase-splitting signal; and a buck-boost control circuit connected to the phase-splitting circuit, the control terminals of each of the buck-side switches, the control terminals of each of the boost-side switches, the phase-splitting circuit, and the output of the comparator, configured to: control each of the buck-side switches of the first phase switching circuit according to the first phase-splitting signal; control each of the boost-side switches according to the comparison signal; and control each of the buck-side switches of the second phase switching circuit according to the second phase-splitting signal.

8. The multiphase power converter as claimed in claim 7, wherein the buck-boost control circuit comprises two phase control circuits, each phase control circuit comprising a plurality of switch control circuits serving as a first phase buck-side control circuit, a first phase boost-side control circuit, and a second phase buck-side control circuit; wherein the first phase buck-side control circuit is connected to the control terminals of the phase-splitting circuit and each buck-side switch of the first phase switch circuit, configured to control each buck-side switch of the first phase switch circuit according to the first phase-splitting signal; wherein the first phase boost-side control circuit is connected to the output terminal of the comparator and the control terminals of each boost-side switch, configured to control each boost-side switch according to the comparator signal; wherein the second phase buck-side control circuit is connected to the control terminals of the phase-splitting circuit and each buck-side switch of the second phase switch circuit, configured to control each buck-side switch of the second phase switch circuit according to the second phase-splitting signal.

9. The multiphase power converter as claimed in claim 8, wherein each of the switch control circuits includes an on-time signal generation circuit and a drive circuit interconnected; wherein the multiple on-time signal generation circuits of the plurality of switch control circuits are configured to output corresponding multiple on-time signals based on the first phase signal, the comparison signal, and the second phase signal; wherein the drive circuit of the first phase buck-side control circuit is configured to control each of the buck-side switches of the first phase switch circuit based on the on-time signal corresponding to the first phase signal; wherein the drive circuit of the first phase boost-side control circuit is configured to control each of the boost-side switches based on the on-time signal corresponding to the comparison signal; wherein the drive circuit of the second phase buck-side control circuit is configured to control each of the buck-side switches of the second phase switch circuit based on the on-time signal corresponding to the second phase signal.

10. The multiphase power converter of claim 9, wherein each of the switch control circuits further includes an on-time setting circuit connected to the on-time signal generation circuit and configured to output an on-time setting signal; wherein the on-time signal generation circuit is configured to output the on-time signal according to the on-time setting signal.

11. A multiphase power converter, comprising: two phase switching circuits, respectively serving as a first phase switching circuit and a second phase switching circuit; and a control circuit; wherein each of the phase switching circuits has two boost-side switches serving as: a boost-side upper bridge switch, the first terminal of which is connected to an output node; and a boost-side lower bridge switch, the first terminal of which is connected to a second terminal of which is grounded; wherein the first phase switching circuit further comprises two buck-side switches serving as: a buck-side upper bridge switch, the first terminal of which is coupled to an input voltage; and a buck-side lower bridge switch, the first terminal of which is connected to a second terminal of which is grounded; wherein the first terminal of the buck-side lower bridge switch is connected to a first terminal of a first inductor, and the first terminal of the boost-side lower bridge switch of the first phase switching circuit is connected to a second terminal of the first inductor; The first terminal of the boost-side lower bridge switch of the second phase switching circuit is connected to the first terminal of a second inductor, and the second terminal of the second inductor is connected to the first terminal of the first inductor; wherein the control circuit is connected to the control terminals of each boost-side switch, the control terminals of each buck-side switch, and the output node, and is configured to control each boost-side switch and each buck-side switch according to an output voltage of the output node.

12. The multiphase power converter of claim 11, wherein the control circuitry comprises: an error amplifier having a first input coupled to a reference voltage and a second input connected to the output node; a comparator having a first input connected to the output of the error amplifier and a second input coupled to a ramp voltage; a phase-splitting circuit connected to the output of the comparator and configured to split a comparison signal received from the output of the comparator into a first phase-splitting signal and a second phase-splitting signal; and a buck-boost control circuit connected to the control terminals of each of the buck-side switches, the control terminals of each of the boost-side switches, the output of the comparator, and the phase-splitting circuit, configured to: control each of the buck-side switches of the first phase switching circuit according to the comparison signal; control each of the boost-side switches of the first phase switching circuit according to the first phase-splitting signal; and control each of the boost-side switches of the second phase switching circuit according to the second phase-splitting signal.

13. The multiphase power converter of claim 12, wherein the buck-boost control circuit comprises two phase control circuits, each phase control circuit comprising a plurality of switch control circuits serving as a first-phase buck-side control circuit, a first-phase boost-side control circuit, and a second-phase boost-side control circuit; wherein the first-phase buck-side control circuit is connected to the output terminal of the comparator and the control terminal of each buck-side switch of the first-phase switch circuit, configured to control each buck-side switch according to the comparison signal; wherein the first-phase boost-side control circuit is connected to the phase-splitting circuit and the control terminal of each boost-side switch of the first-phase switch circuit, configured to control each boost-side switch of the first-phase switch circuit according to the first phase-splitting signal; wherein the second-phase boost-side control circuit is connected to the phase-splitting circuit and the control terminal of each boost-side switch of the second-phase switch circuit, configured to control each boost-side switch of the second-phase switch circuit according to the second phase-splitting signal.

14. The multiphase power converter of claim 13, wherein each of the switch control circuits includes an on-time signal generation circuit and a drive circuit interconnected; wherein the multiple on-time signal generation circuits of the plurality of switch control circuits are configured to output corresponding multiple on-time signals based on the comparison signal, the first phase-splitting signal, and the second phase-splitting signal; wherein the drive circuit of the first phase buck-side control circuit is configured to control each of the buck-side switches based on the on-time signal corresponding to the comparison signal; wherein the drive circuit of the second phase boost-side control circuit is configured to control each of the boost-side switches of the first phase switch circuit based on the on-time signal corresponding to the first phase-splitting signal; wherein the drive circuit of the second phase boost-side control circuit is configured to control each of the boost-side switches of the second phase switch circuit based on the on-time signal corresponding to the second phase-splitting signal.

15. The multiphase power converter of claim 14, wherein each of the switch control circuits further includes an on-time setting circuit connected to the on-time signal generation circuit and configured to output an on-time setting signal; wherein the on-time signal generation circuit is configured to output the on-time signal according to the on-time setting signal.

16. A multiphase power converter, comprising: a plurality of phase switching circuits, one of which serves as a first phase switching circuit; a control circuit; and a plurality of inductors, each inductor including a first terminal and a second terminal; wherein each phase switching circuit includes two buck-side switches serving as: a buck-side upper bridge switch, the first terminal of which is coupled to an input voltage; and a buck-side lower bridge switch, the first terminal of which is connected to the second terminal of which is grounded; wherein the first phase switching circuit further includes two boost-side switches serving as: a boost-side upper bridge switch, the first terminal of which is connected to an output node; and a boost-side lower bridge switch, the first terminal of which is connected to the second terminal of which is grounded. The plurality of first terminals of the plurality of inductors are respectively connected to the plurality of first terminals of the plurality of buck-side lower bridge switches of the plurality of phase switching circuits, and the second terminal of each of the inductors is connected to the first terminal of the boost-side lower bridge switch; wherein the control circuit is connected to the control terminal of each buck-side switch, the control terminal of each boost-side switch and the output node, and is configured to control each buck-side switch and each boost-side switch according to an output voltage of the output node.

17. The multiphase power converter of claim 16, wherein the control circuitry comprises: an error amplifier having a first input coupled to a reference voltage and a second input connected to the output node; and a comparator having a first input connected to the output of the error amplifier and a second input coupled to a ramp voltage. A phase-splitting circuit, connected to the output of the comparator, configured to split a comparison signal received from the output of the comparator into multiple phase-splitting signals; multiple buck-side control circuits, connected to the phase-splitting circuit and connected to the control terminals of each of the buck-side switches, configured to control the multiple buck-side switches respectively according to the multiple phase-splitting signals; And a boost-side control circuit, connected to the output of the comparator and the control terminal of each of the boost-side switches, configured to control each of the boost-side switches according to the comparison signal.

18. The multiphase power converter as claimed in claim 16 further includes: an output circuit connected between the output node and ground.

19. A multiphase power converter, comprising: a plurality of phase switching circuits, one of which serves as a first phase switching circuit; a control circuit; and a plurality of inductors, each inductor including a first terminal and a second terminal; wherein each phase switching circuit includes two boost-side switches serving as: a boost-side upper bridge switch, the first terminal of which is connected to an output node; and a boost-side lower bridge switch, the first terminal of which is connected to a second terminal of which is grounded; wherein the first phase switching circuit further includes two buck-side switches serving as: a buck-side upper bridge switch, the first terminal of which is coupled to an input voltage; and a buck-side lower bridge switch, the first terminal of which is connected to a second terminal of which is grounded. The first terminal of each inductor is connected to the first terminal of the buck-side lower bridge switch, and the multiple second terminals of the multiple inductors are respectively connected to the multiple first terminals of the multiple boost-side lower bridge switches of the multiple phase switch circuits; wherein the control circuit is connected to the control terminal of each boost-side switch, the control terminal of each buck-side switch, and the output node, and is configured to control each boost-side switch and each buck-side switch according to an output voltage of the output node.

20. The multiphase power converter of claim 19, wherein the control circuitry comprises: an error amplifier having a first input coupled to a reference voltage and a second input connected to the output node; and a comparator having a first input connected to the output of the error amplifier and a second input coupled to a ramp voltage. A phase-splitting circuit, connected to the output of the comparator, configured to split a comparison signal received from the output of the comparator into multiple phase-splitting signals; a buck-side control circuit, connected to the output of the comparator and the control terminal of each buck-side switch, configured to control each buck-side switch according to the comparison signal. And multiple boost-side control circuits, connected to the phase-splitting circuit and the control terminals of each of the boost-side switches, configured to control the multiple boost-side switches respectively according to the phase-splitting signal.

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