A switching power supply and computing device

Abstract

The embodiment of the application discloses a switching power supply and a computing device, the switching power supply comprises a multi-phase power factor correction (PFC) circuit, the multi-phase PFC circuit comprises a control circuit and parallel multi-phase PFC branches, wherein each phase PFC branch comprises an inductor and a switching device, the switching device is used for charging and discharging the inductor; the control end of the switching device in each phase PFC branch is electrically connected with the corresponding control end of the control circuit respectively; the control circuit is used for: obtaining the inductor current of each phase PFC branch in the PFC circuit; based on the inductor current of each phase PFC branch, adjusting the maintaining time length of the conduction control signal in the pulse width modulation signal of the switching device of each phase PFC branch, wherein the conduction control signal is used for controlling the switching device to be in the conduction state. The embodiment of the application can ensure that the inductor currents of the phase branches are current-sharing, and can avoid problems such as overcurrent failure or overtemperature failure.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of power supply, in particular to a switching power supply and a computing device. BACKGROUND

[0002] With the progress of power electronics technology, the power consumption of information technology (IT) devices such as servers is getting larger and larger, and the power demand of the power supply for powering the IT devices is also getting larger and larger. The traditional single-phase boost power factor correction (PFC) circuit is not suitable for the rectifier circuit of the front end of a large-power power supply. In a high-power application scenario, a multi-path parallel PFC circuit (such as a multi-path parallel boost PFC circuit) can be generally used. The interleaved multi-path parallel PFC circuit has the advantages of small output current ripple and small branch power level, and is widely used in medium and large power supplies.

[0003] Among them, the multi-path parallel PFC circuit generally needs to ensure that the total input current is in phase with the rectified voltage, and also needs to meet the current sharing requirement of each branch inductance. At the same time, how to ensure the current sharing of each branch inductance in the multi-path parallel PFC circuit is a problem that technicians are concerned about. SUMMARY

[0004] Embodiments of the present application disclose a switching power supply and a computing device, which can ensure the current sharing of each phase branch, thereby avoiding problems such as overcurrent failure or overtemperature failure.

[0005] The first aspect discloses a multi-phase power factor correction (PFC) circuit, the multi-phase PFC circuit comprising a multi-phase PFC branch and a control circuit, wherein the multi-phase PFC branch is in parallel; each phase PFC branch comprises an inductance and a switching device; wherein the switching device is used for charging and discharging the inductance; the control end of the switching device in each phase PFC branch is electrically connected to the corresponding control end of the control circuit; the control end is used for outputting a pulse width modulation signal, and the pulse width modulation signal is used for controlling the working state of the switching device in each phase PFC branch; the control circuit is used for: acquiring the inductance current of each phase PFC branch in the PFC circuit; based on the inductance current of each phase PFC branch, adjusting the maintenance time length of a conduction control signal in the pulse width modulation signal of the switching device of each phase PFC branch, wherein the conduction control signal is used for controlling the switching device to be in a conduction state.

[0006] In the embodiments of the present application, the inductor currents of the PFC branches of each phase can be obtained, and then the conduction time of the switching devices of each phase branch can be adjusted based on the inductor currents of the PFC branches of each phase. By adjusting the conduction time of the switching devices of each phase branch, the charging and discharging time of the inductor in each phase branch can be changed, so that the peak values of the inductor currents of each phase branch can be made the same, achieving the effect of current sharing among the branches. In this way, problems such as overcurrent failure or overtemperature failure can be avoided, and the reliability of the multi-phase PFC circuit can be improved. In addition, the current sharing control scheme of the present application is simple, the cost of the hardware circuit is low, but the practicability is high.

[0007] As a possible implementation, the control circuit is configured to: based on the inductor currents of the PFC branches of each phase, adjust the maintenance time of the conduction control signal in the pulse width modulation signal of the switching device of each PFC branch, including: the control circuit is configured to: based on the inductor currents of the PFC branches of each phase, determine the inductance ratio between the PFC branches of each phase; based on the inductance ratio between the PFC branches of each phase, adjust the maintenance time of the conduction control signal in the pulse width modulation signal of the switching device of each PFC branch.

[0008] In the embodiments of the present application, the inductance ratio between the PFC branches of each phase can be determined based on the inductor currents of the PFC branches of each phase, and then the conduction time of the switching devices of each phase branch can be adjusted based on the inductance ratio between the PFC branches of each phase. In this way, the inductance of each PFC branch can be adjusted in a targeted manner based on the inductance of each PFC branch, so that the problem of uneven current caused by different inductances of the PFC branches of each phase can be avoided, achieving the effect of current sharing among the branches.

[0009] As a possible implementation, the control circuit is configured to: based on the inductance ratio between the PFC branches of each phase, adjust the maintenance time of the conduction control signal in the pulse width modulation signal of the switching device of each PFC branch, including: the control circuit is configured to: based on the inductor currents of the PFC branches of each phase, determine the ratio of the maintenance time of the conduction control signal in the pulse width modulation signal of the switching device of each PFC branch; wherein the ratio of the maintenance time of the conduction control signal in the pulse width modulation signal of the switching device of each PFC branch is equal to the inductance ratio; based on the ratio of the maintenance time of the conduction control signal in the pulse width modulation signal of the switching device of each PFC branch, adjust the maintenance time of the conduction control signal in the pulse width modulation signal of the switching device of each PFC branch.

[0010] In the embodiments of the present application, the ratio of the maintaining time of the on control signal in the pulse width modulation signal of the switching device of each phase PFC branch can be adjusted based on the ratio of the inductance of each phase PFC branch, and then the maintaining time of the on control signal in the pulse width modulation signal of the switching device of each phase PFC branch can be adjusted based on the ratio of the maintaining time of the on control signal. In this way, the ratio of the maintaining time of the on control signal in the pulse width modulation signal of the switching device of each phase PFC branch can be equal to the corresponding ratio of the inductance, so that the peak values of the inductance currents of each phase PFC branch can be the same, achieving the effect of current sharing.

[0011] As a possible implementation, the control circuit is configured to adjust the maintaining time of the on control signal in the pulse width modulation signal of the switching device of each phase PFC branch based on the ratio of the maintaining time of the on control signal in the pulse width modulation signal of the switching device of each phase PFC branch, including that the control circuit is configured to take the maintaining time of the on control signal of the first switch of one phase PFC branch as a reference, and adjust the maintaining time of the on control signal in the pulse width modulation signal of the switching device in other phase PFC branches.

[0012] In the embodiments of the present application, the maintaining time of the on control signal of the first switch of one phase PFC branch can be taken as a reference, so that the maintaining time of the on control signal in the pulse width modulation signal of the switching device in other phase PFC branches can be adjusted conveniently, and the peak values of the inductance currents of other phase PFC branches can be the same as the peak value of the selected PFC branch taken as a reference.

[0013] As a possible implementation, the control circuit is configured to take the maintaining time of the on control signal of the first switch of one phase PFC branch as a reference, and adjust the maintaining time of the on control signal in the pulse width modulation signal of the switching device in other phase PFC branches, including that the maintaining time of the on control signal of the first switch of one phase PFC branch is taken as a reference, and the maintaining time of the on control signal in the pulse width modulation signal of the switching device in other phase PFC branches is increased or decreased.

[0014] In the embodiments of the present application, the maintaining time of the on control signal of the first switch of one phase PFC branch can be taken as a reference, and then the maintaining time of the on control signal in the pulse width modulation signal of the switching device in other phase PFC branches is increased or decreased, so that the charging time of the inductance in other phase PFC branches can be increased or shortened, and thus the peak values of the inductance currents of other phase PFC branches can be the same as the peak value of the selected PFC branch taken as a reference, achieving the effect of current sharing among the phase branches.

[0015] As a possible implementation, the multi-phase PFC branch includes a first phase PFC branch and a second phase PFC branch.

[0016] As a possible implementation, the first phase PFC branch includes a first inductor, a first diode and a first switch tube; a first end of the first inductor is electrically connected to a positive pole of an alternating current power supply; a second end of the first inductor is electrically connected to a first end of the first switch tube and a first end of the first diode; a second end of the first diode is electrically connected to a first end of the first capacitor, and a second end of the first switch tube and a second end of the first capacitor are electrically connected to a negative pole of the alternating current power supply; wherein a third end of the first switch tube is a control end; the second phase PFC branch includes a second inductor, a second diode and a second switch tube; a first end of the second inductor is electrically connected to the positive pole of the alternating current power supply; a second end of the second inductor is electrically connected to a first end of the second switch tube and a first end of the second diode; a second end of the second diode is electrically connected to the first end of the first capacitor, and a second end of the second switch tube and the second end of the first capacitor are electrically connected to the negative pole of the alternating current power supply; wherein a third end of the second switch tube is a control end.

[0017] As a possible implementation, the first phase PFC branch includes a first inductor, a first switch tube and a second switch tube; a first end of the first inductor is electrically connected to a positive pole of an alternating current power supply; a second end of the first inductor is electrically connected to a first end of the first switch tube and a second end of the second switch tube; a first end of the second switch tube is electrically connected to a first end of the first capacitor; a second end of the first switch tube and a second end of the first capacitor are electrically connected to a negative pole of the alternating current power supply; wherein a third end of the first switch tube and a third end of the second switch tube are control ends; the second phase PFC branch includes a second inductor, a third switch tube and a fourth switch tube; a first end of the second inductor is electrically connected to the positive pole of the alternating current power supply; a second end of the second inductor is electrically connected to a first end of the third switch tube and a second end of the fourth switch tube; a first end of the fourth switch tube is electrically connected to the first end of the first capacitor; a second end of the third switch tube and a second end of the first capacitor are electrically connected to the negative pole of the alternating current power supply; wherein a third end of the third switch tube and a third end of the fourth switch tube are control ends.

[0018] As a possible implementation, the inductor in each phase PFC branch is a ferrite inductor.

[0019] In the embodiments of the present application, since the ferrite inductor is less affected by temperature and working state changes, the inductance can remain constant, therefore, using the ferrite inductor can ensure that the inductance relationship between the branches does not change, so that the conduction time of the switching devices in each branch can be more accurately adjusted, and better current sharing effect can be achieved.

[0020] The second aspect discloses a current sharing control method, which can be applied to a multi-phase power factor correction (PFC) circuit, the multi-phase PFC circuit comprising a plurality of PFC branches and a control circuit, wherein the plurality of PFC branches are connected in parallel; each PFC branch comprises an inductor and a switching device; wherein the switching device is used for charging and discharging the inductor; the method comprises: obtaining inductor currents of the PFC branches; and adjusting durations of on control signals in pulse width modulation (PWM) signals of the switching devices of the PFC branches based on the inductor currents of the PFC branches, wherein the on control signals are used for controlling the switching devices to be in an on state.

[0021] As a possible implementation, the adjusting of the durations of the on control signals in the PWM signals of the switching devices of the PFC branches based on the inductor currents of the PFC branches comprises: determining inductance ratios between the PFC branches based on the inductor currents of the PFC branches; and adjusting the durations of the on control signals in the PWM signals of the switching devices of the PFC branches based on the inductance ratios between the PFC branches.

[0022] As a possible implementation, the adjusting of the durations of the on control signals in the PWM signals of the switching devices of the PFC branches based on the inductance ratios between the PFC branches comprises: determining ratios of the durations of the on control signals in the PWM signals of the switching devices of the PFC branches based on the inductor currents of the PFC branches; wherein the ratios of the durations of the on control signals in the PWM signals of the switching devices of the PFC branches are equal to the inductance ratios; and adjusting the durations of the on control signals in the PWM signals of the switching devices of the PFC branches based on the ratios of the durations of the on control signals in the PWM signals of the switching devices of the PFC branches.

[0023] As a possible implementation, the adjusting of the durations of the on control signals in the PWM signals of the switching devices of the PFC branches based on the ratios of the durations of the on control signals in the PWM signals of the switching devices of the PFC branches comprises: taking a duration of an on control signal of a first switching device of one PFC branch as a reference, and adjusting durations of on control signals in PWM signals of switching devices in other PFC branches.

[0024] As a possible implementation, the maintaining time length of the on control signal of the first switch of one phase PFC branch is taken as a reference to adjust the maintaining time length of the on control signal in the pulse width modulation signal of the switching device in the other phase PFC branch, including: taking the maintaining time length of the on control signal of the first switch of one phase PFC branch as a reference, increasing or decreasing the maintaining time length of the on control signal in the pulse width modulation signal of the switching device in the other phase PFC branch.

[0025] The third aspect discloses a switching power supply, which can be a power supply unit (PSU) of a server, and the switching power supply comprises the multi-phase PFC circuit provided by any possible implementation of the first aspect.

[0026] The fourth aspect discloses a computing device, which comprises a load and the switching power supply provided by the third aspect, and the switching power supply is electrically connected with the load; wherein the switching power supply is used to supply power for the load.

[0027] It should be understood that the implementation and beneficial effects of the above aspects or any possible implementation of the present application can be mutually referred to. BRIEF DESCRIPTION OF DRAWINGS

[0028] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed in the embodiment description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0029] Figure 1 is a circuit structure schematic diagram of a current sharing control method disclosed by the embodiments of the present application;

[0030] Figure 2 is a structure schematic diagram of a server internal circuit disclosed by the embodiments of the present application;

[0031] Figure 3 is a structure schematic diagram of a switching power supply disclosed by the embodiments of the present application;

[0032] Figure 4 is a flowchart of a current sharing control method of a multi-path parallel type PFC circuit disclosed by the embodiments of the present application;

[0033] Figure 5 is an effect schematic diagram of current sharing control disclosed by the embodiments of the present application;

[0034] Figure 6 is another effect schematic diagram of current sharing control disclosed by the embodiments of the present application;

[0035] Figure 7is a structural schematic diagram of another switching power supply circuit disclosed by an embodiment of the present application;

[0036] Figure 8 is a structural schematic diagram of another switching power supply circuit disclosed by an embodiment of the present application;

[0037] Figure 9 is a structural schematic diagram of another switching power supply circuit disclosed by an embodiment of the present application;

[0038] Figure 10 is a structural schematic diagram of a computing device disclosed by an embodiment of the present application. DETAILED DESCRIPTION

[0039] The embodiments of the present application disclose a multi-phase power factor correction (PFC) circuit, a switching power supply and a computing device, which can guarantee the current sharing of inductors of each phase branch, thereby avoiding overcurrent failure or overtemperature failure and the like. The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application.

[0040] In order to better understand the embodiments of the present application, the related technologies of the embodiments of the present application will be described first.

[0041] With the progress of power electronics technology, the power consumption of information technology (IT) devices (such as servers) is getting larger and larger, and the power demand of the power supply for supplying power to the IT devices is also getting larger and larger, and the traditional single-phase boost power factor correction (PFC) circuit is not suitable for the rectifier circuit in the front end of a large-power power supply. In a high-power application scenario, a multi-path parallel PFC circuit (such as a multi-path parallel boost PFC circuit) can usually be used. The interleaved multi-path parallel PFC circuit has the advantages of small output current ripple and small branch power level, and is widely used in medium and large power supplies.

[0042] Among them, the multi-path parallel PFC circuit generally needs to ensure that the total input current is in the same phase as the rectified voltage, and also needs to meet the requirement of current sharing of inductors of each branch, that is, the peak values of the inductor currents of each branch need to be the same, that is, the average values of the inductor currents between the branches need to be the same. However, in actual situations, due to the discreteness of components between the power branches, the inductor currents of each branch are usually not shared. At this time, if no current sharing measure is added, the average values of the inductor currents between the branches will not be equal, thereby leading to unbalanced distribution of total power among the branches, which not only increases the power margin left by each branch, but also may cause overcurrent failure or overtemperature failure, greatly reducing the reliability of the system.

[0043] The embodiments of the present application will be described below in combination withFigure 1 This paper introduces a current sharing control scheme for multi-channel parallel PFC circuit. Figure 1 As shown in FIG, the staggered multi-way parallel PFC circuit often adopts closed-loop control to achieve current balancing control of the two inductor currents. Specifically, the circuit includes two control chips, namely UC3854 (1) and UC3854 (2), which can share a reference current generated by a controller and can sample the two-phase inductor current (i.e., the inductor current of the two branches) iL1 and iL2 respectively. Then, the inductor current of the two phases can be compared with the reference current respectively, and the two phases can be controlled separately to achieve the purpose of current balancing. It can be seen that since the two control chips share the reference current generated by the controller, the two branches can independently achieve average current control, and the duty cycle of the two branch switches can be adjusted independently. However, this current balancing control scheme is relatively complicated, and it is necessary to compare the inductor current of the two phases with the reference current respectively. In addition, an additional current balancing circuit is required to implement it, which is costly.

[0044] Currently, to address the impact of uneven total power distribution among branches, one approach is to increase the capacity of power devices. For example, a switching device with greater power capacity (lower on-resistance and greater current-carrying capacity) and a higher-power inductor can be used. This can offset the impact of uneven power distribution and avoid problems such as overcurrent or overtemperature faults. However, while this approach eliminates the need for an additional current-sharing circuit, it results in a large amount of design redundancy (a large power margin is left for each branch), resulting in higher device costs and increased size.

[0045] To solve the above problem, in an embodiment of the present application, the inductor current of each branch in the multi-parallel PFC circuit can be sampled separately. Then, the inductance relationship between the inductors of each branch can be calculated based on the inductor current of each branch. Then, the conduction time of the switching device of each branch can be adjusted based on the inductance relationship between the inductors of each branch, so that the peak value of the inductor current of each branch can be made the same, thereby achieving the effect of current sharing between the branches.

[0046] In order to better understand the embodiments of the present application, the overall circuit structure of the embodiments of the present application is first described below.

[0047] See also Figure 2 , Figure 2 This is a schematic diagram of the internal circuit structure of a server disclosed in an embodiment of the present application. Figure 2As shown, the circuit can include a rectifier circuit 11, a multi-parallel PFC circuit 12, a load 13 and a control circuit 14. The alternating current (AC) V1 can be converted into direct current V2 by the rectifier circuit 11. The direct current V2 output by the rectifier circuit 11 can be converted into direct current V3 by the multi-parallel PFC circuit 12 based on the driving signal of the control circuit 14. In addition, the multi-parallel PFC circuit 12 can also adjust the power factor of the circuit. The direct current V3 output by the multi-parallel PFC circuit 12 can power the load 13.

[0048] In some embodiments, the input alternating current V1 can be provided by an alternating current grid, for example, the alternating current V1 can be 110V, 220V, 380V or the like.

[0049] In the embodiments of the present application, the multi-parallel PFC circuit 12 can include a plurality of branches (multi-phase parallel PFC branches) and a capacitor C (i.e. a first capacitor). The plurality of branches can be connected in parallel to the capacitor C. Each branch can include at least one inductor and at least one switching device. In the following description, 2-phase and 3-phase branches are mainly taken as examples for illustration, but it should be understood that the multi-parallel PFC circuit 12 can be 3-phase or more, which is not limited in the present application.

[0050] The control circuit 14 can be connected to one end of the inductors in each branch of the multi-parallel PFC circuit 12 through the current sampling circuit, sample the current of the inductor in each branch, calculate the inductance relationship between the inductors in each branch based on the inductor current of each branch, and then adjust the on-time of the switching device in each branch based on the inductance relationship between the inductors in each branch, that is, adjust the duty cycle of the pulse width modulation (PWM) control signal for controlling the on and off of each switching device. In this way, the peak values of the inductor currents in each branch can be the same, achieving the effect of current sharing between branches. Since the inductance relationship between the inductors in each branch needs to be calculated in the above process, the inductors in the multi-parallel PFC circuit 12 can preferably use inductors that are less affected by temperature and working state changes and have a constant inductance. This ensures that the inductance relationship between the inductors in each branch does not change, so that the on-time of the switching device in each branch can be adjusted more accurately, and a better current sharing effect can be achieved. For example, the inductor made of ferrite (ferrite inductor) is less affected by temperature and working state changes and has a constant inductance. It should be noted that the working frequency of the switching device in the embodiments of the present application can be in the order of kilohertz (Khz), such as 20Khz, and the corresponding PWM control signal period can be in the order of microseconds.

[0051] It should be understood that the multi-parallel PFC circuit 12 can be a multi-parallel boost PFC circuit, a multi-parallel buck PFC circuit, or other types of multi-parallel PFC circuits, which are not limited in the present application.

[0052] The rectifier circuit 11 can be a bridge rectifier circuit, such as a full-bridge rectifier circuit and a half-bridge rectifier circuit, or a non-bridge rectifier circuit. In addition, the rectifier device in the rectifier circuit can be a diode or a metal oxide semiconductor field effect transistor (MOSFET). Therefore, in actual scenarios, appropriate rectifier circuits and rectifier devices can be selected flexibly.

[0053] The load 13 can be an electronic device such as a server, a smart car, a notebook computer, a desktop computer, and an industrial robot, or an internal component of the electronic device or an external electronic device of the electronic device. For example, when the load is a server, the load can be a processor, a memory, a hard disk, a network card, or other components in the server.

[0054] The control circuit 14 can be configured to provide control signals to the multi-parallel PFC circuit 12 to regulate the output voltage or current of the multi-parallel PFC circuit 12, and can make the peak values of the inductor currents of the branches equal. Specifically, the control circuit 14 can be configured to control the turn-on or turn-off time (regulate the duty cycle) of the switching devices in the multi-parallel PFC circuit 12, so as to realize the adjustment of the power factor, and realize the current sharing of the branches.

[0055] The control circuit 14 can include a controller and a driving circuit, the output of the controller can be connected to the input of the driving circuit, and the output of the driving circuit can be connected to the control end (such as the gate of a metal oxide semiconductor field effect transistor) of the switching device. The controller can output a driving signal to the driving end of the switching device through the driving circuit, wherein the driving signal can include a turn-on signal and a turn-off signal. It should be understood that the controller can output a pulse width modulation (PWM) signal to the driving circuit, and the PWM signal can include a turn-on control signal and a turn-off control signal, wherein the turn-on control signal is used to control the switching device to be in the turn-on state, and the turn-off control signal is used to control the switching device to be in the turn-off state.

[0056] It should be noted that in the embodiments of the present application, the switching device in each branch of the multi-parallel PFC circuit 12 can be any one of a metal oxide semiconductor field effect transistor (MOSFET), an insulated gate bipolar transistor (IGBT), a gallium nitride (GaN) transistor, a silicon carbide (SiC) transistor, or a triode. In the following description, the switching device is taken as an example of MOSFET. It can be understood that in some embodiments, the rectifier circuit 11 described above can also include a switching device.

[0057] It should be understood that when the switching device (such as MOSFET) is used for rectification in the rectifier circuit 11, the control circuit 14 can also be used to provide a control signal for the rectifier circuit 11 to adjust the output voltage or current of the rectifier circuit 11. In the embodiments of the present application, the controller in the control circuit 14 can be a microcontroller unit (MCU), a field programmable gate array (FPGA), a complex programmable logic device (CPLD), a digital signal processing (DSP) chip, etc., which is not limited herein. In the following description, the controller is taken as an example of MCU for illustration.

[0058] In a possible implementation, the rectifier circuit 11 and the multi-parallel PFC circuit 12 can also be controlled by two independent control circuits respectively.

[0059] In a possible implementation, the power supply unit (PSU) of the server can include the rectifier circuit 11 and the multi-parallel PFC circuit 12 described above, that is, the rectifier circuit 11 and the multi-parallel PFC circuit 12 can be part of the PSU of the server. Accordingly, by using the current sharing control method of the multi-parallel PFC circuit provided in the embodiments of the present application, current sharing of each branch in the PSU of the server can be achieved.

[0060] It should be understood that for the application scenarios of the multi-parallel PFC circuit, such as the power supply of different types of electronic devices such as servers, smart cars, notebook computers, desktop computers, and industrial robots, the current sharing of the multi-parallel PFC circuit can be achieved by using the current sharing control method of the multi-parallel PFC circuit provided in the present application. Moreover, the overall hardware circuit structure and the current sharing control scheme are simple, without adding an additional current sharing circuit (i.e. without adding an additional control chip), which can reduce the cost of the overall hardware circuit and has high practicability.

[0061] It should be understood that, Figure 2 The circuit structure shown is only illustrative and does not constitute a limitation. In other embodiments of the present application, Figure 2 The circuit structure shown can include more or less circuits than shown, and is not limited to only including Figure 2 The rectifier circuit 11, the multi-parallel PFC circuit 12, the load 13, and the control circuit 14 shown in the above description. For example, Figure 2 The circuit structure shown can also include a filter circuit for filtering out the AC component in the DC current, so that the output waveform becomes smooth.

[0062] The following describes the multi-parallel PFC circuit and the current sharing control method thereof provided in the present application. Figures 3 to 9

[0063] Please refer to Figure 3 , Figure 3 is a structure diagram of a switching power supply. As shown in Figure 3 , the switching power supply can include a rectifier circuit 11, a two-parallel PFC circuit 12, and a control circuit 14.

[0064] The rectifier circuit 11 can include diodes D1-D4. Among them, the diodes D1-D4 form a rectifier bridge, the anode of diode D2, the cathode of diode D1, and the positive pole of the AC power source are electrically connected; the cathode of diode D3, the anode of diode D4, and the negative pole of the AC power source are electrically connected; the cathode of diode D2 and the cathode of diode D4 are electrically connected and serve as the first output end of the rectifier circuit; the anode of diode D1 and the anode of diode D2 are electrically connected and serve as the second output end of the rectifier circuit. It should be understood that in some embodiments, the diodes D1-D4 can be replaced by 4 MOSFETs.

[0065] The two-parallel PFC circuit 12 can include inductors L1, L2, diodes D5, D6, MOSFETs Q1, Q2, and a capacitor C1. Among them, one end of the inductor L1 and one end of the inductor L2 are electrically connected to the first output end of the rectifier circuit 11. The other end of the inductor L1 is electrically connected to the drain (D) of the MOSFET Q1 and the anode of the diode D5. The other end of the inductor L2 is electrically connected to the drain of the MOSFET Q2 and the anode of the diode D6. The cathode of the diode D5, the cathode of the diode D6, and one end of the capacitor C1 are electrically connected and serve as the first output end of the two-parallel PFC circuit 12. The source (S) of the MOSFET Q1, the source of the MOSFET Q2, and the other end of the capacitor C1 are electrically connected to the second output end of the rectifier circuit 11, and their connection is grounded (GND). After the source of the MOSFET Q1, the source of the MOSFET Q2, and one end of the capacitor C1 are connected, they form the second output end of the two-parallel PFC circuit 12.

[0066] It can be understood that the gates (G) of the MOSFET Q1 and the MOSFET Q2 described above can be connected to a driving circuit (Driver) respectively, so that the control circuit 14 can control the conduction or turn-off of the MOSFET by controlling the gate of the MOSFET.

[0067] ​It should be noted that when the MOSFET Q1 is in the on state, the inductor L1 can be charged, at this time, the current can pass through one end of the power supply, the rectifier circuit 11, the inductor L1 and the MOSFET Q1, and then pass through the rectifier circuit 11 back to the other end of the power supply. When the MOSFET Q1 is in the off state, the inductor L1 can be discharged, and the capacitor C1 can be charged, at this time, the current can pass through one end of the power supply, the rectifier circuit 11, the inductor L1, the diode D5, the capacitor C1, and then pass through the rectifier circuit 11 back to the other end of the power supply.

[0068] Similarly, when the MOSFET Q2 is in the on state, the inductor L2 can be charged, at this time, the current can pass through one end of the power supply, the rectifier circuit 11, the inductor L2 and the MOSFET Q2, and then pass through the rectifier circuit 11 back to the other end of the power supply. When the MOSFET Q2 is in the off state, the inductor L2 can be discharged, and the capacitor C1 can be charged, at this time, the current can pass through one end of the power supply, the rectifier circuit 11, the inductor L2, the diode D6, the capacitor C1, and then pass through the rectifier circuit 11 back to the other end of the power supply. It should be understood that when the MOSFET Q1 and the MOSFET Q2 are in the on state, the capacitor C1 can be discharged to output the direct current V3 to power the load. It should be understood that the above-mentioned two-parallel PFC circuit 12 can include two branches, wherein the above-mentioned inductor L1, MOSFET Q1 and diode D5 can be a branch of the two-parallel PFC circuit 12, and the above-mentioned inductor L2, MOSFET Q2 and diode D6 can be another branch of the two-parallel PFC circuit 12. It should also be understood that Figure 3 The two-parallel PFC circuit 12 shown can be a two-parallel boost type PFC circuit, and correspondingly, the two branches can be boost branches.

[0069] In an alternative embodiment, the controller can be a microcontroller unit (MCU).

[0070] It can be understood that the turn-on and turn-off of the MOSFET Q1 and the MOSFET Q2 are controlled by the control circuit 14. Specifically, the current (iL1 and iL2) on the inductor L1 and the inductor L2 can be sampled by the inductor current sampling circuit, and then iL1 and iL2 can be input to the analog-digital (AD) port of the MCU to be converted into an inductor current value recognizable by the MCU. Then, the MCU can calculate the inductance relationship between the two branches based on the inductor currents of the two branches, and then adjust the conduction time of the switching devices of the two branches (adjust the duty cycle of the PWM control signal for controlling the turn-on and turn-off of each switching device) based on the inductance relationship between the two branches, so that the peak values of the inductor currents of the two branches are the same, achieving the effect of current sharing between the branches.

[0071] It should be noted that the above inductor current sampling circuit can use resistance sampling, current transformer sampling, Hall sampling, etc., which is not limited here. It should be understood that in some embodiments, the above rectifier circuit 11 can be part of the multi-parallel PFC circuit 12.

[0072] The principle of the current sharing control method of the multi-parallel PFC circuit provided in the present application will be described below.

[0073] The uneven current sharing between the branches of the multi-parallel PFC circuit is mainly caused by the discreteness of the components in each branch, so if the differences between the components in each branch (such as the differences between the inductance) can be determined in advance and compensated accordingly, the problem of uneven current sharing between the branches of the multi-parallel PFC circuit can be solved.

[0074] Further, through analysis of the multi-parallel PFC circuit, the main reason for uneven current sharing in the multi-parallel PFC circuit is that the inductance of each branch has differences due to the magnetic permeability and air gap of the magnetic core, so the inductance of each branch can be determined in advance, and then it can be determined whether to compensate for each branch to achieve current sharing in each branch.

[0075] From the voltage formula of the inductor V=L×di / dt=L×ΔI / ΔT, it can be known that ΔI=V×ΔT / L. Wherein, V is the voltage applied to the inductor, L is the inductance, ΔI is the change of inductor current, and ΔT is the change of time. It should be understood that ΔI can be the change of inductor current in the process of charging the inductor in a PWM period, such as the change of current of the inductor L1 when the switching device MOSFET Q1 is in the conduction state in a PWM period. ΔT can be the time for charging the inductor in a PWM period, such as the time for which the switching device MOSFET Q1 is in the conduction state in a PWM period.

[0076] It can be understood that the purpose of current sharing between each branch of the multi-parallel PFC circuit is to ensure that ΔI of each branch is consistent, that is, the change amount of inductance current is consistent, as shown in the two-parallel PFC circuit shown in the above Figure 3 The purpose of 2-phase current sharing of the two-parallel PFC circuit is to ensure that ΔI of the two branches is consistent. Further, since each branch of the multi-parallel PFC circuit is in parallel and uses the same input power supply, the voltage V on the inductance of each branch of the multi-parallel PFC circuit can be the same. When the inductance L of each branch has a difference, in order to ensure that ΔI of each branch is consistent, ΔT of each branch can be adjusted. By adjusting ΔT of each branch appropriately, the charging time of the inductance of each branch, that is, the duty cycle of the PWM control signal for controlling the turn-on and turn-off of each switching device, can be adjusted, so that ΔI of each branch is consistent, so that current sharing of each branch can be ensured.

[0077] Please refer to Figure 4 , Figure 4 is a flowchart of a current sharing control method of a multi-parallel PFC circuit disclosed in the embodiments of the present application. As shown in Figure 4 , the current sharing control method can include but is not limited to the following steps:

[0078] 401. Obtain the inductance current of each phase branch of the multi-parallel PFC circuit.

[0079] Specifically, in order to achieve current sharing between each branch (each phase branch) of the multi-parallel PFC circuit (multi-phase PFC circuit), the inductance difference (i.e., the inductance ratio) between each branch (each phase branch) needs to be obtained. Therefore, the controller, such as the MCU, can first sample the inductance current of each branch of the multi-parallel PFC circuit through the current sampling circuit.

[0080] 402. Calculate the inductance ratio between each phase branch based on the inductance current of each phase branch.

[0081] After the controller samples the inductance current of each branch of the multi-parallel PFC circuit, the inductance ratio between each branch can be calculated based on the inductance current of each branch of the multi-parallel PFC circuit. Specifically, since each branch of the multi-parallel PFC circuit is in parallel and uses the same power supply, the voltage V on the inductance of each branch of the multi-parallel PFC circuit is the same. Therefore, based on V=LxΔI / ΔT, L1xΔI1 / ΔT1=L2xΔI2 / ΔT2 can be determined. Wherein L1 and L2 can be the inductance of any two different branches of the multi-parallel PFC circuit, and correspondingly, ΔI1 and ΔI2 can be the current change amount of the corresponding branch, and ΔT1 and ΔT2 can be the time change amount of the corresponding branch.

[0082] Here, in order to obtain the inductance ratio between the branches, ΔT1 and ΔT2 can be set to be the same. In this case, L1 / L2 = ΔI2 / ΔI1 (the inductance current ratio of each phase PFC branch is equal to the inverse of the corresponding inductance ratio) can be obtained. Thus, based on the relationship L1 / L2 = ΔI2 / ΔI1, the inductance ratio between the branches can be determined by the inductance current of each branch obtained by sampling.

[0083] For example, assuming that the multi-parallel PFC circuit includes three branches, branch 1, branch 2 and branch 3, the period and duty cycle of the PWM control signal of each branch are the same, and the on time is T1 (the duration of the high level is T1), and the off time is T2 (the duration of the low level is T2). When the switching device of each branch is in the on state, the inductance current of each branch can be sampled, the inductance current of branch 1 can be I1, the inductance current of branch 2 can be I2, and the inductance current of branch 3 can be I3. Moreover, I2 is equal to 1.1 times I1, and I3 is equal to 1.2 times I1. Based on the ratio relationship between the inductance currents of each branch, the inductance ratio between the branches can be calculated. The inductance L1 of branch 1 is equal to 1.1 times the inductance L2 of branch 2, and the inductance L1 of branch 1 is also equal to 1.2 times the inductance L3 of branch 3.

[0084] In some embodiments, I1 can be the peak current of branch 1 in one PWM period, and correspondingly, I2 can be the peak current of branch 2 in one PWM period, and I3 can be the peak current of branch 3 in one PWM period.

[0085] 403. Based on the inductance ratio between the branches, the PWM control signal of each branch is adjusted.

[0086] After obtaining the inductance ratio between the branches, in order to ensure that ΔI of each branch is consistent, the controller can adjust ΔT of each branch, i.e. adjust the duty cycle of the PWM control signal of each branch.

[0087] Based on ΔI = V x ΔT / L, it can be determined that ΔI1= ΔI2, i.e. V x ΔT1 / L1= V x ΔT2 / L2. Further, since V is the same, it can be obtained that ΔT1 / L1= ΔT2 / L2 (the ratio of the maintenance time of the on control signal in the pulse width modulation signal of the switching device of each phase PFC branch is equal to the ratio of the inductance of the corresponding phase PFC branch). Therefore, based on the relationship of ΔT1 / L1= ΔT2 / L2 and the ratio of the inductance of each branch, the duty cycle of the PWM control signal of each branch can be adjusted so that the ratio of the maintenance time of the on control signal in the pulse width modulation signal of the switching device of each phase PFC branch is equal to the ratio of the inductance of the corresponding phase PFC branch, so that the ΔI of each branch can be the same. It should be understood that by adjusting the duty cycle of the PWM control signal of each branch, the maintenance time of the on control signal of each branch can be changed, so that the charging time of the inductance of each branch can be adjusted, and thus the inductance of each branch can reach the same current peak value during charging.

[0088] For example, the inductance L1 of the above-mentioned branch 1 is equal to 1.1 times the inductance L2 of the branch 2, and the inductance L1 of the branch 1 is also equal to 1.2 times the inductance L3 of the branch 3. Therefore, in order to ensure that the ΔI of each branch is the same, based on the ratio of the inductance of the branch 1, the branch 2 and the branch 3, it can be determined that the ratio of the maintenance time of the on control signal in the pulse width modulation signal of the switching device of the branch 1, the branch 2 and the branch 3 is ΔT1= 1.1 ΔT2= 1.2 ΔT3. Assuming that the period and the duty cycle of the PWM control signal of each branch are the same, and the on time of the PWM control signal corresponding to the branch 1 is T1, and the off time is T2, then the on time of the PWM control signal corresponding to the branch 2 can be 10 / 11≈0.91T1, and the off time can be T2+0.09T1. Similarly, the on time of the PWM control signal corresponding to the branch 3 can be 5 / 6≈0.83T1, and the off time can be T2+0.17T1.

[0089] It should be understood that when adjusting the maintenance time of the on control signal in the pulse width modulation signal of the switching device of each phase PFC branch, the maintenance time of the on control signal of the switching device of one phase PFC branch (the first switch) can be taken as a reference to adjust the maintenance time of the on control signal in the pulse width modulation signal of the switching device of other phase PFC branches. For example, when adjusting the maintenance time of the on control signal in the pulse width modulation signal of the switching device of the branch 1, the branch 2 and the branch 3, the maintenance time of the on control signal of the switching device of the branch 1 can be taken as a reference to adjust the maintenance time of the on control signal in the pulse width modulation signal of the switching device of the branch 2 and the branch 3.

[0090] It should be noted that, for any two branches in the multi-parallel PFC circuit, the ratio of the inductance currents of the two branches is equal to the reciprocal of the ratio of the inductance of the two branches, and the ratio of the on-time of the PWM control signals of the two branches after adjustment should be equal to the ratio of the inductance of the two branches. Therefore, it can be determined that the ratio of the on-time of the PWM control signals of the two branches after adjustment should be equal to the reciprocal of the ratio of the inductance currents of the two branches, and thus, in some embodiments, the PWM control signals of each branch can be directly adjusted based on the inductance current of each branch, without the need to calculate the ratio of the inductance between each branch according to the inductance current of each branch.

[0091] In the above process, the inductance current of one PWM period can be sampled in advance, then the MCU can calculate the on-time that needs to be compensated for each branch in advance, and the compensation of each branch can be fixed, without the need to calculate the compensation amount in real time according to the inductance current, and the control scheme is relatively simple.

[0092] The examples of the current sharing control method of the multi-parallel PFC circuit provided in the present application will be exemplarily described below in combination with Figure 3 , Figure 5 and Figure 6 .

[0093] Specifically, in order to obtain the difference between the two-phase currents, the AC power supply can provide DC (pulsating DC) with a voltage of V4 for the inductors L1 and L2 through the rectifier circuit. It should be understood that Ton can be the time (the duration of the high level in one PWM period) when the switching device (i.e., MOSFET Q1 and MOSFET Q2) is in the on state in one PWM period. Then, the inductance current sampling circuit can sample the current iL1 through the inductor L1 and the current iL2 through the inductor L2, respectively. And iL1 and iL2 can be input to the AD port of the MCU and converted into inductance current values that can be recognized by the MCU.

[0094] Then, the MCU can calculate the inductance difference between the inductor L1 and the inductor L2 based on iL1 and iL2. For example, it is assumed that iL1 = 0.9iL2 (as shown in FIG. 1, iL1 = 0.9iL2), based on L = V x ΔT / ΔI, and since V and ΔT (i.e., the time when MOSFET Q1 and MOSFET Q2 are in the on state) are the same, the inductance relationship of the two-phase inductors can be obtained as L1 = 1.11L2. Figure 5 max 1 = 0.9i max 2), based on L = V x ΔT / ΔI, and since V and ΔT (i.e., the time when MOSFET Q1 and MOSFET Q2 are in the on state) are the same, the inductance relationship of the two-phase inductors can be obtained as L1 = 1.11L2.

[0095] ​To achieve current sharing of the two branches, the peak current of the two branches is made the same, the duty cycle of the PWM control signal corresponding to the two branches can be adjusted based on the inductance relationship of the two-phase inductor. For example, to make iL1 = iL2 = i max 2, the time of MOSFET Q1 in the on state can be extended. Since L1 = 1.11L2, the time of MOSFET Q1 in the on state can be extended to 1.11Ton, that is, the compensated T1 = 1.11Ton, T1 is the time of MOSFET Q1 in the on state in a PWM period. And T2 can still be Ton, T2 is the time of MOSFET Q2 in the on state in a PWM period. Therefore, when the corresponding PWM wave (PWM1) on MOSFET Q1 issued by the MCU has a conduction time of 1.11Ton in a PWM period, and the corresponding PWM wave (PWM2) on MOSFET Q2 has a conduction time of Ton in a PWM period, iL1 = iL2 can be guaranteed, and 2-phase current sharing can be achieved.

[0096] As shown in Figure 5 , on the basis of Ton, the time of MOSFET Q1 in the on state can be extended by Ton_add, where Ton_add = 0.11Ton. In this way, the charging time of inductor L1 in the branch can be increased, and when the current of inductor L1 reaches i max 1, it can continue to increase, and in the extended conduction time, it can reach i max 2, so that current sharing of the two branches can be achieved.

[0097] It can be understood that the above is to extend the time of MOSFET Q1 in the on state, so that the peak current through inductor L1 reaches i max 2, and 2-phase current sharing is achieved. But in other embodiments of the application, the time of MOSFET Q2 in the on state can also be shortened, so that the peak current through inductor L2 reaches i max 1, and 2-phase current sharing is achieved. As shown in Figure 6 , on the basis of Ton, the time of MOSFET Q2 in the on state can be shortened by Ton_1, where Ton_1 = 0.1Ton. In this way, the charging time of inductor L2 in the branch can be shortened, and when the current of inductor L2 reaches i maxAfter 1, the increase will not continue, and the current sharing of the two branches can be realized. Similarly, in other embodiments, the time for which MOSFET Q1 is in the on state can be appropriately extended, and the time for which MOSFET Q2 is in the on state can be appropriately shortened, so that the current sharing of the two branches can also be realized. Therefore, the duty cycle of the PWM control signal corresponding to each branch can be selected and determined according to actual conditions, and the embodiments of the present application are not limited herein.

[0098] It should be understood that the above is only exemplarily described for the two-way parallel boost PFC circuit, and does not limit the application scenarios of the current sharing control method of the multi-way parallel PFC circuit provided in the embodiments of the present application. The same is applicable to a three-way parallel boost PFC circuit, a four-way parallel boost PFC circuit, and in addition, is also applicable to a multi-way parallel buck PFC circuit.

[0099] Please refer to Figure 7 , Figure 7 which is another structure schematic diagram of a switching power supply circuit disclosed by the embodiments of the present application. Figure 7 The same parts in Figure 3 are not described again. As shown in Figure 7 , the three-way parallel PFC circuit can include three boost branches, and compared with the two-way parallel PFC circuit, can further include an inductor L3, a MOSFET Q1, and a diode D7.

[0100] Specifically, the three-way parallel PFC circuit 12 can include an inductor L1, an inductor L2, an inductor L2, a diode D5, a diode D6, a diode D7, a MOSFET Q1, a MOSFET Q2, a MOSFET Q3, and a capacitor C1. Wherein, one end of the inductor L1, the inductor L2 and the inductor L3 is connected to the first output end of the rectifier circuit 11 respectively. The source (S pole) of the MOSFET Q1, the source of the MOSFET Q2, the source of the MOSFET Q3 and one end of the capacitor C1 are connected to the second output end of the rectifier circuit 11 respectively. The other end of the inductor L1 is connected to the drain (D pole) of the MOSFET Q1 and the anode of the diode D5 respectively. The other end of the inductor L2 is connected to the drain of the MOSFET Q2 and the anode of the diode D6 respectively. The other end of the inductor L3 is connected to the drain of the MOSFET Q3 and the anode of the diode D7 respectively. The cathode of the diode D5, the cathode of the diode D6, the cathode of the diode D7 and the other end of the capacitor C1 are connected to form the first output end of the three-way parallel PFC circuit 12. The source of the MOSFET Q1, the source of the MOSFET Q2, the source of the MOSFET Q3 and one end of the capacitor C1 are connected to form the second output end of the three-way parallel PFC circuit 12, and their connection place can be grounded (GND).

[0101] It can be understood that the gates of the MOSFET Q1, the MOSFET Q2 and the MOSFET Q3 can be connected with a driver circuit (Driver) respectively, so that the control circuit 14 can control the turn-on or turn-off of the MOSFET Q1, the MOSFET Q2 and the MOSFET Q3 by controlling the gates of the MOSFET Q1, the MOSFET Q2 and the MOSFET Q3.

[0102] It should be noted that when the MOSFET Q3 is in the turn-on state, the inductor L3 can be charged, at this time, the current can pass through one end of the power supply, the rectifier circuit 11, the inductor L3 and the MOSFET Q3, and then pass through the rectifier circuit 11 to the other end of the power supply. When the MOSFET Q3 is in the turn-off state, the inductor L3 can be discharged, and the capacitor C1 can be charged, at this time, the current can pass through one end of the power supply, the rectifier circuit 11, the inductor L3, the diode D7, the capacitor C1, and then pass through the rectifier circuit 11 to the other end of the power supply.

[0103] Further, in order to realize the current sharing of the three branches, the inductor currents of the three branches can be sampled, and then the inductance relationships of the three branches can be calculated based on the inductor currents, and then the duty cycles of the PWM control signals corresponding to the three branches can be adjusted based on the inductance relationships of the three branches, so that the current sharing of the three branches can be realized. In a possible implementation, one of the three branches can be taken as a reference, and the maintenance time of the turn-on control signal in the pulse width modulation signal of the switching device in the other branches can be adjusted.

[0104] Please refer to Figure 8 , Figure 8 is another structure schematic diagram of a switching power supply circuit disclosed by the embodiment of the present application. Figure 8 The two-parallel PFC circuit shown in the figure can be a two-parallel buck PFC circuit. As shown in Figure 8 , the circuit can include the rectifier circuit 11, the two-parallel PFC circuit 12 and the control circuit 14. Figure 8 The same parts in Figure 3 are the same as those in

[0105] The two-way parallel PFC circuit 12 can include inductor LI, inductor L2, diode D5, diode D6, MOSFET Q1, MOSFET Q2 and capacitor CI. The drain of MOSFET Q1 and the drain of MOSFET Q2 are connected to the first output end of the rectifier circuit 11 respectively. The anode of diode D5, the anode of diode D6 and one end of capacitor CI are connected to the second output end of the rectifier circuit 11 respectively. The source of MOSFET Q1 is connected to the cathode of diode D5 and one end of inductor LI respectively. The source of MOSFET Q2 is connected to the cathode of diode D6 and one end of inductor L2 respectively. The other end of inductor LI, the other end of inductor L2 and the other end of capacitor CI are connected to form the first output end of the two-way parallel PFC circuit 12. The anode of diode D5, the anode of diode D6 and one end of capacitor CI are connected to form the second output end of the two-way parallel PFC circuit 12.

[0106] It can be understood that the gates of MOSFET Q1 and MOSFET Q2 can be connected to a driving circuit (i.e. Driver) respectively, so that the control circuit 14 can control the conduction or turn-off of MOSFET Q1 and MOSFET Q2 by controlling the gates of MOSFET Q1 and MOSFET Q2.

[0107] It should be noted that when MOSFET Q1 is in the conduction state, inductor LI and capacitor CI can be charged, at this time, the current can pass through one end of the power supply, the rectifier circuit 11, MOSFET Q1, inductor LI and capacitor CI, and then pass through the rectifier circuit 11 to the other end of the power supply. When MOSFET Q1 is in the turn-off state, inductor LI can be discharged, and capacitor CI can be charged, at this time, the current can pass through one end of inductor LI, capacitor CI, and then pass through diode D5 to the other end of inductor LI.

[0108] Similarly, when MOSFET Q2 is in the conduction state, inductor L2 and capacitor CI can be charged, at this time, the current can pass through one end of the power supply, the rectifier circuit 11, MOSFET Q2, inductor L2 and capacitor CI, and then pass through the rectifier circuit 11 to the other end of the power supply. When MOSFET Q2 is in the turn-off state, inductor L2 can be discharged, and capacitor CI can be charged, at this time, the current can pass through one end of inductor L2, capacitor CI, and then pass through diode D6 to the other end of inductor LI. It should be understood that when MOSFET Q1 and MOSFET Q2 are in the conduction and turn-off states, capacitor CI can be discharged to output direct current V3 to power the load.

[0109] Further, in order to realize the current sharing of the two branches of the two-parallel PFC circuit, the inductor currents of the two branches can be sampled respectively, and then the inductor quantity relationship of the two branches can be calculated based on the inductor currents of the two branches, and then the duty cycles of the PWM control signals corresponding to the two branches can be adjusted based on the inductor quantity relationship of the two branches, so that the current sharing of the two branches can be realized.

[0110] It should be understood that, in some embodiments, the freewheeling diodes in the multi-parallel PFC circuit described above can be replaced by MOSFETs or the like. For example, Figure 3 The freewheeling diodes in the two-parallel PFC circuit shown can be replaced by MOSFETs. Please refer to Figure 9 , Figure 9 is another structure diagram of a switching power supply circuit disclosed in the embodiments of the present application. Figure 9 the same as in Figure 3 , and will not be described again. As shown in Figure 9 , the diode D5 in the two-parallel PFC circuit 12 can be replaced by the MOSFET Q3, and the diode D6 can be replaced by the MOSFET Q4. Compared with the freewheeling diode, the MOSFET can reduce the conduction loss of the circuit and improve the working efficiency of the multi-parallel PFC circuit.

[0111] Specifically, the two-parallel PFC circuit 12 can include the inductor L1, the inductor L2, the MOSFET Q1, the MOSFET Q2, the MOSFET Q3, the MOSFET Q4, and the capacitor C1. Wherein, one end of the inductor L1 and one end of the inductor L2 are connected to the first output end of the rectifier circuit 11 respectively. The source of the MOSFET Q1, the source of the MOSFET Q2, and one end of the capacitor C1 are connected to the second output end of the rectifier circuit 11 respectively. The other end of the inductor L1 is connected to the drain of the MOSFET Q1 and the drain of the MOSFET Q3 respectively. The other end of the inductor L2 is connected to the drain of the MOSFET Q2 and the drain of the MOSFET Q4 respectively. The source of the MOSFET Q3, the source of the MOSFET Q4, and the other end of the capacitor C1 are connected to form the first output end of the two-parallel PFC circuit 12. The source of the MOSFET Q1, the source of the MOSFET Q2, and one end of the capacitor C1 are connected to form the second output end of the two-parallel PFC circuit 12, and their connection place can be grounded (GND).

[0112] It can be understood that the gates of the MOSFET Q1, the MOSFET Q2, the MOSFET Q3, and the MOSFET Q4 described above can be connected to the driving circuit (i.e. Driver) respectively, so that the control circuit 14 can control the conduction or turn-off of the MOSFET by controlling the gates of the MOSFET.

[0113] It should be noted that when MOSFET Q1 is in the on state, it can charge inductor L1. In this case, the current can pass through one end of the power supply, the rectifier circuit 11, the inductor L1, and the MOSFET Q1, and then return to the other end of the power supply through the rectifier circuit 11. When MOSFET Q1 is in the off state and MOSFET Q3 is in the on state, the inductor L1 can discharge and can charge capacitor C1. In this case, the current can pass through one end of the power supply, the rectifier circuit 11, the inductor L1, the MOSFET Q3, the capacitor C1, and then return to the other end of the power supply through the rectifier circuit 11.

[0114] Similarly, when MOSFET Q2 is in the on state, it can charge inductor L2. At this time, the current can pass through one end of the power supply, the rectifier circuit 11, the inductor L2, and the MOSFET Q2, and then return to the other end of the power supply through the rectifier circuit 11. When MOSFET Q2 is in the off state and MOSFET Q4 is in the on state, the inductor L2 can discharge and charge capacitor C1. At this time, the current can pass through one end of the power supply, the rectifier circuit 11, the inductor L2, the MOSFET Q4, the capacitor C1, and then return to the other end of the power supply through the rectifier circuit 11. It should be understood that when MOSFET Q1 and MOSFET Q2 are in the on state, capacitor C1 can discharge and output DC power V3 to power the load.

[0115] It should be noted that the above Figure 3 、 Figure 7 、 Figure 8 and Figure 9 The circuit shown is for illustrative purposes only and is not intended to be limiting. It will be appreciated that in some embodiments, the switching devices in each branch of a multi-phase parallel PFC circuit can be phase-shifted to switch on and off at a specific switching cycle, thereby reducing output current ripple. For example, for multi-phase branches in a PFC circuit connected in parallel, the phase difference between the PWM signals of two adjacent phase branches can be 360 / N, where N is the number of phases in the parallel branches of the PFC circuit.

[0116] In the embodiment of the present application, the inductor current of each branch in the multi-way parallel PFC circuit can be sampled in advance, and then the inductance ratio of each branch can be calculated. Based on the inductance ratio of each branch, the duty cycle of the PWM control signal corresponding to each branch can be adjusted to achieve current sharing in each circuit. This method can achieve current sharing without increasing the capacity of the power device, save costs, and improve system reliability. In addition, this method can calculate the compensation parameters of each branch in advance (such as Figure 5The Ton_add can be calculated in advance, and then the preset compensation parameter can be directly called without real-time calculation of the compensation amount.

[0117] It can be understood that the steps in the current sharing control method can be adjusted, combined and deleted according to actual needs.

[0118] As shown in the figure, Figure 10 As shown in the figure, Figure 10 is a structural schematic diagram of a computing device disclosed by the embodiments of the present application. The computing device 1000 can be a server, a switch and a computer, etc. electronic device; the computing device 1000 can include a switching power supply 1004, which can include any kind of multi-parallel PFC circuit, and the controller in the PFC circuit can be used to execute the current sharing control method shown in the figure. Figure 4

[0119] The computing device 1000 can also include a processor 1001, a memory 1003 and a transceiver 1002. Among them, the processor 1001, the memory 1003, the transceiver 1002 and the switching power supply 1004 can communicate with each other through internal connection path to transfer control and / or data signal, the memory 1003 is used to store computer program, the processor 1001 is used to call and run the computer program from the memory 1003 to control the transceiver 1002 to transceive signal. The processor 1001 is used to execute the program code stored in the memory 1003 to realize the above-mentioned functions. In specific implementation, the memory 1003 can also be integrated in the processor 1001, or independent of the processor 1001. The above-mentioned transceiver 1002 can also be called transceiving unit or transceiving module. The transceiver 1002 can include receiver (or receiver, receiving circuit) and transmitter (or transmitter, transmitting circuit). Among them, the receiver is used to receive signal, and the transmitter is used to transmit signal. The transceiver 1002 can be used to communicate with other devices.

[0120] It should be understood that the "connection" in the present application can be understood as direct connection (i.e. electrical connection); it can also be understood as indirect connection, i.e. connection through other devices, elements, modules, apparatuses, etc.

[0121] The above specific embodiments have further detailed the purposes, technical solutions and beneficial effects of the present application. It should be understood that the above description is only a specific embodiment of the present application and is not used to limit the protection scope of the present application. Any modification, equivalent replacement, improvement, etc. made on the basis of the technical solutions of the present application shall be included in the protection scope of the present application.​

Claims

1. A switching power supply, characterized by comprising: The switching power supply comprises a multi-phase power factor correction (PFC) circuit; wherein the multi-phase PFC circuit comprises a multi-phase PFC branch and a control circuit; the multi-phase PFC branch is in parallel; each phase PFC branch comprises an inductor and a switching device; wherein the switching device is used for charging and discharging the inductor; The control end of the switching device in each phase PFC branch is electrically connected with the corresponding control end of the control circuit respectively; the control end is used for outputting a pulse width modulation signal, and the pulse width modulation signal is used for controlling the working state of the switching device in each phase PFC branch; The control circuit is used for: obtaining the inductor current of each phase PFC branch in the PFC circuit; based on the inductor current of each phase PFC branch, adjusting the maintenance time length of the conduction control signal in the pulse width modulation signal of the switching device of each phase PFC branch, wherein the conduction control signal is used for controlling the switching device to be in the conduction state; The control circuit is used for: based on the inductor current of each phase PFC branch, adjusting the maintenance time length of the conduction control signal in the pulse width modulation signal of the switching device of each phase PFC branch, comprising: The control circuit is used for: based on the inductor current of each phase PFC branch, determining the inductance ratio between the phases PFC branch; based on the inductance ratio between the phases PFC branch, adjusting the maintenance time length of the conduction control signal in the pulse width modulation signal of the switching device of each phase PFC branch.

2. The switching power supply according to claim 1, characterized in that The control circuit is used for: based on the inductance ratio between the phases PFC branch, adjusting the maintenance time length of the conduction control signal in the pulse width modulation signal of the switching device of each phase PFC branch, comprising: The control circuit is used for: based on the inductance ratio between the phases PFC branch, determining the ratio of the maintenance time length of the conduction control signal in the pulse width modulation signal of the switching device of each phase PFC branch; wherein the ratio of the maintenance time length of the conduction control signal in the pulse width modulation signal of the switching device of each phase PFC branch is equal to the inductance ratio; based on the ratio of the maintenance time length of the conduction control signal in the pulse width modulation signal of the switching device of each phase PFC branch, adjusting the maintenance time length of the conduction control signal in the pulse width modulation signal of the switching device of each phase PFC branch.

3. The switching power supply of claim 2, wherein The control circuit is used for: based on the ratio of the maintenance time length of the conduction control signal in the pulse width modulation signal of the switching device of each phase PFC branch, adjusting the maintenance time length of the conduction control signal in the pulse width modulation signal of the switching device of each phase PFC branch, comprising: The control circuit is used for: taking the maintenance time length of the conduction control signal of the first switch of one phase PFC branch as a reference, adjusting the maintenance time length of the conduction control signal in the pulse width modulation signal of the switching device in other phase PFC branches.

4. The switching power supply according to claim 3, characterized in that The control circuit is used for: taking the maintenance time length of the conduction control signal of the first switch of one phase PFC branch as a reference, adjusting the maintenance time length of the conduction control signal in the pulse width modulation signal of the switching device in other phase PFC branches, comprising: The maintaining time length of the turn-on control signal of the first switch of one phase PFC branch is taken as a reference, and the maintaining time length of the turn-on control signal in the pulse width modulation signal of the switching device in the other phase PFC branch is increased or decreased.

5. Switching power supply according to any of claims 1-4, characterized in that The multi-phase PFC branch includes a first phase PFC branch and a second phase PFC branch.

6. The switching power supply of claim 5, wherein The first phase PFC branch includes a first inductor, a first diode and a first switch tube; a first end of the first inductor is electrically connected to a positive pole of a direct current power supply; a second end of the first inductor is electrically connected to a first end of the first switch tube and a first end of the first diode; a second end of the first diode is electrically connected to a first end of a first capacitor; a second end of the first switch tube and a second end of the first capacitor are electrically connected to a negative pole of the direct current power supply; wherein a third end of the first switch tube is a control end; The second phase PFC branch includes a second inductor, a second diode and a second switch tube; a first end of the second inductor is electrically connected to a positive pole of a direct current power supply; a second end of the second inductor is electrically connected to a first end of the second switch tube and a first end of the second diode; a second end of the second diode is electrically connected to a first end of the first capacitor; a second end of the second switch tube and a second end of the first capacitor are electrically connected to a negative pole of the direct current power supply; wherein a third end of the second switch tube is a control end.

7. The switching power supply of claim 5, wherein The first phase PFC branch includes a first inductor, a first switch tube and a second switch tube; a first end of the first inductor is electrically connected to a positive pole of an alternating current power supply; a second end of the first inductor is electrically connected to a first end of the first switch tube and a second end of the second switch tube; a first end of the second switch tube is electrically connected to a first end of a first capacitor; a second end of the first switch tube and a second end of the first capacitor are electrically connected to a negative pole of the alternating current power supply; wherein a third end of the first switch tube and a third end of the second switch tube are control ends; The second phase PFC branch includes a second inductor, a third switch tube and a fourth switch tube; a first end of the second inductor is electrically connected to a positive pole of an alternating current power supply; a second end of the second inductor is electrically connected to a first end of the third switch tube and a second end of the fourth switch tube; a first end of the fourth switch tube is electrically connected to a first end of the first capacitor; a second end of the third switch tube and a second end of the first capacitor are electrically connected to a negative pole of the alternating current power supply; wherein a third end of the third switch tube and a third end of the fourth switch are control ends.

8. The switching power supply according to any one of claims 1 to 4, 6, 7, characterized in that, The inductor in each phase PFC branch is a ferrite inductor.

9. A computing device, comprising: The computing device includes the switching power supply and the load according to any one of claims 1-8, and the switching power supply is electrically connected to the load; wherein the switching power supply is used to supply power to the load.

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