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 power factor correction (PFC) circuit, and the PFC circuit comprises a main circuit and a control circuit. The main circuit comprises an inductor, a first switch tube, a second switch tube and a capacitor. The control circuit comprises a first control signal output end, a second control signal output end, an input voltage sampling input end, an output voltage sampling input end and an inductor current sampling input end. The first control signal output end is electrically connected with the control end of the first switch tube, and the second control signal output end is electrically connected with the control end of the second switch tube. The application can make the totem column PFC main circuit in the switching power supply generate a negative current with a proper size, and realize the soft switching of the switch tube in the totem column PFC main circuit.

Description

Technical Field

[0001] This application relates to the field of power supply technology, and in particular to a switching power supply and a computing device. Background Technology

[0002] Power factor correction (PFC) circuits, while providing boost functionality, can also correct the power factor, improving the quality of the input current. To ensure the proper functioning of the PFC circuit, a control circuit is typically included to control the switching transistors within it. Due to inherent hardware delays, the control circuit exhibits a delay effect, leading to lag in regulation and affecting its control performance. Summary of the Invention

[0003] This application provides a switching power supply and computing device that generates a suitable negative current in the totem pole PFC main circuit, thereby achieving soft switching of the switching transistor in the totem pole PFC main circuit.

[0004] In a first aspect, embodiments of this application provide a switching power supply, characterized in that the switching power supply includes a power factor correction (PFC) circuit, wherein the PFC circuit includes a main circuit and a control circuit.

[0005] The main circuit described above includes an inductor, a first switching transistor, a second switching transistor, and a capacitor. The first terminal of the inductor is electrically connected to the positive terminal of an external input power supply. The second terminal of the inductor, the first terminal of the first switching transistor, and the second terminal of the second switching transistor are electrically connected. The first terminal of the second switching transistor and the first terminal of the capacitor are electrically connected to the first terminal of an external load. The second terminal of the first switching transistor, the second terminal of the capacitor, the negative terminal of the external input power supply, and the second terminal of the external load are electrically connected.

[0006] The aforementioned control circuit includes a first control signal output terminal, a second control signal output terminal, an input voltage sampling input terminal, an output voltage sampling input terminal, and an inductor current sampling input terminal. The first control signal output terminal is electrically connected to the control terminal of the first switching transistor, and the second control signal output terminal is electrically connected to the control terminal of the second switching transistor. The control circuit is used to control the operating states of the first and second switching transistors.

[0007] The input voltage sampling input terminal of the above control circuit is used to obtain the first voltage between the positive terminal and the negative terminal of the above input power supply.

[0008] The output voltage sampling input terminal of the above control circuit is used to obtain the second voltage output by the above PFC circuit.

[0009] The inductor current sampling input terminal of the above control circuit is used to obtain the inductor current.

[0010] The above control circuit is also used for:

[0011] The reference current is determined based on the first voltage and the second voltage described above.

[0012] An adjustment signal is generated based on the aforementioned inductor current and reference current.

[0013] Based on the aforementioned adjustment signals, the first control signal for the first switching transistor and the second control signal for the second switching transistor are adjusted. The first control signal is used to control the on / off state of the first switching transistor. The second control signal is used to control the on / off state of the second switching transistor.

[0014] The control circuit determines a reference current by acquiring the input and output voltages of the main circuit, and generates two control signals based on this reference current and the inductor current of the main circuit. These two control signals control the on and off states of the first and second switching transistors in the main circuit, respectively.

[0015] In one possible implementation, the control circuit includes a controller and a comparator. The controller includes a first control signal output terminal, a second control signal output terminal, an input voltage sampling input terminal, an output voltage sampling input terminal, a reference current output terminal, and an adjustment signal input terminal. The reference current output terminal of the controller is electrically connected to the first terminal of the comparator. The second terminal of the comparator is used to acquire the inductor current. The input voltage sampling input terminal of the controller is used to acquire the first voltage. The output voltage sampling input terminal of the controller is used to acquire the second voltage. The output terminal of the comparator is electrically connected to the adjustment signal input terminal of the controller.

[0016] The aforementioned control circuit is also used to: determine an adjustment signal based on the aforementioned reference current and the aforementioned inductor current, including:

[0017] The comparator determines the adjustment signal based on the inductor current and the reference current.

[0018] In one possible implementation, the control circuit is further configured to: determine a reference current based on the first voltage and the second voltage, including:

[0019] The above control circuit is used for: based on the formula: Determine the above reference current I ref .

[0020] Among them, V bus V is the second voltage output of the aforementioned PFC circuit. in The voltage between the positive and negative terminals of the input power supply is given by V, where L is the inductance of the inductor, and t′ is the voltage obtained from the input power supply. busor V in The point in time. T delay This is the delay time for the first or second switch to turn off after the inductor current crosses zero.

[0021] Through the formula: The subsequent T can be calculated. delay The change in inductor current over a time period, when the inductor current is less than I ref The first time to output the control signal, at T delay This ensures that the inductor current is exactly 0, preventing excessive negative current from affecting the normal operation of the main circuit.

[0022] In one possible implementation, the control circuit is used to: determine a reference current based on the first voltage and the second voltage, including: the control circuit based on the formula: Determine the above reference current I ref .

[0023] Among them, V bus V is the first voltage output of the above PFC circuit. in T is the second voltage between the positive and negative terminals of the input power supply, L is the inductance value of the inductor, and t′ is the zero-crossing time of the inductor current. delay This is the delay time for the first or second switch to turn off after the inductor current crosses zero.

[0024] Through the formula: The subsequent T can be calculated. delay The change in inductor current over a time period, when the inductor current is less than I ref The first time to output the control signal, at T delay This allows the inductor current to be exactly I. offset On the one hand, it can avoid generating excessive negative current that would affect the normal operation of the main circuit; on the other hand, it can generate a suitable amount of negative current, enabling the switching transistors in the main circuit to achieve soft switching.

[0025] In one possible implementation, the controller is further configured to: adjust the first control signal of the first switch and the second control signal of the second switch based on the adjustment signal, including:

[0026] If the above adjustment signal is high, the second switch is turned off and the first switch is turned on.

[0027] When the inductor current is less than I ref The output is high level when the inductor current is greater than I. ref When the output is low, the signal is adjusted to a high level. This turns off the second switch on the upper brush and turns on the first switch, controlling the negative current in the main circuit to the target value.

[0028] In one possible implementation, the PFC circuit further includes an input voltage sampling circuit, the first input terminal of which is electrically connected to the positive terminal of the external power supply. The second input terminal of the input voltage sampling circuit is electrically connected to the negative terminal of the external power supply, and the output terminal of the input voltage sampling circuit is electrically connected to the first input voltage sampling input terminal of the control circuit.

[0029] In one possible implementation, the PFC control circuit described above further includes an output voltage sampling circuit.

[0030] The input terminal of the aforementioned output voltage sampling circuit is electrically connected to the voltage output terminal of the aforementioned PFC main circuit, and is used to obtain the output voltage of the aforementioned PFC main circuit.

[0031] The output terminal of the aforementioned output voltage sampling circuit is electrically connected to the input terminal of the aforementioned control unit.

[0032] In one possible implementation, the voltage input to the above-mentioned input voltage source is a DC voltage or an AC voltage.

[0033] Secondly, a control method for a totem-pole PFC main circuit is disclosed. This method is applied to a totem-pole PFC circuit, which includes a totem-pole PFC main circuit and a control circuit. The totem-pole PFC main circuit includes an inductor and a switching transistor, wherein the switching transistor is used to control the charging or discharging of the inductor. The method includes: acquiring the input voltage and output voltage of the totem-pole PFC main circuit, and generating a given current based on the inductor magnitude; comparing the acquired inductor current with the given current to generate a control signal; and using the control signal to control the switching transistor to turn on or off.

[0034] In one possible implementation, a control signal is generated the moment the inductor current falls below a given current. This control signal switches the first switch in the totem-pole PFC main circuit to the off state and the second switch to the on state. After the switching is complete, the inductor begins to charge.

[0035] One possible implementation is given by the formula: We obtain V. bus V is the output voltage of the PFC main circuit. in The input voltage of the PFC main circuit is given by V, where L is the inductance value of the inductor, and t′ is the value at which the V is obtained. bus or V in The point in time; T delay This is the delay time for the turn-off signal of the first or second switch.

[0036] One possible implementation is given by the formula: We obtain V. bus V is the output voltage of the PFC main circuit. in The input voltage of the PFC main circuit is given by V, where L is the inductance value of the inductor, and t′ is the value at which the V is obtained. bus or V in The point in time; T delay I is the delay time for the turn-off signal of the first or second switch. offset It is the bias current given by the negative current.

[0037] Thirdly, a switching power supply is disclosed, which can be a power supply unit (PSU) for a server, and the switching power supply includes the switching power supply provided in any possible implementation of the first aspect.

[0038] Fourthly, embodiments of this application provide a computing device, characterized in that the computing device includes the aforementioned switching power supply and load, wherein the switching power supply is electrically connected to the load; wherein the switching power supply is used to supply power to the load.

[0039] It should be understood that the implementation and beneficial effects of the above-mentioned aspects or any possible implementation methods of this application can be referred to each other. Attached Figure Description

[0040] The accompanying drawings are provided to more clearly illustrate the technical solutions of the embodiments of this application. The drawings used in the following description of the embodiments will be briefly introduced. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0041] Figure 1 This is a schematic diagram of a PFC circuit structure disclosed in an embodiment of this application;

[0042] Figures 2A to 2G This is a schematic diagram of a totem pole PFC circuit disclosed in an embodiment of this application;

[0043] Figure 3 This is a schematic diagram showing the relationship between inductor current and input voltage in the totem pole PFC circuit disclosed in this application embodiment;

[0044] Figure 4A and Figure 4B This is a schematic diagram of a switching power supply structure disclosed in an embodiment of this application;

[0045] Figure 5A , Figure 5B as well as Figure 6 This is a schematic diagram illustrating the current compensation effect of alternating current disclosed in an embodiment of this application;

[0046] Figure 7A and Figure 7B This is a schematic diagram illustrating the current compensation effect of a DC current disclosed in an embodiment of this application;

[0047] Figure 8 This is a schematic flowchart of a totem pole PFC circuit control method disclosed in an embodiment of this application;

[0048] Figure 9 This is a schematic diagram of the internal circuitry of a server disclosed in an embodiment of this application;

[0049] Figure 10 This is a schematic diagram of the structure of a computing device disclosed in an embodiment of this application. Detailed Implementation

[0050] This application discloses a switching power supply and a computing device. The technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings.

[0051] The switching power supply and computing device provided in this application are applicable to power systems of various devices employing totem-pole PFC circuits, such as servers, user terminals, storage devices, network devices, and charging devices. The user terminal can be an electronic device such as a smartphone, tablet, laptop, desktop computer, smart speaker, smartwatch, or wearable device. The charging device can be a charging device or power adapter for devices such as smartphones, tablets, laptops, desktop computers, smart speakers, smartwatches, wearable devices, and electric vehicles.

[0052] Figure 1 An exemplary schematic diagram 100 of one implementation of a PFC circuit is shown. This PFC boost circuit 100 includes an inductor 102, a diode 103, a switching transistor 104, and a capacitor 105. An input voltage source 101 supplies power to the PFC boost circuit 100. When the switching transistor 104 is on, the input voltage source charges the inductor 102. When the switching transistor 104 is off, the inductor 102 freewheels through the diode 103, supplying power to the load 106. In this case, the conduction loss of the diode 103 is extremely high, affecting the operating efficiency of the PFC circuit.

[0053] The aforementioned switching transistors refer to power electronic devices that can be controlled to both turn on and off via control signals. Examples include gate-turn-off thyristors (GTOs), metal-oxide-semiconductor field-effect transistors (MOSFETs), insulated-gate bipolar transistors (IGBTs), gallium nitride transistors, and silicon carbide transistors.

[0054] To improve the efficiency of PFC, a totem-pole PFC main circuit 200 can be constructed, as exemplified by... Figure 2A As shown. The totem pole PFC main circuit 200 includes: an inductor 202, a first switching transistor 203, a second switching transistor 204, a third switching transistor 205, a fourth switching transistor 206, and a capacitor 207. The input voltage source 201 supplies power to the PFC main circuit 200, and the PFC main circuit 200 supplies power to the load 208.

[0055] For example, taking the first switch 203, the second switch 204, the third switch 205, and the fourth switch 206 as MOSFETs, the connection relationship of the components in the totem-pole PFC circuit is described. The positive terminal of the input voltage source 201 is electrically connected to the first terminal of the inductor 202. The second terminal of the inductor 202 is electrically connected to the drain of the first MOSFET 203 and the source of the second MOSFET 204. The drain of the second MOSFET 204, the drain of the fourth MOSFET 206, the first terminal of the capacitor 207, and the first terminal of the load are electrically connected. The source of the first MOSFET 203, the source of the third MOSFET 205, the second terminal of the capacitor 207, and the second terminal of the load are electrically connected. The drain of the third MOSFET 205, the source of the fourth MOSFET 206, and the negative terminal of the input voltage source 201 are electrically connected.

[0056] The input voltage source 201 can be either AC or DC, and this application makes no restriction. Here, we take the end of the input voltage source 201 closest to the inductor as representing a high potential and the other end as representing a low potential as an example to illustrate the working principle of the totem-pole PFC main circuit 200. When the first MOSFET 203 is turned on and the second MOSFET 204 is turned off, the input voltage source 201 stores energy in the inductor 202. After the first MOSFET 203 is turned off, the second MOSFET 204 is turned on, and the inductor 202 freewheels through the second MOSFET 204. Compared to freewheeling through a diode, the freewheeling through the MOSFET effectively reduces circuit losses and improves the efficiency of the PFC circuit.

[0057] For example, when the input voltage source 201 is close to the first end of the inductor, representing a high potential, the third MOSFET 205 is in the on state and the fourth MOSFET 206 is in the off state. When the input voltage source 201 is close to the first end of the inductor, representing a low potential, the third MOSFET 205 is in the off state and the fourth MOSFET 206 is in the on state.

[0058] In the totem-pole PFC main circuit 200, the input voltage source can be either AC or DC. When the input voltage source is AC, and it is during the positive half-cycle of the AC input voltage source.

[0059] Examples such as Figure 2B As shown, the first terminal of the input voltage source 201 connected to the inductor 202 is at a high potential. The first switch 203 acts as the main conductor, and when it is turned on, the second switch 204 is turned off. The input voltage source 201 charges the inductor 202. The current flows through the positive terminal of the input voltage source 201, the inductor 202, the first switch 203, the fourth switch 206, and back to the negative terminal of the input voltage source 201, forming a loop. At this time, the capacitor 207 supplies power to the load 208.

[0060] Examples such as Figure 2C As shown, the first terminal of the input voltage source 201 connected to the inductor 202 is at a high potential. The first switch 203 is turned off, the second switch 204 is turned on, the inductor 202 discharges, and the current flows through the positive terminal of the input voltage source 201, the inductor 202, the second switch 204, the capacitor 207, the third switch 205, and back to the negative terminal of the input voltage source 201, forming a loop.

[0061] During the negative half-cycle of the AC input voltage source, for example, as shown below. Figure 2D As shown, the input voltage source 201 is connected to the first terminal of the inductor 202 at a low potential. The second switch 204 acts as the main switch. When the first switch 204 is off and the second switch 204 is on, the input voltage source 201 charges the inductor 202. The current flows through the negative terminal of the input voltage source 201, the fourth switch 206, the second switch 204, the inductor 202, and the positive terminal of the input voltage source 201, forming a loop. At this time, the capacitor 207 supplies power to the load 208.

[0062] Examples such as Figure 2E As shown, one end of the inductor 202 at node input voltage source 201 is at a low potential, the first switch 203 is turned on, the second switch 204 is turned off, the inductor 202 discharges, and the current flows through the positive terminal of input voltage source 201, the fourth switch 206, the capacitor 207, the first switch 203, the inductor 202 and the negative terminal of input voltage source 201, forming a loop.

[0063] When the input voltage source is DC, there is no distinction between the positive and negative half-cycles of the voltage; the current flow direction can be referenced to the current flow direction along any half-axis when the input voltage source is AC. For example, [the following is an example]. Figure 2B and Figure 2C A schematic diagram showing the current flow direction during the charging and discharging of an inductor when the input voltage source is DC.

[0064] By properly controlling the on / off state of the switching transistor in the totem-pole PFC circuit, the inductor in the circuit is continuously charged and discharged to maintain the normal operation of the PFC circuit. The change of inductor current in the totem-pole PFC circuit over time is shown below.

[0065] For example, in the totem pole PFC main circuit 200 described above, the normal operation of the circuit is ensured by reasonably controlling the turn-on and turn-off times of the first switch 203 and the second switch 204. When the inductor 202 is charging, the charging current I1(t) is:

[0066] I1(t)=I1(t0)+∫V in (t)dt / L

[0067] Where t0 represents the start time of inductor charging; I1(t0) represents the current value of the inductor when it switches to charging mode; V in (t) represents the input voltage; L represents the inductance value, for example, could be... Figure 2B The value of inductor 202 in the circuit is, for example, 2H. The energy stored during charging is W. L (t)=0.5*L*I1 2 (T on )–0.5*L*I1 2 (t0). Wherein, T on This indicates the duration of inductor charging; for example, it could be 1 millisecond; for example, T... on This information can be obtained from the chip and component datasheet in the circuit. When the main circuit is turned off, the voltage across the inductor, u = L*(di) / (dt), gives the magnitude of the freewheeling current:

[0068] I2(t)=I1(t1)-∫(V bus -V in (t))dt / L.

[0069] Where t1 represents the start time of inductor discharge, and I1(t1) represents the current value of the inductor when it switches to discharge mode; V bus This represents the bus voltage, which is the output voltage of the PFC circuit, for example, 12V. When the freewheeling current drops to 0, it controls the freewheeling diode to turn off and the main control diode to turn on. The main control diode could be, for example, a... Figure 2BThe first switching transistor 203 in the circuit, the freewheeling transistor mentioned above can be, for example, a... Figure 2B The second switching transistor 204 is used. Due to hardware delay, there is a certain delay from the controller issuing the control command to the actual action of the switching transistor. This delay time T delay This will cause a negative current I3 to be generated in the circuit, flowing in the opposite direction to I2. The magnitude of the negative current I3 is:

[0070]

[0071] Here, t2 is the time corresponding to when I2(t) is 0. The following relationship exists between t0, t1, and t2: t0 + T on =t1, where T on This indicates the charging time of the inductor. t1+T off =t3, where T off This indicates the discharge duration of the inductor. t3–T delay = t2, where T delay This represents the hardware latency. Where T... delay It can be obtained through relevant time measurements, and T delay The duration it represents remains constant. For example, T delay It can also be obtained from the chip and / or device datasheet in the circuit.

[0072] The negative current flow direction of the totem pole PFC circuit due to the hardware fixed delay is shown below.

[0073] For example, in the totem pole PFC main circuit 200, when the input voltage source is AC, and during the positive half-cycle of the AC input, due to the hardware delay, a negative current is generated in the circuit. The direction of the current flow is as follows: Figure 2F As shown. At this time, the input voltage source 201 is electrically connected to the first terminal of the inductor 202 at a high potential. The first switch 203 acts as the main conductor and is in the off state, while the second switch 204 is in the on state. The negative current consists of two loops. The first negative current loop consists of the high potential terminal of the capacitor 207, the second switch 204, the inductor 202, the input voltage source 201, the third switch 205, and the low potential terminal of the capacitor 207, forming a loop. The second negative current loop consists of the negative terminal of the input voltage 201, the third switch 205, the first switch 203, and the inductor 202, forming a loop.

[0074] At this time, capacitor 207 supplies power to load 208.

[0075] For example, in the totem-pole PFC main circuit 200, when the input voltage source is AC, and it is during the negative half-cycle of the AC input, a negative current is generated in the circuit due to the hardware delay. The direction of the current flow is as follows: Figure 2GAs shown. At this time, the input voltage source 201 is electrically connected to the first terminal of the inductor 202 at a low potential. The second switch 204 acts as the main conductor, the first switch 203 is in the on state, and the second switch 204 is in the off state. The negative current consists of two loops. The first negative current loop is formed by the high potential terminal of the capacitor 207, the fourth switch 206, the input voltage 201, the inductor 202, the first switch 203, and the low potential terminal of the capacitor 207. The second negative current loop is formed by the negative terminal of the input voltage 201, the second switch 204, the fourth switch 206, and the positive terminal of the input voltage 201.

[0076] At this time, capacitor 207 supplies power to load 208.

[0077] For example, when the input voltage source is DC, the current flow direction can be referenced to the current flow direction along any half-axis when the input voltage source is AC. For example, Figure 2F A schematic diagram showing the reverse current flow in a circuit when the input voltage source is DC.

[0078] From the above analysis, it can be seen that if the controller issues a control command to turn off the freewheeling transistor just as the freewheeling current drops to 0, by the time the transistor is actually turned off, due to the drive delay, the freewheeling current has already reversed and become a negative current. From the formula for calculating I3, it can be seen that the magnitude of the negative current is related to V. bus -V in The pressure difference is related to (t), therefore, near the zero-crossing point of the AC input, due to V bus -V in A large voltage difference at (t) will result in a relatively large negative current. And near the peak value of the AC input voltage source, V... bus -V in (t) Small pressure difference, small negative current.

[0079] Figure 3 An exemplary diagram illustrating the relationship between inductor current and input voltage in a totem-pole PFC circuit is provided. The waveform of input voltage source 301 is a sine wave, the waveform of inductor current 302 is a triangular wave, and the negative current envelope 303 of the negative half-cycle and the negative current envelope 304 of the positive half-cycle of the AC input voltage source are both horseshoe-shaped. It is understood that the voltage 301, inductor current 302, negative current envelope 303, and negative current envelope 304 in the waveform diagram 300 are provided illustratively. When the negative current in the circuit is small, soft switching of the switching transistor cannot be achieved. When the negative current in the circuit is large, it will cause the switching transistor to overheat severely, affecting its lifespan and even the normal operation of the entire circuit. How to control the magnitude of the negative current generated in the circuit is a problem that urgently needs to be solved.

[0080] Furthermore, this application provides a possible implementation method, which can be exemplarily referred to in the following examples. Figure 4A . Figure 4A An exemplary schematic diagram of a switching power supply structure is shown.

[0081] The switching power supply 400 includes a voltage input terminal 201, a totem-pole PFC main circuit 410, and a totem-pole PFC control circuit 420. The voltage input terminal 201 receives the input voltage from the totem-pole PFC main circuit 410, and the totem-pole PFC control circuit 420 controls the operating state of the totem-pole PFC main circuit 410.

[0082] The totem pole PFC main circuit 410 includes an inductor 202 and an inductor state control circuit 411. The totem pole PFC control circuit 420 includes a first input terminal 401, a second input terminal 402, a third input terminal 403, a fourth input terminal 404, a fifth input terminal 405, and a control output terminal 406.

[0083] For example, the inductor state control circuit 411 includes a first switch 203 and a second switch 204.

[0084] For example, the first switch 203 and the second switch 204 are MOSFETs.

[0085] For example, the first input terminal 401 is connected to the positive terminal of the voltage input terminal 201, and the second input terminal 402 is connected to the negative terminal of the voltage input terminal 201. The control circuit 420 of the totem pole PFC samples the input voltage of the totem pole PFC main circuit 410 through the first input terminal 401 and the second input terminal 402.

[0086] For example, the third input terminal 403 and the fourth input terminal 404 are connected to the output terminal of the PFC main circuit, and the control circuit 420 of the totem pole PFC samples the output voltage of the totem pole PFC main circuit 410 through the third input terminal 403 and the fourth input terminal 404.

[0087] For example, the fifth input terminal 405 is connected to an inductor, and the control circuit 420 of the totem-pole PFC samples the inductor current of the totem-pole PFC main circuit 410 through the fifth input terminal 405. The fifth input terminal 405 can also be connected to the positive or negative terminal of the voltage input terminal 201. The fifth input terminal 405 is used to sample the inductor current of the inductor 202. The specific connection position of the fifth input terminal 405 and the totem-pole PFC main circuit 410 is not limited in this application.

[0088] One possible implementation involves calculating a control signal based on the input voltage, output voltage, and inductor current. This control signal is then output to the inductor state control circuit 411 via control output terminal 406, controlling the operating state of the inductor state control circuit 411 and further controlling the inductor current of inductor 202. This overcomes the control lag caused by inherent hardware delays, reduces the heating of the switching transistor, and achieves soft switching of the switching transistor.

[0089] For example, Figure 4B A circuit diagram of a switching power supply is shown, including a totem pole PFC main circuit 200, a totem pole PFC control circuit 420, a current sampling circuit 430, an input voltage sampling circuit 440, an output voltage sampling circuit 450, and a drive circuit 460.

[0090] For a detailed introduction to the Totem Pole PFC main circuit 200, please refer to the aforementioned... Figure 2A The details of the introduction will not be repeated here.

[0091] In one possible implementation, the control circuit 420 includes a comparator 421 and a controller 422. Wherein:

[0092] In one possible implementation, the control circuit 420 can be a digital signal processing (DSP), a 51 microcontroller, an ARM microcontroller, a microcontroller unit (MCU), or a field-programmable gate array (FPGA), etc.

[0093] For example, the two voltage sampling terminals of the input voltage sampling circuit 440 are electrically connected to the two ends of the input voltage source 201, and the input voltage sampling output terminal of the input voltage sampling circuit 440 is electrically connected to the input voltage sampling input terminal of the controller 422.

[0094] For example, the two voltage sampling segments of the output voltage sampling circuit 450 are connected to the two output terminals of the totem pole PFC main circuit, respectively, to obtain the output voltage of the PFC main circuit, also known as the bus voltage.

[0095] For example, the inductor current sampling input terminal of the current sampling circuit 430 is electrically connected to either the first or second terminal of the inductor 202. This inductor current sampling input terminal can also be connected to the positive or negative terminal of the voltage source 201. The location of the inductor current sampling input terminal, used to obtain the magnitude of the inductor current, is not limited in this application.

[0096] The reference current output terminal of the controller 422 is electrically connected to the first terminal ("+") of the comparator 421, and the input current sampling output terminal of the current sampling circuit 430 is electrically connected to the second terminal ("-") of the comparator 421.

[0097] The output of comparator 421 is connected to controller 422. Controller 422 processes the output information of the comparator and generates two PWM waves, PWM1 and PWM2, to control switching transistors 203 and 204. These PWM waves are then sent to drive circuit 460. The control signal output of drive circuit 460 is electrically connected to the control terminal of the first switching transistor 203 and the control terminal of the second switching transistor 204.

[0098] The specific working principle of negative current compensation is as follows:

[0099] In one possible implementation, the input voltage sampling circuit 440 is used to sample the voltage across the input voltage source 201 and transmit the sampled voltage to the controller 422.

[0100] For example, the input voltage sampling circuit 440 includes any one or more of the following: resistors, capacitors, slide wire rheostats, voltage comparators, clamping protection circuits, and voltage sensors, etc. The specific implementation of the voltage sampling circuit 440 is not limited in this application. The sampling frequency of the input voltage sampling circuit 440 can, for example, be 10kHz, 10-300kHz, etc., and this application does not limit the sampling frequency.

[0101] For example, the output voltage sampling circuit 450 includes any one or more of the following: resistors, capacitors, voltage comparators, clamping protection circuits, and voltage sensors, etc. The specific implementation of the output voltage sampling circuit 450 is not limited in this application. The sampling frequency of the output voltage sampling circuit 450 can, for example, be 10kHz, 10-300kHz, etc., and this application does not limit the sampling frequency.

[0102] In one possible implementation, the controller 422 calculates the reference current I based on the input voltage sampled by the input voltage sampling circuit 440 and the output voltage sampled by the output voltage sampling circuit 450. ref and the reference current I ref It is sent to the first end of comparator 422.

[0103] For example, the controller 422 may be a digital signal processing (DSP), a 51 microcontroller, an ARM microcontroller, a microcontroller unit (MCU), or a field-programmable gate array (FPGA).

[0104] In one possible implementation, the controller 422 is based on the input voltage source V sampled by the circuit input voltage sampling circuit 440. in The output voltage V is sampled by the output voltage sampling circuit 450. bus The reference current I is calculated. ref The calculation method can be exemplarily represented by the following formula:

[0105]

[0106] The above V bus and V in Let t' be the voltage obtained at the same time. Here, t′ is the input voltage source V obtained by the input voltage sampling circuit 440. in The time t′ can also be the output voltage obtained by the output voltage sampling circuit 450. bus The time. L represents the magnitude of inductor 202, T... delay This represents the time delay from when the processor issues a control command to when the switching transistor actually operates. For example, V... in and V bus It can be something that changes over time.

[0107] Figure 5A An example is shown with I ref Waveform and V in Waveform diagram 500. (Example) Figure 5A As shown, taking the positive half-cycle of the AC input as an example, as the input voltage 501 increases, the positive half-cycle I of the AC input voltage source... ref The current value 503 gradually decreases. When the input voltage 501 is at its peak, the reference current I... ref The current value 503 drops to a minimum. As the input voltage 501 decreases, I... ref The current value 503 gradually increases, and when the input voltage 501 is 0, I ref The maximum current value is 503. This occurs on the negative half-axis (I) of the AC input voltage source. ref The changing trend, and the negative half-axis I of the AC input voltage source. ref The trend of change is similar, so I will not go into details here.

[0108] In one possible implementation, the controller 422 is based on the input voltage source V sampled by the circuit input voltage sampling circuit 440. in The output voltage V is sampled by the output voltage sampling circuit 450. bus The reference current I is calculated. ref The calculation method can be exemplarily represented by the following formula:

[0109]

[0110] Among them, I offset It is a bias current given by a negative current, with respect to I. offset For detailed information, please see the following sections. Figure 6 The relevant content will not be detailed here. The added I offset It will make Figure 5A The I shown ref The current envelope shifts vertically up and down along the t-axis, and the magnitude of the shift is related to I. offset The value is related to its magnitude.

[0111] For example, if controller 422 receives I ref It is in the form of a pulse width modulation (PWM) wave, and I also needs to be... ref Multiply by the coefficient K to get I ref The analog signal is used as the reference current I at the first input of the comparator. ref .

[0112] Understandably, if the controller 422 calculates I... ref If it is in the form of an analog signal, then I can be directly... ref Send to comparator 421.

[0113] In one possible implementation, the current sampling circuit 430 is used to obtain the current I flowing through the inductor 202. real The sampled current is then output to the second terminal ("-") of comparator 422.

[0114] For example, the current sampling circuit 430 includes any one or more of the following: resistors, capacitors, slide wire rheostats, voltage comparators, clamping protection circuits, and current sensors, etc. The specific implementation of the current sampling circuit 430 is not limited in this application. The sampling frequency of the current sampling circuit 430 can, for example, be 10kHz, 10-300kHz, etc., and this application does not limit the sampling frequency.

[0115] In one possible implementation, comparator 421 is used to compare the reference current I. ref and sampling current I real The controller 422 determines the magnitude of the comparison result signal and outputs it to the controller 422. The controller 422 generates two PWM signals based on the comparison result signal output by the comparator 421 and outputs them to the drive circuit 460 respectively. The drive circuit 460 then controls the first switch 203 and the second switch 204 to turn on and off according to the control signal output by the controller 422.

[0116] For example, comparator 421 may be a single-limit comparator, a hysteresis comparator, a window comparator, or a three-state voltage comparator. This application does not limit the specific type of comparator used.

[0117] Taking the single-limit comparator 421 as an example, the voltage comparator outputs a high level when the voltage at the "+" input is higher than that at the "-" input. The voltage comparator outputs a low level when the voltage at the "+" input is lower than that at the "-" input.

[0118] As can be seen from the above related content, the sampled current I is obtained by sampling. real The reference current I is calculated by the controller 422 and input to the comparator's "-" input terminal. ref The input is given to the "+" input of the comparator. Therefore, in the current I... real Less than current I ref In this case, comparator 421 outputs a high level signal, which is then sent to controller 422. Controller 422 generates two PWM signals based on this high-level signal and outputs them to drive circuit 460. Drive circuit 460 amplifies the PWM signals and outputs them to the first switch 203 and the second switch 204, controlling the switching states of the first switch 203 and the second switch 204. For example, when the switch is off, it is switched to on; when the switch is on, it is switched to off.

[0119] One possible implementation is to use the reference current I ref When the input is given to the "+" input of the comparator, through Figure 4B The control circuit shown yields the following result: Figure 5B The waveforms of the inductor current and the input voltage source are shown in Figure 510. The input voltage 501 has a sinusoidal waveform, the inductor current has a triangular waveform, and the reference current I during the negative half-cycle of the AC input voltage is... ref The current value 502 and the I of the positive half-cycle of the AC input voltage source ref The reference current value 503 is horseshoe-shaped. Within one control cycle, the inductor current includes: T on Inductor current during time period, T off Inductor current during the time period and T delay The inductor current during the time period. Where, T on Inductor current during time period and T off The inductor current during the time period is represented by the solid black line, T. delay The inductor current during a given period is represented by a black dashed line. The inductor current is related to the voltage 501 in the waveform diagram 510 and the negative half-cycle I of the AC input voltage source. ref Current value 502, positive half-cycle I of AC input voltage source ref The current value 503 and the inductor current are both exemplary.

[0120] For example, the above T on It is a fixed time, during the positive half-cycle of the AC input voltage, that inductor 202, after T... on After charging for a certain period of time, the control circuit turns off the first switch 203 and turns on the second switch 204, causing the inductor 202 to be in a discharging state. While the inductor is discharging, when the inductor current is less than I... ref Under these conditions, comparator 421 outputs a high level to controller 422, and controller 422 generates two control signals for control purposes: the first switch 203 is turned on and the second switch 204 is turned off. After T... delay After a certain time, the first switch 203 completes the conduction action, the second switch 204 completes the turn-off action, and the inductor 202 enters the next charging and discharging cycle.

[0121] Waveform diagram 510 provides an example of T on Time period, T off Time period and T delay The time period range. Where T... on The time period refers to the period during which the inductor is charged, specifically the time period during which the inductor current continuously increases over time. T off The time period refers to the period during which the inductor discharges, specifically the time period corresponding to the solid black line in the diagram where the inductor current continuously decreases over time. T delay The time period refers to the period from when the control command is issued to when the switching transistor actually switches states; specifically, it is the time period represented by the black dashed line indicating that the inductor current is decreasing over time. The aforementioned control command is used to control the switching transistor to switch states.

[0122] As can be seen from waveform 510, during the inductor discharge phase, comparator 422 determines that the inductor current is less than the reference current I. ref The first time the current value is measured is the time when the control command was issued.

[0123] One possible implementation is based on the reference current formula:

[0124]

[0125] One possible implementation is based on the reference current formula:

[0126]

[0127] Figure 4B The switching power supply shown can, on the one hand, avoid overheating of the switching transistor due to excessive negative current, thereby increasing the lifespan of the switching transistor and the stability of the circuit. On the other hand, it can also prevent overheating of the switching transistor due to excessive negative current, thus increasing the lifespan of the switching transistor and the stability of the circuit. offsetThe size of the current can be flexibly generated to indicate the end of the inductor discharge.

[0128] because Figure 4B The switching power supply shown can be configured by setting the bias current I. offset The size of the current can be flexibly adjusted to generate the current at the end of the inductor discharge. Therefore, this method can also achieve soft switching of the switching transistor in the totem-pole PFC main circuit during operation.

[0129] For example, with Figure 2F For example. Figure 2F This is a schematic diagram of the negative current flow in the totem pole PFC main circuit 200. Under operating conditions, Figure 2F Switch 204 is in the ON state, and switch 203 is in the OFF state. Figure 2F It can be seen that the negative current charges the junction capacitance of switch 204 and simultaneously discharges the junction capacitance of switch 203. When the magnitude of the negative current reaches a certain threshold, soft switching of both switch 203 and switch 204 can be achieved simultaneously. The magnitude of the negative current can be set by adjusting the bias current I. offset Adjust the size. offset The specific value needs to be set according to the current required for the switching transistor to achieve soft switching, which affects I. offset Factors affecting the value include one or more of the following: the type of switching transistor, the power of the switching transistor, the operating frequency of the switching transistor, and the size of the load. Regarding I... offset The value of is not restricted in this application.

[0130] like Figure 6 As shown, this application exemplarily illustrates a waveform diagram 600 of the inductor current versus the input voltage source obtained using the aforementioned method. From Figure 6 As can be seen, the magnitude of the negative current 604 in the circuit is a constant value. By adjusting the magnitude of the negative current 604, soft switching of the switching transistor in the totem-pole PFC main circuit can be achieved. Since the magnitude of the negative current is controllable, soft switching of the switching transistor in the totem-pole PFC main circuit can be achieved at both full input and full load.

[0131] Here, "full input" refers to all input voltages of the totem-pole PFC main circuit, meaning that within the allowable range of the input voltage source, all voltages can be adjusted by I... offset Implement soft switching of the switching transistor in the totem pole PFC main circuit.

[0132] Full load refers to the totem pole PFC main circuit being able to operate under load within its permissible range by adjusting I. offset Implement soft switching of the switching transistor in the totem pole PFC main circuit.

[0133] One possible implementation is to Figure 2AFor example, the input voltage is a DC voltage. When the input voltage is a DC voltage, Figure 4B The switching power supply shown is also applicable. The specific implementation process is similar to that when the input voltage is AC voltage, so it will not be described in detail here.

[0134] For example, Figure 7A The waveform diagram 700 shows the inductor current versus the input voltage source when the input voltage is DC. The input voltage source 701 is a fixed voltage, and since the bus voltage is also a fixed voltage, the inductor current can be obtained from the aforementioned formulas for I1 and I2. During one charge / discharge cycle, T... delay The inductor current during the specified time period is represented by a black dashed line, while the inductor current during other time periods is represented by a black solid line. When the inductor current is 0, a control command is issued to control the switching state of the switching transistor in the circuit. During the delay time T... delay Afterwards, the switching state of the switching transistor is switched, resulting in a negative current of 702. This negative current may be too small to meet the soft switching requirements of the switching transistor, or it may be too large, causing the switching transistor to overheat, thereby affecting the lifespan of the switching transistor and the stability of the circuit.

[0135] For example, Figure 7B Waveform 710 shows the inductor current versus input voltage source obtained using the aforementioned circuit control method when the input voltage source is a DC voltage. Waveform 710 adds I compared to waveform 700. ref The current value is 713. The Iref current value of 713 is obtained through the aforementioned circuit control method; please refer to the relevant content above for the specific implementation process, which will not be repeated here. Through I... ref The current value of 713 can also be used to adjust the magnitude of the negative current, achieving the same effect when the input voltage source is AC voltage.

[0136] Figure 8 A schematic flowchart of a totem pole PFC circuit control method provided in this application embodiment is shown below. Figure 8 As shown, the totem pole PFC circuit control method can include the following steps.

[0137] S801: Obtain a first voltage and a second voltage of the target circuit, wherein the first voltage is the input voltage of the target circuit and the second voltage is the output voltage of the target circuit.

[0138] For example, the target circuit described above can be a totem pole PFC circuit and an extension circuit of the totem pole PFC circuit. For example, it could be... Figure 2A The circuit shown.

[0139] In one possible implementation, the input voltage of the target circuit described above can be either a DC voltage or an AC voltage.

[0140] S802: Obtain the first current based on the first voltage and the second voltage mentioned above.

[0141] For example, the first current described above is obtained by the following formula.

[0142]

[0143] In the above formula, V in The first voltage, V bus The second voltage is L, and the inductance in the target circuit described above can be, for example, [the voltage could be L]. Figure 2A The inductor in the middle is 202. t3 and T delay Please refer to the above. Figure 4B The details of the introduction will not be repeated here.

[0144] For example, the first current described above can also be obtained using the following formula.

[0145]

[0146] For more information on the above formula, please refer to [link / reference]. Figure 5A The details of the introduction will not be repeated here.

[0147] S803: Obtain the second current of the target circuit mentioned above, which is associated with the first voltage mentioned above.

[0148] For example, the aforementioned second current could be, for instance, Figure 2A The current in inductor 202.

[0149] S804: Compares the first current and the second current, and outputs a first signal. The first signal is used to control the target circuit.

[0150] For example, when the second current is less than the first current, the first signal is output. The first signal is used to control the switching transistor in the target circuit to switch its switching state.

[0151] by Figure 2C For example, when inductor 202 is in the freewheeling phase, the first switch 203 is off and the second switch 204 is on. This freewheeling current is equivalent to the second current mentioned above. When the freewheeling current is less than the first current mentioned above, the first switch 203 and the second switch 204 are switched between states. That is, switch 203 is switched to the off state and switch 204 is switched to the on state.

[0152] Figure 8 For the implementation principle and technical effects of the method shown, please refer to the aforementioned related solutions, which will not be repeated here.

[0153] This application discloses a schematic diagram of the internal circuitry of a server, as shown in the embodiments below. Figure 9 As shown in the diagram, this circuit may include a totem-pole PFC main circuit 901, a load 902, and a control circuit 903. AC power V1 is converted into DC power V2 by the totem-pole PFC main circuit 901 based on the drive signal from the control circuit 903. Furthermore, the totem-pole PFC main circuit 901 can also adjust the power factor of the circuit. The DC power V2 output by the totem-pole PFC main circuit 901 can power the load 902.

[0154] For example, the input AC power V1 can be provided by the AC power grid, such as 110V, 220V, 380V, etc.

[0155] For example, the control circuit 903 is as described above. Figure 4A The control circuit shown generates a given current based on the input and output voltages of the totem-pole PFC main circuit. This given current is compared with the inductor current of the totem-pole PFC main circuit to generate a control signal. This control signal is used to control the on / off state of the switching transistor in the totem-pole PFC main circuit, and the control signal exists in the form of a PWM wave. It should be noted that the operating frequency of the switching transistor in this embodiment can be in the kilohertz (kHz) range, such as 20 kHz, and correspondingly, the period of the PWM control signal for the switching transistor can be in the microsecond range.

[0156] A load 902 can be an electronic device such as a server, a smart car, a laptop, a desktop computer, or an industrial robot, or its internal components or external electronic devices. For example, in the case of a server load, the load can specifically be components such as the server's processor, memory, hard drive, and network card.

[0157] like Figure 10 As shown, Figure 10 This is a schematic diagram of the structure of a computing device disclosed in an embodiment of this application. The computing device 1000 can be an electronic device such as a server, switch, or computer; the computing device 1000 can include a switching power supply 1004, which can include any totem pole PFC circuit, and the controller in the PFC circuit can be used to execute the current calculation method shown in step S802 above.

[0158] The computing device 1000 may further include a processor 1001, a memory 1003, and a transceiver 1002. The processor 1001, memory 1003, transceiver 1002, and switching power supply 1004 can communicate with each other via internal connections to transmit control and / or data signals. The memory 1003 stores computer programs, and the processor 1001 retrieves and runs the computer program from the memory 1003 to control the transceiver 1002 to transmit and receive signals. The processor 1001 executes the program code stored in the memory 1003 to achieve the above functions. In specific implementations, the memory 1003 may be integrated into the processor 1001 or independent of the processor 1001. The transceiver 1002 may also be referred to as a transceiver unit or transceiver module. The transceiver 1002 may include a receiver (or receiver circuit) and a transmitter (or transmitter circuit). The receiver is used to receive signals, and the transmitter is used to transmit signals. Transceiver 1002 can be used to communicate with other devices.

[0159] It should be understood that the term "connection" in this application can be understood as a direct connection (i.e., an electrical connection) or an indirect connection, that is, a connection made through other devices, components, modules, or apparatuses.

[0160] In the circuits and / or methods provided in this application, it should be understood that the disclosed circuits, systems, and methods can be implemented in other ways. For example, the control circuit embodiments described above are merely illustrative; for instance, the division of modules or units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another device, or some features may be ignored or not executed. Furthermore, the mutual coupling or direct coupling or communication connection shown or discussed may be through some interfaces, indirect coupling or communication connection between devices or units, and may be electrical, mechanical, or other forms.

[0161] The units described as separate components may or may not be physically separate. A component shown as a unit can be one or more physical units; that is, it can be located in one place or distributed in multiple different locations. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0162] It should be understood that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. In this application, "at least one" means one or more, and "more than one" means two or more. It should be understood that such data can be interchanged where appropriate so that the embodiments described herein can be implemented in a sequence other than that illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0163] Obviously, the embodiments described above are only some embodiments of this application, and not all embodiments. Those skilled in the art will recognize that, with technological advancements and the emergence of new scenarios, the technical solutions provided in the embodiments of this application are also applicable to similar technical problems.

[0164] Finally, it should be noted that the above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A switching power supply, characterized by comprising: The switching power supply comprises a power factor correction (PFC) circuit, the PFC circuit comprising a main circuit and a control circuit; The main circuit comprises an inductor, a first switch tube, a second switch tube and a capacitor; a first end of the inductor is electrically connected to a positive pole of an input power supply; a second end of the inductor, a first end of the first switch tube and a second end of the second switch tube are electrically connected; a first end of the second switch tube and a first end of the capacitor are electrically connected to a first end of an external load; a second end of the first switch tube, a second end of the capacitor and a negative pole of the input power supply are electrically connected to a second end of the external load; The control circuit comprises a first control signal output end, a second control signal output end, an input voltage sampling input end, an output voltage sampling input end and an inductor current sampling input end; wherein the first control signal output end is electrically connected to a control end of the first switch tube, and the second control signal output end is electrically connected to a control end of the second switch tube; the control circuit is used for controlling working states of the first switch tube and the second switch tube; The input voltage sampling input end of the control circuit is used for acquiring a first voltage between the positive pole of the input power supply and a negative pole of the input power supply; The output voltage sampling input end of the control circuit is used for acquiring a second voltage output by the PFC circuit; The inductor current sampling input end of the control circuit is used for acquiring an inductor current; The control circuit is further used for: determining a reference current based on the first voltage and the second voltage; generating an adjustment signal according to the inductor current and the reference current; adjusting a first control signal and a second control signal based on the adjustment signal; wherein the first control signal is used for controlling conduction and turn-off of the first switch tube, and the second control signal is used for controlling conduction and turn-off of the second switch tube.

2. The switching power supply according to claim 1, characterized in that The control circuit comprises a controller and a comparator; the controller comprises a first control signal output end, a second control signal output end, an input voltage sampling input end, an output voltage sampling input end, a reference current output end and an adjustment signal input end; the reference current output end of the controller is electrically connected to a first end of the comparator; a second end of the comparator is electrically connected to one end of the inductor, and is used for acquiring the inductor current; the input voltage sampling input end of the controller is used for acquiring the first voltage; the output voltage sampling input end of the controller is used for acquiring the second voltage; an output end of the comparator is electrically connected to the adjustment signal input end of the controller; The control circuit is further used for determining an adjustment signal based on the reference current and the inductor current, comprising: the comparator determines the adjustment signal based on magnitudes of the inductor current and the reference current.

3. The switching power supply of claim 2, wherein The control circuit is further used for determining a reference current based on the first voltage and the second voltage, comprising: The control circuit is configured to determine the reference current based on a formula: Iref = K * (Vref - Vout) ; wherein, V is a second voltage outputted by the PFC circuit, in L is an inductance value of the inductor, V is a first voltage between the input positive and negative poles, bus or V in is a time point at which the V delay is acquired; and T is a delay time of the first switch tube or the second switch tube off signal.

4. The switching power supply according to claim 2, wherein the control circuit is used for determining a reference current based on the first voltage and the second voltage, comprising: the control The circuit is based on the formula: Iref = Vref / R / L + I offset determining the reference current ; wherein, V is a first voltage output of the PFC circuit, in L is an inductance value of the inductor, T is a zero-crossing time of the inductor current, delay I is a delay time of the first switch or the second switch, offset I is a bias current given to the negative current.

5. Switching power supply according to any of claims 2-4, characterized in that The controller is further configured to adjust a first control signal of the first switch tube and a second control signal of the second switch tube based on the adjustment signal, including: If the adjustment signal is high, the second switch tube is turned off and the first switch tube is turned on.

6. Switching power supply according to any of claims 2-4, characterized in that The PFC circuit further comprises an input voltage sampling circuit; a first input end of the input voltage sampling circuit is electrically connected with a positive pole of the input power supply; a second input end of the input voltage sampling circuit is electrically connected with a negative pole of the input power supply; and an output end of the input voltage sampling circuit is electrically connected with an input voltage sampling input end of the controller.

7. Switching power supply according to any of claims 2-4, characterized in that The PFC circuit further comprises an output voltage sampling circuit. An input end of the output voltage sampling circuit is electrically connected with a voltage output end of the PFC main circuit, for obtaining an output voltage of the PFC main circuit. An output end of the output voltage sampling circuit is electrically connected with an output voltage sampling input end of the controller.

8. Switching power supply according to any of claims 2-4, characterized in that The PFC circuit further comprises a current sampling circuit; a first end of the current sampling circuit is electrically connected with a first end or a second end of the inductor; and a second end of the current sampling circuit is electrically connected with a second end of the comparator.

9. Switching power supply according to any of claims 1-4, characterized in that The input voltage of the input power supply is a direct current voltage or an alternating current voltage.

10. A computing device, comprising: The computing device comprises the switching power supply and the load according to any one of claims 1-9, the switching power supply being electrically connected with the load; wherein the switching power supply is configured to supply power to the load.

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