Power factor correction converter and method of operation thereof

Abstract

To provide a power factor correction converter and a method for operating the same.SOLUTION: In a power supply device 10, a power factor correction (PFC) converter 12 includes an inductor 100, a main switch 110, a voltage divider 120, a diode 130, and a controller 140. The main switch controls an inductor that performs magnetization and demagnetization, and voltage difference between two ends of the main switch is a switch voltage. The voltage divider divides the switch voltage to generate a divided voltage. The controller performs, periodically in a general mode, the steps of: turning on the main switch; turning off the main switch after the main switch is turned on for a period of time; obtaining the switch voltage according to the divided voltage; determining, according to the switch voltage and a predetermined output voltage of the PFC converter, a period in which the main switch is turned on next time; and obtaining an output voltage according to the switch voltage in a period after the main switch is turned off.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to Chinese Patent Application No. 202211381861.X, filed on November 4, 2022, entitled "POWER FACTOR CORRECTION CONVERTER AND OPERATION METHOD THEREOF," the disclosure of which is incorporated herein by reference in its entirety.

[0002] The present invention relates to converters, and more particularly to power factor correction converters. [Background technology]

[0003]

[0003] A power factor correction converter can reduce the phase difference between voltage and current during voltage conversion. When applied to a high voltage (for example, in a transient mode or a discontinuous mode), the power factor correction converter needs to detect the voltages at the two ends of the main switch and the voltage at the output end using a complex method, which significantly increases the circuit layout area and standby power consumption of the power factor correction converter. Therefore, how to reduce the circuit size and standby power consumption of the power factor correction converter is one of the urgent problems to be solved in the art. Summary of the Invention [Problem to be solved by the invention]

[0004]

[0004] One of the purposes of this application is to disclose a power factor correction converter and an operating method thereof to solve the above problems. [Means for solving the problem]

[0005]

[0005] One embodiment of the present application relates to a power factor correction converter having an input terminal and an output terminal and operable in a normal mode, the power factor correction converter comprising an inductor, a main switch, a voltage divider, a diode, and a controller. A first end of the inductor is coupled to the input terminal. The main switch is coupled between a second end of the inductor and a ground terminal and configured to control the inductor to perform a magnetizing operation and a demagnetizing operation, and a voltage difference between the two ends of the main switch is a switch voltage. The voltage divider is coupled to the two ends of the main switch, and the voltage divider and the main switch are connected in parallel, and the voltage divider is configured to perform a voltage dividing operation on the switch voltage to generate a divided voltage lower than the switch voltage. The diode is coupled to the output terminal and the second end of the inductor. The controller is coupled to the main switch and the voltage divider and is configured to periodically turn on the main switch in a normal mode, turn off the main switch after the main switch has been turned on for a certain length of time, obtain a switch voltage according to a divided voltage generated by the voltage dividing operation, determine a length of time for which the main switch will next be turned on according to the switch voltage and a predetermined output voltage of the power factor correction converter, and obtain an output voltage according to the switch voltage within a certain length of time after the main switch has been turned off.

[0006] Another embodiment of the present application relates to a power supply device including a power factor correction converter and a voltage regulation circuit. The voltage regulation circuit is coupled to an output end of the power factor correction converter and a controller, and is configured to regulate the output voltage of the power factor correction converter to a regulated voltage and generate a feedback signal according to a change in the regulated voltage. The power factor correction converter is further operable in a sleep mode, and when the power factor correction converter is operated in the sleep mode, the frequency at which the main switch is turned on by the controller is lower than the frequency at which the main switch is turned on when the power factor correction converter is operated in the normal mode. When the power factor correction converter is operated in the sleep mode, the controller determines whether to increase the frequency at which the main switch is turned on according to the feedback signal.

[0007] Another embodiment of the present application relates to a method for operating a power factor correction converter, the power factor correction converter being operable in a normal mode, the power factor correction converter comprising an inductor, a main switch, a voltage divider, and a diode, wherein a first end of the inductor is coupled to an input end of the power factor correction converter, the main switch is coupled between a second end of the inductor and ground, a voltage difference between the two ends of the main switch is a switch voltage, the voltage divider is coupled to the two ends of the main switch, the voltage divider and the main switch are connected in parallel, and the diode is coupled to an output end of the power factor correction converter and the second end of the inductor. The method includes periodically turning on a main switch in a normal mode, turning off the main switch after the main switch has been turned on for a certain length of time, obtaining a switch voltage according to a divided voltage generated by a voltage dividing operation performed on the switch voltage by a voltage divider and lower than the switch voltage, determining a length of time for which the main switch will next be turned on according to the switch voltage and a predetermined output voltage of the power factor correction converter, and obtaining an output voltage according to the switch voltage within a certain length of time after the main switch has been turned off.

[0008] Another embodiment of the present application relates to a method for operating a power supply device including a power factor correction converter, the method including adjusting an output voltage of the power factor correction converter to a regulated voltage and generating a feedback signal according to a change in the regulated voltage, the feedback signal determining whether a controller of the power factor correction converter operated in a sleep mode should increase the frequency at which a main switch of the power factor correction converter is turned on.

[0009]

[0009] Since the power factor correction converter of the present application takes the switch voltage detected after the main switch is turned off as the output voltage, only one group of voltage dividers is required to detect the switch voltage and obtain the output voltage, and therefore the circuit design area and standby power consumption of the power factor correction converter of the present application can be significantly reduced compared with the circuit design area and power consumption of a general power factor correction converter.

[0010] Aspects of the present disclosure will be better understood from the following embodiments when read in conjunction with the accompanying drawings. It should be noted that, according to standard practice in the industry, the various structures are not drawn to scale. In fact, the sizes of the various structures may be arbitrarily increased or decreased for clarity of illustration. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a schematic diagram of one embodiment of a power supply device according to the present application; [Figure 2] 3A and 3B are voltage or current waveform diagrams of each assembly in a power factor correction converter according to the present application. [Figure 3] 1 is a schematic diagram of one embodiment of a power supply device according to the present application; DETAILED DESCRIPTION OF THE INVENTION

[0012]

[0014] The following disclosure provides numerous different embodiments or examples for implementing different structural members of the provided subject matter. To simplify the disclosure, specific examples of assemblies and configurations are described below. Of course, the foregoing are merely examples and are not intended to be limiting. For example, in the following description, a first structural member formed above or on a second structural member may include embodiments in which the first and second structural members are in direct contact with each other, and may also include embodiments in which an additional structural member is formed between the first and second structural members, such that the first and second structural members are not in direct contact with each other. Furthermore, the disclosure may repeatedly refer to numbers and / or letters in various examples. This repetition is for simplicity and clarity and does not, in itself, indicate a relationship between the various embodiments and / or configurations described.

[0013]

[0015] Additionally, for convenience of description, spatially relative terms, such as "beneath," "below," "lower," "above," "upper," "on," etc., may be used herein to describe the relationship between one assembly or structural member and another assembly or structural member depicted in the figures. In addition to the orientation shown in the figures, spatially relative terms may be intended to encompass different orientations of the device during use or operation. Devices may be oriented in some cases (by rotating 90 degrees or in other orientations), and therefore, spatially relative descriptors used herein may be interpreted similarly.

[0014]

[0016] As used herein, terms such as "first," "second," and "third" are used to describe various assemblies, structural members, regions, layers, and / or portions, but such assemblies, structural members, regions, layers, and / or portions should not be limited by such terms. Such terms may be used only to distinguish one assembly, structural member, region, layer, or portion from another. Terms such as "first," "second," and "third" do not imply a sequence or order when used herein unless clearly indicated by context.

[0015]

[0017] The singular forms "a," "an," and "the" may include the plural forms unless the context clearly dictates otherwise. The term "connected," along with its derivatives, may be used herein to describe a structural relationship between components. "Connected" may be used to describe two or more assemblies that are in direct physical or electrical contact with each other. "Connected" may also be used to indicate that two or more assemblies are in physical or electrical contact with each other, directly or indirectly (with an intervening assembly therebetween), and / or that two or more assemblies cooperate or interact with each other.

[0016]

[0018] A voltage converter can adjust the AC input voltage to a target output voltage. During the conversion process, if the phase difference between the generated voltage and the current is too large, the gap between the active power and the apparent power of the voltage converter will be too large. The voltage converter can reduce the phase difference between the voltage and the current by introducing power factor correction (PFC), so that the input current of the voltage converter is close to the current in a pure resistive load, and therefore the active power is close to the apparent power.

[0017]

[0019] In some embodiments, in applications where the power factor correction converter is at a high voltage (such as in a transient mode or a discontinuous mode), two groups of voltage dividers are used to perform a voltage division operation on the voltages at the two ends of the main switch and the output voltage, respectively, and the controller therein requires two input terminals connected to the two groups of voltage dividers to detect the divided voltages at the two ends of the main switch and the divided voltage of the output voltage subjected to the voltage division operation. However, in order to further reduce the layout area of the resistors included in the voltage divider in the circuit design and reduce the standby power consumption of the power factor correction converter, the present application also provides other embodiments as follows:

[0018]

[0020] In particular, this application discloses a power factor correction converter and its operation method. Only one group of voltage dividers can be used to detect the voltages at the two ends of the main switch, and in this case, the output voltage is obtained according to the characteristic that the voltage between the two ends of the main switch is close to the output voltage. The power factor correction converter and its operation method are further described as follows.

[0019]

[0021] FIG. 1 is a schematic diagram of one embodiment of a power supply device 10 according to the present application. In FIG. 1, the power supply device 10 includes a power factor correction converter 12 and a voltage regulation circuit 14. The power factor correction converter 12 has an input terminal E_in and an output terminal E_out and is operable in a normal mode. The input terminal E_in may be coupled to a full-wave rectifier circuit (not shown). The full-wave rectifier circuit may convert an AC voltage received from an external source (e.g., a wall socket) into a rectified voltage by performing a rectification operation. The rectified voltage is supplied to a capacitor C of the power factor correction converter 12. in The input voltage V in The output terminal E_out can function as the output voltage V generated by the power factor correction converter 12. out The output voltage is supplied to the capacitor C out The voltage regulation circuit 14 is coupled to the output terminal E_out of the power factor correction converter 12 and regulates the output voltage V outto generate regulated voltage V2. In some embodiments, voltage regulation circuit 14 may be implemented using a switching buck converter or a boost converter. In applications where power conversion efficiency is not strictly required, voltage regulation circuit 14 may be a linear voltage regulator. Voltage regulation circuit 14 has an output E_out2 configured to couple to a load or electronic device (not shown). Voltage regulation circuit 14 may supply the generated regulated voltage V2 to the load or electronic device.

[0020]

[0022] The power factor correction converter 12 includes an inductor 100 , a main switch 110 , a voltage divider 120 , a diode 130 , and a controller 140 .

[0021]

[0023] A first end of the inductor 100 is coupled to the input terminal E_in of the power factor correction converter 12 and is coupled to the input voltage V in The stored energy is converted into an output voltage V out can be supplied to generate

[0022]

[0024] The main switch 110 is coupled between the second end of the inductor 100 and the ground end, and is configured to control the inductor 100 to perform magnetizing and demagnetizing operations. When the main switch 110 is turned on, the input voltage V in is the induced current I flowing through inductor 100 L The induced current I L increases with time, and the inductor 100 performs a magnetizing operation and stores energy. After the energy has been stored for a period of time, the main switch 110 is turned off and the induced current I L decreases over time, and the inductor 100 releases the stored energy and performs a demagnetizing operation. Furthermore, the voltage difference between the two ends of the main switch decreases to the switch voltage V sw is.

[0023]

[0025] The voltage divider 120 is coupled to two ends of the main switch 110, and the voltage divider 120 and the main switch 110 are connected in parallel. The voltage divider 120 divides the switch voltage V sw It performs a voltage divider operation on the switch voltage V sw A divided voltage V that is lower than ms Generally, the switch voltage V of the power factor correction converter 12 is sw is at a high voltage and cannot be directly sensed by the power factor correction converter 12. Instead, the switch voltage V sw It performs a voltage divider operation on the switch voltage V sw A divided voltage V that is lower than ms It is necessary to generate a switch voltage V sw and the divided voltage V generated by the voltage division operation ms There is a multiple relationship between the power factor correction converter 12 and the divided voltage V ms After detecting the switch voltage V sw The magnitude of can be obtained by multiple relations.

[0024]

[0026] The diode 130 is coupled to the output terminal E_out and the second end of the inductor 100. When the main switch 110 is turned on, the diode 130 is turned off. When the main switch 110 is turned off, the diode 130 is turned on, and when the inductor 100 performs a demagnetizing operation, the stored energy is supplied to the output terminal E_out to generate the output voltage V out When the diode 130 is turned on, the two ends of the diode 130 are connected to a turn-on voltage V D Generally, the turn-on voltage V D is approximately 0.7 to 1 volt.

[0025]

[0027] When the main switch 110 is turned off, the switch voltage V sw and turn-on voltage V D and the output voltage V out The relationship between can be written as equation (Eq. 1): V sw =-VD +V out (Formula 1)

[0026]

[0028] Switch voltage V sw and the output voltage V out is several hundred volts, and the turn-on voltage V D Since the magnitude of is only 0.7 to 1 volts, the turn-on voltage V D The magnitude of the switch voltage V sw and the output voltage V out In other words, the turn-on voltage V D The magnitude of the switch voltage V sw The magnitude of the output voltage V out Therefore, the obtained output voltage V out When the magnitude of V does not need to be very accurate, and when only one group of voltage dividers 120 is used, the power factor correction converter 12 can be configured to sw The magnitude of the output voltage V out Another group of voltage dividers may be taken as the magnitude of the output voltage V out To obtain the output voltage V out , thereby saving circuit layout area in the design of the power factor correction circuit 12. out The preferred voltage swing of the output voltage V may be 50 volts or greater, or may be less than 100 volts depending on the specific application requirements. out The voltage amplitude may be up to 50 volts.

[0027]

[0029] The controller 140 is coupled to the main switch 110 and the voltage divider 120 and is configured to control the main switch 110 to be turned on or off, and the voltage divider 120 to generate a switch voltage V sw The divided voltage V generated after performing a voltage division operation on ms The device is configured to detect:

[0028]

[0030] 2 is a voltage or current waveform diagram 20 of each assembly in the power factor correction converter 12 according to the present application. In FIG. 2, the horizontal axis represents time, and the vertical axis represents, from top to bottom, the voltage or current waveforms V 100, which are output by the controller 140. d , the switch voltage V of the main switch 110 sw , the turn-on voltage V of the diode 130 D , the induced current I flowing through the inductor 100 L , and the output voltage V out A complete switching cycle 200 includes the controller 140 turning the main switch 110 on, the controller 140 turning the main switch 110 off, and then the controller 140 turning the main switch 110 on again.

[0029]

[0031] Please refer simultaneously to Figures 1 and 2. When the power factor correction converter 12 is operated in normal mode, the controller 140 periodically performs the following steps.

[0030]

[0032] First, the controller 140 turns on the main switch 110, causing the inductor 100 to perform a magnetizing operation, and an induced current I L rises, and the output voltage V out The above steps may correspond to the first stage 201 of the switching cycle 200 in FIG. 2. At the moment when the switching cycle 200 enters the first stage 201, the driving voltage V d rises from 0 to turn on the main switch 110, and after the main switch 110 is turned on, the inductor 100 starts to magnetize, and an induced current I L gradually rises from 0, and the main switch 110 is turned on, so that the switch voltage V sw is 0.

[0031]

[0033] Then, after the main switch 110 has been turned on for a certain length of time, the controller 140 turns the main switch 110 off, and the inductor 100 performs a demagnetizing operation, releasing the stored energy to lower the output voltage V out , the diode 130 is turned on, causing an induced current I to flow through the inductor 100. L decreases, and the controller 140 controls the divided voltage V ms According to the switch voltage V sw and the controller 140 controls the switch voltage V sw and the predetermined output voltage of the power factor correction converter 12. The above steps may correspond to the second phase 202 of the switching cycle 200 in FIG. 2. At the moment when the switching cycle 200 enters the second phase 202, the driving voltage V of the main switch 110 is d is controlled to drop to 0 to turn off the main switch 110, and after the main switch 110 is turned off, the inductor 100 starts to demagnetize, and the induced current I L gradually decreases, at which point diode 130 is turned on and the two ends of diode 130 are connected together with a turn-on voltage V of approximately 0.7 to 1 volts. D According to the formula (1), the magnitude of the turn-on voltage is the switch voltage V sw and the output voltage V out When the switch voltage V sw The magnitude of the output voltage V out In the second stage 202, the controller 140 adjusts the switch voltage V sw By detecting the output voltage V out The size of the

[0032]

[0034] Furthermore, the controller 140 controls the obtained switch voltage V sw The controller 140 then determines the length of time that the main switch 110 will be turned on by comparing the switch voltage Vsw is lower than the predetermined output voltage, the controller 140 determines that the length of time that the main switch 110 is turned on next will be increased, so that the inductor 100 can store more energy in the next phase that the main switch 110 is turned on, and thus the output voltage V out reaches a predetermined output voltage magnitude. Conversely, the switch voltage V obtained by the controller 140 sw is higher than the predetermined output voltage, the controller 140 determines that the length of time that the main switch 110 is next turned on is reduced, the inductor 100 stores less energy in the next phase that the main switch 110 is turned on, and therefore the output voltage V out reaches a predetermined output voltage magnitude.

[0033]

[0035] Finally, after the inductor 100 has completed the demagnetizing operation, the induced current I L drops to 0 and the switch voltage V sw begins to resonate, and the switch voltage V sw is between the peak and valley values of the resonance. To minimize energy loss when the main switch 110 is switched, the controller 140 adjusts the switch voltage V sw is at the valley value of resonance. This step may correspond to the third stage 203 of the switching cycle 200 in FIG. 2. After the switching cycle 200 enters the third stage 203, the main switch 110 is still turned off, so the driving voltage V of the main switch 110 d is still controlled to be 0. After the demagnetization operation is completed, the switch voltage V sw and the induced current I L The divided voltage V ms Switch voltage V sw Since the ratio of the detected divided voltage V ms is at the valley of resonance (current switch voltage V swis also at the resonance valley value), the controller 140 turns on the main switch 110 and the switching cycle 200 enters the first phase 201 from the third phase 203 to enter the next switching cycle 200. Upon entering the first phase 201 of the next switching cycle 200, according to the length of time that the main switch 110 will be turned on as previously determined in the second phase 202, the controller 140 turns on the main switch 110 for that length of time.

[0034]

[0036] From the above explanation, it can be seen that the power factor correction converter 12 is given a predetermined output voltage in advance. The time during which the main switch 110 is turned on is determined by the output voltage V out is related to the energy stored by inductor 100 to provide the divided voltage V ms The switch voltage V obtained by inverse inference from sw (According to the above explanation, the switch voltage V sw The magnitude of the output voltage V out According to whether the voltage V reaches a predetermined output voltage, the controller 140 can dynamically adjust the time when the main switch 110 is next turned on, and the switch voltage V sw reaches a predetermined output voltage.

[0035]

[0037] The power factor correction converter 12 of the present application reduces the output voltage V out To obtain the magnitude of the switch voltage V sw Note that only the magnitude of the switch voltage V can be used. sw can be detected within a very short time after the main switch 110 is turned off (i.e., entering the second stage 202 from the first stage 201), or after the switch voltage V sw is the switch voltage V sw can be detected after starting to resonate (i.e., going from the second stage 202 to the third stage 203).

[0036]

[0038] The power factor correction converter 12 can be operated in a sleep mode in addition to a normal mode. For example, when the controller 140 out to a predetermined output voltage magnitude, the power factor correction converter 12 enters a sleep mode, and the frequency at which the main switch 110 is turned on by the controller 140 is reduced compared to the frequency at which the main switch 110 is turned on when the power factor correction converter 12 is operated in a normal mode. That is, when the power factor correction converter 12 enters a sleep mode, the frequency at which the main switch 110 is switched on and off is reduced, and the switching of the main switch 110 between on and off may even be stopped completely. However, the power factor correction converter 12 does not change the switch voltage V in the second stage 202 in FIG. 2 . sw Only through the output voltage V out can be obtained, so the output voltage V out When the output voltage V deviates from the predetermined value due to a load change at the output terminal E_out or other factors, the power factor correction converter 12 in the sleep mode out In order to improve this problem, the power factor correction converter 12 of the present application can also use the output signal of the voltage regulation circuit as a reference to determine whether to wake up the power factor correction converter 12 in the sleep mode to enter the normal mode, and the power factor correction converter 12 can adjust the output voltage V in response to load changes or out Considering other factors that cause the output voltage V to deviate from the desired output voltage, out can be maintained in real time at a predetermined output voltage.

[0037]

[0039] 3 is a schematic diagram of one embodiment of a power supply 10 according to the present application. In FIG. 3, the power supply 10 includes a power factor correction converter 12 and a voltage regulation circuit 14 connected in series with the power factor correction converter 12.

[0038]

[0040] The voltage regulation circuit 14 is coupled to the output terminal E_out of the power factor correction converter 12 and regulates the output voltage V out For example, the voltage regulation circuit 14 may include a transformer (not shown in FIG. 3 ) to regulate the output voltage V of the power factor correction converter 12. out is converted into a regulated voltage V2 and the output voltage V out and the regulated voltage V2 have a multiple relationship.

[0039]

[0041] The voltage regulation circuit 14 may include a controller 300. The controller 300 is coupled to the controller 140 of the power factor correction converter 12 and configured to generate a feedback signal FB according to changes in the regulated voltage V2. When the power factor correction converter 12 is operated in a sleep mode, the controller 140 determines whether to increase the frequency of turning on the main switch 110 according to the feedback signal FB. That is, when the output voltage V2 changes due to a load change at the output terminal E_out or other factors, the controller 300 determines whether to increase the frequency of turning on the main switch 110 according to the feedback signal FB. out When the output voltage V deviates from the desired output voltage, out may not be maintained at a given output voltage and will vary, out The voltage regulation circuit 14 adjusts the output voltage V of the power factor correction converter 12 in accordance with the change in the regulation voltage V. out The controller 140 of the power factor correction converter 12 may know that V changes and accordingly generate a feedback signal FB to notify the power factor correction converter 12, which is operated in the sleep mode. After receiving the feedback signal FB, the controller 140 of the power factor correction converter 12 determines whether to increase the frequency of turning on the main switch 110. When the feedback signal indicates that the difference between the regulated voltage V2 and the predetermined regulated voltage is greater than a critical value, the controller 140 increases the frequency of turning on the main switch 110 or controls the power factor correction converter 12 to enter the normal mode from the sleep mode, and the power factor correction converter 12 decreases the output voltage V out can be maintained in real time at a predetermined output voltage.

[0040]

[0042] In conclusion, when using only one group of voltage dividers, the power factor correction converter of the present application can obtain the voltage value of the output voltage from the detected voltages at the two ends of the switch according to the characteristic that the magnitude of the voltages at the two ends of the switch is close to the magnitude of the output.Compared with existing power factor correction converters that use two groups of voltage dividers, the power factor correction converter of the present application not only saves circuit layout area during design, but also reduces the standby power consumption of the power factor correction converter by reducing the use of one group of voltage dividers.

[0041]

[0043] The above summarizes the structures of several embodiments, which may enable those skilled in the art to better understand the aspects of the present disclosure. Those skilled in the art will appreciate that they may readily use this disclosure as a basis for designing or modifying other manufacturing processes and structures to carry out the same purposes and / or achieve the same advantages of the embodiments introduced herein. Those skilled in the art will also appreciate that such equivalent constructions do not depart from the spirit and scope of the present disclosure, and that various changes, substitutions, and alterations may be made herein without departing from the spirit and scope of the present disclosure. [Explanation of symbols]

[0042] 10 Power supply 12 Power factor correction converter, power factor correction circuit 14 Voltage Regulator Circuit 20 Voltage or current waveform diagram 100 inductor 110 Main switch 120 Voltage divider 130 Diode 140 Controller 200 switching cycles 201 First Stage 202 Second Stage 203 Third Stage 300 Controller C in capacitor C out capacitor E_in Input terminal E_out output terminal E_out2 Output end FB Feedback signal I L induced current V d Drive voltage V D Turn-on Voltage V in Input voltage V ms Divided voltage V out Output Voltage V sw Switch Voltage V2 adjustment voltage

Claims

1. A power factor correction converter having an input and an output, the power factor correction converter being operable in a normal mode, an inductor, a first end of the inductor coupled to the input; a main switch coupled between a second end of the inductor and a ground end, configured to control the inductor to perform magnetizing and demagnetizing operations, wherein a voltage difference between two ends of the main switch is a switch voltage; and a voltage divider coupled to the two ends of the main switch, the voltage divider and the main switch being connected in parallel, the voltage divider configured to perform a voltage dividing operation on the switch voltage to generate a divided voltage that is lower than the switch voltage; a diode coupled to the output and the second end of the inductor; coupled to the main switch and the voltage divider, and periodically in the normal mode: turning on the main switch; turning off the main switch after the main switch has been turned on for a length of time; obtaining the switch voltage according to the divided voltage generated by the voltage dividing operation, and determining the length of time for which the main switch is next turned on according to the switch voltage and a predetermined output voltage of the power factor correction converter; obtaining an output voltage according to the switch voltage within a length of time after the main switch is turned off; a controller configured to: a power factor correction converter comprising: a voltage regulation circuit coupled to the output of the power factor correction converter and to the controller, the voltage regulation circuit configured to regulate the output voltage of the power factor correction converter to a regulated voltage and to generate a feedback signal according to changes in the regulated voltage; Equipped with the power factor correction converter is further operable in a sleep mode, and when the power factor correction converter is operated in the sleep mode, the frequency at which the main switch is turned on by the controller is lower than the frequency at which the main switch is turned on when the power factor correction converter is operated in the normal mode, and when the power factor correction converter is operated in the sleep mode, the controller determines whether to increase the frequency at which the main switch is turned on according to the feedback signal; power supply.

2. 2. The power supply device of claim 1, wherein when the controller turns on the main switch, the inductor begins the magnetizing operation and an induced current passing through the inductor rises.

3. 2. The power supply of claim 1, wherein when the controller turns off the main switch, the inductor begins the demagnetizing operation, the diode is turned on, and an induced current passing through the inductor decreases.

4. 2. The power supply of claim 1, wherein the switch voltage begins to resonate when the inductive current drops to zero, and the switch voltage is between a peak value and a valley value of the resonance.

5. 5. The power supply of claim 4, wherein the controller turns on the main switch when the switch voltage is at the valley value of the resonance.

6. 2. The power supply of claim 1, wherein if the switch voltage obtained by the controller is lower than the predetermined output voltage, the controller determines that the length of time that the main switch is turned on is then increased.

7. 2. The power supply of claim 1, wherein if the switch voltage obtained by the controller is higher than the predetermined output voltage, the controller determines that the length of time that the main switch is turned on is then reduced.

8. 2. The power supply of claim 1, wherein the controller controls the power factor correction converter to increase the frequency of turning on the main switch or enter the normal mode when the feedback signal indicates that a difference between the regulated voltage and a predetermined regulated voltage is greater than a critical value.

9. A method for operating a power supply device, the power supply device comprising a power factor correction converter, the power factor correction converter being operable in a normal mode, the power factor correction converter comprising an inductor, a main switch, a voltage divider and a diode, a first end of the inductor coupled to an input end of the power factor correction converter, the main switch coupled between a second end of the inductor and ground, a voltage difference between the two ends of the main switch being a switch voltage, the voltage divider coupled to the two ends of the main switch, the voltage divider and the main switch being connected in parallel, the diode coupled to an output end of the power factor correction converter and the second end of the inductor, the method comprising: periodically, in the normal mode, turning on the main switch; turning off the main switch after the main switch has been turned on for a length of time; obtaining a switch voltage according to a divided voltage, which is lower than the switch voltage, generated by a voltage dividing operation performed on the switch voltage by the voltage divider; and determining the length of time for which the main switch is next turned on according to the switch voltage and a predetermined output voltage of the power factor correction converter; obtaining an output voltage according to the switch voltage within a length of time after the main switch is turned off; adjusting the output voltage of the power factor correction converter to a regulated voltage; generating a feedback signal according to a change in the regulated voltage, such that a controller of the power factor correction converter operated in a sleep mode determines whether to increase the frequency of turning on a main switch of the power factor correction converter; A method comprising:

10. 10. The method of claim 9, wherein when the main switch is turned on, the inductor begins to magnetize and an induced current passing through the inductor rises.

11. 10. The method of claim 9, wherein when the main switch is turned off, the inductor begins to demagnetize, the diode is turned on, and the induced current passing through the inductor decreases.

12. 10. The method of claim 9, wherein the switch voltage begins to resonate when the inductive current drops to zero, and the switch voltage is between a peak value and a valley value of the resonance.

13. turning on the main switch when the switch voltage is at the valley value of the resonance; The method of claim 12 further comprising:

14. determining that if the switch voltage obtained by the power factor correction converter is lower than the predetermined output voltage, then the length of time that the main switch is turned on is increased; 10. The method of claim 9, further comprising:

15. determining that if the switch voltage obtained by the power factor correction converter is higher than the predetermined output voltage, then the length of time that the main switch is turned on is reduced; 10. The method of claim 9, further comprising:

16. 1. A method for operating a power supply, comprising: the power supply device includes a power factor correction converter; The power factor correction converter comprises: an input end and an output end; an inductor, a first end of the inductor coupled to the input; a main switch coupled between a second end of the inductor and a ground end, configured to control the inductor to perform magnetizing and demagnetizing operations, wherein a voltage difference between two ends of the main switch is a switch voltage; and a voltage divider coupled to the two ends of the main switch, the voltage divider and the main switch being connected in parallel, the voltage divider configured to perform a voltage dividing operation on the switch voltage to generate a divided voltage that is lower than the switch voltage; a diode coupled to the output and the second end of the inductor; coupled to the main switch and the voltage divider, and periodically in normal mode: turning on the main switch; turning off the main switch after the main switch has been turned on for a length of time; obtaining the switch voltage according to the divided voltage generated by the voltage dividing operation, and determining the length of time for which the main switch is next turned on according to the switch voltage and a predetermined output voltage of the power factor correction converter; obtaining an output voltage according to the switch voltage within a length of time after the main switch is turned off; a controller configured to: Equipped with The method comprises: adjusting the output voltage of the power factor correction converter to a regulated voltage; generating a feedback signal according to a change in the regulated voltage, such that a controller of the power factor correction converter operated in a sleep mode determines whether to increase the frequency of turning on a main switch of the power factor correction converter; A method comprising:

17. 17. The method of claim 16, wherein the controller controls the power factor correction converter to increase the frequency of turning on the main switch or enter the normal mode when the feedback signal indicates that the difference between the regulated voltage and a predetermined regulated voltage is greater than a critical value.

18. 17. The method of claim 16, wherein when the controller turns on the main switch, the inductor begins the magnetizing action and an induced current passing through the inductor rises.

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