BUCK circuit and its control method, controller, control device, storage medium

Abstract

A BUCK circuit, a control method thereof, a controller, a control device, and a storage medium, the control method including a step of identifying load information of the BUCK circuit (S102), a step of determining a control type and a control method of the BUCK circuit based on the load information (S104), and a step of controlling a carrier frequency and a duty ratio of a first switch transistor in the BUCK circuit based on the control type and the control method to change the switching frequency of the BUCK circuit and operate it (S106).

Description

Technical Field

[0001] The present disclosure relates to the field of power supply technology, and particularly to a BUCK circuit, its control method, a controller, a control device, and a storage medium.

Background Art

[0002] The BUCK circuit is widely used as a step-down circuit in various scenarios. However, the currently commonly used BUCK circuit, as shown in FIG. 1, during the operation of the BUCK circuit, generally high-frequency on-off control is performed on the switching transistors Q1 and Q2 by the control method shown in FIG. 2. The dotted frame in (b) of FIG. 2 indicates that throughout the step-down operation time, both the switching transistors Q1 and Q2 are in a high-frequency on-off state, which causes a very large switching loss in the circuit and deteriorates the circuit efficiency.

Summary of the Invention

Problems to be Solved by the Invention

[0003] The present disclosure aims to at least to some extent solve one of the technical problems in the related art.

[0004] Therefore, the first object of the present disclosure is to provide a control method for a BUCK circuit, which determines the control type and control method of the BUCK circuit based on the load information of the BUCK circuit, and thereby controls the carrier frequency and duty ratio of the first switching transistor in the BUCK circuit, so as to operate the BUCK circuit with a changed switching frequency, reduce the average switching frequency of the switching transistor without affecting the normal operation of the load, effectively reduce the switching loss of the switching transistor, and improve the operation efficiency of the BCUK circuit.

[0005] The second object of the present disclosure is to provide a controller for a BUCK circuit.

[0006] A third object of this disclosure is to provide a computer-readable storage medium.

[0007] A fourth object of this disclosure is to provide a control device for a BUCK circuit.

[0008] A fifth object of this disclosure is to provide a BUCK circuit. [Means for solving the problem]

[0009] To achieve the above objectives, a method for controlling a BUCK circuit provided in an embodiment of the first aspect of this disclosure includes the steps of: identifying load information for the BUCK circuit; determining a control type and control method for the BUCK circuit based on the load information; and controlling the carrier frequency and duty cycle of a first switch transistor in the BUCK circuit according to the control type and control method to cause the BUCK circuit to operate with a different switching frequency.

[0010] According to the control method for a BUCK circuit in the embodiment of this disclosure, the control type and control method of the BUCK circuit are determined based on the load information of the BUCK circuit, and the carrier frequency and duty cycle of the first switch transistor in the BUCK circuit are controlled accordingly, thereby causing the BUCK circuit to operate with a different switching frequency. This makes it possible to lower the average switching frequency of the switch transistor without affecting the normal operation of the load, thereby effectively reducing the switching loss of the switch transistor and improving the operating efficiency of the BUCK circuit.

[0011] To achieve the above objective, the BUCK circuit controller provided in the second embodiment of this disclosure comprises a memory, a processor, and a BUCK circuit control program stored in the memory and running on the processor, and when the processor executes the BUCK circuit control program, the above-described BUCK circuit control method is realized.

[0012] The controller for the BUCK circuit according to the embodiment of this disclosure implements the above-described method of controlling the BUCK circuit using a processor, causing the BUCK circuit to operate with a different switching frequency, thereby lowering the average switching frequency of the switch transistor without affecting the normal operation of the load. This effectively reduces the switching loss of the switch transistor and improves the operating efficiency of the BUCK circuit.

[0013] To achieve the above objective, the computer-readable storage medium provided in the third embodiment of this disclosure stores a control program for the BUCK circuit and, when the control program for the BUCK circuit is executed by a processor, realizes the above-described method for controlling the BUCK circuit.

[0014] The computer-readable storage medium according to the embodiments of this disclosure can operate the BUCK circuit with a different switching frequency by the above-described control method of the BUCK circuit, thereby lowering the average switching frequency of the switch transistor without affecting the normal operation of the load. This effectively reduces the switching loss of the switch transistor and improves the operating efficiency of the BUCK circuit.

[0015] To achieve the above objectives, the control device for a BUCK circuit provided in an embodiment of the fourth aspect of this disclosure includes: a determination module for identifying load information of the BUCK circuit and determining the control type and control method of the BUCK circuit based on the load information; and a control module for controlling the carrier frequency and duty cycle of the first switch transistor in the BUCK circuit based on the control type and control method, thereby causing the BUCK circuit to operate with a different switching frequency.

[0016] The control device for a BUCK circuit according to the embodiment of this disclosure identifies load information of the BUCK circuit using a determination module, determines the control type and control method of the BUCK circuit based on the load information, controls the carrier frequency and duty cycle of the first switch transistor using the control module, and operates the BUCK circuit with a changed switching frequency. This lowers the average switching frequency of the switch transistor without affecting the normal operation of the load, thereby effectively reducing the switching loss of the switch transistor and improving the operating efficiency of the BUCK circuit.

[0017] To achieve the above objectives, the BUCK circuit provided in the fifth embodiment of this disclosure comprises an input capacitor, a first switch transistor with one end connected to one end of the input capacitor, a flyback element with one end connected to the other end of the first switch transistor and the other end connected to the other end of the input capacitor, an inductor with one end connected to the other end of the first switch transistor, an output capacitor with one end connected to the other end of the inductor and the other end connected to the other end of the flyback element, and a controller used to identify load information for the BUCK circuit, determine the control type and control method of the BUCK circuit based on the load information, and control the carrier frequency and duty cycle of the first switch transistor based on the control type and control method to operate the BUCK circuit with a different switching frequency.

[0018] The BUCK circuit according to the embodiment of this disclosure identifies the load information of the BUCK circuit using a controller, determines the control type and control method of the BUCK circuit based on the load information, and thereby controls the carrier frequency and duty cycle of the first switch transistor, thereby causing the BUCK circuit to operate with a different switching frequency, and lowering the average switching frequency of the switch transistor without affecting the normal operation of the load. This effectively reduces the switching loss of the switch transistor and improves the operating efficiency of the BUCK circuit.

[0019] Additional aspects and advantages of the present disclosure will be shown in part in the following description, will become apparent in part from the following description, or can be understood through the practice of the present disclosure.

Brief Description of the Drawings

[0020] [Figure 1] It is a circuit diagram of a BUCK circuit in the related art. [Figure 2] It is a relationship diagram between the operation of the switch transistor of the BUCK circuit in the related art and voltage and current. [Figure 3] It is a circuit diagram of a BUCK circuit according to an embodiment of the present disclosure. [Figure 4] It is a circuit diagram of a BUCK circuit according to another embodiment of the present disclosure. [Figure 5] It is a flowchart of a control method for a BUCK circuit according to an embodiment of the present disclosure. [Figure 6] It is a flowchart of a control method for a BUCK circuit according to an embodiment of the present disclosure. [Figure 7a] It is a relationship diagram between the operation of the switch transistor of the BUCK circuit according to some embodiments of the present disclosure and voltage and current. [Figure 7b] It is a relationship diagram between the operation of the switch transistor of the BUCK circuit according to some embodiments of the present disclosure and voltage and current. [Figure 7c] It is a relationship diagram between the operation of the switch transistor of the BUCK circuit according to some embodiments of the present disclosure and voltage and current. [Figure 7d] It is a relationship diagram between the operation of the switch transistor of the BUCK circuit according to some embodiments of the present disclosure and voltage and current. [Figure 8] It is a flowchart of a control method for a BUCK circuit according to another embodiment of the present disclosure. [Figure 9a] It is a relationship diagram between the operation of the switch transistor of the BUCK circuit according to some other embodiments of the present disclosure and voltage and current. [Figure 9b] It is a relationship diagram between the operation of the switch transistor of the BUCK circuit according to some other embodiments of the present disclosure and voltage and current. [Figure 9c] This diagram shows the relationship between the operation of the switch transistor in a BUCK circuit and the voltage and current according to some other embodiments of the present disclosure. [Figure 9d] This diagram shows the relationship between the operation of the switch transistor in a BUCK circuit and the voltage and current according to some other embodiments of the present disclosure. [Figure 10] This is a flowchart of a control method for a BUCK circuit according to one embodiment of the present invention. [Figure 11a] This diagram shows the relationship between the operation of the switch transistor in a BUCK circuit according to several embodiments of the present invention and the voltage and current. [Figure 11b] This diagram shows the relationship between the operation of the switch transistor in a BUCK circuit according to several embodiments of the present invention and the voltage and current. [Figure 11c] This diagram shows the relationship between the operation of the switch transistor in a BUCK circuit according to several embodiments of the present invention and the voltage and current. [Figure 11d] This diagram shows the relationship between the operation of the switch transistor in a BUCK circuit according to several embodiments of the present invention and the voltage and current. [Figure 12] This is a flowchart of a control method for a BUCK circuit according to one embodiment of the present invention. [Figure 13] This is a flowchart of a control method for a BUCK circuit according to one embodiment of the present invention. [Figure 14] This is a flowchart of a control method for a BUCK circuit according to one embodiment of the present invention. [Figure 15a] This diagram shows the relationship between the operation of the switch transistor in a BUCK circuit and the voltage and current according to some other embodiments of the present invention. [Figure 15b] This diagram shows the relationship between the operation of the switch transistor in a BUCK circuit and the voltage and current according to some other embodiments of the present invention. [Figure 15c] This diagram shows the relationship between the operation of the switch transistor in a BUCK circuit and the voltage and current according to some other embodiments of the present invention. [Figure 15d] This diagram shows the relationship between the operation of the switch transistor in a BUCK circuit and the voltage and current according to some other embodiments of the present invention. [Figure 16] This is a schematic diagram of the structure of a BUCK circuit controller according to one embodiment of the present disclosure. [Figure 17] This is a schematic diagram of the structure of a control device for a BUCK circuit according to one embodiment of the present disclosure. [Figure 18] This is a circuit diagram of a BUCK circuit according to one embodiment of the present disclosure. [Modes for carrying out the invention]

[0021] The embodiments of this disclosure shown in the drawings will be described in detail below, and in all drawings, the same or similar reference numerals indicate the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the drawings are illustrative and for illustrative purposes only, and should not be understood as limitations to this disclosure.

[0022] The control method disclosed herein can be applied to the BUCK circuit shown in Figure 3 or Figure 4. As shown in Figures 3-4, the BUCK circuit comprises an input capacitor C1, a first switch transistor Q1, a flyback element, an inductor L1, and an output capacitor C2, the flyback element may be a diode D shown in Figure 3 or a second switch transistor Q2 shown in Figure 4. One end of the first switch transistor Q1 is connected to one end of the input capacitor C1, one end of the flyback element is connected to the other end of the first switch transistor Q1, the other end of the flyback element is connected to the other end of the input capacitor C1, one end of the inductor L1 is connected to the other end of the first switch transistor Q1, one end of the output capacitor C2 is connected to the other end of the inductor L1, and the other end of the output capacitor C2 is connected to the other end of the flyback element. As shown in Figure 4, the step-down function of the BUCK circuit can be realized by controlling the on / off state of the first switch transistor Q1 and the second switch transistor Q2, thereby stepping down the input voltage (i.e., the voltage across the input side capacitor C1) to obtain the output voltage (i.e., the voltage across the output side capacitor C2), and the input voltage is greater than the output voltage. As shown in Figure 3, the step-down function of the BUCK circuit can be realized by controlling the on / off state of the first switch transistor Q1.

[0023] Figure 5 is a flowchart of a control method for a BUCK circuit according to one embodiment of the present disclosure. For the sake of simplicity, the following explanation will mainly use the control method shown in Figure 3 as an example.

[0024] As shown in Figure 5, the control method for the BUCK circuit may include the following steps.

[0025] S102, Identify the load information of the BUCK circuit.

[0026] The load information for the BUCK circuit can include the load type and load magnitude. The load type can be divided into current-sensitive and voltage-sensitive types. Current-sensitive means that current fluctuations in the BUCK circuit significantly affect the load and may cause load failure. Voltage-sensitive means that voltage fluctuations in the BUCK circuit significantly affect the load and may cause load failure.

[0027] S104, Based on the load information, the control type and control method of the BUCK circuit are determined.

[0028] The control type of the BUCK circuit can include current control type and voltage control type. The current control type controls the BUCK circuit based on current parameters so that the current parameters satisfy a preset requirement, while the voltage control type controls the BUCK circuit based on voltage parameters so that the voltage parameters satisfy a preset requirement. Both are applied to different loads; for example, if the load is sensitive to current parameters, the BUCK circuit can be controlled using the current control type, and if the load is sensitive to voltage parameters, the BUCK circuit can be controlled using the voltage control type. The control method of the BUCK circuit refers to a method of controlling the carrier frequency and duty cycle of the first switch transistor in the BUCK circuit based on the corresponding voltage parameter or current parameter.

[0029] In some embodiments, the step of determining the control type and control method of the BUCK circuit based on load information includes determining the control type according to the load type and determining the control method according to the magnitude of the load, and the control type includes current control type and voltage control type.

[0030] Specifically, different load types correspond to different control types. For example, if the load type is current-sensitive, a current control type is used to control the BUCK circuit to limit the inductor current to an appropriate range. If the load type is voltage-sensitive, a voltage control type is used to control the BUCK circuit to limit the output capacitor voltage to an appropriate range. After identifying the load type, the load magnitude (i.e., the load power magnitude) can be determined using multiple methods, and the control method for the BUCK circuit can be determined according to the load magnitude. For example, a current detection module can be provided on the input side of the converter shown in Figure 3, and the current detected by the current detection module can be used as the input current. The input voltage is a fixed value, and for example, the input voltage may be a normal 220V commercial voltage, so the load magnitude can be determined according to the input current magnitude, and the control method for the BUCK circuit can be determined according to the load magnitude.

[0031] The method of determining the load size according to the input current is merely an illustrative example and does not limit this disclosure. The load size may also be directly determined by detecting the output voltage and output current at the load terminal and calculating the load power based on the product of the two.

[0032] Furthermore, the step of determining the control method according to the magnitude of the load includes determining the control method to be a low carrier frequency, high duty cycle control method when the load of the BUCK circuit is greater than or equal to a preset value, and determining the control method to be a high carrier frequency, high duty cycle control method when the load of the BUCK circuit is less than a preset value.

[0033] In other words, different load sizes correspond to different control methods; for example, a low carrier frequency and high duty cycle control method is used when the load is large, while a high carrier frequency and high duty cycle control method is used when the load is small.

[0034] For example, when the input current of the BUCK circuit is greater than or equal to a preset current threshold, it indicates that the load is greater than or equal to a preset value. In this case, the control method is set to a low carrier frequency and a high duty cycle, increasing the inductor current and the voltage of the output capacitor. The low carrier frequency control method also reduces the switching loss of the first switch transistor. When the input current is less than a preset current threshold, it indicates that the load is less than a preset value. In this case, the control method is set to a high carrier frequency and a high duty cycle, increasing the inductor current and the voltage of the output capacitor. Furthermore, the high carrier frequency control method reduces the ripple current and ripple voltage of the first switch transistor, preventing excessive ripple current from affecting the operation of the load.

[0035] S106 controls the carrier frequency and duty cycle of the first switch transistor in the BUCK circuit according to the control type and control method, thereby changing the switching frequency of the BUCK circuit.

[0036] Furthermore, the carrier frequency affects the switching loss of the first switch transistor; that is, the higher the carrier frequency, the higher the switching loss of the first switch transistor, and the lower the carrier frequency, the lower the switching loss of the first switch transistor. The duty cycle affects the trend of change in the inductor current and output capacitor voltage of the BUCK circuit; that is, a large duty cycle increases the inductor current and output capacitor voltage, and a small duty cycle decreases the inductor current and output capacitor voltage.

[0037] Once the control type and method of the BUCK circuit are determined by the steps described above, the BUCK circuit is operated with a different switching frequency by controlling the carrier frequency and duty cycle of the first switch transistor based on the control type and method. This not only meets the load demands but also lowers the switching frequency of the switch transistor by changing the switching frequency of the BUCK circuit and controlling the first switch transistor at a low frequency at certain timings, thereby reducing the switching loss of the switch transistor and improving the efficiency of the BUCK circuit.

[0038] As one implementation, when controlling the BUCK circuit using a current control type, the step of controlling the carrier frequency and duty cycle of the first switch transistor in the BUCK circuit includes, when the first switch transistor is controlled with a low carrier frequency, high duty cycle control method, the step of acquiring the current of the inductor in the BUCK circuit, and when the inductor current reaches a first predetermined current, controlling the first switch transistor with a high carrier frequency, low duty cycle control method to reduce the inductor current to a second predetermined current, or, when the first switch transistor is controlled with a high carrier frequency, high duty cycle control method, the step of acquiring the current of the inductor in the BUCK circuit, and when the inductor current reaches a first predetermined current, controlling the first switch transistor with a low carrier frequency, low duty cycle control method to reduce the inductor current to a second predetermined current.

[0039] Specifically, as shown in Figures 3 and 6, if the load type is current-sensitive and the corresponding control type is current-controlled, the magnitude of the load can be determined by the method used to acquire the input current of the BUCK circuit when the BUCK circuit is operating (the magnitude of the load may be determined by other methods, but is not limited here). If the load of the BUCK circuit is determined to be greater than or equal to a preset value based on the input current, the first switch transistor Q1 is first controlled using a low carrier frequency, high duty cycle control method. At this time, as shown in Figure 7a or 7b, the relationship between the operation of the switch transistor and the voltage current is such that the duty cycle is relatively high, the inductor current increases, and the switching frequency is low, resulting in low switching loss for the first switch transistor Q1. When the inductor current rises to a first predetermined current, the control method for the first switch transistor Q1 is adjusted, and the first switch transistor Q1 continues to be controlled using a high carrier frequency, low duty cycle control method. Because the duty cycle decreases, the inductor current decreases, and the switching frequency increases, the ripple current of the BUCK circuit is small, avoiding excessive ripple current that would affect the operation of the load. When the inductor current drops to a second predetermined current, the input current is re-detected to determine the load magnitude.

[0040] When the load of the BCUK circuit is determined to be smaller than a preset value based on the input current, the first switch transistor Q1 is first controlled using a high carrier frequency, high duty cycle control method. At this time, the relationship between the operation of the switch transistor and the voltage current is as shown in Figures 7c-7d. Because the duty cycle is relatively high, the inductor current increases, and the switching frequency is high, the ripple current is small, thus avoiding excessive ripple current affecting the operation of the load. When the inductor current rises to a first predetermined current, the control method for the first switch transistor Q1 is adjusted, and the first switch transistor Q1 continues to be controlled using a low carrier frequency, low duty cycle control method. Because the duty cycle decreases, the inductor current decreases, and the switching frequency is low, the switching loss of the first switch transistor Q1 decreases. When the inductor current falls to a second predetermined current, the input current is re-detected to determine the magnitude of the load.

[0041] Repeat the above process until the BUCK circuit stops stepping down the voltage.

[0042] Furthermore, in order to ensure that each element is not damaged by excessive current (for example, that the first switch transistor is not damaged by breakdown and that the inductor does not saturate), the first predetermined current must be less than or equal to the maximum current required by the load and less than or equal to the maximum allowable current of each element in the BUCK circuit (for example, less than or equal to the smaller of the current withstand current of the first switch transistor and the saturation current of the inductor). The second predetermined current must be greater than or equal to zero and less than the first predetermined current. As shown in Figures 7a and 7c, the second predetermined current is zero, and as shown in Figures 7b and 7d, the second predetermined current is greater than zero and less than the first predetermined current. The current difference between the first predetermined current and the second predetermined current is the current ripple, and this current ripple must satisfy the operating requirements of the load. The average current of the inductor is equal to the operating current required by the load, so that the load operates normally.

[0043] In the above embodiment, different control methods for the first switch transistor are selected according to the magnitude of the load. In the different control methods, high and low frequencies are alternately used to control the first switch transistor, and the current of the inductor of the BUCK circuit is controlled within a target range. This ensures that the load can operate normally and reduces the average switching frequency of the first switch transistor without affecting the operating state of the load. This reduces the switching loss of the switch transistor and improves the efficiency of the BUCK circuit.

[0044] As another implementation, when controlling the BUCK circuit using a voltage control type, controlling the carrier frequency and duty cycle of the first switch transistor in the BUCK circuit includes, when the first switch transistor is controlled with a low carrier frequency, high duty cycle control method, obtaining the voltage of the output side capacitor of the BUCK circuit, and when the voltage of the output side capacitor reaches a first predetermined voltage, controlling the first switch transistor with a high carrier frequency, low duty cycle control method to reduce the voltage of the output side capacitor to a second predetermined voltage, or, when the first switch transistor is controlled with a high carrier frequency, high duty cycle control method, obtaining the voltage of the output side capacitor of the BUCK circuit, and when the voltage of the output side capacitor reaches a first predetermined voltage, controlling the first switch transistor with a low carrier frequency, low duty cycle control method to reduce the voltage of the output side capacitor to a second predetermined voltage.

[0045] Specifically, as shown in Figures 3 and 8, if the load type is voltage-sensitive and the corresponding control type is voltage-controlled, the magnitude of the load can be determined by the method used to acquire the input current of the BUCK circuit when the BUCK circuit is operating (the magnitude of the load may be determined by other methods, but is not limited here). If the load of the BUCK circuit is determined to be greater than or equal to a preset value based on the input current, the first switch transistor Q1 is first controlled using a low carrier frequency, high duty cycle control method. At this time, as shown in Figure 7a or 7b, the relationship between the operation of the switch transistor and the voltage-current is such that the duty cycle is relatively high, the voltage of the output capacitor rises, and the switching frequency is relatively low, resulting in low switching loss for the first switch transistor Q1. When the voltage of the output capacitor reaches a first predetermined voltage, the control method for the first switch transistor Q1 is adjusted, and the first switch transistor Q1 is continued to be controlled using a high carrier frequency, low duty cycle control method. As the duty cycle decreases, the voltage across the output capacitor drops, and the switching frequency is relatively high, the ripple voltage in the BUCK circuit is small, preventing excessive ripple voltage from affecting load operation. When the voltage across the output capacitor drops to a second predetermined voltage, the input current is re-detected to determine the load magnitude.

[0046] When the load of the BCUK circuit is determined to be smaller than a preset value based on the input current, the first switch transistor Q1 is first controlled using a high carrier frequency, high duty cycle control method. At this time, the relationship between the operation of the switch transistor and voltage / current is as shown in Figures 7c-7d. Because the duty cycle is relatively high, the voltage of the output capacitor rises, and because the switching frequency is relatively high, the ripple voltage is small, thus avoiding excessive ripple voltage affecting the load operation. When the voltage of the output capacitor rises to a first predetermined voltage, the control method for the first switch transistor Q1 is adjusted, and the first switch transistor Q1 continues to be controlled using a low carrier frequency, low duty cycle control method. As the duty cycle decreases, the voltage of the output capacitor decreases, and the switching frequency is relatively low, the switching loss of the first switch transistor Q1 decreases. When the voltage of the output capacitor falls to a second predetermined voltage, the input current is re-detected to determine the magnitude of the load.

[0047] Repeat the above process until the BUCK circuit stops stepping down the voltage.

[0048] Furthermore, to prevent the output capacitor from being damaged by overvoltage, the first predetermined voltage must be less than or equal to the maximum voltage required by the load and less than or equal to the withstand voltage value of each element in the BUCK circuit, for example, less than or equal to the withstand voltage value of the output capacitor. The second predetermined voltage must be greater than zero and less than the first predetermined voltage, and as shown in Figures 7a-7d, the second predetermined voltage is always greater than zero and less than the first predetermined voltage. The voltage difference between the first predetermined voltage and the second predetermined voltage is the voltage ripple, and this voltage ripple must satisfy the load operation requirements.

[0049] In the above embodiment, different control methods for the first switch transistor are selected according to the magnitude of the load. In the different control methods, high and low frequencies are alternately used to control the first switch transistor, and the voltage of the output capacitor of the BUCK circuit is controlled within a target range. This ensures that the load can operate normally and reduces the average switching frequency of the first switch transistor without affecting the operating state of the load. This reduces the switching loss of the switch transistor and improves the efficiency of the BUCK circuit.

[0050] In some embodiments, when the flyback element in the BUCK circuit is a second switch transistor, the method further includes the steps of controlling the second switch transistor to turn off when the first switch transistor is turned on, and controlling the second switch transistor to turn on when the first switch transistor is turned off.

[0051] Specifically, as shown in Figure 4, a second switch transistor Q2 can be used instead of diode D. In this case, the relationship between the operation of the switch transistor and voltage / current is as shown in Figures 9a-9d. When the first switch transistor Q1 is turned off, the second switch transistor Q2 is turned on, providing a flyback circuit to inductor L1. When the first switch transistor Q1 is turned on, the second switch transistor Q2 is turned off, disconnecting its circuit and not affecting the power supply function of the BUCK circuit to the load. Thus, the second switch transistor Q2 achieves all the functions of diode D.

[0052] In the case of a BUCK circuit where the flyback element is a second switch transistor, the only difference from a circuit where the flyback element is a diode is the control of the second switch transistor; the control of the first switch transistor is the same, and therefore it has the same effect as when the flyback element is a diode. Please refer to the explanation above for details, as it will not be repeated here.

[0053] Figure 10 is a flowchart of a control method for a BUCK circuit according to one embodiment of the present invention. For the sake of simplicity, the following explanation will mainly describe the case where the control method is applied to the BUCK circuit shown in Figure 3 as an example.

[0054] As shown in Figure 10, the control method for the BUCK circuit may include the following steps.

[0055] S202, Identify the load type of the BUCK circuit.

[0056] Furthermore, the load types of a BUCK circuit can be divided into current-sensitive and voltage-sensitive types. A current-sensitive type means that current fluctuations in the BUCK circuit significantly affect the load and can potentially cause load failure, while a voltage-sensitive type means that voltage fluctuations in the BUCK circuit significantly affect the load and can potentially cause load failure.

[0057] S204, When controlling the BUCK circuit using a current control type according to the load type, the magnitude of the load on the BUCK circuit is obtained.

[0058] Specifically, different load types correspond to different control types. For example, if the load type is current-sensitive, the control type is current-controlled; if the load type is voltage-sensitive, the control type is voltage-controlled. If the currently identified load type is current-sensitive, the BUCK circuit can be controlled using a current-controlled type, and in this case, the magnitude of the load on the BUCK circuit (i.e., the magnitude of the load power) can be obtained using various methods. For example, a current detection module can be provided on the input side of the converter shown in Figure 3, and the current detected by the current detection module can be used as the input current of the BUCK circuit. Since the input voltage of the converter is a fixed value, the input power is proportional to the input current, and since the conversion efficiency of the converter and the BUCK circuit is constant, the load power is proportional to the input power. Therefore, the magnitude of the load can be determined according to the magnitude of the input current.

[0059] The method of determining the load size according to the input current is merely an illustrative example and does not limit the present invention. The load size may also be directly determined by detecting the output voltage and output current and calculating the load power based on the product of the two.

[0060] S206, When the load of the BUCK circuit is greater than or equal to a preset value, the first switch transistor in the BUCK circuit is controlled to turn on, increasing the current of the inductor in the BUCK circuit. When the inductor current rises to a first predetermined current, high-frequency switching control is performed on the first switch transistor to reduce the inductor current to a second predetermined current.

[0061] Specifically, to determine whether the load is greater than a preset value, a corresponding preset threshold can be set for the physical quantity detected to identify the load magnitude. For example, if a method is adopted to identify the load magnitude based on the input current, when the input current of the BUCK circuit is greater than or equal to a preset current threshold, it can be determined that the load of the BUCK circuit is greater than or equal to a preset value. At this time, the first switch transistor in the BUCK circuit can be controlled to remain on so that the inductor current of the BUCK circuit continues to rise. When the inductor current rises to a first predetermined current, high-frequency switching control is performed on the first switch transistor. By rationally setting the duty cycle of the first switch transistor, the inductor current continues to decrease from the first predetermined current until it falls to a second predetermined current. After that, the load magnitude of the BUCK circuit is identified again, and if the load is greater than or equal to a preset value, the first switch transistor is controlled to turn on again, and this process is repeated.

[0062] Furthermore, as shown in Figures 3 and 11a-11b, if the load type is current-sensitive and the corresponding control type is current-controlled, the magnitude of the load can be determined by the method used to acquire the input current of the BUCK circuit when the BUCK circuit is operating (the magnitude of the load may be determined by other methods, but is not limited here). If the load of the BUCK circuit is determined to be greater than or equal to a preset value based on the input current, the first switch transistor Q1 is first controlled to remain on. At this time, the input voltage charges the inductor L1 and the output capacitor C2 by the first switch transistor Q1, and the inductor current continues to rise. When the inductor current rises to a first predetermined current, the control method of the first switch transistor Q1 is changed, that is, the first switch transistor Q1 is controlled to be turned on and off using a high-frequency switching control method. As shown in the dotted frame in Figures 11a-11b, if the first switch transistor Q1 is turned off during this period, the inductor L1 is flybacked by the diode D, and the inductor current decreases. When the first switch transistor Q1 is turned on, the input voltage charges the inductor L1 and the output capacitor C2 via the first switch transistor Q1, causing the inductor current to rise. By setting an appropriate duty cycle, the inductor current tends to decrease overall, and the inductor current can be gradually reduced from a first predetermined current to a second predetermined current. Then, the input current of the BUCK circuit is acquired again, and if it is determined that the load of the BUCK circuit is greater than or equal to a preset value based on the input current, the first switch transistor Q1 is controlled again to remain on, and this process is repeated.

[0063] Furthermore, when the load exceeds a preset value, the duty cycle of the first switch transistor is kept from becoming too large during high-frequency operation to ensure that the inductor current remains low. To ensure that each element is not damaged by excessive current (for example, that the first switch transistor is not damaged by breakdown and that the inductor does not saturate), the first predetermined current must be less than or equal to the maximum current required by the load and less than or equal to the maximum allowable current of each element in the BUCK circuit (for example, less than or equal to the smaller of the current withstand current of the first switch transistor and the saturation current of the inductor). The second predetermined current must be greater than or equal to zero and less than the first predetermined current. As shown in Figure 11a, the second predetermined current is zero, and as shown in Figure 11b, the second predetermined current is greater than zero and less than the first predetermined current. The current difference between the first predetermined current and the second predetermined current is the current ripple, and this current ripple must satisfy the operating requirements of the load. The average current of the inductor is equal to the operating current required by the load, so that the load operates normally.

[0064] In some embodiments, when the load of the BUCK circuit is less than a preset value, high-frequency switching control is performed on the first switch transistor to increase the current of the inductor in the BUCK circuit. When the inductor current rises to a first predetermined current, the first switch transistor is controlled to turn off, reducing the inductor current to a second predetermined current.

[0065] Specifically, when the input current of the BUCK circuit is smaller than a preset current threshold, it can be determined that the load of the BUCK circuit is smaller than a preset value. In this case, high-frequency switching control is first applied to the first switch transistor in the BUCK circuit. By rationally setting the duty cycle of the first switch transistor, the current of the inductor in the BUCK circuit continues to rise. When the inductor current rises to a first predetermined current, the first switch transistor is controlled to remain off, and the inductor current continues to decrease until it drops to a second predetermined current. After that, the magnitude of the load of the BUCK circuit is determined again, and if the load is smaller than a preset value, high-frequency switching control is applied to the first switch transistor again, and this process is repeated.

[0066] Furthermore, as shown in Figures 3 and 11c-11d, if the load type is current-sensitive and the corresponding control type is current-controlled, the magnitude of the load can be determined by the method used to obtain the input current of the BUCK circuit when the BUCK circuit is operating (the magnitude of the load may be determined by other methods, but is not limited here). If the load of the BUCK circuit is determined to be smaller than a preset value based on the input current, the on / off switching of the first switch transistor Q1 is controlled by a high-frequency switching control method. As shown in the dotted box in Figures 11c-11d, during this period, when the first switch transistor Q1 is turned on, the input voltage charges the inductor L1 and the output capacitor C2 by the first switch transistor Q1, and the inductor current increases. When the first switch transistor Q1 is turned off, the inductor L1 is flybacked by the diode D, and the inductor current decreases. By setting an appropriate duty cycle, the inductor current generally shows an upward trend until it rises to a first predetermined current. If the control method of the first switch transistor Q1 is changed, i.e., controlled to keep the first switch transistor Q1 off, then the inductor current continues to decrease until it falls to a second predetermined current. Subsequently, the input current of the BUCK circuit is acquired again, and if it is determined that the load of the BUCK circuit is less than a preset value based on the input current, the on / off control of the first switch transistor Q1 is controlled again using a high-frequency switching control method, and this is repeated.

[0067] Furthermore, when the load is smaller than a preset value, the duty cycle of the first switch transistor is not made too small during high-frequency operation to ensure that the inductor current remains elevated. Figures 11a and 11b show the relationship between the operation of the switch transistors and voltage / current when the load is greater than or equal to the preset value, while Figures 11c and 11d show the relationship between the operation of the switch transistors and voltage / current when the load is smaller than the preset value. In actual use, the load and input current change, so during the operation of the BUCK circuit, the load may be greater than, less than, or equal to the preset value. For details, please refer to the explanation above and Figure 12, and will not be explained again here.

[0068] In the above embodiment, when the control type is determined to be a current control type according to the load type, intermittent high-frequency switching control is performed on the first switch transistor based on the magnitude of the load when the BUCK circuit is operating. This not only ensures that the BUCK circuit meets the load needs, but also reduces the switching loss of the switch transistor in the BUCK circuit, improves the operating efficiency of the BUCK circuit, and at the same time, by rationally setting the first predetermined current, it is possible to avoid the destruction of each element in the BUCK circuit due to excessive current.

[0069] In some embodiments, after determining the load type of the BUCK circuit, as shown in Figure 13, the method further includes the following steps.

[0070] S210, when controlling the BUCK circuit using a voltage control type depending on the load type, the magnitude of the load on the BUCK circuit is obtained.

[0071] Furthermore, if the currently determined load type is voltage-sensitive, the BUCK circuit can be controlled using a voltage-controlled type. In this case, the magnitude of the load on the BUCK circuit (i.e., the magnitude of the load power) can be obtained using various methods. For example, a current detection module can be installed on the input side of the converter shown in Figure 3, and the current detected by the current detection module can be used as the input current to the BUCK circuit.

[0072] S212 determines the load on the BUCK circuit based on the input voltage.

[0073] S214, When the load of the BUCK circuit is greater than or equal to a preset value, the first switch transistor in the BUCK circuit is controlled to turn on, increasing the voltage of the output side capacitor of the BUCK circuit. When the voltage of the output side capacitor rises to a first predetermined voltage, high-frequency switching control is performed on the first switch transistor to decrease the voltage of the output side capacitor to a second predetermined voltage.

[0074] Specifically, when the input current of the BUCK circuit is greater than or equal to a preset current threshold, it can be determined that the load of the BUCK circuit is greater than or equal to a preset value. At this time, the first switch transistor in the BUCK circuit can be controlled to remain on so that the output voltage of the BUCK circuit (i.e., the voltage across the output side capacitor C2) continues to rise. When the output voltage rises to a first predetermined voltage, high-frequency switching control is performed on the first switch transistor. By rationally setting the duty cycle of the first switch transistor, the output voltage continues to decrease from the first predetermined voltage until it drops to a second predetermined voltage. After that, the magnitude of the load of the BUCK circuit is determined again, and if the load is greater than or equal to a preset value, the first switch transistor is controlled to turn on again, and this process is repeated.

[0075] Furthermore, as shown in Figures 3, 11a-11b, if the load type is voltage-sensitive and the corresponding control type is voltage-controlled, the magnitude of the load can be determined by the method used to acquire the input current of the BUCK circuit during operation (the magnitude of the load may be determined by other methods, but is not limited here). If the load of the BUCK circuit is determined to be greater than or equal to a preset value based on the input current, the first switch transistor Q1 is first controlled to remain on. At this time, the input voltage charges the inductor L1 and the output capacitor C2 by the first switch transistor Q1, and the output voltage continues to rise. When the output voltage rises to a first predetermined voltage, the control method of the first switch transistor Q1 is changed, that is, the first switch transistor Q1 is controlled to be turned on and off using a high-frequency switching control method. As shown in the dotted box in Figures 11a-11b, during this period, when the first switch transistor Q1 is turned off, the output capacitor C2 supplies power to the load, causing the output voltage to decrease. When the first switch transistor Q1 is turned on, the input voltage charges the inductor L1 and the output capacitor C2 via the first switch transistor Q1, causing the output voltage to increase. By setting an appropriate duty cycle, the output voltage tends to decrease overall, and the output voltage can be gradually reduced from a first predetermined voltage to a second predetermined voltage. Subsequently, the input current of the BUCK circuit is acquired again, and if it is determined based on the input current that the load of the BUCK circuit is greater than or equal to a preset value, the first switch transistor Q1 is controlled again to remain on, and this process is repeated.

[0076] Furthermore, when the load is greater than or equal to a preset value, the duty cycle of the first switch transistor is kept from becoming too large during high-frequency operation to ensure that the output voltage remains in a reduced state. To ensure that the output capacitor is not damaged by overvoltage, the first predetermined voltage must be less than or equal to the maximum voltage required by the load and less than or equal to the withstand voltage value of each element in the BUCK circuit, for example, the withstand voltage value of the output capacitor. The second predetermined voltage must be greater than zero and less than the first predetermined voltage. As shown in Figures 11a and 11b, the second predetermined voltage is always greater than zero and less than the first predetermined voltage. The voltage difference between the first predetermined voltage and the second predetermined voltage is the voltage ripple, and this voltage ripple must satisfy the load operation requirements.

[0077] In some embodiments, when the load of the BUCK circuit is less than a preset value, high-frequency switching control is performed on the first switch transistor to increase the voltage of the output capacitor of the BUCK circuit. When the voltage of the output capacitor rises to a first predetermined voltage, the first switch transistor is controlled to turn off, reducing the voltage of the output capacitor to a second predetermined voltage.

[0078] Specifically, when the input current of the BUCK circuit is smaller than a preset current threshold, it can be determined that the load of the BUCK circuit is smaller than a preset value. In this case, high-frequency switching control can be performed on the first switch transistor in the BUCK circuit. By rationally setting the duty cycle of the first switch transistor, the output voltage of the BUCK circuit continues to rise. When the output voltage rises to a first predetermined voltage, the first switch transistor is controlled to remain off, and the output voltage continues to decrease until it falls to a second predetermined voltage. After that, the magnitude of the load of the BUCK circuit is determined again, and if the load is smaller than a preset value, high-frequency switching control is performed on the first switch transistor again, and this process is repeated.

[0079] Furthermore, as shown in Figures 3 and 11c-11d, if the load type is voltage-sensitive and the corresponding control type is voltage-controlled, the magnitude of the load can be determined by the method used to acquire the input current of the BUCK circuit during operation (the magnitude of the load may be determined by other methods, but is not limited here). If the load of the BUCK circuit is determined to be smaller than a preset value based on the input current, the on / off switching of the first switch transistor Q1 is first controlled using a high-frequency switching control method. As shown in the dotted box in Figures 11c-11d, during this period, when the first switch transistor Q1 is turned on, the input voltage charges the inductor L1 and the output capacitor C2 by the first switch transistor Q1, and the output voltage rises. When the first switch transistor Q1 is turned off, the output capacitor C2 supplies power to the load, and the output voltage falls. By setting an appropriate duty cycle, the output voltage generally tends to rise until it reaches a first predetermined voltage. If the control method of the first switch transistor Q1 is changed, i.e., controlled to keep the first switch transistor Q1 off, then the output voltage will continue to fall until it reaches a second predetermined voltage. Subsequently, the input current of the BUCK circuit is acquired again, and if it is determined that the load of the BUCK circuit is less than a preset value according to the input current, the on / off control of the first switch transistor Q1 is controlled again using a high-frequency switching control method, and this process is repeated.

[0080] Furthermore, when the load is smaller than a preset value, the duty cycle of the first switch transistor is kept from becoming too small during high-frequency operation to ensure that the output voltage remains elevated. Figures 11a and 11b show the relationship between the operation of the switch transistors and voltage / current when the load is greater than or equal to the preset value, while Figures 11c and 11d show the relationship between the operation of the switch transistors and voltage / current when the load is smaller than the preset value. In actual use, the load and input current change, so during the operation of the BUCK circuit, the load may be greater than, less than, or equal to the preset value. For details, please refer to the explanation above and Figure 14, and will not be explained again here.

[0081] In the above embodiment, when the control type is determined to be a voltage control type according to the load type, intermittent high-frequency switching control is performed on the first switch transistor based on the magnitude of the load when the BUCK circuit is operating. This not only ensures that the BUCK circuit meets the load needs, but also reduces the switching loss of the switch transistor in the BUCK circuit, improving the operating efficiency of the BUCK circuit. At the same time, by rationally setting the first predetermined voltage, it is possible to avoid damage to each element in the BUCK circuit due to excessive voltage.

[0082] In some embodiments, when the flyback element in the BUCK circuit is a second switch transistor, the method further includes the steps of controlling the second switch transistor to turn off when the first switch transistor is turned on, and controlling the second switch transistor to turn on when the first switch transistor is turned off.

[0083] Specifically, as shown in Figure 4, a second switch transistor Q2 can be used instead of diode D. In this case, the relationship between the operation of the switch transistor and the voltage and current is as shown in Figures 15a-15d. When the first switch transistor Q1 is turned off, the second switch transistor Q2 is turned on, supplying a flyback circuit to inductor L1. When the first switch transistor Q1 is turned on, the second switch transistor Q2 is turned off, disconnecting its circuit and not affecting the power supply function of the BUCK circuit to the load. Thus, the second switch transistor Q2 achieves all the functions of diode D.

[0084] In the case of a BUCK circuit where the flyback element is a second switch transistor, the only difference from a circuit where the flyback element is a diode is the control of the second switch transistor; the control of the first switch transistor is the same, and therefore it has the same effect as when the flyback element is a diode. Please refer to the explanation above for details, as it will not be repeated here.

[0085] As described above, according to the control method for the BUCK circuit in the embodiment of this disclosure, the control type and control method of the BUCK circuit are determined based on the load information of the BUCK circuit, and by controlling the carrier frequency and duty cycle of the first switch transistor in the BUCK circuit, the BUCK circuit is made to operate with a different switching frequency, and the average switching frequency of the switch transistor can be lowered without affecting the normal operation of the load. This effectively reduces the switching loss of the switch transistor and improves the operating efficiency of the BUCK circuit.

[0086] In accordance with the above embodiments, the embodiments of this disclosure further provide a controller for a BUCK circuit.

[0087] Figure 16 is a schematic diagram of the structure of a controller for a BUCK circuit according to one embodiment of the present disclosure. As shown in Figure 10, the controller 110 includes a memory 111, a processor 112, and a control program for the BUCK circuit stored in the memory 111 and operable on the processor 112. The processor 112 implements the above-described control method for the BUCK circuit when executing the control program for the BUCK circuit.

[0088] The controller for the BUCK circuit according to the embodiment of this disclosure implements the above-described method of controlling the BUCK circuit using a processor, causing the BUCK circuit to operate with a different switching frequency, thereby lowering the average switching frequency of the switch transistor without affecting the normal operation of the load. This effectively reduces the switching loss of the switch transistor and improves the operating efficiency of the BUCK circuit.

[0089] Corresponding to the above embodiment, the embodiment of the present disclosure further provides a computer-readable storage medium in which a control program for a BUCK circuit is stored, and when the control program for the BUCK circuit is executed by a processor, the above-mentioned method for controlling the BUCK circuit is realized.

[0090] The computer-readable storage medium according to the embodiments of this disclosure can operate the BUCK circuit with a different switching frequency by the above-described control method of the BUCK circuit, thereby lowering the average switching frequency of the switch transistor without affecting the normal operation of the load. This effectively reduces the switching loss of the switch transistor and improves the operating efficiency of the BUCK circuit.

[0091] In accordance with the above embodiments, the embodiments of this disclosure further provide a control device for a BUCK circuit.

[0092] Figure 17 is a schematic diagram of the structure of a control device for a BUCK circuit according to one embodiment of the present disclosure, and as shown in Figure 11, the control device 200 comprises a decision module 210 and a control module 220.

[0093] The determination module 210 is used to identify the load information of the BUCK circuit and to determine the control type and control method of the BUCK circuit based on the load information. The control module 220 is used to control the carrier frequency and duty cycle of the first switch transistor Q1 in the BUCK circuit according to the control type and control method, thereby causing the BUCK circuit to operate with a different switching frequency.

[0094] According to one embodiment of the present disclosure, the load information includes the load type and the load magnitude, and the determination module 210 is further used to determine the control type according to the load type and the control method according to the load magnitude, the control type including current control type and voltage control type.

[0095] According to one embodiment of the present disclosure, the determination module 210 is further used to determine the control method to a low carrier frequency, high duty cycle control method when the load of the BUCK circuit is greater than or equal to a preset value, and to determine the control method to a high carrier frequency, high duty cycle control method when the load of the BUCK circuit is less than a preset value.

[0096] According to one embodiment of the present disclosure, when controlling the BUCK circuit using a current control type, the control module 220 is further used to acquire the current of the inductor of the BUCK circuit when the first switch transistor is controlled with a low carrier frequency, high duty cycle control method, and when the inductor current reaches a first predetermined current, to control the first switch transistor with a high carrier frequency, low duty cycle control method to reduce the inductor current to a second predetermined current, or when the first switch transistor is controlled with a high carrier frequency, high duty cycle control method, the control module 220 is used to acquire the current of the inductor of the BUCK circuit, and when the inductor current reaches a first predetermined current, to control the first switch transistor with a low carrier frequency, low duty cycle control method to reduce the inductor current to a second predetermined current.

[0097] According to one embodiment of the present disclosure, when controlling the BUCK circuit using a voltage control type, the control module 220 is further used to acquire the voltage of the output side capacitor of the BUCK circuit when the first switch transistor is controlled with a low carrier frequency, high duty cycle control method, and when the voltage of the output side capacitor reaches a first predetermined voltage, to control the first switch transistor with a high carrier frequency, low duty cycle control method to reduce the voltage of the output side capacitor to a second predetermined voltage, or when the first switch transistor is controlled with a high carrier frequency, high duty cycle control method, the control module 220 is used to acquire the voltage of the output side capacitor of the BUCK circuit, and when the voltage of the output side capacitor reaches a first predetermined voltage, to control the first switch transistor with a low carrier frequency, low duty cycle control method to reduce the voltage of the output side capacitor to a second predetermined voltage.

[0098] According to one embodiment of the present invention, the determination module 210 is used to determine the load type of the BUCK circuit, the control module 220 is used to obtain the magnitude of the load of the BUCK circuit when controlling the BUCK circuit using a current control type according to the load type, and the control module 220 is further used to control the first switch transistor in the BUCK circuit to turn on when the load of the BUCK circuit is greater than or equal to a preset value, thereby increasing the current of the inductor in the BUCK circuit, and when the inductor current has risen to a first predetermined current, to perform high-frequency switching control on the first switch transistor to reduce the inductor current to a second predetermined current.

[0099] According to one embodiment of the present invention, the control module 220 is further used to perform high-frequency switching control on the first switch transistor when the load of the BUCK circuit is less than a preset value to increase the current of the inductor of the BUCK circuit, and to control the turning off of the first switch transistor when the inductor current has risen to a first predetermined current to reduce the inductor current to a second predetermined current.

[0100] According to one embodiment of the present invention, the first predetermined current is less than or equal to the maximum current required for the load and less than or equal to the smaller of the current withstand capability of the first switch transistor and the saturation current of the inductor, and the second predetermined current is greater than or equal to zero and less than the first predetermined current.

[0101] According to one embodiment of the present invention, after identifying the load type of the BUCK circuit, the control module 220 further controls the BUCK circuit using a voltage control type according to the load type. This module acquires the magnitude of the load on the BUCK circuit, and when the load on the BUCK circuit is greater than or equal to a preset value, it controls the first switch transistor in the BUCK circuit to turn on, thereby increasing the voltage of the output side capacitor of the BUCK circuit. When the voltage of the output side capacitor rises to a first predetermined voltage, it performs high-frequency switching control on the first switch transistor to decrease the voltage of the output side capacitor to a second predetermined voltage.

[0102] According to one embodiment of the present invention, the control module 220 is further used to perform high-frequency switching control on the first switch transistor when the load of the BUCK circuit is less than a preset value to increase the voltage of the output side capacitor of the BUCK circuit, and to control the first switch transistor to turn off when the voltage of the output side capacitor rises to a first predetermined voltage to decrease the voltage of the output side capacitor to a second predetermined voltage.

[0103] According to one embodiment of the present disclosure, the first predetermined voltage is less than or equal to the maximum voltage required for the load and less than or equal to the breakdown voltage of the output capacitor, and the second predetermined voltage is greater than zero and less than the first predetermined voltage.

[0104] According to one embodiment of the present disclosure, when the flyback element in the BUCK circuit is a second switch transistor, the control module 220 is further used to control the second switch transistor to turn off when the first switch transistor is turned on, and to control the second switch transistor to turn on when the first switch transistor is turned off.

[0105] For a description of the control device for the BUCK circuit in this disclosure, please refer to the related description of the control method for the BUCK circuit in this disclosure, as further details will not be repeated here.

[0106] The control device for a BUCK circuit according to the embodiment of this disclosure identifies the load information of the BUCK circuit using a determination module, determines the control type and control method of the BUCK circuit based on the load information, and controls the carrier frequency and duty cycle of the first switch transistor using the control module, thereby causing the BUCK circuit to operate with a different switching frequency, and lowering the average switching frequency of the switch transistor without affecting the normal operation of the load. This effectively reduces the losses of the switch transistor and improves the operating efficiency of the BUCK circuit.

[0107] In accordance with the above embodiments, the embodiments of this disclosure further provide a BUCK circuit.

[0108] Figure 18 is a circuit diagram of a BUCK circuit according to one embodiment of the present disclosure. As shown in Figure 18, the BUCK circuit 100 comprises an input capacitor C1, a first switch transistor Q1, a flyback element XL, an inductor L1, an output capacitor C2, and a controller 110.

[0109] One end of the first switch transistor Q1 is connected to one end of the input capacitor, one end of the flyback element XL is connected to the other end of the first switch transistor Q1, the other end of the flyback element XL is connected to the other end of the input capacitor C1, one end of the inductor L1 is connected to the other end of the first switch transistor Q1, one end of the output capacitor C2 is connected to the other end of the inductor L1, and the other end of the output capacitor C2 is connected to the other end of the flyback element. The controller 110 is used to identify the load information of the BUCK circuit, determine the control type and control method of the BUCK circuit 100 based on the load information, and control the carrier frequency and duty cycle of the first switch transistor Q1 according to the control type and control method to operate the BUCK circuit 100 with a different switching frequency.

[0110] According to one embodiment of the present disclosure, load information includes load type and load magnitude, and the controller 110 is further used to determine the control type according to the load type and the control method according to the load magnitude, the control type including current control type and voltage control type.

[0111] According to one embodiment of the present disclosure, the controller 110 is further used to determine the control method to be a low carrier frequency, high duty cycle control method when the load of the BUCK circuit is greater than or equal to a preset value, and to determine the control method to be a high carrier frequency, high duty cycle control method when the load of the BUCK circuit is less than a preset value.

[0112] According to one embodiment of the present disclosure, when controlling the BUCK circuit using a current control type, the controller 110 is further used to acquire the current of the inductor of the BUCK circuit when the first switch transistor Q1 is controlled with a low carrier frequency, high duty cycle control method, and when the inductor current reaches a first predetermined current, to control the first switch transistor Q1 with a high carrier frequency, low duty cycle control method to reduce the inductor current to a second predetermined current, or when the first switch transistor Q1 is controlled with a high carrier frequency, high duty cycle control method, the controller 110 is used to acquire the current of the inductor of the BUCK circuit, and when the inductor current reaches a first predetermined current, to control the first switch transistor Q1 with a low carrier frequency, low duty cycle control method to reduce the inductor current to a second predetermined current.

[0113] According to one embodiment of the present disclosure, when controlling the BUCK circuit using a voltage control type, the controller 110 is further used to acquire the voltage of the output side capacitor of the BUCK circuit when the first switch transistor Q1 is controlled with a low carrier frequency, high duty cycle control method, and when the voltage of the output side capacitor reaches a first predetermined voltage, to control the first switch transistor Q1 with a high carrier frequency, low duty cycle control method to reduce the voltage of the output side capacitor to a second predetermined voltage, or when the first switch transistor Q1 is controlled with a high carrier frequency, high duty cycle control method, the controller 110 is used to acquire the voltage of the output side capacitor of the BUCK circuit, and when the voltage of the output side capacitor reaches a first predetermined voltage, to control the first switch transistor Q1 with a low carrier frequency, low duty cycle control method to reduce the voltage of the output side capacitor to a second predetermined voltage.

[0114] According to one embodiment of the present invention, the controller 110 identifies the load type of the BUCK circuit, and when controlling the BUCK circuit using a current control type according to the load type, it acquires the magnitude of the load of the BUCK circuit, and when the load of the BUCK circuit is greater than or equal to a preset value, it controls the first switch transistor in the BUCK circuit to turn on to increase the current of the inductor in the BUCK circuit, and when the inductor current rises to a first predetermined current, it performs high-frequency switching control on the first switch transistor to reduce the inductor current to a second predetermined current.

[0115] According to one embodiment of the present invention, the controller 110 is further used to perform high-frequency switching control on the first switch transistor when the load of the BUCK circuit is less than a preset value to increase the current of the inductor of the BUCK circuit, and to control the off of the first switch transistor when the inductor current has risen to a first predetermined current to reduce the inductor current to a second predetermined current.

[0116] According to one embodiment of the present invention, the first predetermined current is less than or equal to the maximum current required for the load and less than or equal to the smaller of the current withstand capability of the first switch transistor and the saturation current of the inductor, and the second predetermined current is greater than or equal to zero and less than the first predetermined current.

[0117] According to one embodiment of the present invention, after identifying the load type of the BUCK circuit, the controller 110 further controls the BUCK circuit using a voltage control type according to the load type. This is done by acquiring the magnitude of the load of the BUCK circuit, and when the load of the BUCK circuit is greater than or equal to a preset value, controlling the ON state of the first switch transistor in the BUCK circuit to increase the voltage of the output side capacitor of the BUCK circuit. When the voltage of the output side capacitor rises to a first predetermined voltage, high-frequency switching control is performed on the first switch transistor to decrease the voltage of the output side capacitor to a second predetermined voltage.

[0118] According to one embodiment of the present invention, the controller 110 is further used to perform high-frequency switching control on the first switch transistor when the load of the BUCK circuit is less than a preset value to increase the voltage of the output side capacitor of the BUCK circuit, and to control the off of the first switch transistor when the voltage of the output side capacitor has risen to a first predetermined voltage to decrease the voltage of the output side capacitor to a second predetermined voltage.

[0119] According to one embodiment of the present disclosure, the first predetermined voltage is less than or equal to the maximum voltage required for the load and less than or equal to the breakdown voltage of the output capacitor, and the second predetermined voltage is greater than zero and less than the first predetermined voltage.

[0120] According to one embodiment of the present disclosure, when the flyback element in the BUCK circuit is a second switch transistor, the controller 110 is further used to control the second switch transistor to turn off when the first switch transistor Q1 is turned on, and to control the second switch transistor to turn on when the first switch transistor Q1 is turned off.

[0121] For a description of the BUCK circuit in this disclosure, please refer to the related description of the control method for the BUCK circuit in this disclosure, as detailed explanations will not be repeated here.

[0122] The BUCK circuit according to the embodiment of this disclosure uses a controller to identify load information for the BUCK circuit, determines the control type and control method of the BUCK circuit based on the load information, and controls the carrier frequency and duty cycle of the first switch transistor accordingly to change the switching frequency and operate the BCUK circuit. This lowers the average switching frequency of the switch transistor without affecting the normal operation of the load, thereby effectively reducing the losses of the switch transistor and improving the operating efficiency of the BCUK circuit.

[0123] The logic and / or steps shown in the flowchart or otherwise described herein can be thought of, for example, as an ordered list of executable instructions for realizing a logical function, which can be concretely realized on any computer-readable medium and used in or in combination with instruction execution systems, devices or equipment (for example, computer-based systems, which include a processor or a system that reads instructions from an instruction execution system, device or equipment and executes those instructions). For the purposes of this specification, “computer-readable medium” may be any device that stores, communicates, propagates or transmits a program, which can be used in combination with an instruction execution system, device or equipment or such instruction execution systems, devices or equipment. More specific examples of computer-readable mediums (a non-exclusive list) include electrical connections with one or more wires (electronic devices), portable computer disk cartridges (magnetic devices), random access memory (RAM), read-only memory (ROM), erasable and editable read-only memory (EPROM or flash memory), optical fiber devices, and portable disk read-only memory (CDROM). Furthermore, the computer-readable medium may also be paper or other suitable medium on which the program is printed. For example, the program may be acquired electronically by optically scanning paper or other suitable medium, and then editing, interpreting, or processing it in any other suitable manner, and then stored in computer memory.

[0124] It should be understood that each part of this disclosure can be implemented in hardware, software, firmware, or a combination thereof. In the embodiments described above, multiple steps or methods can be implemented in software or firmware stored in memory and executed by an appropriate instruction execution system. When implemented in hardware, as in other embodiments, it can be implemented in any or a combination of technologies known in the art, such as discrete logic circuits having logic gate circuits for implementing logic functions for data signals, dedicated integrated circuits having appropriate combinational logic gate circuits, programmable gate arrays (PGAs), and field-programmable gate arrays (FPGAs).

[0125] In this specification, reference terms such as “one embodiment,” “several embodiments,” “example,” “specific example,” or “several examples” refer to specific features, structures, materials, or characteristics described in combination with such embodiments or examples that are included in at least one embodiment or example of this disclosure. In this specification, illustrative descriptions of the above terms do not necessarily apply to the same embodiment or example. Furthermore, specific features, structures, materials, or characteristics described may be combined in an appropriate manner in any or more embodiments or examples.

[0126] Furthermore, the terms “first” and “second” are used solely for descriptive purposes and should not be understood as indicating the number of technical features that express or imply relative importance. Thus, features limited by “first” and “second” may explicitly or implicitly include at least one such feature. In this disclosure, “multiple” means at least two, e.g., two, three, etc., unless otherwise specified.

[0127] In this disclosure, terms such as “attachment,” “connection,” “connection,” and “fixing” should be understood broadly unless otherwise specified and limited, and may include, for example, being fixedly connected, detachably connected, integrated, mechanically connected, electrically connected, directly connected, indirectly connected via an intermediate medium, or an internal communication or interaction relationship between two elements. Unless otherwise explicitly limited, the specific meaning of the above terms in this disclosure can be understood by those skilled in the art depending on the context.

[0128] Although examples have been described in this disclosure, these examples are illustrative and should not be understood as limiting the disclosure. Those skilled in the art will understand that various changes, modifications, substitutions, and variations are possible within the scope of this disclosure. Cross-reference to related applications

[0129] This disclosure claims priority to the Chinese patent applications filed on July 22, 2022, with application number 202210869341.7, titled "BUCK circuit and its control method, controller, control device, and storage medium," and filed on July 22, 2022, with application number 202210872129.6, titled "BUCK circuit and its control method, controller, control device, and storage medium," the entire contents of which are incorporated herein by reference.

Claims

1. A method for controlling a BUCK circuit, The steps include identifying the load type and load magnitude of the aforementioned BUCK circuit, The steps include determining the control type according to the load type and determining the control method according to the magnitude of the load, The step includes controlling the carrier frequency and duty cycle of the first switch transistor in the BUCK circuit according to the control type and control method, thereby causing the BUCK circuit to operate with a different switching frequency. The load type includes a current-sensitive type that is easily affected by current fluctuations in the BUCK circuit and a voltage-sensitive type that is easily affected by voltage fluctuations in the BUCK circuit, and the control type includes a current-controlled type and a voltage-controlled type. The step of determining the control method according to the magnitude of the load is: When the load of the BUCK circuit is greater than or equal to a preset value, the control method is set to a low carrier frequency, high duty cycle control method, thereby increasing the inductor current and the output capacitor voltage. A method for controlling a BUCK circuit, comprising the step of increasing the current of the inductor and the voltage of the output capacitor by determining the control method to a high carrier frequency, high duty cycle control method when the load of the BUCK circuit is smaller than a preset value.

2. When controlling the BUCK circuit using the current control type described above, the steps of controlling the carrier frequency and duty cycle of the first switch transistor in the BUCK circuit are as follows: When the first switch transistor is controlled using a low carrier frequency, high duty cycle control method, the current of the inductor in the BUCK circuit is obtained, and when the current of the inductor reaches a first predetermined current, the first switch transistor is controlled using a high carrier frequency, low duty cycle control method to reduce the current of the inductor to a second predetermined current, or A method for controlling a BUCK circuit according to claim 1, comprising the step of obtaining the current of the inductor of the BUCK circuit when the first switch transistor is controlled by a high carrier frequency, high duty cycle control method, and when the current of the inductor reaches a first predetermined current, controlling the first switch transistor by a low carrier frequency, low duty cycle control method to reduce the current of the inductor to a second predetermined current.

3. When controlling the BUCK circuit using the voltage control type described above, the steps of controlling the carrier frequency and duty cycle of the first switch transistor in the BUCK circuit are as follows: When the first switch transistor is controlled using a low carrier frequency, high duty cycle control method, the voltage of the output side capacitor of the BUCK circuit is obtained, and when the voltage of the output side capacitor reaches a first predetermined voltage, the first switch transistor is controlled using a high carrier frequency, low duty cycle control method to reduce the voltage of the output side capacitor to a second predetermined voltage, or A method for controlling a BUCK circuit according to claim 1, comprising the step of obtaining the voltage of the output side capacitor of the BUCK circuit when the first switch transistor is controlled by a high carrier frequency, high duty cycle control method, and when the voltage of the output side capacitor reaches a first predetermined voltage, controlling the first switch transistor by a low carrier frequency, low duty cycle control method to reduce the voltage of the output side capacitor to a second predetermined voltage.

4. A method for controlling a BUCK circuit, The steps include identifying that the load type of the BUCK circuit is a current-sensitive type that is easily affected by current fluctuations in the BUCK circuit, and obtaining the magnitude of the load of the BUCK circuit, When the load of the BUCK circuit is greater than or equal to a preset value, the first switch transistor in the BUCK circuit is controlled to turn on to increase the current of the inductor in the BUCK circuit, and when the current of the inductor rises to a first predetermined current, high-frequency switching control is performed on the first switch transistor to reduce the current of the inductor to a second predetermined current, A method for controlling a BUCK circuit, comprising the steps of: when the load of the BUCK circuit is less than a preset value, performing high-frequency switching control on the first switch transistor to increase the current of the inductor of the BUCK circuit; and when the current of the inductor rises to a first predetermined current, controlling the off state of the first switch transistor to reduce the current of the inductor to a second predetermined current.

5. A method for controlling a BUCK circuit, The steps include identifying that the load type of the BUCK circuit is a voltage-sensitive type that is easily affected by voltage fluctuations of the BUCK circuit, and obtaining the magnitude of the load of the BUCK circuit, When the load of the BUCK circuit is greater than or equal to a preset value, the first switch transistor in the BUCK circuit is controlled to turn on to increase the voltage of the output side capacitor of the BUCK circuit, and when the voltage of the output side capacitor rises to a first predetermined voltage, high-frequency switching control is performed on the first switch transistor to reduce the voltage of the output side capacitor to a second predetermined voltage, A method for controlling a BUCK circuit, comprising the steps of: when the load of the BUCK circuit is less than a preset value, performing high-frequency switching control on the first switch transistor to increase the voltage of the output side capacitor of the BUCK circuit; and when the voltage of the output side capacitor rises to a first predetermined voltage, controlling the first switch transistor to turn off to decrease the voltage of the output side capacitor to a second predetermined voltage.

6. A method for controlling a BUCK circuit according to claim 2 or 4, wherein the first predetermined current is less than or equal to the maximum current required for the load and less than or equal to the smaller of the current withstand capability of the first switch transistor and the inductor saturation current, and the second predetermined current is zero or greater and less than the first predetermined current.

7. A method for controlling a BUCK circuit according to claim 3 or 5, wherein the first predetermined voltage is less than or equal to the maximum voltage required for the load and less than or equal to the withstand voltage of the output side capacitor, and the second predetermined voltage is greater than zero and less than the first predetermined voltage.

8. When the flyback element in the BUCK circuit is a second switch transistor, the control method for the BUCK circuit is: When the first switch transistor is controlled to turn on, the second switch transistor is controlled to turn off, A method for controlling a BUCK circuit according to any one of claims 1 to 5, further comprising the step of controlling the second switch transistor to turn on when the first switch transistor is turned off.

9. A controller for a BUCK circuit, comprising memory, a processor, and a BUCK circuit control program stored in memory and operable on the processor, wherein when the processor executes the BUCK circuit control program, the BUCK circuit control method described in any one of claims 1 to 5 is realized.

10. A computer-readable storage medium in which a control program for a BUCK circuit is stored, and when the control program for the BUCK circuit is executed by a processor, the control method for a BUCK circuit according to any one of claims 1 to 5 is realized.

11. A control device for a BUCK circuit, A determination module for identifying the load type and load magnitude of the BUCK circuit, and for determining the control type and control method of the BUCK circuit based on the load type and load magnitude, The system includes a control module that controls the carrier frequency and duty cycle of the first switch transistor in the BUCK circuit according to the control type and control method, thereby causing the BUCK circuit to operate with a different switching frequency. The load type includes a current-sensitive type that is easily affected by current fluctuations in the BUCK circuit and a voltage-sensitive type that is easily affected by voltage fluctuations in the BUCK circuit, and the control type includes a current-controlled type and a voltage-controlled type. The control module is a control device for a BUCK circuit, which, when the load of the BUCK circuit is greater than or equal to a preset value, determines the control method to a low carrier frequency, high duty cycle control method, thereby increasing the current of the inductor and the voltage of the output capacitor, and when the load of the BUCK circuit is less than a preset value, determines the control method to a high carrier frequency, high duty cycle control method, thereby increasing the current of the inductor and the voltage of the output capacitor.

12. It is a BUCK circuit, Input capacitor and One end of the first switch transistor is connected to one end of the input capacitor, A flyback element is provided, with one end connected to the other end of the first switch transistor and the other end connected to the other end of the input capacitor. One end is connected to an inductor that is connected to the other end of the first switch transistor, An output capacitor, one end of which is connected to the other end of the inductor and the other end of which is connected to the other end of the flyback element, A controller is used to identify the load type and magnitude of the BUCK circuit, determine the control type and control method of the BUCK circuit based on the load type and magnitude, and control the carrier frequency and duty cycle of the first switch transistor according to the control type and control method to operate the BUCK circuit with a different switching frequency. The load type includes a current-sensitive type that is easily affected by current fluctuations in the BUCK circuit and a voltage-sensitive type that is easily affected by voltage fluctuations in the BUCK circuit, and the control type includes a current-controlled type and a voltage-controlled type. The controller increases the inductor current and output capacitor voltage when the load of the BUCK circuit is greater than or equal to a preset value by setting the control method to a low carrier frequency, high duty cycle control method, and increases the inductor current and output capacitor voltage when the load of the BUCK circuit is less than a preset value by setting the control method to a high carrier frequency, high duty cycle control method.

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