CN116683764A

CN116683764A - Control method and device of switching power supply, switching power supply and storage medium

Info

Publication number: CN116683764A
Application number: CN202310751778.5A
Authority: CN
Inventors: 宋蒙恩; 魏兵戌; 张祥; 刘蓝田; 赵向阳; 李白雪
Original assignee: Gree Electric Appliances Inc of Zhuhai
Current assignee: Gree Electric Appliances Inc of Zhuhai
Priority date: 2023-06-25
Filing date: 2023-06-25
Publication date: 2023-09-01

Abstract

The invention discloses a control method and device of a switching power supply, the switching power supply and a storage medium, wherein the method comprises the following steps: after the first-stage BUCK circuit and the second-stage BUCK circuit work, the first-stage BUCK circuit is subjected to double closed-loop control of a voltage loop and a current loop according to an input voltage sampling value, an output voltage sampling value and an inductance current of the first-stage BUCK circuit; and performing double closed loop control of a voltage loop and a current loop on the second-stage BUCK circuit according to the input voltage sampling value, the output voltage sampling value and the inductance current of the second-stage BUCK circuit so as to enable the first-stage BUCK circuit and the second-stage BUCK circuit to work alternately. According to the scheme, through controlling the two-stage BUCK circuits to work alternately, the current passing through each stage of BUCK circuit can be reduced, so that the size of power devices (such as a switch tube, a diode and an inductor) in each stage of BUCK circuit can be correspondingly reduced.

Description

Control method and device of switching power supply, switching power supply and storage medium

Technical Field

The invention belongs to the technical field of switching power supplies, and particularly relates to a control method and device of a switching power supply, the switching power supply and a storage medium, in particular to a protection and control method and device of a DC-DC converter circuit, and the switching power supply (such as the DC-DC converter circuit) and the storage medium.

Background

In an electronic system, a BUCK circuit with DC-DC conversion is required to be used as a power supply. As the operating frequency and operating voltage of electronic systems are continuously increased and decreased, ripple of the output current of the power supply is required to be smaller and smaller. In addition, in the electronic system, since the installation space of the portable electronic device is limited and the overall structure of the portable electronic device is increasingly "slim", electronic components having a small size and a low height are required to be used in the design of the power supply of the portable electronic device.

In the related scheme, the ripple of the output current of the BUCK circuit is larger, and the volume of a power device (such as a switch tube, a diode, an inductor, etc.) in the BUCK circuit is increased due to the magnitude of the output current of the BUCK circuit (i.e. the current of the power device in the BUCK circuit) under the high power condition, but the ripple is not consistent with the design requirement of the power supply of the portable electronic equipment.

The foregoing is provided merely for the purpose of facilitating understanding of the technical solutions of the present invention and is not intended to represent an admission that the foregoing is prior art.

Disclosure of Invention

The invention aims to provide a control method, a device, a switching power supply and a storage medium of a switching power supply, which are used for solving the problem that the design requirement of the power supply of portable electronic equipment is that electronic components with small size and low height are needed, but when the portable electronic equipment needs to adopt a BUCK circuit with DC-DC conversion as the power supply, the size of a power device (such as a switching tube, a diode, an inductor and the like) in the BUCK circuit is increased due to the size of the output current of the BUCK circuit under the high power condition because of larger ripple of the output current of the BUCK circuit, and the problem that the size of the power device is not consistent with the design requirement of the power supply of the portable electronic equipment is solved.

The invention provides a control method of a switching power supply, which comprises the following steps: a BUCK conversion circuit and a driving circuit of the BUCK conversion circuit; the BUCK conversion circuit comprises: a first stage BUCK circuit and a second stage BUCK circuit, each stage BUCK circuit having two sub BUCK circuits; the first stage BUCK circuit and the second stage BUCK circuit are arranged in series between a direct current power supply at the input side and a load at the output side; the first-stage BUCK circuit is provided with a first switching tube module, a second switching tube module, a first inductance module and a second inductance module; the second-stage BUCK circuit is provided with a third switching tube module, a fourth switching Guan Mokuai, a third inductance module and a fourth inductance module; the driving circuit of the BUCK conversion circuit is respectively connected with the first switching tube module, the second switching tube module, the third switching tube module and the fourth switching tube module; the control method of the switching power supply comprises the following steps: enabling a driving circuit of the BUCK conversion circuit under the condition that a self-checking instruction of the BUCK conversion circuit is received; under the condition that a driving circuit of the BUCK conversion circuit is enabled, enabling the first-stage BUCK circuit and the second-stage BUCK circuit to work; the first-stage BUCK circuit is used for carrying out first-stage voltage reduction treatment on the direct-current power supply at the input side to obtain intermediate voltage; the second-stage BUCK circuit is used for performing second-stage voltage reduction processing on the intermediate voltage at the output side of the first-stage BUCK circuit to obtain output voltage so as to supply power to a load at the output side; after the first-stage BUCK circuit and the second-stage BUCK circuit work, sampling the voltage of a direct-current power supply at the input side to obtain an input voltage sampling value of the BUCK conversion circuit; sampling the intermediate voltage at the output side of the first-stage BUCK circuit to obtain an output voltage sampling value of the first-stage BUCK circuit; sampling currents on a first inductance module and a second inductance module in the first-stage BUCK circuit to obtain inductance currents of the first-stage BUCK circuit; sampling the output voltage of the output side of the second-stage BUCK circuit to obtain an output voltage sampling value of the second-stage BUCK circuit; sampling currents on a third inductance module and a fourth inductance module in the second-stage BUCK circuit to obtain inductance currents of the second-stage BUCK circuit; according to the input voltage sampling value of the BUCK conversion circuit, the output voltage sampling value of the first-stage BUCK circuit and the inductance current of the first-stage BUCK circuit, performing double closed-loop control on a voltage loop and a current loop of the first-stage BUCK circuit; and performing double closed loop control of a voltage loop and a current loop on the second-stage BUCK circuit according to an input voltage sampling value of the BUCK conversion circuit, an output voltage sampling value of the second-stage BUCK circuit and an inductance current of the second-stage BUCK circuit, so that the first-stage BUCK circuit and the second-stage BUCK circuit work simultaneously, and two sub-BUCK circuits in each stage BUCK circuit can work alternately.

In some embodiments, the method for performing dual closed loop control of a voltage loop and a current loop on the first stage BUCK circuit according to an input voltage sampling value of the BUCK conversion circuit, an output voltage sampling value of the first stage BUCK circuit and an inductor current of the first stage BUCK circuit includes: the difference value between the output voltage set value of the first-stage BUCK circuit and the output voltage sampling value of the first-stage BUCK circuit is controlled by PI to obtain output voltage, and the output voltage is recorded as the voltage loop output voltage of the first-stage BUCK circuit; determining the product of the output voltage of the voltage loop of the first-stage BUCK circuit and the sampling value of the input voltage of the BUCK conversion circuit as an output current set value of the first-stage BUCK circuit; the difference value between the output current set value of the first-stage BUCK circuit and the inductance current of the first-stage BUCK circuit is controlled by PI to obtain output current, and the output current is recorded as the current loop output current of the first-stage BUCK circuit; determining the duty ratio of PWM signals for controlling a first switching tube module and a second switching tube module in the first-stage BUCK circuit according to the output current of a current loop of the first-stage BUCK circuit; and outputting PWM signals for controlling the first switching tube module and the second switching tube module in the first-stage BUCK circuit according to the duty ratio of PWM signals for controlling the first switching tube module and the second switching tube module in the first-stage BUCK circuit so as to control the first switching tube module and the second switching tube module in the first-stage BUCK circuit to act.

In some embodiments, the method further includes performing a double closed loop control of a voltage loop and a current loop on the first stage BUCK circuit according to an input voltage sampling value of the BUCK conversion circuit, an output voltage sampling value of the first stage BUCK circuit, and an inductor current of the first stage BUCK circuit: according to the duty ratio of PWM signals used for controlling a first switching tube module and a second switching tube module in the first-stage BUCK circuit, calculating the triggering time of the next sampling so as to: resampling is carried out under the condition that the triggering time of the next sampling arrives, so that a new input voltage sampling value of the BUCK conversion circuit, a new output voltage sampling value of the first-stage BUCK circuit and an inductance current of the first-stage BUCK circuit are obtained, and double closed-loop control of a voltage ring and a current ring is carried out on the first-stage BUCK circuit according to the new input voltage sampling value of the BUCK conversion circuit, the new output voltage sampling value of the first-stage BUCK circuit and the inductance current of the first-stage BUCK circuit; the specific mode of performing the double closed-loop control of the voltage loop and the current loop on the second-stage BUCK circuit is the same as the specific mode of performing the double closed-loop control of the voltage loop and the current loop on the first-stage BUCK circuit according to the input voltage sampling value of the BUCK conversion circuit, the output voltage sampling value of the first-stage BUCK circuit and the inductance current of the first-stage BUCK circuit.

In some embodiments, further comprising: acquiring the temperature of components in the first-stage BUCK circuit and acquiring the temperature of components in the second-stage BUCK circuit; according to at least one of the output voltage sampling value of the first-stage BUCK circuit, the inductance current of the first-stage BUCK circuit and the temperature of components in the first-stage BUCK circuit, the first-stage BUCK circuit is protected; and protecting the second-stage BUCK circuit according to at least one of an output voltage sampling value of the second-stage BUCK circuit, an inductance current of the second-stage BUCK circuit and a temperature of a component in the second-stage BUCK circuit.

In some embodiments, protecting the first stage BUCK circuit according to at least one of an output voltage sampling value of the first stage BUCK circuit, an inductor current of the first stage BUCK circuit, and a temperature of a component in the first stage BUCK circuit, includes: if the sampling value of the output voltage of the first-stage BUCK circuit is larger than the set voltage, the PWM signal of the first-stage BUCK circuit is turned off to control the first-stage BUCK circuit to stop working; if the inductance current of the first-stage BUCK circuit is larger than the set current, the PWM signal of the first-stage BUCK circuit is turned off to control the first-stage BUCK circuit to stop working; if the temperature of the components in the first-stage BUCK circuit is higher than the set temperature, carrying out preset frequency limiting or frequency reducing treatment on the first-stage BUCK circuit; the specific way of protecting the second stage BUCK circuit according to at least one of the output voltage sampling value of the second stage BUCK circuit, the inductance current of the second stage BUCK circuit and the temperature of the components in the second stage BUCK circuit is the same as the specific way of protecting the first stage BUCK circuit according to at least one of the output voltage sampling value of the first stage BUCK circuit, the inductance current of the first stage BUCK circuit and the temperature of the components in the first stage BUCK circuit.

In accordance with another aspect of the present invention, there is provided a control device for a switching power supply, including: a BUCK conversion circuit and a driving circuit of the BUCK conversion circuit; the BUCK conversion circuit comprises: a first stage BUCK circuit and a second stage BUCK circuit, each stage BUCK circuit having two sub BUCK circuits; the first stage BUCK circuit and the second stage BUCK circuit are arranged in series between a direct current power supply at the input side and a load at the output side; the first-stage BUCK circuit is provided with a first switching tube module, a second switching tube module, a first inductance module and a second inductance module; the second-stage BUCK circuit is provided with a third switching tube module, a fourth switching Guan Mokuai, a third inductance module and a fourth inductance module; the driving circuit of the BUCK conversion circuit is respectively connected with the first switching tube module, the second switching tube module, the third switching tube module and the fourth switching tube module; the control device of the switching power supply comprises: a control unit configured to enable a driving circuit of the BUCK conversion circuit in a case where a self-test instruction of the BUCK conversion circuit is received; the control unit is further configured to enable the first-stage BUCK circuit and the second-stage BUCK circuit to operate under the condition that a driving circuit of the BUCK conversion circuit is enabled; the first-stage BUCK circuit is used for carrying out first-stage voltage reduction treatment on the direct-current power supply at the input side to obtain intermediate voltage; the second-stage BUCK circuit is used for performing second-stage voltage reduction processing on the intermediate voltage at the output side of the first-stage BUCK circuit to obtain output voltage so as to supply power to a load at the output side; the acquisition unit is configured to sample the voltage of the direct current power supply at the input side after the first-stage BUCK circuit and the second-stage BUCK circuit work, so as to obtain an input voltage sampling value of the BUCK conversion circuit; sampling the intermediate voltage at the output side of the first-stage BUCK circuit to obtain an output voltage sampling value of the first-stage BUCK circuit; sampling currents on a first inductance module and a second inductance module in the first-stage BUCK circuit to obtain inductance currents of the first-stage BUCK circuit; sampling the output voltage of the output side of the second-stage BUCK circuit to obtain an output voltage sampling value of the second-stage BUCK circuit; sampling currents on a third inductance module and a fourth inductance module in the second-stage BUCK circuit to obtain inductance currents of the second-stage BUCK circuit; the control unit is further configured to perform double closed-loop control of a voltage loop and a current loop on the first-stage BUCK circuit according to an input voltage sampling value of the BUCK conversion circuit, an output voltage sampling value of the first-stage BUCK circuit and an inductance current of the first-stage BUCK circuit; and performing double closed loop control of a voltage loop and a current loop on the second-stage BUCK circuit according to an input voltage sampling value of the BUCK conversion circuit, an output voltage sampling value of the second-stage BUCK circuit and an inductance current of the second-stage BUCK circuit, so that the first-stage BUCK circuit and the second-stage BUCK circuit work simultaneously, and two sub-BUCK circuits in each stage BUCK circuit can work alternately.

In some embodiments, the control unit performs dual closed loop control of a voltage loop and a current loop on the first stage BUCK circuit according to an input voltage sampling value of the BUCK conversion circuit, an output voltage sampling value of the first stage BUCK circuit, and an inductor current of the first stage BUCK circuit, including: the difference value between the output voltage set value of the first-stage BUCK circuit and the output voltage sampling value of the first-stage BUCK circuit is controlled by PI to obtain output voltage, and the output voltage is recorded as the voltage loop output voltage of the first-stage BUCK circuit; determining the product of the output voltage of the voltage loop of the first-stage BUCK circuit and the sampling value of the input voltage of the BUCK conversion circuit as an output current set value of the first-stage BUCK circuit; the difference value between the output current set value of the first-stage BUCK circuit and the inductance current of the first-stage BUCK circuit is controlled by PI to obtain output current, and the output current is recorded as the current loop output current of the first-stage BUCK circuit; determining the duty ratio of PWM signals for controlling a first switching tube module and a second switching tube module in the first-stage BUCK circuit according to the output current of a current loop of the first-stage BUCK circuit; and outputting PWM signals for controlling the first switching tube module and the second switching tube module in the first-stage BUCK circuit according to the duty ratio of PWM signals for controlling the first switching tube module and the second switching tube module in the first-stage BUCK circuit so as to control the first switching tube module and the second switching tube module in the first-stage BUCK circuit to act.

In some embodiments, the control unit performs dual closed loop control of a voltage loop and a current loop on the first stage BUCK circuit according to an input voltage sampling value of the BUCK conversion circuit, an output voltage sampling value of the first stage BUCK circuit, and an inductor current of the first stage BUCK circuit, and further includes: according to the duty ratio of PWM signals used for controlling a first switching tube module and a second switching tube module in the first-stage BUCK circuit, calculating the triggering time of the next sampling so as to: resampling is carried out under the condition that the triggering time of the next sampling arrives, so that a new input voltage sampling value of the BUCK conversion circuit, a new output voltage sampling value of the first-stage BUCK circuit and an inductance current of the first-stage BUCK circuit are obtained, and double closed-loop control of a voltage ring and a current ring is carried out on the first-stage BUCK circuit according to the new input voltage sampling value of the BUCK conversion circuit, the new output voltage sampling value of the first-stage BUCK circuit and the inductance current of the first-stage BUCK circuit; the specific mode of performing the double closed-loop control of the voltage loop and the current loop on the second-stage BUCK circuit is the same as the specific mode of performing the double closed-loop control of the voltage loop and the current loop on the first-stage BUCK circuit according to the input voltage sampling value of the BUCK conversion circuit, the output voltage sampling value of the first-stage BUCK circuit and the inductance current of the first-stage BUCK circuit.

In some embodiments, further comprising: the acquisition unit is further configured to acquire the temperature of the components in the first-stage BUCK circuit and acquire the temperature of the components in the second-stage BUCK circuit; the control unit is further configured to protect the first-stage BUCK circuit according to at least one of an output voltage sampling value of the first-stage BUCK circuit, an inductance current of the first-stage BUCK circuit and a temperature of a component in the first-stage BUCK circuit; and protecting the second-stage BUCK circuit according to at least one of an output voltage sampling value of the second-stage BUCK circuit, an inductance current of the second-stage BUCK circuit and a temperature of a component in the second-stage BUCK circuit.

In some embodiments, the control unit protects the first stage BUCK circuit according to at least one of an output voltage sampling value of the first stage BUCK circuit, an inductor current of the first stage BUCK circuit, and a temperature of a component in the first stage BUCK circuit, and includes: if the sampling value of the output voltage of the first-stage BUCK circuit is larger than the set voltage, the PWM signal of the first-stage BUCK circuit is turned off to control the first-stage BUCK circuit to stop working; if the inductance current of the first-stage BUCK circuit is larger than the set current, the PWM signal of the first-stage BUCK circuit is turned off to control the first-stage BUCK circuit to stop working; if the temperature of the components in the first-stage BUCK circuit is higher than the set temperature, carrying out preset frequency limiting or frequency reducing treatment on the first-stage BUCK circuit; the specific way of protecting the second stage BUCK circuit according to at least one of the output voltage sampling value of the second stage BUCK circuit, the inductance current of the second stage BUCK circuit and the temperature of the components in the second stage BUCK circuit is the same as the specific way of protecting the first stage BUCK circuit according to at least one of the output voltage sampling value of the first stage BUCK circuit, the inductance current of the first stage BUCK circuit and the temperature of the components in the first stage BUCK circuit.

In accordance with another aspect of the present invention, there is provided a switching power supply comprising: the control device of the switching power supply.

In accordance with the above method, a further aspect of the present invention provides a storage medium, where the storage medium includes a stored program, and when the program runs, the device where the storage medium is controlled to execute the above method for controlling a switching power supply.

Therefore, according to the scheme of the invention, the output voltage of the first-stage BUCK circuit and the inductance current of the first-stage BUCK circuit, the output voltage of the second-stage BUCK circuit and the inductance current of the second-stage BUCK circuit are sampled for the two-stage BUCK circuit formed by the first-stage BUCK circuit and the second-stage BUCK circuit, and the first-stage BUCK circuit is subjected to double closed-loop control of a voltage ring and a current ring according to the output voltage of the first-stage BUCK circuit and the inductance current of the first-stage BUCK circuit; and according to the output voltage of the second-stage BUCK circuit and the inductance current of the second-stage BUCK circuit, the second-stage BUCK circuit is subjected to double closed-loop control of a voltage loop and a current loop, so that the alternating work of the two-stage BUCK circuits is realized, and therefore, the alternating work of the two-stage BUCK circuits is controlled by adopting a DC-DC converter circuit formed by the two-stage BUCK circuits as a power supply of the portable electronic equipment, the current passing through each stage BUCK circuit can be reduced, and the volume of power devices (such as a switch tube, a diode, an inductor and the like) in each stage BUCK circuit can be correspondingly reduced.

Additional features and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention.

The technical scheme of the invention is further described in detail through the drawings and the embodiments.

Drawings

FIG. 1 is a flow chart of a control method of a switching power supply according to an embodiment of the invention;

FIG. 2 is a flow chart of an embodiment of the method of the present invention for performing dual closed loop control of the voltage loop and the current loop on the first stage BUCK circuit;

FIG. 3 is a flow chart of an embodiment of the protection of the first stage BUCK circuit and the second stage BUCK circuit in the method of the present invention;

FIG. 4 is a schematic diagram illustrating a control device of a switching power supply according to an embodiment of the present invention;

FIG. 5 is a schematic diagram illustrating a control apparatus of a DC-DC converter circuit according to an embodiment of the present invention;

FIG. 6 is a schematic diagram of a control device of a DC-DC converter circuit according to an embodiment of the present invention;

fig. 7 is a schematic diagram showing a control flow of the BUCK circuit 1 in the control device of the DC-DC converter circuit of the present invention;

FIG. 8 is a schematic diagram illustrating a protection circuit of the control device of the DC-DC converter circuit according to an embodiment of the present invention;

Fig. 9 is a flowchart of a control method of the DC-DC converter circuit according to an embodiment of the invention.

In the embodiment of the present invention, reference numerals are as follows, in combination with the accompanying drawings:

102-an acquisition unit; 104-a control unit.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the technical solutions of the present invention will be clearly and completely described below with reference to specific embodiments of the present invention and corresponding drawings. It will be apparent that the described embodiments are only some, but not all, embodiments of the invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

In consideration of the design requirement of the power supply of the portable electronic device, electronic components with small size and low height are required to be adopted, however, when the portable electronic device needs to adopt a BUCK circuit with DC-DC conversion as the power supply, the size of a power device (such as a switch tube, a diode, an inductor and the like) in the BUCK circuit is increased under the high power condition due to the large ripple of the output current of the BUCK circuit, and the size of the power device is not consistent with the design requirement of the power supply of the portable electronic device. Therefore, aiming at the design requirement of the power supply of the portable electronic equipment, when the DC-DC converted BUCK circuit is adopted as the power supply, the volume of the DC-DC converted BUCK circuit is required to be reduced, so that the volume of the power supply when the DC-DC converted BUCK circuit is adopted as the power supply of the portable electronic equipment is reduced.

Therefore, the scheme of the invention provides a control method of a switching power supply, in particular to a protection and control method of a DC-DC converter circuit, which aims at a two-stage BUCK circuit formed by double BUCK circuits (namely a first-stage BUCK circuit and a second-stage BUCK circuit), and controls the two-stage BUCK circuits to alternately work according to the output voltage of the first-stage BUCK circuit and the inductance current of the first-stage BUCK circuit, the output voltage of the second-stage BUCK circuit and the inductance current of the second-stage BUCK circuit, so that the protection of the DC-DC converter circuit is realized, and the volume of each stage BUCK circuit in the DC-DC converter circuit is reduced under the high-power condition. Under the condition that the two-stage BUCK circuits alternately work, the current passing through each stage of BUCK circuit only accounts for half of the total current passing through the DC-DC converter circuit, under the condition that the current passing through each stage of BUCK circuit is small, the current passing through power devices (such as a switch tube, a diode and an inductor) in each stage of BUCK circuit is also small, and the volume of the power devices (such as the switch tube, the diode and the inductor) in each stage of BUCK circuit can be correspondingly reduced, so that the volume of each stage of BUCK circuit can be effectively reduced.

According to an embodiment of the present invention, a control method of a switching power supply is provided, and a flowchart of an embodiment of the method of the present invention is shown in fig. 1. The switching power supply includes: a BUCK conversion circuit and a driving circuit of the BUCK conversion circuit; the BUCK conversion circuit comprises: a first stage BUCK circuit and a second stage BUCK circuit, each stage BUCK circuit having two sub BUCK circuits; the first stage BUCK circuit and the second stage BUCK circuit are arranged in series between a direct current power supply at the input side and a load at the output side; the first-stage BUCK circuit is provided with a first switching tube module, a second switching tube module, a first inductance module and a second inductance module, wherein the first switching tube module is a switching tube G1, the second switching tube module is a switching tube G2, the first inductance module is an inductance L1, and the second inductance module is an inductance L2; the second stage BUCK circuit is provided with a third switching tube module, a fourth switching tube module Guan Mokuai, a third inductance module and a fourth inductance module, wherein the third switching tube module is a switching tube G3, the fourth switching tube module is a switching tube G4, the third inductance module is an inductance L3, and the fourth inductance module is an inductance L4; the driving circuit of the BUCK conversion circuit is respectively connected with the first switching tube module, the second switching tube module, the third switching tube module and the fourth switching tube module; specifically, the input end of the driving circuit of the BUCK conversion circuit is connected with the output end of a control circuit such as an MCU or the output end of a protection circuit; the output end of the driving circuit of the BUCK conversion circuit is respectively connected with the driving end of the first switching tube module, the driving end of the second switching tube module, the driving end of the third switching tube module and the driving end of the fourth switching tube module, the driving end of the first switching tube module is a base electrode of a switching tube G1, the driving end of the second switching tube module is a base electrode of a switching tube G2, the driving end of the third switching tube module is a base electrode of a switching tube G3, and the driving end of the fourth switching tube module is a base electrode of a switching tube G4. Specifically, fig. 5 is a schematic structural diagram of an embodiment of a control device of the DC-DC converter circuit of the present invention. As shown in fig. 5, the control device of the DC-DC converter circuit includes: the device comprises a filter circuit, a BUCK conversion circuit, a driving circuit, a sampling circuit, a protection circuit and an MCU. Wherein, BUCK conversion circuit includes: a BUCK circuit 1 and a BUCK circuit 2. The power supply is output to the load after passing through the filter circuit and the BUCK conversion circuit. MCU is connected with the drive circuit, the protection circuit and the sampling circuit respectively. MCU is also connected to a driving circuit after passing through the protection circuit, and the driving circuit is connected to the BUCK conversion circuit. The BUCK conversion circuit is also connected to the protection circuit after passing through the sampling circuit, and the protection circuit is connected to the MCU. The control device of the DC-DC converter circuit shown in fig. 5 is configured to supply power to the BUCK circuit 1 and the BUCK circuit 2 after the power is input, and send the voltages and currents of the BUCK circuit 1 and the BUCK circuit 2 to the MCU and the protection circuit through the sampling circuit, and the MCU processes the data received from the sampling circuit and the protection circuit and then sends a driving signal to the driving circuit to drive the BUCK circuit 1 and the BUCK circuit 2.

Fig. 6 is a schematic diagram of a main circuit of the control device of the DC-DC converter circuit according to an embodiment of the present invention. As shown in fig. 6, a BUCK circuit 1 and a BUCK circuit 2 constitute a two-stage interleaved BUCK conversion circuit; VIN is the dc input voltage of the power supply. As shown in fig. 6, the first stage BUCK circuit (i.e., BUCK circuit 1) includes: switching tube G1 and switching tube G2, diode D1 and diode D2, inductor L1 and inductor L2, capacitor C1, dc output voltage V _OUT1 . A sampling circuit, comprising: a voltage sampling module 1, a voltage sampling module 2 and a current sampling module 1. The voltage sampling module 1 is used for sampling voltage V _in The voltage sampling module 1 includes a resistor R1 and a resistor R2. The voltage sampling module 2 is used for sampling voltage V _fdb1 The voltage sampling module 2 includes a resistor R3 and a resistor R4. The current sampling module 1 is used for sampling current I _fdb1 The current sampling module 1 includes a sampling resistor Rs1, and an operational amplifier circuit or a current sensor. A second stage BUCK (i.e., BUCK circuit 2) comprising: switching tube G3 and switching tube G4, diode D3 and diode D4, inductor L3 and inductor L4, capacitor C2, dc output voltage V _OUT2 . The sampling circuit further comprises a voltage sampling module 3 and a current sampling module 2. The voltage sampling module 3 is used for sampling voltage V _fdb2 The voltage sampling module 3 includes a resistor R5 and a resistor R6. The current sampling module 2 is used for sampling current I _fdb2 The current sampling module 2 includes a sampling resistor Rs2, and an operational amplifier circuit or a current sensor. The driving circuit comprises a driving circuit, the driving circuit can receive the MCU to output PWM signals, the voltage and the current of the PWM signals are very small, and the switching tube G1, the switching tube G2, the switching tube G3 and the switching tube G4 can be driven only by driving the push-pull amplifying circuit to amplify the voltage and the current.

In the example shown in fig. 6, the dc input voltage VIN is grounded through the resistor R1 and the resistor R2. The common end of the resistor R1 and the resistor R2 outputs the voltage V after passing through the voltage sampling module 1 _in To a first input of the MCU. The DC input voltage VIN is also respectively connected to the collectors of the switch tubes G1C and collector C of the switching tube G2. The G1 signal driving end of the driving circuit is connected to the base electrode of the switching tube G1. The G2 signal driving end of the driving circuit is connected to the base electrode of the switching tube G2. The emitter E of the switching tube G1 is connected to the cathode of the diode D1, and the anode of the diode D1 is connected to the first connection terminal of the sampling resistor Rs 1. The emitter E of the switching tube G1 is further connected to the first connection terminal of the capacitor C1 via an inductance L1. The emitter E of the switching tube G2 is connected to the cathode of the diode D2, and the anode of the diode D2 is connected to the first connection terminal of the sampling resistor Rs 1. The emitter E of the switching tube G2 is further connected to the second connection terminal of the capacitor C1 via an inductance L2. A second connection of the capacitor C1 is connected to a second connection of the sampling resistor Rs 1. The output end of the capacitor C1 outputs a DC output voltage V _OUT1 . The first connection end of the sampling resistor Rs1 outputs current I after passing through the current sampling module 1 _fdb1 To a second input of the MCU.

In the example shown in fig. 6, the dc output voltage VOUT1 is connected to the second terminal of the capacitor C1 via the resistor R3 and the resistor R4. That is, the resistor R3 and the resistor R4 are connected in series and then connected in parallel to both ends of the capacitor C1. The common end of the resistor R3 and the resistor R4 outputs the voltage V after passing through the voltage sampling module 2 _fdb1 To a third input of the MCU. DC output voltage V _OUT1 And also to the collector C of the switching tube G3 and the collector C of the switching tube G4, respectively. The G3 signal driving end of the driving circuit is connected to the base electrode of the switching tube G3. The G4 signal driving end of the driving circuit is connected to the base electrode of the switching tube G4. The emitter E of the switching tube G3 is connected to the cathode of the diode D3, and the anode of the diode D3 is connected to the first connection terminal of the sampling resistor Rs 2. The emitter E of the switching tube G3 is further connected to the first connection of the capacitor C2 via an inductance L3. The emitter E of the switching tube G4 is connected to the cathode of the diode D4, and the anode of the diode D4 is connected to the first connection terminal of the sampling resistor Rs 2. The emitter E of the switching tube G4 is further connected to the second connection terminal of the capacitor C2 via an inductance L4. A second connection of the capacitor C2 is connected to a second connection of the sampling resistor Rs 2. The output end of the capacitor C2 outputs a DC output voltage V _OUT2 . After the resistor R5 and the resistor R6 are connected in series, the resistor R6 is connected in parallel with the two ends of the capacitor C2, one end of the resistor R6 far away from the resistor R5 is grounded,and the resistor R7 is connected in parallel with two ends of a serial branch of the resistor R5 and the resistor R6. The first connection end of the sampling resistor Rs2 outputs current I after passing through the current sampling module 2 _fdb2 To a fourth input of the MCU. The common end of the resistor R5 and the resistor R6 outputs the voltage V after passing through the voltage sampling module 3 _fdb2 A fifth input of the value MCU. The MCU is capable of outputting signals G1, G2, G3, G4 to the drive circuit to cause the drive circuit to output signals G1, G2, G3, G4 based on signal G1, G2, G3, G4.

In an aspect of the present invention, as shown in fig. 1, the control method of the switching power supply includes: step S110 to step S140.

At step S110, in the case of receiving a self-test instruction of the BUCK conversion circuit, a driving circuit of the BUCK conversion circuit is enabled.

At step S120, in the case where the driving circuit of the BUCK conversion circuit is enabled, operating both the first stage BUCK circuit and the second stage BUCK circuit; the first-stage BUCK circuit is used for carrying out first-stage voltage reduction treatment on the direct-current power supply at the input side to obtain intermediate voltage; and the second-stage BUCK circuit is used for carrying out second-stage voltage reduction processing on the intermediate voltage at the output side of the first-stage BUCK circuit to obtain output voltage so as to supply power to a load at the output side.

At step S130, after the first stage BUCK circuit and the second stage BUCK circuit are both operated, the voltage of the DC power supply at the input side is sampled to obtain an input voltage sampling value of the BUCK conversion circuit, such as the input voltage V of the control device of the DC-DC converter circuit _in The method comprises the steps of carrying out a first treatment on the surface of the Sampling the intermediate voltage at the output side of the first-stage BUCK circuit to obtain an output voltage sampling value of the first-stage BUCK circuit, such as output voltage V of the first-stage BUCK circuit _fdb1 The method comprises the steps of carrying out a first treatment on the surface of the Sampling the current on the first inductance module and the second inductance module in the first-stage BUCK circuit to obtain the inductance current of the first-stage BUCK circuit, such as the inductance current I of the first-stage BUCK circuit _fdb1 The method comprises the steps of carrying out a first treatment on the surface of the And, for the output of the output side of the second stage BUCK circuitSampling the voltage to obtain an output voltage sampling value of the second-stage BUCK circuit, such as output voltage V of the second-stage BUCK circuit _fdb2 The method comprises the steps of carrying out a first treatment on the surface of the Sampling the current on the third inductance module and the fourth inductance module in the second-stage BUCK circuit to obtain the inductance current of the second-stage BUCK circuit, such as the inductance current I of the first-stage BUCK circuit _fdb2 。

At step S140, performing dual closed loop control of a voltage loop and a current loop on the first stage BUCK circuit according to an input voltage sampling value of the BUCK conversion circuit, an output voltage sampling value of the first stage BUCK circuit, and an inductor current of the first stage BUCK circuit; and performing double closed loop control of a voltage loop and a current loop on the second-stage BUCK circuit according to an input voltage sampling value of the BUCK conversion circuit, an output voltage sampling value of the second-stage BUCK circuit and an inductance current of the second-stage BUCK circuit, so that the first-stage BUCK circuit and the second-stage BUCK circuit work simultaneously, and two sub-BUCK circuits in each stage BUCK circuit can work alternately.

According to the protection and control method of the DC-DC converter circuit, aiming at the two-stage BUCK circuit formed by the double BUCK circuits (namely the first-stage BUCK circuit and the second-stage BUCK circuit), the two-stage BUCK circuit is controlled to work alternately according to the output voltage of the first-stage BUCK circuit and the inductance current of the first-stage BUCK circuit, and the output voltage of the second-stage BUCK circuit and the inductance current of the second-stage BUCK circuit, so that the protection of the DC-DC converter circuit is realized, and the reduction of the volume of each stage BUCK circuit in the DC-DC converter circuit under the high-power condition is realized. Under the condition that the two-stage BUCK circuits alternately work, the current passing through each stage of BUCK circuit only accounts for half of the total current passing through the DC-DC converter circuit, under the condition that the current passing through each stage of BUCK circuit is small, the current passing through power devices (such as a switch tube, a diode and an inductor) in each stage of BUCK circuit is also small, and the volume of the power devices (such as the switch tube, the diode and the inductor) in each stage of BUCK circuit can be correspondingly reduced, so that the volume of each stage of BUCK circuit can be effectively reduced.

In some embodiments, the specific process of performing the dual closed loop control of the voltage loop and the current loop on the first stage BUCK circuit in step S140 according to the input voltage sampling value of the BUCK conversion circuit, the output voltage sampling value of the first stage BUCK circuit, and the inductor current of the first stage BUCK circuit is described in the following exemplary description.

The following is a schematic flow chart of an embodiment of the method of the present invention for performing dual closed-loop control on the voltage loop and the current loop in the first stage BUCK circuit in conjunction with fig. 2, which further describes a specific process for performing dual closed-loop control on the voltage loop and the current loop in step S140, including: step S210 to step S250.

Step S210, obtaining an output voltage after PI control of a difference between the output voltage set value of the first stage BUCK circuit and the output voltage sampling value of the first stage BUCK circuit, and recording the output voltage as a voltage loop output voltage of the first stage BUCK circuit, such as an output voltage V of a voltage loop controller 1 _out1 。

Step S220, determining the product of the output voltage of the voltage loop of the first-stage BUCK circuit and the sampling value of the input voltage of the BUCK conversion circuit as the output current set value of the first-stage BUCK circuit.

Step S230, obtaining an output current after PI control of a difference between the output current set value of the first stage BUCK circuit and the inductance current of the first stage BUCK circuit, and recording the output current as a current loop output current of the first stage BUCK circuit, such as an output current I of an output end of a current loop controller 1 _out1 。

Step S240, after outputting the current loop output current of the first stage BUCK circuit, determining a duty ratio of PWM signals for controlling the first switching transistor module and the second switching transistor module in the first stage BUCK circuit according to the current loop output current of the first stage BUCK circuit.

Step S250, after determining the duty ratio of the PWM signals for controlling the first switching tube module and the second switching tube module in the first stage BUCK circuit, outputs the PWM signals for controlling the first switching tube module and the second switching tube module in the first stage BUCK circuit according to the duty ratio of the PWM signals for controlling the first switching tube module and the second switching tube module in the first stage BUCK circuit, so as to control the first switching tube module and the second switching tube module in the first stage BUCK circuit to operate.

Specifically, fig. 7 is a schematic diagram of a control flow of the BUCK circuit 1 in the control device of the DC-DC converter circuit of the present invention. As shown in fig. 7, V _fdb1 Is the output voltage of the first stage BUCK circuit, V _set For the output voltage set value of the first stage BUCK circuit, error1 is offset 1, V _out1 For the output voltage of the voltage loop controller 1, V _in Input voltage of control device of DC-DC converter circuit, I _set To output the current set value, I _fdb1 Is the inductance current of the first stage BUCK circuit, error2 is the deviation 2, I _out1 Is the output current of the current loop controller 1.

As shown in FIG. 7, the output voltage of the first stage BUCK circuit is set at a value V _set The output voltage V of the first stage BUCK circuit is input to the non-inverting input end of the comparator 1 _fdb1 Is input to the inverting input of the comparator 1, and the output of the comparator 1 outputs the offset 1, error1, to the input of the voltage loop controller 1. The output end of the voltage ring controller 1 outputs voltage V _out1 . Output voltage V of voltage ring controller 1 _out1 Input voltage V to the first input of the multiplier, the control means of the DC-DC converter circuit _in Input to the second input end of the multiplier, and the output end of the multiplier outputs an output current set value I _set . Output current set point I _set The inductor current I of the first stage BUCK circuit is input to the non-inverting input end of the comparator 2 _fdb1 Is input to the inverting input of the comparator 2, the comparator 2 outputs the offset 2, error2, to the input of the current loop controller 1. The output end of the current loop controller 1 outputs current I _out1 。

Referring to the examples shown in fig. 6 and 7, the control device of the DC-DC converter circuit is implemented by two-stage BUCK by two-stage interleaved BUCK circuits, and the input voltage of the power supply is filtered to obtain the DC input voltage VI of the power supply N, the first stage BUCK circuit is reduced to an intermediate voltage, namely the direct current output voltage V of the first stage BUCK circuit _OUT1 The second-stage BUCK circuit is reduced in voltage again and then stabilizes the output voltage V _OUT2 And stable output of the direct current power supply with low voltage and large current is realized.

Taking the first stage BUCK circuit as an example, the input voltage of the power supply is filtered to obtain the direct current input voltage VIN of the power supply, and the direct current input voltage VIN of the power supply is subjected to voltage sampling by a voltage division detection circuit formed by a resistor R1 and a resistor R2 to obtain the input voltage V of a control device of the DC-DC converter circuit _in . The current sampling module 1 is used for current sampling, for example, the voltage difference between the front end and the rear end of the sampling resistor Rs1 is detected for current detection, and the operational amplifier circuit is used for amplifying the sampling signal for current sampling to obtain the inductance current I of the first-stage BUCK circuit _fdb1 . Specifically, the voltage sampling value obtained according to the A/D input, namely the output voltage V of the first stage BUCK circuit _fdb1 Input voltage sampling value V _in The inductance current sampling value is the inductance current I of the first stage BUCK circuit _fdb1 Output voltage V of voltage loop controller 1 _out1 Is the output voltage V of the first stage BUCK circuit _fdb1 With the output voltage set point V of the first stage BUCK circuit _set The difference error1 is the value output by the PI controller (i.e. the voltage loop controller 1 in FIG. 7), the output voltage V of the voltage loop controller 1 _out1 Input voltage V to control device of DC-DC converter circuit _in Multiplying to obtain an output current set point I _set The output end of the current loop controller 1 outputs a current I _out1 Inductor current I for first stage BUCK circuit _fdb1 And output current set point I _set The difference error2 is the value output by the PI controller (i.e., current loop controller 1 in fig. 7). The signal G1 and the signal G2 are the duty ratios of the switch tube G1 and the switch tube G2 to be switched on or off, and the current I is output according to the output end of the current loop controller 1 obtained by calculation _out1 The duty cycles of signals g1 and g2 are set. For example: if the calculated output end of the current loop controller 1 outputs current I _out1 If the current is too high, the current is fed back to a Main Chip (MCU) through sampling the current at the output end, and the main chip performs error comparison (such as comparison setting and comparisonActual current difference value), and g1 and g2 control signals with smaller duty ratio are output for adjustment.

As shown in fig. 9, the control flow of the control device of the DC-DC converter circuit includes:

step 1, in the case of receiving a self-test instruction for self-testing the DC-DC converter circuit, the driving circuit of the BUCK conversion circuit (including the BUCK circuit 1 and the BUCK circuit 2) starts to be enabled according to the self-test instruction, and then step 2 is executed. In the case where the self-test instruction is not received, the driving circuit of the BUCK conversion circuit (including the BUCK circuit 1 and the BUCK circuit 2) is not enabled. The self-checking instruction is sent by the main chip MCU, can detect data (such as voltage, current, temperature, fault signals and the like) of each module, and can send out an enabling instruction to work if no abnormality exists.

Step 2, obtaining A/D trigger time to read output voltage sampling value such as output voltage V of first stage BUCK circuit _fdb1 Input voltage V of control device of input voltage sampling value such as DC-DC converter circuit _in The current sampling value is as the inductance current I of the first stage BUCK circuit _fdb1 Step 3 is then performed.

Step 3, reading an output voltage sampling value such as the output voltage V of the first stage BUCK circuit according to the A/D trigger time _fdb1 Input voltage V of control device of input voltage sampling value such as DC-DC converter circuit _in The current sampling value is as the inductance current I of the first stage BUCK circuit _fdb1 The duty ratio of the PWM signal for driving the switching transistor is calculated, and then steps 4 and 5 are performed.

And 5, outputting a PWM signal according to the duty ratio of the PWM signal for driving the switching tube calculated in the step 3, and executing the step 6.

Step 6, according to the PWM signal output in step 5, controlling the switching tube G1 and the switching tube G2 in the first-stage BUCK circuit to act, reducing the voltage of the first-stage BUCK circuit, returning to step 3, and continuously updating and calculating the duty ratio of the PWM signal for driving the switching tube to realize output voltage followingSet value V _set Keeping ripple of the output current small.

In some embodiments, in step S140, according to the input voltage sampling value of the BUCK conversion circuit, the output voltage sampling value of the first stage BUCK circuit, and the inductor current of the first stage BUCK circuit, the method further includes: after the duty ratio of the PWM signals for controlling the first switching tube module and the second switching tube module in the first-stage BUCK circuit is determined, calculating the triggering time of the next sampling according to the duty ratio of the PWM signals for controlling the first switching tube module and the second switching tube module in the first-stage BUCK circuit so as to: and resampling is carried out under the condition that the triggering time of the next sampling arrives so as to obtain a new input voltage sampling value of the BUCK conversion circuit, a new output voltage sampling value of the first-stage BUCK circuit and an inductance current of the first-stage BUCK circuit, and double closed-loop control of a voltage ring and a current ring is carried out on the first-stage BUCK circuit according to the new input voltage sampling value of the BUCK conversion circuit, the new output voltage sampling value of the first-stage BUCK circuit and the new inductance current of the first-stage BUCK circuit, so that the cyclic control is carried out.

The specific manner of performing the double closed-loop control of the voltage ring and the current ring on the second stage BUCK circuit in step S140 according to the input voltage sampling value of the BUCK conversion circuit, the output voltage sampling value of the second stage BUCK circuit, and the inductance current of the second stage BUCK circuit is the same as the specific manner of performing the double closed-loop control of the voltage ring and the current ring on the first stage BUCK circuit in step S140 according to the input voltage sampling value of the BUCK conversion circuit, the output voltage sampling value of the first stage BUCK circuit, and the inductance current of the first stage BUCK circuit.

Specifically, as shown in fig. 9, the control flow of the control device of the DC-DC converter circuit further includes: in step 3, the sampling value of the output voltage such as the output voltage V of the first stage BUCK circuit is read according to the A/D trigger time _fdb1 Sampling of input voltageValue such as input voltage V of control device of DC-DC converter circuit _in The current sampling value is as the inductance current I of the first stage BUCK circuit _fdb1 The duty cycle of the PWM signal for driving the switching tube is calculated, after which step 4 is also performed.

And 4, calculating the trigger time of the next A/D sampling according to the duty ratio of the PWM signal for driving the switching tube calculated in the step 3 so as to return to the step 2.

The switching time of the switching tube can be determined through the duty ratio, and the AD sampling can be performed only by sampling at the switching time.

In some embodiments, the method for controlling a switching power supply according to the present invention further includes: and protecting the first-stage BUCK circuit and the second-stage BUCK circuit.

The following is a schematic flow chart of an embodiment of the method of the present invention for protecting the first stage BUCK circuit and the second stage BUCK circuit in combination with fig. 3, which further describes a specific process for protecting the first stage BUCK circuit and the second stage BUCK circuit, including: step S310 to step S320.

Step S310, obtaining the temperature of the components in the first-stage BUCK circuit and obtaining the temperature of the components in the second-stage BUCK circuit.

Step S320, protecting the first stage BUCK circuit according to at least one of an output voltage sampling value of the first stage BUCK circuit, an inductance current of the first stage BUCK circuit and a temperature of a component in the first stage BUCK circuit; and protecting the second-stage BUCK circuit according to at least one of an output voltage sampling value of the second-stage BUCK circuit, an inductance current of the second-stage BUCK circuit and a temperature of a component in the second-stage BUCK circuit.

Specifically, fig. 8 is a schematic structural diagram of an embodiment of a protection circuit in the control device of the DC-DC converter circuit of the present invention. The comparator U1, the comparator U2 and the comparator U3 respectively detect voltage, current and temperature and trigger protection, and a NAND gate logic chip or an OR gate logic chip is used as a logic judging unit U4 to output fault protection signals to the MCU and the driving circuit, so that the MCU and the driving circuit can simultaneously receive the fault protection signals to carry out fault shutdown, and the reliability is improved.

In the scheme of the invention, the two stages of BUCK circuits are controlled to work alternately according to the output voltage of the first stage BUCK circuit, the inductance current of the first stage BUCK circuit, the output voltage of the second stage BUCK circuit and the inductance current of the second stage BUCK circuit, so that the detection and protection of the current, the voltage and the temperature of the DC-DC converter circuit can be realized, and the reliability of the DC-DC converter circuit can be higher. For example: if any abnormality of any working parameter of current, voltage and temperature of the DC-DC converter circuit is detected, the DC-DC converter circuit stops working, and electronic components in the DC-DC converter circuit are prevented from being damaged.

In some embodiments, in step S320, the first stage BUCK circuit is protected according to at least one of the output voltage sampling value of the first stage BUCK circuit, the inductor current of the first stage BUCK circuit, and the temperature of the components in the first stage BUCK circuit, including any one of the following protection cases:

First protection case: if the sampling value of the output voltage of the first-stage BUCK circuit is larger than the set voltage, the PWM signal of the first-stage BUCK circuit is turned off to control the first-stage BUCK circuit to stop working. Referring to the example shown in fig. 8, taking the first stage BUCK circuit as an example, voltage sampling is performed by a voltage division detection circuit (e.g., voltage sampling module 2). Sampling voltage signals (e.g. output voltage V of first-stage BUCK circuit _fdb1 ) Input comparator U1 and a set voltage (e.g. output voltage set value V of the first stage BUCK circuit) _set ) If the sampling voltage is higher than the set voltage, the level output by the comparator U1 is inverted and the high level is output to the logic determination unit U4.

Second protection case: if the inductance current of the first-stage BUCK circuit is larger than the set current, the PWM signal of the first-stage BUCK circuit is turned off to control the first-stage BUCK circuit to stop working. Referring to the example shown in FIG. 8, taking the first stage BUCK circuit as an example, the current is sampled through a sampling resistor Rs (e.g. sampling resistorRs 1) to sample current, and sampling current signal (such as inductor current I of first stage BUCK circuit _fdb1 ) And setting the protection current (such as output current set point I _set ) The comparison is performed by the comparator U2, and if the sampling current is higher than the set current, a high level is output to the logic determination unit U4.

Third protection case: if the temperature of the components in the first-stage BUCK circuit is higher than the set temperature, the first-stage BUCK circuit is subjected to preset frequency limiting or frequency reducing treatment. Referring to the example shown in fig. 8, taking the first stage BUCK circuit as an example, a temperature detection circuit may be added to detect the temperature of the components of the first stage BUCK circuit, and compare with the set temperature, if the temperature exceeds the set temperature, the level output by the comparator U3 is inverted, and a high level is output to the logic determination unit U4, so that the frequency-limiting and frequency-reducing process may be performed. For example: if the temperature is too high, the logic determination unit U4 receives the temperature too high signal, and the MCU limits the PWM output, so that the PWM output works in a low-frequency mode, and the switching frequency and the output become low, thereby realizing frequency limiting processing.

The specific way of protecting the second stage BUCK circuit according to at least one of the output voltage sampling value of the second stage BUCK circuit, the inductance current of the second stage BUCK circuit, and the temperature of the component in the second stage BUCK circuit in step S320 is the same as the specific way of protecting the first stage BUCK circuit according to at least one of the output voltage sampling value of the first stage BUCK circuit, the inductance current of the first stage BUCK circuit, and the temperature of the component in the first stage BUCK circuit in step S320.

Specifically, referring to the example shown in fig. 8, taking the first stage BUCK circuit as an example, when the logic determination unit U4 determines that the first stage BUCK circuit is faulty, a fault signal is sent to the MCU and the driving circuit, at which time the driving circuit stops sending the PWM signal (i.e., performs hard shutdown), and the MCU stops sending the PWM signal.

Referring to the examples shown in fig. 5 to 9, the two-stage BUCK circuits each have a protection circuit such as the protection module shown in fig. 8, and voltage sampling is performed by a voltage division detection circuit (such as the voltage sampling module 2). Sampling voltage signals (e.g. first-stage BUCKOutput voltage V of the circuit _fdb1 Output voltage V of second stage BUCK circuit _fdb2 ) Input comparator U1 and a set voltage (e.g., output voltage set point V _set ) If the sampling voltage is higher than the set voltage, the level output by the comparator U1 is inverted and the high level is output to the logic determination unit U4. Current sampling is performed through a sampling resistor Rs (such as a sampling resistor Rs 1), and a current signal (such as an inductance current I of a first stage BUCK circuit) is sampled _fdb1 Inductor current I of second-stage BUCK circuit _fdb2 ) And setting the protection current (such as output current set point I _set ) The comparison is performed by the comparator U2, and if the sampling current is higher than the set current, a high level is output to the logic determination unit U4. When the logic determination unit U4 determines that the first-stage BUCK circuit or the first-stage BUCK circuit fails, a failure signal is sent to the MCU and the driving circuit, at the moment, the driving circuit stops sending the PWM signal (namely, hard shutdown is carried out), and the MCU stops sending the PWM signal until the failure is cleared.

In the scheme of the invention, according to the output voltage of the first-stage BUCK circuit and the inductance current of the first-stage BUCK circuit, and the output voltage of the second-stage BUCK circuit and the inductance current of the second-stage BUCK circuit, the two-stage BUCK circuits are controlled to work alternately, which is equivalent to the alternate work of two paths of BUCK circuits (namely, the two-stage BUCK circuits), and only half of the total current of the DC-DC converter circuit is needed in each path of BUCK circuit, so that the current stress of each path of BUCK circuit is reduced by half, and the volume and the cost of each path of BUCK circuit are correspondingly reduced. Thus, under the high-power condition, the two-stage BUCK circuit can reduce the current passing through the power device (such as a switch tube, a diode, an inductor and the like) of each stage BUCK circuit by half, so that the volume of the inductor in the power device of each stage BUCK circuit is at least reduced, the volume of the DC-DC converter circuit is effectively reduced, and the cost of a controller (namely the whole control board of a switch power supply) and the area of a PCB (printed circuit board) are also reduced, for example: taking a switching tube in an integral control panel of a switching power supply as an example, if a staggered BUCK circuit is adopted, two 10A switching tubes are used, but the effect of one 20A switching tube can be achieved, and the price of 2 10A switching tubes is cheaper than that of a single 20A switching tube, so that the cost is reduced; in addition, in the scheme of the invention, only the BUCK circuit and the detection circuit are required to be arranged, and other complex topological circuits are not required to be arranged, so that the DC-DC converter circuit has a simple structure. In the scheme of the invention, under the condition that each BUCK circuit reduces half of current stress, the output voltage of the DC-DC converter circuit is more stable, and the dynamic performance is good.

By adopting the technical scheme of the embodiment, the output voltage of the first-stage BUCK circuit and the inductance current of the first-stage BUCK circuit, the output voltage of the second-stage BUCK circuit and the inductance current of the second-stage BUCK circuit are sampled for the two-stage BUCK circuit formed by the first-stage BUCK circuit and the second-stage BUCK circuit, and the first-stage BUCK circuit is subjected to double closed-loop control of a voltage ring and a current ring according to the output voltage of the first-stage BUCK circuit and the inductance current of the first-stage BUCK circuit; and according to the output voltage of the second-stage BUCK circuit and the inductance current of the second-stage BUCK circuit, the second-stage BUCK circuit is subjected to double closed-loop control of a voltage loop and a current loop, so that the alternating work of the two-stage BUCK circuits is realized, and therefore, the alternating work of the two-stage BUCK circuits is controlled by adopting a DC-DC converter circuit formed by the two-stage BUCK circuits as a power supply of the portable electronic equipment, the current passing through each stage BUCK circuit can be reduced, and the volume of power devices (such as a switch tube, a diode, an inductor and the like) in each stage BUCK circuit can be correspondingly reduced.

According to an embodiment of the present invention, there is also provided a control device of a switching power supply corresponding to the control method of the switching power supply. Referring to fig. 4, a schematic diagram of an embodiment of the apparatus of the present invention is shown. The switching power supply includes: a BUCK conversion circuit and a driving circuit of the BUCK conversion circuit; the BUCK conversion circuit comprises: a first stage BUCK circuit and a second stage BUCK circuit, each stage BUCK circuit having two sub BUCK circuits; the first stage BUCK circuit and the second stage BUCK circuit are arranged in series between a direct current power supply at the input side and a load at the output side; the first-stage BUCK circuit is provided with a first switching tube module, a second switching tube module, a first inductance module and a second inductance module, wherein the first switching tube module is a switching tube G1, the second switching tube module is a switching tube G2, the first inductance module is an inductance L1, and the second inductance module is an inductance L2; the second stage BUCK circuit is provided with a third switching tube module, a fourth switching tube module Guan Mokuai, a third inductance module and a fourth inductance module, wherein the third switching tube module is a switching tube G3, the fourth switching tube module is a switching tube G4, the third inductance module is an inductance L3, and the fourth inductance module is an inductance L4; the driving circuit of the BUCK conversion circuit is respectively connected with the first switching tube module, the second switching tube module, the third switching tube module and the fourth switching tube module; specifically, the input end of the driving circuit of the BUCK conversion circuit is connected with the output end of a control circuit such as an MCU or the output end of a protection circuit; the output end of the driving circuit of the BUCK conversion circuit is respectively connected with the driving end of the first switching tube module, the driving end of the second switching tube module, the driving end of the third switching tube module and the driving end of the fourth switching tube module, the driving end of the first switching tube module is a base electrode of a switching tube G1, the driving end of the second switching tube module is a base electrode of a switching tube G2, the driving end of the third switching tube module is a base electrode of a switching tube G3, and the driving end of the fourth switching tube module is a base electrode of a switching tube G4. Specifically, fig. 5 is a schematic structural diagram of an embodiment of a control device of the DC-DC converter circuit of the present invention. As shown in fig. 5, the control device of the DC-DC converter circuit includes: the device comprises a filter circuit, a BUCK conversion circuit, a driving circuit, a sampling circuit, a protection circuit and an MCU. Wherein, BUCK conversion circuit includes: a BUCK circuit 1 and a BUCK circuit 2. The power supply is output to the load after passing through the filter circuit and the BUCK conversion circuit. MCU is connected with the drive circuit, the protection circuit and the sampling circuit respectively. MCU is also connected to a driving circuit after passing through the protection circuit, and the driving circuit is connected to the BUCK conversion circuit. The BUCK conversion circuit is also connected to the protection circuit after passing through the sampling circuit, and the protection circuit is connected to the MCU. The control device of the DC-DC converter circuit shown in fig. 5 is configured to supply power to the BUCK circuit 1 and the BUCK circuit 2 after the power is input, and send the voltages and currents of the BUCK circuit 1 and the BUCK circuit 2 to the MCU and the protection circuit through the sampling circuit, and the MCU processes the data received from the sampling circuit and the protection circuit and then sends a driving signal to the driving circuit to drive the BUCK circuit 1 and the BUCK circuit 2.

In the example shown in fig. 6, the dc input voltage VIN is grounded through the resistor R1 and the resistor R2. The common end of the resistor R1 and the resistor R2 outputs the voltage V after passing through the voltage sampling module 1 _in To a first input of the MCU. The dc input voltage VIN is also connected to the collector C of the switching tube G1 and the collector C of the switching tube G2, respectively.The G1 signal driving end of the driving circuit is connected to the base electrode of the switching tube G1. The G2 signal driving end of the driving circuit is connected to the base electrode of the switching tube G2. The emitter E of the switching tube G1 is connected to the cathode of the diode D1, and the anode of the diode D1 is connected to the first connection terminal of the sampling resistor Rs 1. The emitter E of the switching tube G1 is further connected to the first connection terminal of the capacitor C1 via an inductance L1. The emitter E of the switching tube G2 is connected to the cathode of the diode D2, and the anode of the diode D2 is connected to the first connection terminal of the sampling resistor Rs 1. The emitter E of the switching tube G2 is further connected to the second connection terminal of the capacitor C1 via an inductance L2. A second connection of the capacitor C1 is connected to a second connection of the sampling resistor Rs 1. The output end of the capacitor C1 outputs a DC output voltage V _OUT1 . The first connection end of the sampling resistor Rs1 outputs current I after passing through the current sampling module 1 _fdb1 To a second input of the MCU.

In the example shown in fig. 6, the dc output voltage VOUT1 is connected to the second terminal of the capacitor C1 via the resistor R3 and the resistor R4. That is, the resistor R3 and the resistor R4 are connected in series and then connected in parallel to both ends of the capacitor C1. The common end of the resistor R3 and the resistor R4 outputs the voltage V after passing through the voltage sampling module 2 _fdb1 To a third input of the MCU. DC output voltage V _OUT1 And also to the collector C of the switching tube G3 and the collector C of the switching tube G4, respectively. The G3 signal driving end of the driving circuit is connected to the base electrode of the switching tube G3. The G4 signal driving end of the driving circuit is connected to the base electrode of the switching tube G4. The emitter E of the switching tube G3 is connected to the cathode of the diode D3, and the anode of the diode D3 is connected to the first connection terminal of the sampling resistor Rs 2. The emitter E of the switching tube G3 is further connected to the first connection of the capacitor C2 via an inductance L3. The emitter E of the switching tube G4 is connected to the cathode of the diode D4, and the anode of the diode D4 is connected to the first connection terminal of the sampling resistor Rs 2. The emitter E of the switching tube G4 is further connected to the second connection terminal of the capacitor C2 via an inductance L4. A second connection of the capacitor C2 is connected to a second connection of the sampling resistor Rs 2. The output end of the capacitor C2 outputs a DC output voltage V _OUT2 . After the resistor R5 and the resistor R6 are connected in series, the resistor R6 is connected in parallel with the two ends of the capacitor C2, one end of the resistor R6 far away from the resistor R5 is grounded, the resistor R7 is connected in parallel with the resistor R5Both ends of the series branch of the resistor R6. The first connection end of the sampling resistor Rs2 outputs current I after passing through the current sampling module 2 _fdb2 To a fourth input of the MCU. The common end of the resistor R5 and the resistor R6 outputs the voltage V after passing through the voltage sampling module 3 _fdb2 A fifth input of the value MCU. The MCU is capable of outputting signals G1, G2, G3, G4 to the drive circuit to cause the drive circuit to output signals G1, G2, G3, G4 based on signal G1, G2, G3, G4.

In an aspect of the present invention, as shown in fig. 4, the control device for a switching power supply includes: an acquisition unit 102 and a control unit 104.

Wherein the control unit 104 is configured to enable a driving circuit of the BUCK conversion circuit upon receiving a self-test instruction of the BUCK conversion circuit. The specific function and process of the control unit 104 refer to step S110.

The control unit 104 is further configured to operate both the first stage BUCK circuit and the second stage BUCK circuit in a case where a driving circuit of the BUCK conversion circuit is enabled; the first-stage BUCK circuit is used for carrying out first-stage voltage reduction treatment on the direct-current power supply at the input side to obtain intermediate voltage; and the second-stage BUCK circuit is used for carrying out second-stage voltage reduction processing on the intermediate voltage at the output side of the first-stage BUCK circuit to obtain output voltage so as to supply power to a load at the output side. The specific function and process of the control unit 104 is also referred to as step S120.

The obtaining unit 102 is configured to sample the voltage of the direct current power supply at the input side after the first stage BUCK circuit and the second stage BUCK circuit are operated to obtain an input voltage sampling value of the BUCK conversion circuit, such as the input voltage V of the control device of the DC-DC converter circuit _in The method comprises the steps of carrying out a first treatment on the surface of the Sampling the intermediate voltage at the output side of the first-stage BUCK circuit to obtain an output voltage sampling value of the first-stage BUCK circuit, such as output voltage V of the first-stage BUCK circuit _fdb1 The method comprises the steps of carrying out a first treatment on the surface of the Collecting currents on a first inductance module and a second inductance module in the first-stage BUCK circuitObtaining the inductance current of the first stage BUCK circuit, such as the inductance current I of the first stage BUCK circuit _fdb1 The method comprises the steps of carrying out a first treatment on the surface of the Sampling the output voltage of the output side of the second-stage BUCK circuit to obtain an output voltage sampling value of the second-stage BUCK circuit, such as output voltage V of the second-stage BUCK circuit _fdb2 The method comprises the steps of carrying out a first treatment on the surface of the Sampling the current on the third inductance module and the fourth inductance module in the second-stage BUCK circuit to obtain the inductance current of the second-stage BUCK circuit, such as the inductance current I of the first-stage BUCK circuit _fdb2 . The specific function and process of the acquisition unit 102 refer to step S130.

The control unit 104 is further configured to perform dual closed loop control of a voltage loop and a current loop on the first stage BUCK circuit according to an input voltage sampling value of the BUCK conversion circuit, an output voltage sampling value of the first stage BUCK circuit, and an inductance current of the first stage BUCK circuit; and performing double closed loop control of a voltage loop and a current loop on the second-stage BUCK circuit according to an input voltage sampling value of the BUCK conversion circuit, an output voltage sampling value of the second-stage BUCK circuit and an inductance current of the second-stage BUCK circuit, so that the first-stage BUCK circuit and the second-stage BUCK circuit work simultaneously, and two sub-BUCK circuits in each stage BUCK circuit can work alternately. The specific function and process of the control unit 104 also refer to step S140.

According to the protection and control device of the DC-DC converter circuit, aiming at the two-stage BUCK circuit formed by the double BUCK circuits (namely the first-stage BUCK circuit and the second-stage BUCK circuit), the two-stage BUCK circuit is controlled to work alternately according to the output voltage of the first-stage BUCK circuit and the inductance current of the first-stage BUCK circuit, and the output voltage of the second-stage BUCK circuit and the inductance current of the second-stage BUCK circuit, so that the protection of the DC-DC converter circuit is realized, and the reduction of the volume of each stage BUCK circuit in the DC-DC converter circuit under the high-power condition is realized. Under the condition that the two-stage BUCK circuits alternately work, the current passing through each stage of BUCK circuit only accounts for half of the total current passing through the DC-DC converter circuit, under the condition that the current passing through each stage of BUCK circuit is small, the current passing through power devices (such as a switch tube, a diode and an inductor) in each stage of BUCK circuit is also small, and the volume of the power devices (such as the switch tube, the diode and the inductor) in each stage of BUCK circuit can be correspondingly reduced, so that the volume of each stage of BUCK circuit can be effectively reduced.

In some embodiments, the control unit 104 performs dual closed loop control of the voltage loop and the current loop on the first stage BUCK circuit according to the input voltage sampling value of the BUCK conversion circuit, the output voltage sampling value of the first stage BUCK circuit, and the inductor current of the first stage BUCK circuit, including:

the control unit 104 is specifically further configured to obtain an output voltage after PI control by using a difference between the output voltage set value of the first stage BUCK circuit and the output voltage sampling value of the first stage BUCK circuit, and record the output voltage as a voltage loop output voltage of the first stage BUCK circuit, such as the output voltage V of the voltage loop controller 1 _out1 . The specific function and process of the control unit 104 also refer to step S210.

The control unit 104 is specifically further configured to determine a product of the voltage loop output voltage of the first stage BUCK circuit and the input voltage sampling value of the BUCK conversion circuit as an output current setting value of the first stage BUCK circuit. The specific function and process of the control unit 104 is also referred to as step S220.

The control unit 104 is specifically further configured to obtain an output current after PI control by using a difference between the output current set value of the first stage BUCK circuit and the inductor current of the first stage BUCK circuit, and record the output current as a current loop output current of the first stage BUCK circuit, such as the output current I of the output terminal of the current loop controller 1 _out1 . The specific function and process of the control unit 104 is also referred to as step S230.

The control unit 104 is specifically further configured to determine, after outputting the current loop output current of the first stage BUCK circuit, duty ratios of PWM signals for controlling the first switching transistor module and the second switching transistor module in the first stage BUCK circuit according to the current loop output current of the first stage BUCK circuit. The specific function and process of the control unit 104 also refer to step S240.

The control unit 104 is specifically further configured to, after determining the duty ratios of the PWM signals for controlling the first switching tube module and the second switching tube module in the first stage BUCK circuit, output the PWM signals for controlling the first switching tube module and the second switching tube module in the first stage BUCK circuit according to the duty ratios of the PWM signals for controlling the first switching tube module and the second switching tube module in the first stage BUCK circuit, so as to control the actions of the first switching tube module and the second switching tube module in the first stage BUCK circuit. The specific function and processing of the control unit 104 is also referred to in step S250.

Referring to the examples shown in fig. 6 and 7, the control device of the DC-DC converter circuit is implemented by two-stage BUCK by two-stage interleaved BUCK circuits, the input voltage of the power supply is filtered by a filter circuit to obtain the DC input voltage VIN of the power supply, and the first stage BUCK circuit is stepped down to an intermediate voltage, i.e., the DC output voltage V of the first stage BUCK circuit _OUT1 The second-stage BUCK circuit is reduced in voltage again and then stabilizes the output voltage V _OUT2 And stable output of the direct current power supply with low voltage and large current is realized.

Taking the first stage BUCK circuit as an example, the input voltage of the power supply is filtered to obtain the direct current input voltage VIN of the power supply, and the direct current input voltage VIN of the power supply is subjected to voltage sampling by a voltage division detection circuit formed by a resistor R1 and a resistor R2 to obtain the input voltage V of a control device of the DC-DC converter circuit _in . The current sampling module 1 is used for current sampling, for example, the voltage difference between the front end and the rear end of the sampling resistor Rs1 is detected for current detection, and the operational amplifier circuit is used for amplifying the sampling signal for current sampling to obtain the inductance current I of the first-stage BUCK circuit _fdb1 . Specifically, the voltage sampling value obtained according to the A/D input, namely the output voltage V of the first stage BUCK circuit _fdb1 Input voltage sampling value V _in The inductance current sampling value is the inductance current I of the first stage BUCK circuit _fdb1 Output voltage V of voltage loop controller 1 _out1 Is the output voltage V of the first stage BUCK circuit _fdb1 With the output voltage set point V of the first stage BUCK circuit _set The difference error1 is the value output by the PI controller (i.e. the voltage loop controller 1 in FIG. 7), the output voltage V of the voltage loop controller 1 _out1 Input voltage V to control device of DC-DC converter circuit _in Multiplying to obtain an output current set point I _set The output end of the current loop controller 1 outputs a current I _out1 Inductor current I for first stage BUCK circuit _fdb1 And output current set point I _set The difference error2 is controlled by PI controller (i.e. current loop controller 1 in FIG. 7)) And (5) outputting the value. The signal G1 and the signal G2 are the duty ratios of the switch tube G1 and the switch tube G2 to be switched on or off, and the current I is output according to the output end of the current loop controller 1 obtained by calculation _out1 The duty cycles of signals g1 and g2 are set.

Fig. 9 is a flow chart of a control device of the DC-DC converter circuit according to an embodiment of the invention.

step 1, in the case of receiving a self-test instruction for self-testing the DC-DC converter circuit, the driving circuit of the BUCK conversion circuit (including the BUCK circuit 1 and the BUCK circuit 2) starts to be enabled according to the self-test instruction, and then step 2 is executed. In the case where the self-test instruction is not received, the driving circuit of the BUCK conversion circuit (including the BUCK circuit 1 and the BUCK circuit 2) is not enabled.

Step 6, according to the PWM signal output in step 5, controlling the switching tube G1 and the switching tube G2 in the first-stage BUCK circuit to act, the first-stage BUCK circuit implementing voltage reduction, and then returning to step 3, implementing output voltage following set value V by continuously updating and calculating the duty ratio of the PWM signal for driving the switching tube _set Keeping ripple of the output current small.

In some embodiments, the control unit 104 performs dual closed loop control of the voltage loop and the current loop on the first stage BUCK circuit according to the input voltage sampling value of the BUCK conversion circuit, the output voltage sampling value of the first stage BUCK circuit, and the inductor current of the first stage BUCK circuit, and further includes: the control unit 104 is specifically further configured to calculate, after determining the duty ratios of the PWM signals for controlling the first switching tube module and the second switching tube module in the first stage BUCK circuit, a trigger time of the next sampling according to the duty ratios of the PWM signals for controlling the first switching tube module and the second switching tube module in the first stage BUCK circuit, so as to: and resampling is carried out under the condition that the triggering time of the next sampling arrives so as to obtain a new input voltage sampling value of the BUCK conversion circuit, a new output voltage sampling value of the first-stage BUCK circuit and an inductance current of the first-stage BUCK circuit, and double closed-loop control of a voltage ring and a current ring is carried out on the first-stage BUCK circuit according to the new input voltage sampling value of the BUCK conversion circuit, the new output voltage sampling value of the first-stage BUCK circuit and the new inductance current of the first-stage BUCK circuit, so that the cyclic control is carried out.

The control unit 104 is specifically configured to perform a dual closed-loop control of the voltage ring and the current ring on the second stage BUCK circuit according to the input voltage sampling value of the BUCK conversion circuit, the output voltage sampling value of the second stage BUCK circuit, and the inductance current of the second stage BUCK circuit, which is the same as the control unit 104.

Specifically, as shown in fig. 9, the control flow of the control device of the DC-DC converter circuit further includes: in step 3, reading according to A/D trigger timeOutput voltage sampling value is as output voltage V of first stage BUCK circuit _fdb1 Input voltage V of control device of input voltage sampling value such as DC-DC converter circuit _in The current sampling value is as the inductance current I of the first stage BUCK circuit _fdb1 The duty cycle of the PWM signal for driving the switching tube is calculated, after which step 4 is also performed.

In some embodiments, the control device for a switching power supply according to the aspect of the present invention further includes: the protection process for the first stage BUCK circuit and the second stage BUCK circuit comprises the following steps:

the obtaining unit 102 is further configured to obtain a temperature of a component in the first stage BUCK circuit, and obtain a temperature of a component in the second stage BUCK circuit. The specific function and processing of the acquisition unit 102 is also referred to in step S310.

The control unit 104 is further configured to protect the first stage BUCK circuit according to at least one of an output voltage sampling value of the first stage BUCK circuit, an inductance current of the first stage BUCK circuit, and a temperature of a component in the first stage BUCK circuit; and protecting the second-stage BUCK circuit according to at least one of an output voltage sampling value of the second-stage BUCK circuit, an inductance current of the second-stage BUCK circuit and a temperature of a component in the second-stage BUCK circuit. The specific function and process of the control unit 104 also refer to step S320.

In some embodiments, the control unit 104 protects the first stage BUCK circuit according to at least one of an output voltage sampling value of the first stage BUCK circuit, an inductor current of the first stage BUCK circuit, and a temperature of a component in the first stage BUCK circuit, including any one of the following protection situations:

first protection case: the control unit 104 is specifically further configured to turn off the PWM signal of the first stage BUCK circuit to control the first stage BUCK circuit to stop working if the output voltage sampling value of the first stage BUCK circuit is greater than the set voltage. Referring to the example shown in fig. 8, taking the first stage BUCK circuit as an example, voltage sampling is performed by a voltage division detection circuit (e.g., voltage sampling module 2). Sampling voltage signals (e.g. output voltage V of first-stage BUCK circuit _fdb1 ) Input comparator U1 and a set voltage (e.g. output voltage set value V of the first stage BUCK circuit) _set ) If the sampling voltage is higher than the set voltage, the level output by the comparator U1 is inverted and the high level is output to the logic determination unit U4.

Second protection case: the control unit 104 is specifically further configured to turn off the PWM signal of the first stage BUCK circuit to control the first stage BUCK circuit to stop working if the inductance current of the first stage BUCK circuit is greater than the set current. Referring to the example shown in FIG. 8, taking the first stage BUCK circuit as an example, current sampling is performed through a sampling resistor Rs (e.g., sampling resistor Rs 1), and a current signal (e.g., first stage BUCKInductor current I of circuit _fdb1 ) And setting the protection current (such as output current set point I _set ) The comparison is performed by the comparator U2, and if the sampling current is higher than the set current, a high level is output to the logic determination unit U4.

Third protection case: the control unit 104 is specifically further configured to perform a preset frequency limiting or frequency reducing process on the first stage BUCK circuit if the temperature of the components in the first stage BUCK circuit is greater than a set temperature. Referring to the example shown in fig. 8, taking the first stage BUCK circuit as an example, a temperature detection circuit may be added to detect the temperature of the components of the first stage BUCK circuit, and compare with the set temperature, if the temperature exceeds the set temperature, the level output by the comparator U3 is inverted, and a high level is output to the logic determination unit U4, so that the frequency-limiting and frequency-reducing process may be performed.

The specific manner in which the control unit 104 is specifically configured to protect the second stage BUCK circuit according to at least one of the output voltage sampling value of the second stage BUCK circuit, the inductance current of the second stage BUCK circuit, and the temperature of the component in the second stage BUCK circuit is the same as the specific manner in which the control unit 104 is specifically configured to protect the first stage BUCK circuit according to at least one of the output voltage sampling value of the first stage BUCK circuit, the inductance current of the first stage BUCK circuit, and the temperature of the component in the first stage BUCK circuit.

Referring to the examples shown in fig. 5 to 9, the two-stage BUCK circuits each have a protection circuit such as the protection module shown in fig. 8, and voltage sampling is performed by a voltage division detection circuit (such as the voltage sampling module 2). Sampling voltage signals (e.g. output voltage V of first-stage BUCK circuit _fdb1 Output voltage V of second stage BUCK circuit _fdb2 ) Input comparator U1 and a set voltage (e.g., output voltage set point V _set ) If the sampling voltage is higher than the set voltage, the level output by the comparator U1 is inverted and the high level is output to the logic determination unit U4. Current sampling is performed through a sampling resistor Rs (such as a sampling resistor Rs 1), and a current signal (such as an inductance current I of a first stage BUCK circuit) is sampled _fdb1 Inductor current I of second-stage BUCK circuit _fdb2 ) And setting the protection current (such as output current set point I _set ) The comparison is performed by the comparator U2, and if the sampling current is higher than the set current, a high level is output to the logic determination unit U4. When the logic determination unit U4 determines that the first-stage BUCK circuit or the first-stage BUCK circuit fails, a failure signal is sent to the MCU and the driving circuit, at the moment, the driving circuit stops sending the PWM signal (namely, hard shutdown is carried out), and the MCU stops sending the PWM signal until the failure is cleared.

In the scheme of the invention, according to the output voltage of the first-stage BUCK circuit and the inductance current of the first-stage BUCK circuit, and the output voltage of the second-stage BUCK circuit and the inductance current of the second-stage BUCK circuit, the two-stage BUCK circuits are controlled to work alternately, which is equivalent to the alternate work of two paths of BUCK circuits (namely, the two-stage BUCK circuits), and only half of the total current of the DC-DC converter circuit is needed in each path of BUCK circuit, so that the current stress of each path of BUCK circuit is reduced by half, and the volume and the cost of each path of BUCK circuit are correspondingly reduced. Therefore, under the high-power condition, the two-stage BUCK circuit can reduce the current passing through the power devices (such as a switch tube, a diode, an inductor and the like) of each stage BUCK circuit by half, so that the volume of the inductor in the power devices of each stage BUCK circuit is at least reduced, the volume of the DC-DC converter circuit is effectively reduced, and the cost of a controller and the area of a PCB (printed circuit board) are also reduced; in addition, in the scheme of the invention, the DC-DC converter circuit has a simple structure. In the scheme of the invention, under the condition that each BUCK circuit reduces half of current stress, the output voltage of the DC-DC converter circuit is more stable, and the dynamic performance is good.

Since the processes and functions implemented by the apparatus of the present embodiment substantially correspond to the embodiments, principles and examples of the foregoing methods, the descriptions of the embodiments are not exhaustive, and reference may be made to the descriptions of the foregoing embodiments and their descriptions are omitted herein.

By adopting the technical scheme, the output voltage of the first-stage BUCK circuit and the inductance current of the first-stage BUCK circuit, the output voltage of the second-stage BUCK circuit and the inductance current of the second-stage BUCK circuit are sampled by aiming at the two-stage BUCK circuit formed by the first-stage BUCK circuit and the second-stage BUCK circuit, and the first-stage BUCK circuit is subjected to double closed-loop control of a voltage ring and a current ring according to the output voltage of the first-stage BUCK circuit and the inductance current of the first-stage BUCK circuit; and according to the output voltage of the second-stage BUCK circuit and the inductance current of the second-stage BUCK circuit, the second-stage BUCK circuit is subjected to double closed-loop control of a voltage loop and a current loop, so that the alternating work of the two-stage BUCK circuits is realized, and under the condition that the current stress of each circuit of BUCK circuit is reduced by half, the output voltage of the DC-DC converter circuit is more stable, and the DC-DC converter circuit has good dynamic performance.

According to an embodiment of the present invention, there is also provided a switching power supply corresponding to the control device of the switching power supply. The switching power supply may include: the control device of the switching power supply.

Since the processing and functions implemented by the switching power supply of the present embodiment basically correspond to the embodiments, principles and examples of the foregoing apparatus, the descriptions of the present embodiment are not detailed, and reference may be made to the related descriptions of the foregoing embodiments, which are not repeated herein.

By adopting the technical scheme, the output voltage of the first-stage BUCK circuit and the inductance current of the first-stage BUCK circuit, the output voltage of the second-stage BUCK circuit and the inductance current of the second-stage BUCK circuit are sampled by aiming at the two-stage BUCK circuit formed by the first-stage BUCK circuit and the second-stage BUCK circuit, and the first-stage BUCK circuit is subjected to double closed-loop control of a voltage ring and a current ring according to the output voltage of the first-stage BUCK circuit and the inductance current of the first-stage BUCK circuit; and according to the output voltage of the second-stage BUCK circuit and the inductance current of the second-stage BUCK circuit, the second-stage BUCK circuit is subjected to double closed-loop control of a voltage loop and a current loop, so that the alternating work of the two-stage BUCK circuits is realized, and under the condition that the two-stage BUCK circuits work alternately, the current passing through each stage BUCK circuit only accounts for half of the total current passing through the DC-DC converter circuit, so that the volume of each stage BUCK circuit can be effectively reduced.

According to an embodiment of the present invention, there is also provided a storage medium corresponding to a control method of a switching power supply, the storage medium including a stored program, wherein a device in which the storage medium is controlled to execute the above-described control method of the switching power supply when the program runs.

Since the processes and functions implemented by the storage medium of the present embodiment substantially correspond to the embodiments, principles and examples of the foregoing methods, the descriptions of the present embodiment are not exhaustive, and reference may be made to the related descriptions of the foregoing embodiments, which are not repeated herein.

By adopting the technical scheme, the output voltage of the first-stage BUCK circuit and the inductance current of the first-stage BUCK circuit, the output voltage of the second-stage BUCK circuit and the inductance current of the second-stage BUCK circuit are sampled by aiming at the two-stage BUCK circuit formed by the first-stage BUCK circuit and the second-stage BUCK circuit, and the first-stage BUCK circuit is subjected to double closed-loop control of a voltage ring and a current ring according to the output voltage of the first-stage BUCK circuit and the inductance current of the first-stage BUCK circuit; and according to the output voltage of the second-stage BUCK circuit and the inductance current of the second-stage BUCK circuit, the second-stage BUCK circuit is subjected to double closed-loop control of a voltage loop and a current loop, so that the alternating work of the two-stage BUCK circuits is realized, the protection of the DC-DC converter circuit is realized, and the reduction of the volume of each stage of BUCK circuit in the DC-DC converter circuit under the high-power condition is realized.

In summary, it is readily understood by those skilled in the art that the above-described advantageous ways can be freely combined and superimposed without conflict.

The above description is only an example of the present invention and is not intended to limit the present invention, but various modifications and variations can be made to the present invention by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the scope of the claims of the present invention.

Claims

1. A control method of a switching power supply, characterized in that the switching power supply comprises: a BUCK conversion circuit and a driving circuit of the BUCK conversion circuit; the BUCK conversion circuit comprises: a first stage BUCK circuit and a second stage BUCK circuit, each stage BUCK circuit having two sub BUCK circuits; the first stage BUCK circuit and the second stage BUCK circuit are arranged in series between a direct current power supply at the input side and a load at the output side; the first-stage BUCK circuit is provided with a first switching tube module, a second switching tube module, a first inductance module and a second inductance module; the second-stage BUCK circuit is provided with a third switching tube module, a fourth switching Guan Mokuai, a third inductance module and a fourth inductance module; the driving circuit of the BUCK conversion circuit is respectively connected with the first switching tube module, the second switching tube module, the third switching tube module and the fourth switching tube module; the control method of the switching power supply comprises the following steps:

Enabling a driving circuit of the BUCK conversion circuit under the condition that a self-checking instruction of the BUCK conversion circuit is received;

under the condition that a driving circuit of the BUCK conversion circuit is enabled, enabling the first-stage BUCK circuit and the second-stage BUCK circuit to work; the first-stage BUCK circuit is used for carrying out first-stage voltage reduction treatment on the direct-current power supply at the input side to obtain intermediate voltage; the second-stage BUCK circuit is used for performing second-stage voltage reduction processing on the intermediate voltage at the output side of the first-stage BUCK circuit to obtain output voltage so as to supply power to a load at the output side;

after the first-stage BUCK circuit and the second-stage BUCK circuit work, sampling the voltage of a direct-current power supply at the input side to obtain an input voltage sampling value of the BUCK conversion circuit; sampling the intermediate voltage at the output side of the first-stage BUCK circuit to obtain an output voltage sampling value of the first-stage BUCK circuit; sampling currents on a first inductance module and a second inductance module in the first-stage BUCK circuit to obtain inductance currents of the first-stage BUCK circuit; sampling the output voltage of the output side of the second-stage BUCK circuit to obtain an output voltage sampling value of the second-stage BUCK circuit; sampling currents on a third inductance module and a fourth inductance module in the second-stage BUCK circuit to obtain inductance currents of the second-stage BUCK circuit;

According to the input voltage sampling value of the BUCK conversion circuit, the output voltage sampling value of the first-stage BUCK circuit and the inductance current of the first-stage BUCK circuit, performing double closed-loop control on a voltage loop and a current loop of the first-stage BUCK circuit; and performing double closed loop control of a voltage loop and a current loop on the second-stage BUCK circuit according to an input voltage sampling value of the BUCK conversion circuit, an output voltage sampling value of the second-stage BUCK circuit and an inductance current of the second-stage BUCK circuit, so that the first-stage BUCK circuit and the second-stage BUCK circuit work simultaneously, and two sub-BUCK circuits in each stage BUCK circuit can work alternately.

2. The control method of a switching power supply according to claim 1, wherein performing double closed loop control of a voltage loop and a current loop on the first stage BUCK circuit according to an input voltage sampling value of the BUCK conversion circuit, an output voltage sampling value of the first stage BUCK circuit, and an inductor current of the first stage BUCK circuit, comprises:

the difference value between the output voltage set value of the first-stage BUCK circuit and the output voltage sampling value of the first-stage BUCK circuit is controlled by PI to obtain output voltage, and the output voltage is recorded as the voltage loop output voltage of the first-stage BUCK circuit;

Determining the product of the output voltage of the voltage loop of the first-stage BUCK circuit and the sampling value of the input voltage of the BUCK conversion circuit as an output current set value of the first-stage BUCK circuit;

the difference value between the output current set value of the first-stage BUCK circuit and the inductance current of the first-stage BUCK circuit is controlled by PI to obtain output current, and the output current is recorded as the current loop output current of the first-stage BUCK circuit;

determining the duty ratio of PWM signals for controlling a first switching tube module and a second switching tube module in the first-stage BUCK circuit according to the output current of a current loop of the first-stage BUCK circuit;

and outputting PWM signals for controlling the first switching tube module and the second switching tube module in the first-stage BUCK circuit according to the duty ratio of PWM signals for controlling the first switching tube module and the second switching tube module in the first-stage BUCK circuit so as to control the first switching tube module and the second switching tube module in the first-stage BUCK circuit to act.

3. The control method of a switching power supply according to claim 2, wherein the control method further comprises performing double closed loop control of a voltage loop and a current loop on the first stage BUCK circuit according to an input voltage sampling value of the BUCK conversion circuit, an output voltage sampling value of the first stage BUCK circuit, and an inductance current of the first stage BUCK circuit, and further comprising:

According to the duty ratio of PWM signals used for controlling a first switching tube module and a second switching tube module in the first-stage BUCK circuit, calculating the triggering time of the next sampling so as to: resampling is carried out under the condition that the triggering time of the next sampling arrives, so that a new input voltage sampling value of the BUCK conversion circuit, a new output voltage sampling value of the first-stage BUCK circuit and an inductance current of the first-stage BUCK circuit are obtained, and double closed-loop control of a voltage ring and a current ring is carried out on the first-stage BUCK circuit according to the new input voltage sampling value of the BUCK conversion circuit, the new output voltage sampling value of the first-stage BUCK circuit and the inductance current of the first-stage BUCK circuit;

the specific mode of performing the double closed-loop control of the voltage loop and the current loop on the second-stage BUCK circuit is the same as the specific mode of performing the double closed-loop control of the voltage loop and the current loop on the first-stage BUCK circuit according to the input voltage sampling value of the BUCK conversion circuit, the output voltage sampling value of the first-stage BUCK circuit and the inductance current of the first-stage BUCK circuit.

4. A control method of a switching power supply according to any one of claims 1 to 3, further comprising:

acquiring the temperature of components in the first-stage BUCK circuit and acquiring the temperature of components in the second-stage BUCK circuit;

according to at least one of the output voltage sampling value of the first-stage BUCK circuit, the inductance current of the first-stage BUCK circuit and the temperature of components in the first-stage BUCK circuit, the first-stage BUCK circuit is protected; and protecting the second-stage BUCK circuit according to at least one of an output voltage sampling value of the second-stage BUCK circuit, an inductance current of the second-stage BUCK circuit and a temperature of a component in the second-stage BUCK circuit.

5. The method according to claim 4, wherein protecting the first-stage BUCK circuit according to at least one of an output voltage sampling value of the first-stage BUCK circuit, an inductor current of the first-stage BUCK circuit, and a temperature of a component in the first-stage BUCK circuit, comprises:

if the sampling value of the output voltage of the first-stage BUCK circuit is larger than the set voltage, the PWM signal of the first-stage BUCK circuit is turned off to control the first-stage BUCK circuit to stop working;

If the inductance current of the first-stage BUCK circuit is larger than the set current, the PWM signal of the first-stage BUCK circuit is turned off to control the first-stage BUCK circuit to stop working;

if the temperature of the components in the first-stage BUCK circuit is higher than the set temperature, carrying out preset frequency limiting or frequency reducing treatment on the first-stage BUCK circuit;

the specific way of protecting the second stage BUCK circuit according to at least one of the output voltage sampling value of the second stage BUCK circuit, the inductance current of the second stage BUCK circuit and the temperature of the components in the second stage BUCK circuit is the same as the specific way of protecting the first stage BUCK circuit according to at least one of the output voltage sampling value of the first stage BUCK circuit, the inductance current of the first stage BUCK circuit and the temperature of the components in the first stage BUCK circuit.

6. A control device for a switching power supply, the switching power supply comprising: a BUCK conversion circuit and a driving circuit of the BUCK conversion circuit; the BUCK conversion circuit comprises: a first stage BUCK circuit and a second stage BUCK circuit, each stage BUCK circuit having two sub BUCK circuits; the first stage BUCK circuit and the second stage BUCK circuit are arranged in series between a direct current power supply at the input side and a load at the output side; the first-stage BUCK circuit is provided with a first switching tube module, a second switching tube module, a first inductance module and a second inductance module; the second-stage BUCK circuit is provided with a third switching tube module, a fourth switching Guan Mokuai, a third inductance module and a fourth inductance module; the driving circuit of the BUCK conversion circuit is respectively connected with the first switching tube module, the second switching tube module, the third switching tube module and the fourth switching tube module; the control device of the switching power supply comprises:

A control unit configured to enable a driving circuit of the BUCK conversion circuit in a case where a self-test instruction of the BUCK conversion circuit is received;

the control unit is further configured to enable the first-stage BUCK circuit and the second-stage BUCK circuit to operate under the condition that a driving circuit of the BUCK conversion circuit is enabled; the first-stage BUCK circuit is used for carrying out first-stage voltage reduction treatment on the direct-current power supply at the input side to obtain intermediate voltage; the second-stage BUCK circuit is used for performing second-stage voltage reduction processing on the intermediate voltage at the output side of the first-stage BUCK circuit to obtain output voltage so as to supply power to a load at the output side;

the acquisition unit is configured to sample the voltage of the direct current power supply at the input side after the first-stage BUCK circuit and the second-stage BUCK circuit work, so as to obtain an input voltage sampling value of the BUCK conversion circuit; sampling the intermediate voltage at the output side of the first-stage BUCK circuit to obtain an output voltage sampling value of the first-stage BUCK circuit; sampling currents on a first inductance module and a second inductance module in the first-stage BUCK circuit to obtain inductance currents of the first-stage BUCK circuit; sampling the output voltage of the output side of the second-stage BUCK circuit to obtain an output voltage sampling value of the second-stage BUCK circuit; sampling currents on a third inductance module and a fourth inductance module in the second-stage BUCK circuit to obtain inductance currents of the second-stage BUCK circuit;

The control unit is further configured to perform double closed-loop control of a voltage loop and a current loop on the first-stage BUCK circuit according to an input voltage sampling value of the BUCK conversion circuit, an output voltage sampling value of the first-stage BUCK circuit and an inductance current of the first-stage BUCK circuit; and performing double closed loop control of a voltage loop and a current loop on the second-stage BUCK circuit according to an input voltage sampling value of the BUCK conversion circuit, an output voltage sampling value of the second-stage BUCK circuit and an inductance current of the second-stage BUCK circuit, so that the first-stage BUCK circuit and the second-stage BUCK circuit work simultaneously, and two sub-BUCK circuits in each stage BUCK circuit can work alternately.

7. The control device of the switching power supply according to claim 6, wherein the control unit performs double closed loop control of the voltage loop and the current loop on the first stage BUCK circuit according to an input voltage sampling value of the BUCK conversion circuit, an output voltage sampling value of the first stage BUCK circuit, and an inductor current of the first stage BUCK circuit, comprising:

8. The control device of claim 7, wherein the control unit performs double closed loop control of a voltage loop and a current loop on the first stage BUCK circuit according to an input voltage sampling value of the BUCK conversion circuit, an output voltage sampling value of the first stage BUCK circuit, and an inductor current of the first stage BUCK circuit, and further comprises:

9. The control device of a switching power supply according to any one of claims 6 to 8, characterized by further comprising:

the acquisition unit is further configured to acquire the temperature of the components in the first-stage BUCK circuit and acquire the temperature of the components in the second-stage BUCK circuit;

the control unit is further configured to protect the first-stage BUCK circuit according to at least one of an output voltage sampling value of the first-stage BUCK circuit, an inductance current of the first-stage BUCK circuit and a temperature of a component in the first-stage BUCK circuit; and protecting the second-stage BUCK circuit according to at least one of an output voltage sampling value of the second-stage BUCK circuit, an inductance current of the second-stage BUCK circuit and a temperature of a component in the second-stage BUCK circuit.

10. The control device of a switching power supply according to claim 9, wherein the control unit protects the first stage BUCK circuit based on at least one of an output voltage sampling value of the first stage BUCK circuit, an inductor current of the first stage BUCK circuit, and a temperature of a component in the first stage BUCK circuit, comprising:

11. A switching power supply, comprising: a control device of a switching power supply as claimed in any one of claims 6 to 10.

12. A storage medium comprising a stored program, wherein the program, when run, controls a device in which the storage medium is located to perform the control method of the switching power supply of any one of claims 1 to 5.