Mode switching circuit, control method and device of DC-DC converter

Abstract

The present application discloses a mode switching circuit, control method, and device for a DC-DC converter. The mode switching circuit includes: a voltage comparison module for comparing the output voltage of the DC-DC converter with a reference voltage and obtaining a voltage comparison result; a zero-crossing detection module for detecting the zero-crossing current of the DC-DC converter; a mode switching module for operating when the zero-crossing current detection module detects the zero-crossing current, and switching the DC-DC converter to PFM mode or PSM mode based on the voltage comparison result after a preset time has elapsed. The mode switching module of the present application operates after the zero-point detection module detects the zero-point current, and achieves flexible switching between the two operating modes based on the voltage comparison result after a preset time has elapsed. The present application can control the magnitude of the load current when the DC-DC converter switches modes, thereby improving the working efficiency of the DC-DC converter. The present application can be widely used in the field of DC-DC converter technology.

Description

Technical Field

[0001] The present application relates to the technical field of DC-DC converters, and in particular to a DC-DC converter, a control method, a device, and an apparatus. Background Art

[0002] A DC-DC converter is a DC voltage converter that can step up, step down, or reverse the polarity of the input DC voltage.

[0003] The modulation modes of DC-DC converters mainly include pulse width modulation (PWM), pulse frequency modulation (PFM) and pulse skip modulation (PSM). In order to improve the efficiency of the DC-DC converter, when the DC-DC converter load is heavy, the DC-DC converter is controlled to operate in PWM mode, and when the DC-DC load is light, the DC-DC converter is controlled to operate in PFM mode, thereby reducing the switching frequency, reducing the quiescent current and switching loss. When the DC-DC load is ultra-light, the DC-DC converter is controlled to operate in PSM mode, skipping most switching cycles and further reducing quiescent power consumption.

[0004] Traditional DC-DC converter mode switching methods determine whether the DC-DC converter's output load is light by detecting whether the inductor current crosses zero (a moment when the current equals zero at a certain moment during the current change from positive to negative), thereby controlling whether the DC-DC converter switches to PWM mode or PFM mode. Although this mode switching method does not require additional load current detection circuitry, it is only applicable to switching between PWM and PFM modes. For both PFM and PSM modes, since the inductor current crosses zero, the presence of zero current cannot be used to determine the presence of zero current for mode switching. One solution is to detect the average inductor current over a cycle and compare it with a set reference current. The comparison result determines the load condition at that moment and controls the DC-DC converter's mode switching. However, the introduction of the average inductor current detection circuit and comparison circuit increases the system's quiescent current loss, thereby reducing the efficiency of the DC-DC converter. Summary of the Invention

[0005] Embodiments of the present application provide a mode switching circuit, control method, and device for a DC-DC converter, which can achieve flexible switching of operating modes and improve the operating efficiency of the DC-DC converter.

[0006] According to a first aspect of an embodiment of the present application, a mode switching circuit of a DC-DC converter is provided, wherein the DC-DC converter includes a voltage output terminal and an inductor, and the mode switching circuit includes:

[0007] a voltage comparison module, wherein an input terminal of the voltage comparison module is connected to the voltage output terminal, and the voltage comparison module is used to compare the output voltage of the DC-DC converter with a reference voltage and obtain a voltage comparison result;

[0008] a zero-crossing detection module, wherein an input end of the zero-crossing detection module is connected to the inductor, and the zero-crossing detection module is used to detect the zero-crossing current of the DC-DC converter;

[0009] a mode switching module, wherein an input end of the mode switching module is connected to an output end of the zero-crossing detection module, and an input end of the mode switching module is further connected to an output end of the voltage comparison module;

[0010] The mode switching module is configured to operate when the zero-crossing current detection module detects the zero-crossing current, and switch the DC-DC converter to the PFM mode or the PSM mode according to the voltage comparison result after a preset time period has elapsed;

[0011] The preset time length is used to adjust the load current when the DC-DC converter performs mode switching, and the preset time length is adjusted by the mode switching module.

[0012] Furthermore, the voltage comparison module includes:

[0013] a voltage detection unit connected to the voltage output terminal;

[0014] a first comparator, wherein a positive input terminal of the first comparator is connected to the output terminal of the voltage detection unit, and a negative input terminal of the first comparator is connected to the reference voltage;

[0015] The output terminal of the first comparator is connected to the input terminal of the mode switching module.

[0016] Further, the zero-crossing detection module includes a current detection unit and a second comparator;

[0017] The input end of the current detection unit is connected to the positive input end of the second comparator, the negative input end of the second comparator is grounded, and the output end of the second comparator is connected to the input end of the mode switching module.

[0018] Furthermore, the mode switching module includes an oscillator, a delay unit, an inverter and an AND gate;

[0019] The input end of the oscillator is connected to the output end of the second comparator, the output end of the oscillator is connected to the input end of the delay unit, and the output end of the delay unit is connected to the first input end of the AND gate;

[0020] The input end of the inverter is connected to the output end of the first comparator, and the output end of the inverter is connected to the second input end of the AND gate.

[0021] Furthermore, the delay unit includes a plurality of D flip-flops.

[0022] According to a second aspect of an embodiment of the present application, a control method is provided, which is applied to a mode switching circuit of a DC-DC converter as described in the first aspect, and the control method comprises the following steps:

[0023] Comparing the output voltage of the DC-DC converter with a reference voltage using a voltage comparison module to obtain a voltage comparison result;

[0024] Detecting the zero-crossing current of the DC-DC converter using a zero-crossing detection module;

[0025] Controlling the mode switching module to operate when the zero-crossing current detection module detects the zero-crossing current, and controlling the mode switching module to switch the DC-DC converter to the PFM mode or the PSM mode according to the voltage comparison result after a preset time period has expired;

[0026] The preset time length is used to adjust the load current of the DC-DC converter when performing mode switching, and the preset time length is adjusted by the mode switching module.

[0027] Furthermore, the step of controlling the DC-DC converter to switch to the PFM mode or the PSM mode according to the voltage comparison result includes the following steps:

[0028] Determining that the voltage comparison result is 0, and controlling the mode switching module to switch the DC-DC converter to the PFM mode;

[0029] Determine that the voltage comparison result is 1, and control the mode switching module to switch the DC-DC converter to the PSM mode.

[0030] According to a third aspect of an embodiment of the present application, there is provided an apparatus, including:

[0031] at least one processor;

[0032] at least one memory for storing at least one program;

[0033] When the at least one program is executed by the at least one processor, the at least one processor implements the control method described in the second aspect.

[0034] According to a fourth aspect of the embodiments of the present application, a DC-DC converter is provided, comprising a mode switching circuit of the DC-DC converter according to the first aspect.

[0035] According to a fifth aspect of an embodiment of the present application, a storage medium is provided, wherein the storage medium stores a program, and when the program is executed by a processor, the program is used to implement a control method as described in the second aspect.

[0036] The technical solution provided by the embodiment of the present application is that the mode switching module of the present application operates after the zero-point detection module detects the zero-point current, and switches the DC-DC converter to the PSM mode or the PFM mode according to the voltage comparison result after the preset time is reached, thereby realizing flexible switching between the two working modes and improving the working efficiency of the DC-DC converter. In addition, the present application can control the length of the preset time through the mode switching module according to actual conditions, thereby controlling the magnitude of the load current when the DC-DC converter mode is switched, so that the load current is more adapted to production needs and the working efficiency of the DC-DC converter is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following introduction is made to the drawings of the embodiments of the present application or the related technical solutions in the prior art. It should be understood that the drawings introduced below are only for the convenience of clearly describing some embodiments of the technical solutions of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without any creative work.

[0038] Figure 1 is a circuit schematic diagram of a mode switching circuit of a DC-DC converter provided in an embodiment of the present application;

[0039] Figure 2 is a circuit schematic diagram of the mode switching module provided in an embodiment of the present application;

[0040] Figure 3 This is a flow chart of the steps of a control method provided in an embodiment of the present application;

[0041] Figure 4 1 is a timing waveform diagram of the DC-DC converter of the embodiment of the present application switching from PFM mode to PSM mode;

[0042] Figure 5 1 is a timing waveform diagram of the DC-DC converter of the embodiment of the present application switching from PSM mode to PFM mode;

[0043] Figure 6 It is a schematic diagram of a device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0044] In order to enable those skilled in the art to better understand the present invention, the following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of this application.

[0045] The terms "first," "second," "third," and "fourth," etc., in the specification and claims of this application and the accompanying drawings are used to distinguish between different objects, rather than to describe a specific order. In addition, the terms "including," "having," and any variations thereof, are intended to cover non-exclusive inclusions. For example, a process, method, system, product, or apparatus comprising a series of steps or elements is not limited to the listed steps or elements, but may optionally include steps or elements not listed, or may optionally include other steps or elements inherent to the process, method, product, or apparatus.

[0046] References herein to "embodiments" mean that a particular feature, structure, or characteristic described in connection with the embodiments may be included in at least one embodiment of the present application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0047] The present invention will be further explained and illustrated below with reference to the accompanying drawings and specific embodiments.

[0048] Reference Figure 1 A mode switching circuit of a DC-DC converter, the DC-DC converter including a voltage output terminal and an inductor L0, the mode switching circuit including:

[0049] A voltage comparison module 20, wherein the input terminal of the voltage comparison module 20 is connected to the voltage output terminal, and the voltage comparison module 20 is used to compare the output voltage V0 of the DC-DC converter with the reference voltage and obtain a voltage comparison result;

[0050] A zero-crossing detection module 10, wherein the input end of the zero-crossing detection module 10 is connected to one end of the delay unit 300, and the zero-crossing detection module 10 is used to detect the zero-crossing current of the DC-DC converter;

[0051] A mode switching module, wherein the input end of the mode switching module is connected to the output end of the zero-crossing detection module 10 , and the input end of the mode switching module is also connected to the output end of the voltage comparison module 20 ;

[0052] The mode switching module is used to operate when the zero-crossing current detection module detects zero-crossing current, and after the preset time is reached, the DC-DC converter switches to PFM mode or PSM mode according to the voltage comparison result;

[0053] The preset time length is used to adjust the load current when the DC-DC converter performs mode switching, and the preset time length is adjusted by the mode switching module.

[0054] Specifically, refer to Figure 1 , the present application provides a specific embodiment of a DC-DC converter, the DC-DC converter is a Buck-Boost DC-DC converter, the Buck-Boost DC-DC converter includes a first PMOS transistor MP1, a second PMOS transistor MP2, a first NMOS transistor MN1, a second NMOS transistor MN2, an inductor L0, a filter capacitor C0, and a load R0;

[0055] The source of the first PMOS transistor MP1 is connected to the power supply voltage VDD, the drain of the first PMOS transistor MP1 is connected to one end of the inductor L0, the drain of the first NMOS transistor MN1 is connected to one end of the inductor L0, the drain of the second NMOS transistor MN2 is connected to the other end of the inductor L0, the source of the second PMOS transistor MP2 is connected to the other end of the inductor L0, the source of the first NMOS transistor MN1 is grounded GND, the source of the second NMOS transistor MN2 is grounded GND, the drain of the second PMOS transistor MP2 is connected to the voltage output end, one end of the filter capacitor C0 is connected to the voltage output end, one end of the load R0 is connected to the voltage output end, the other end of the filter capacitor C0 is grounded GND, and the other end of the load R0 is grounded GND.

[0056] The zero-crossing detection module 10 is used to detect the zero-crossing current of the DC-DC converter. The zero-crossing detection module 10 detects the zero-crossing current of the DC-DC converter by detecting the current flowing through the delay unit 300. When the zero-crossing current is detected, the zero-crossing detection module 10 outputs a low-level signal to the mode switching module; otherwise, it outputs a high-level signal.

[0057] The voltage comparison module 20 is used to obtain the output voltage V0 of the DC-DC converter and compare the output voltage V0 with a reference voltage. When it is determined that the output voltage V0 is greater than the reference voltage, the voltage comparison module 20 outputs a high-level signal to the mode switching module; otherwise, it outputs a low-level signal to the mode switching module.

[0058] The driving circuit is used to enhance the driving capability of the control signal output by the PFM control module or the PSM control module, and control the first PMOS transistor MP1, the second PMOS transistor MP2, the first NMOS transistor MN1, and the second NMOS transistor MN2 to be alternately turned on and off, thereby stabilizing the output voltage V0 of the DC-DC converter.

[0059] The mode switching module controls the operating mode of the DC-DC converter according to the output signals of the zero-crossing detection module 10 and the voltage comparison module 20 , wherein the operating mode includes one of a PFM mode and a PSM mode.

[0060] The input of the PFM control module is connected to the output of the mode switching module, and the input of the PFM control module is also connected to the output of the voltage comparison module 20. The input of the PSM control module is connected to the output of the mode switching module, and the input of the PFM control module is also connected to the output of the voltage comparison module 20. The PFM control module and the PSM control module are used to determine whether the output of the DC-DC converter is insufficiently supplied based on changes in the output voltage V0 and output corresponding control signals to the drive circuit. In one embodiment, the PFM control module may include a comparator and a control logic circuit, and the PSM control module may include a hysteresis comparator and a control logic circuit.

[0061] The moment when the mode switching module works is the first time node, the time node after the preset time length of the first time node is the second time node, and the voltage comparison result input to the mode switching module and used to determine whether mode switching is required refers to the voltage comparison result output by the voltage comparison module 20 at the second time node.

[0062] When the zero-crossing detection module 10 detects the zero-crossing current of the DC-DC converter, it outputs a low-level signal to the mode switching module. After receiving the low-level signal, the mode switching module starts working (first time node). After the preset time is reached, the mode switching module switches the working mode of the DC-DC converter from PSM to PFM mode or from PFM mode to PSM mode according to the voltage comparison result (at the second time node), thereby realizing flexible switching between the two working modes and improving the working efficiency of the DC-DC converter. If the voltage comparison result is determined to be 1, that is, the output voltage V0 of the DC-DC converter is greater than the reference voltage, then the output load of the DC-DC converter is a light load at this moment, and the control mode switching module switches the working mode of the DC-DC converter from PFM mode to PSM mode; if the voltage comparison result is determined to be 0, that is, the output voltage V0 of the DC-DC converter is less than or equal to the reference voltage, then the output load of the DC-DC converter is a heavy load at this moment, and the control mode switching module switches the working mode of the DC-DC converter from PSM mode to PFM mode.

[0063] In one embodiment, the preset time length may be determined by the circuit structure of the mode switching module, and the value of the preset time length may be changed by changing the circuit structure of the mode switching module.

[0064] Generally speaking, the working mode of the DC-DC converter is switched at different time nodes / moments, and the load current of the DC-DC converter at the mode switching moment is different. Therefore, the present application can control the length of the preset time through the mode switching module according to actual conditions, and then control the size of the load current when the DC-DC converter mode is switched, so that the load current is more adapted to production needs and the working efficiency of the DC-DC converter is improved.

[0065] Moreover, the mode switching circuit of the present application is implemented using a fully digital circuit, which does not consume any static current and is beneficial to improving the efficiency of the DC-DC converter.

[0066] As an optional embodiment, refer to Figure 1 , the voltage comparison module 20 includes:

[0067] A voltage detection unit connected to the voltage output terminal;

[0068] A first comparator U1, wherein a positive input terminal of the first comparator U1 is connected to the output terminal of the voltage detection unit, and a negative input terminal of the first comparator is connected to a reference voltage VREF;

[0069] The output terminal of the first comparator U1 is connected to the input terminal of the mode switching module.

[0070] Specifically, the present application provides an embodiment of a voltage comparison module 20, which includes a voltage detection unit and a first comparator U1. The voltage detection unit is connected to the voltage output terminal of the DC-DC converter to collect the output voltage V0 of the DC-DC converter. The voltage detection unit can be implemented using a voltage detection circuit known in the art, such as a voltage divider circuit.

[0071] The first comparator U1 is used to compare the output voltage V0 with the reference voltage VREF, so as to determine the magnitude relationship between the output voltage V0 and the reference voltage VREF.

[0072] The positive electrode of the first comparator U1 is connected to the output voltage V0, and the negative electrode of the first comparator U1 is connected to the reference voltage VREF. Therefore, when the output voltage V0 is greater than the reference voltage VREF, the voltage comparison result output by the first comparator U1 is 1; otherwise, when the output voltage V0 is less than or equal to the reference voltage VREF, the voltage comparison result output by the first comparator U1 is 0.

[0073] As an optional embodiment, refer to Figure 1 , the zero-crossing detection module 10 includes a current detection unit and a second comparator U2;

[0074] The input end of the current detection unit is connected to the positive input end of the second comparator U2 , the negative input end of the second comparator U2 is grounded GND, and the output end of the second comparator U2 is connected to the input end of the mode switching module.

[0075] Specifically, the current detection unit is used to detect the zero-crossing current of the DC-DC converter. The second comparator U2 compares the inductor current with a reference ground, thereby determining the zero-crossing current of the DC-DC converter based on the inductor current. The positive input terminal of the second comparator U2 is connected to one end of the inductor, thereby receiving the inductor current, and the negative input terminal of the second comparator U2 is grounded to GND. When the second comparator U2 outputs a low-level signal, it indicates that the zero-crossing current of the DC-DC converter has been detected.

[0076] As an optional embodiment, refer to Figure 2 , the mode switching module includes an oscillator, a delay unit 300, an inverter and an AND gate;

[0077] The input end of the oscillator is connected to the output end of the second comparator U2, the output end of the oscillator is connected to the input end of the delay unit, and the output end of the delay unit is connected to the first input end of the AND gate;

[0078] The input terminal of the inverter is connected to the output terminal of the first comparator U1 , and the output terminal of the inverter is connected to the second input terminal of the AND gate.

[0079] Specifically, the present application provides an embodiment of a mode switching module, which includes an oscillator, a delay unit 300 , an inverter, and an AND gate.

[0080] The oscillator is connected to the output of the second comparator U2. When the second comparator U2 outputs a high-level signal, it indicates that no zero-crossing current of the DC-DC converter has been detected. When the second comparator U2 outputs a low-level signal, it indicates that zero-crossing current of the DC-DC converter has been detected. Then, under the action of the low-level signal, the oscillator generates a clock signal CLK of a preset frequency. This clock signal CLK is provided to the delay unit 300, and the delay unit 300 begins to operate. The delay duration of the delay unit 300 is also the preset duration. After the preset duration is reached, the delay unit 300 outputs a high-level signal to the first input of the AND gate.

[0081] After the preset time is reached, the first input of the AND gate is connected to the high-level signal output by the delay unit 300. At the same time, the second input of the AND gate is connected to the voltage comparison result output by the output of the first comparator U1. That is, the mode switching module starts from the moment when the zero current is detected and uses the output voltage result at the second time node to determine the output load condition of the DC-DC converter.

[0082] As an optional embodiment, refer to Figure 2 , the delay unit 300 includes several D flip-flops.

[0083] Specifically, the present application also provides an embodiment of a delay unit 300. In this embodiment, the delay unit 300 includes a plurality of D flip-flops. In a specific embodiment, referring to Figure 2 The delay unit 300 includes three D flip-flops. The second comparator U2 outputs a low-level signal. The oscillator generates a clock signal CLK after oscillation. The data input terminal D of the first D flip-flop D0 inputs a high-level signal. After the first clock signal cycle of the first D flip-flop D0, the output terminal Q of the first D flip-flop D0 outputs a high-level signal. The high-level signal enters the data input terminal D of the second D flip-flop. After the second clock signal cycle, the output terminal Q of the second D flip-flop D1 outputs a high-level signal. Similarly, the output terminal Q of the third D flip-flop D2 outputs a high-level signal after the third clock signal cycle.

[0084] It can be seen that the number of D flip-flops determines the length of the preset time. The greater the number of D flip-flops, the longer the preset time.

[0085] In order to more clearly illustrate the working process of the mode switching circuit of the DC-DC converter of the present application, the present application also provides another embodiment, referring to Figure 1 and Figure 2In this embodiment, the current detection unit detects the inductor current in real time, and the second comparator U2 compares the inductor current with the reference ground. When the inductor current is detected to be 0, the second comparator U2 outputs a low-level signal (otherwise, the second comparator U2 outputs a high-level signal). The oscillator in the mode switching module starts to oscillate under the action of the low level and generates a clock signal CLK. The delay unit 300 starts to work under the action of the clock signal. After the preset time is reached, the delay unit 300 outputs a high-level signal to the AND gate in the mode switching module. At the same time as the preset time is reached, the second input end of the AND gate is connected to the voltage comparison result output by the output end of the first comparator U1. The output result of the AND gate depends on the voltage ratio of the output end of the first comparator U1. As a result of the comparison, when the output voltage V0 of the DC-DC converter is greater than the reference voltage VREF, the output terminal of the first comparator U1 outputs a high-level signal, and the AND gate also outputs a high-level signal, indicating that the current output load of the DC-DC converter is a light load. The high-level signal output by the AND gate is used to control the PFM control module and the PSM control module, thereby controlling the working mode of the DC-DC converter to switch from the PFM mode to the PSM mode. Similarly, when the AND gate outputs a low-level signal, indicating that the current output load of the DC-DC converter is a heavy load, the low-level signal output by the AND gate is used to control the PFM control module and the PSM control module, thereby controlling the working mode of the DC-DC converter to switch from the PSM mode to the PFM mode.

[0086] The present application also changes the structure of the mode switching module, more precisely, by changing the number of D flip-flops inside the delay unit 300 to change the length of the preset time, thereby controlling the load current of the DC-DC converter during mode switching, making the load current more adaptable to production needs and improving the working efficiency of the DC-DC converter.

[0087] Reference Figure 3 The present invention further provides a control method, which is applied to the mode switching circuit of the above-mentioned DC-DC converter. The control method includes the following steps S101-S103:

[0088] S101, using a voltage comparison module to compare the output voltage of the DC-DC converter with a reference voltage and obtain a voltage comparison result;

[0089] S102, detecting the zero-crossing current of the DC-DC converter using a zero-crossing detection module;

[0090] S103, the control mode switching module operates when the zero-crossing current detection module detects a zero-crossing current, and controls the mode switching module to switch the DC-DC converter to the PFM mode or the PSM mode according to the voltage comparison result after the preset time period is reached;

[0091] The preset time length is used to adjust the load current when the DC-DC converter performs mode switching, and the preset time length is adjusted by the mode switching module.

[0092] The control method in the embodiment of the present application is described below with reference to the above-mentioned embodiment of the mode switching circuit of a DC-DC converter.

[0093] In an embodiment of the present application, a control method is proposed based on a mode switching circuit of a DC-DC converter in the above embodiment. The method first uses a zero-crossing detection module to determine the zero-crossing current of the DC-DC converter. The zero-crossing detection module 10 detects the inductor current flowing through the inductor of the DC-DC converter. When the magnitude of the inductor current is zero, it determines that the zero-crossing current of the DC-DC converter has been detected. After the zero-crossing current is detected, the zero-crossing current is used as a trigger condition to operate the mode switching module. After the mode switching operation time reaches a preset time, the mode switching module determines the severity of the output load of the DC-DC converter based on the voltage comparison result at the moment when the preset time is reached. According to the severity of the output load, the operating mode of the DC-DC converter is switched from PFM to PSM mode or from PSM mode to PFM mode, thereby achieving flexible switching between the two operating modes and improving the working efficiency of the DC-DC converter.

[0094] In addition, the working mode of the DC-DC converter is switched at different time nodes / moments, and the load current of the DC-DC converter at the mode switching moment is different. Therefore, the present application can control the length of the preset time by controlling the circuit structure inside the mode switching module according to actual conditions, and then control the size of the load current when the DC-DC converter mode is switched, so that the load current is more adapted to production needs and the working efficiency of the DC-DC converter is improved.

[0095] In one embodiment, step S103 includes the following steps S1031-S1032:

[0096] S1031: Determine that the voltage comparison result is 0, and control the mode switching module to switch the DC-DC converter to the PFM mode;

[0097] S1022: Determine that the voltage comparison result is 1, and control the mode switching module to switch the DC-DC converter to the PSM mode.

[0098] The moment when the mode switching module works is the first time node, the time node after the preset time length of the first time node is the second time node, and the voltage comparison result input to the mode switching module and used to determine whether mode switching is required refers to the voltage comparison result output by the voltage comparison module at the second time node.

[0099] If the voltage comparison result is determined to be 1, that is, the output voltage of the DC-DC converter is greater than the reference voltage, then the output load of the DC-DC converter is a light load at this moment, and the control mode switching module switches the operating mode of the DC-DC converter from the PFM mode to the PSM mode; if the voltage comparison result is determined to be 0, that is, the output voltage of the DC-DC converter is less than or equal to the reference voltage, then the output load of the DC-DC converter is a heavy load at this moment, and the control mode switching module switches the operating mode of the DC-DC converter from the PSM mode to the PFM mode.

[0100] In one embodiment, referring to Figure 4 , Figure 4 The following waveforms show the timing of the DC-DC converter switching from PFM mode to PSM mode. The waveform at the bottom shows the output voltage change waveform, and the waveform at the top shows the inductor current change waveform. ILIM is the inductor current limit value of the DC-DC converter, VPSMH and VPSML are the reference voltages of the DC-DC converter in PSM mode, and VPFM is the reference voltage of the DC-DC converter in PFM mode. VPSML should be greater than VPFM to prevent the output voltage from dropping too much when the output load changes from light to heavy load, causing the subsequent circuit to malfunction. It can be seen that when the output load is light, when zero current is detected and the preset time duration T has passed, the detected output voltage is less than the preset reference voltage. At this time, the load is determined to be light, and the DC-DC converter is controlled to enter PSM mode.

[0101] See Figure 5 , which is a timing waveform diagram of the DC-DC converter switching from PSM mode to PFM mode. When the output load is a heavy load, when the zero current is detected and the preset time T has passed, the detected output voltage is less than the preset reference voltage. At this time, it is determined that the output load is a heavy load, and the DC-DC converter is controlled to enter the PFM mode.

[0102] Reference Figure 6 , an embodiment of the present application further provides a device, including:

[0103] at least one processor 301;

[0104] At least one memory 302, configured to store at least one program;

[0105] When at least one program is executed by at least one processor 301 , the at least one processor 301 implements the above-mentioned control method embodiment.

[0106] The contents of the above-mentioned method embodiments are all applicable to the present device embodiments. The functions specifically implemented by the present device embodiments are the same as those of the above-mentioned method embodiments, and the beneficial effects achieved are also the same as those achieved by the above-mentioned method embodiments.

[0107] An embodiment of the present application further provides a DC-DC converter, comprising the aforementioned mode switching circuit of the DC-DC converter.

[0108] An embodiment of the present application further provides a storage medium storing a program, which is used to implement the above-mentioned control method embodiment when executed by a processor.

[0109] Similarly, the contents of the above-mentioned mode switching circuit and device embodiments of a DC-DC converter are applicable to the embodiments of the present DC-DC converter and storage medium. The functions specifically implemented by the present DC-DC converter and storage medium embodiments are the same as those of the above-mentioned mode switching circuit and device embodiments of a DC-DC converter, and the beneficial effects achieved are also the same as those achieved by the above-mentioned mode switching circuit and device embodiments of a DC-DC converter.

[0110] It is understood that all or some steps, systems in the disclosed method above can be implemented as software, firmware, hardware and appropriate combinations thereof. Some physical components or all physical components can be implemented as software by a processor, such as a central processing unit, a digital signal processor or a microprocessor, or implemented as hardware, or implemented as an integrated module, such as a dedicated integrated module. Such software can be distributed on a computer-readable medium, and the computer-readable medium can include a computer storage medium (or non-transitory medium) and a communication medium (or temporary medium). As known to those of ordinary skill in the art, the term computer storage medium is included in any method or technology for storing information (such as computer-readable instructions, data structures, program modules or other data) and is volatile and non-volatile, removable and non-removable. Computer storage media includes but is not limited to RAM, ROM, EEPROM, flash memory or other memory technology, CD-ROM, digital versatile disk (DVD) or other optical disk storage, magnetic cassette, magnetic tape, disk storage or other magnetic storage device, or can be used to store desired information and any other medium that can be accessed by a computer. Furthermore, as is well known to those skilled in the art, communication media typically embodies computer-readable instructions, data structures, program modules, or other data in a modulated data signal such as a carrier wave or other transport mechanism, and may include any information delivery media.

[0111] The embodiments of the present application are described in detail above in conjunction with the accompanying drawings, but the present application is not limited to the above embodiments. Various changes can be made within the scope of knowledge possessed by ordinary technicians in the technical field without departing from the purpose of the present application.

Claims

1. A mode switching circuit for a DC-DC converter, the DC-DC converter comprising a voltage output terminal and an inductor, characterized in that: The mode switching circuit includes: a voltage comparison module, wherein an input terminal of the voltage comparison module is connected to the voltage output terminal, and the voltage comparison module is used to compare the output voltage of the DC-DC converter with a reference voltage and obtain a voltage comparison result; a zero-crossing detection module, wherein an input end of the zero-crossing detection module is connected to the inductor, and the zero-crossing detection module is used to detect the zero-crossing current of the DC-DC converter; a mode switching module, wherein an input end of the mode switching module is connected to an output end of the zero-crossing detection module, and an input end of the mode switching module is further connected to an output end of the voltage comparison module; The mode switching module is configured to operate when the zero-crossing detection module detects the zero-crossing current, and switch the DC-DC converter to the PFM mode or the PSM mode according to the voltage comparison result after a preset time period has elapsed; The preset time length is used to adjust the load current of the DC-DC converter when performing mode switching, and the preset time length is adjusted by the mode switching module.

2. The mode switching circuit of a DC-DC converter according to claim 1, wherein: The voltage comparison module includes: a voltage detection unit connected to the voltage output terminal; a first comparator, wherein a positive input terminal of the first comparator is connected to the output terminal of the voltage detection unit, and a negative input terminal of the first comparator is connected to the reference voltage; The output terminal of the first comparator is connected to the input terminal of the mode switching module.

3. The mode switching circuit of a DC-DC converter according to claim 2, wherein: The zero-crossing detection module includes a current detection unit and a second comparator; The input end of the current detection unit is connected to the positive input end of the second comparator, the negative input end of the second comparator is grounded, and the output end of the second comparator is connected to the input end of the mode switching module.

4. The mode switching circuit of a DC-DC converter according to claim 3, characterized in that: The mode switching module includes an oscillator, a delay unit, an inverter and an AND gate; The input end of the oscillator is connected to the output end of the second comparator, the output end of the oscillator is connected to the input end of the delay unit, and the output end of the delay unit is connected to the first input end of the AND gate; The input end of the inverter is connected to the output end of the first comparator, and the output end of the inverter is connected to the second input end of the AND gate.

5. The mode switching circuit of a DC-DC converter according to claim 4, characterized in that: The delay unit includes a plurality of D flip-flops.

6. A control method, characterized in that: The mode switching circuit of the DC-DC converter according to any one of claims 1 to 5, wherein the control method comprises the following steps: Comparing the output voltage of the DC-DC converter with a reference voltage using a voltage comparison module to obtain a voltage comparison result; Detecting the zero-crossing current of the DC-DC converter using a zero-crossing detection module; Controlling the mode switching module to operate when the zero-crossing detection module detects the zero-crossing current, and controlling the mode switching module to switch the DC-DC converter to the PFM mode or the PSM mode according to the voltage comparison result after a preset time period has expired; The preset time length is used to adjust the load current of the DC-DC converter when performing mode switching, and the preset time length is adjusted by the mode switching module.

7. A control method according to claim 6, characterized in that: The step of controlling the DC-DC converter to switch to the PFM mode or the PSM mode according to the voltage comparison result includes the following steps: Determining that the voltage comparison result is 0, and controlling the mode switching module to switch the DC-DC converter to the PFM mode; Determine that the voltage comparison result is 1, and control the mode switching module to switch the DC-DC converter to the PSM mode.

8. A mode switching device for a DC-DC converter, characterized in that: include: at least one processor; at least one memory for storing at least one program; When the at least one program is executed by the at least one processor, the at least one processor implements a control method as claimed in claim 6 or 7.

9. A DC-DC converter, characterized in that: A mode switching circuit comprising a DC-DC converter according to any one of claims 1 to 5.

10. A storage medium, characterized in that The storage medium stores a program, and when the program is executed by the processor, it is used to implement a control method according to claim 6 or 7.

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