Direct-current voltage conversion circuit

Abstract

The utility model discloses a DC voltage conversion circuit, which comprises a first control module based on a PWM control mode, a second control module based on a PFM control mode and a switching circuit, the input end of the first control module is used for inputting a PWM control signal, the output end of the first control module is connected with the input end of the switching circuit, and the input end of the switching circuit is connected with the first control module. The output end of the switching circuit is used for outputting a first signal, the input end of the second control module is used for inputting a PFM control signal, the output end of the second control module is connected with the input end of the switching circuit, and the output end of the switching circuit is used for outputting a second signal. Compared with a traditional parallel connection mode of converter circuits with different control architectures, only one circuit is used, the design of the whole system circuit is simplified, and the same application requirement is met.

Description

TECHNICAL FIELD

[0001] The utility model relates to the field of electric converter especially relates to a direct current voltage conversion circuit. BACKGROUND

[0002] DC / DC circuit is a kind of circuit in direct current circuit one voltage value electric energy is converted into another voltage value electric energy.The traditional DC / DC circuit generally only uses one switching circuit architecture,for example PWM control architecture or PFM control architecture,wherein, the DC / DC circuit based on PWM control architecture is high in efficiency under heavy load condition, and is low in efficiency under light load condition, the DC / DC circuit based on PFM control mode is high in efficiency under light load condition, and is lower than PWM control mode in efficiency under heavy load condition.

[0003] In the prior art, in order to optimize the shortcomings of single circuit control architecture of DC / DC circuit, two DC / DC circuits of different control architectures can be connected in parallel to meet the demand of different loads and static power consumption, but the parallel mode in the prior art optimizes the shortcomings of single circuit control architecture, but also has problems such as high complexity of circuit design, high design cost and poor conversion effect.

[0004] Therefore, how to maintain the conversion efficiency of direct current voltage conversion circuit under different load conditions, further simplify the complexity of its circuit design and reduce the design cost has become a problem to be solved. UTILITY MODEL CONTENTS

[0005] The utility model embodiment provides a direct current voltage conversion circuit to solve how to maintain the conversion efficiency of direct current voltage conversion circuit under different load conditions, further simplify the complexity of its circuit design and reduce the design cost.

[0006] Therefore, the utility model embodiment provides a direct current voltage conversion circuit.

[0007] In the first aspect, the utility model embodiment provides a direct current voltage conversion circuit, comprising:

[0008] The first control module based on PWM control mode, the second control module based on PFM control mode and switching circuit;

[0009] The input end of the first control module is used to input PWM control signal, the output end of the first control module is connected the input end of the switching circuit, and the output end of the switching circuit is used to output first signal;

[0010] The input end of the second control module is used for inputting a PFM control signal, the output end of the second control module is connected with the input end of the switching circuit, and the output end of the switching circuit is used for outputting a second signal.

[0011] Further, the direct-current voltage conversion circuit further comprises a comparator;

[0012] The output end of the comparator is connected with the current detection end of the first control module and the current detection end of the second control module respectively, and is used for outputting the PWM control signal or the PFM control signal.

[0013] Further, the direct-current voltage conversion circuit further comprises a current detection resistor;

[0014] The first end of the current detection resistor is used for connecting the output end of a load, the second end of the current detection resistor is connected with the non-inverting input end of the comparator, and the inverting input end of the comparator is used for inputting a reference signal.

[0015] Further, the direct-current voltage conversion circuit further comprises a reference circuit;

[0016] The output end of the reference circuit is connected with the inverting input end of the comparator, and is used for outputting the reference signal.

[0017] Further, the switching circuit comprises a first switch tube and a second switch tube;

[0018] The input end of the first switch tube is connected with a power supply, the control end of the first switch tube is connected with the output end of the first control module, and the output end of the first switch tube is used as the output end of the switching circuit to output the first signal;

[0019] The input end of the second switch tube is connected with the power supply, the control end of the second switch tube is connected with the output end of the second control module, and the output end of the second switch tube is used as the output end of the switching circuit to output the second signal;

[0020] The output end of the first switch tube is connected with the input end of the second switch tube, and the output end of the second switch tube is connected with the ground.

[0021] Further, the direct-current voltage conversion circuit further comprises a voltage dividing unit;

[0022] The input end of the voltage dividing unit is used for connecting the output end of the switching circuit, and the output end of the voltage dividing unit is used for connecting the feedback end of the first control module and the feedback end of the second control module respectively.

[0023] Further, the voltage dividing unit comprises a first voltage dividing resistor and a second voltage dividing resistor;

[0024] The first end of the first voltage dividing resistor is used for connecting the output end of the switching circuit, the second end of the first voltage dividing resistor is used for connecting the feedback end of the first control module and the feedback end of the second control module respectively, the second end of the first voltage dividing resistor is connected with the first end of the second voltage dividing resistor, and the second end of the second voltage dividing resistor is connected with the ground.

[0025] Further, the direct-current voltage conversion circuit further comprises a voltage stabilizing unit.

[0026] The input end of the voltage stabilizing unit is connected with the input end of the voltage dividing unit, and the output end of the voltage stabilizing unit is connected with the ground.

[0027] Further, the voltage stabilizing unit comprises a capacitor.

[0028] The first end of the capacitor is connected with the input end of the voltage dividing unit, and the second end of the capacitor is connected with the ground.

[0029] Further, the direct-current voltage conversion circuit further comprises an inductor.

[0030] The first end of the inductor is connected with the output end of the switching circuit, and the second end of the inductor is connected with the input end of the voltage dividing unit.

[0031] The direct-current voltage conversion circuit of the utility model has the beneficial effects that the direct-current voltage conversion circuit comprises a first control module based on a PWM control mode, a second control module based on a PFM control mode and a switching circuit, the input end of the first control module is used for inputting a PWM control signal, the output end of the first control module is connected with the input end of the switching circuit, the output end of the switching circuit is used for outputting a first signal, the input end of the second control module is used for inputting a PFM control signal, the output end of the second control module is connected with the input end of the switching circuit, and the output end of the switching circuit is used for outputting a second signal.

[0032] The direct-current voltage conversion circuit of the utility model has the beneficial effects that the direct-current voltage conversion circuit comprises a first control module based on a PWM control mode, a second control module based on a PFM control mode and a switching circuit, the input end of the first control module is used for inputting a PWM control signal, the output end of the first control module is connected with the input end of the switching circuit, the output end of the switching circuit is used for outputting a first signal, the input end of the second control module is used for inputting a PFM control signal, the output end of the second control module is connected with the input end of the switching circuit, and the output end of the switching circuit is used for outputting a second signal. BRIEF DESCRIPTION OF DRAWINGS

[0033] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the description of the embodiments of the present application. Obviously, the drawings in the following description only some of the embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor.

[0034] Figure 1 is a circuit schematic diagram of a direct current voltage conversion circuit in an embodiment of the present application.

[0035] Among them, 100 is a direct current voltage conversion circuit, 110 is a first control module, 120 is a second control module, 130 is a switching circuit, 131 is a first switch tube, 132 is a second switch tube, 200 is a comparator, 300 is a current detection resistor, 400 is a reference circuit, 500 is a voltage dividing unit, 501 is a first voltage dividing resistor, 502 is a second voltage dividing resistor, 600 is a voltage stabilizing unit, 601 is a capacitor, 700 is an inductor, 800 is a load. DETAILED DESCRIPTION

[0036] The technical solutions in the embodiments of the present application will be described clearly and completely below in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are some of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all the other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0037] It should be understood that the present application can be implemented in different forms and should not be interpreted as being limited to the embodiments presented here. On the contrary, providing these embodiments will make the disclosure complete and complete, and will fully convey the scope of the present application to those skilled in the art. In the drawings, the size and relative size of the layers and regions may be exaggerated for clarity throughout the same reference signs represent the same elements.

[0038] It will be understood that when an element or layer is referred to as being "on" or "connected to" another element or layer, it can be directly on or connected to the other element or layer or intervening elements or layers can be present. In contrast, when an element is referred to as being "directly on" or "directly connected to" another element or layer, there are no intervening elements or layers present. It will be understood that, although the terms first, second, third, etc. can be used herein to describe various elements, components, regions, layers and / or sections, these elements, components, regions, layers and / or sections should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer or section from another element, component, region, layer or section. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the present application.

[0039] Spatially relative terms, such as "beneath", "below", "lower", "under", "above", "upper" and the like, can be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use and / or

[0040] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the present application. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and / or "comprising", when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. As used herein the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0041] For a thorough understanding of the present application, reference is made to the following detailed description taken in conjunction with the accompanying drawings, in which:

[0042] In one embodiment, asFigure 1 As shown, a direct current-direct current voltage conversion circuit is provided, comprising:

[0043] a first control module 110 based on a PWM control mode, a second control module 120 based on a PFM control mode, and a switching circuit 130;

[0044] An input end of the first control module 110 is configured to input a PWM control signal, an output end of the first control module 110 is connected to an input end of the switching circuit 130, and an output end of the switching circuit 130 is configured to output a first signal;

[0045] An input end of the second control module 120 is configured to input a PFM control signal, an output end of the second control module 120 is connected to an input end of the switching circuit 130, and an output end of the switching circuit 130 is configured to output a second signal.

[0046] PWM and PFM are two output voltage regulation modes, PWM control mode, which can be referred to as fixed-frequency pulse width modulation, that is, the switching frequency remains constant, and the purpose of modulation is achieved by changing the duty cycle of the driving signal in each frequency signal, and PFM control mode, which can be referred to as fixed-width frequency modulation, that is, when the output voltage or load working condition changes, the frequency of switching control is changed to achieve control and adjustment of the circuit function.

[0047] The working process of the direct current voltage conversion circuit is as follows: the current detection resistor 300 detects the load of the circuit output, and then the comparator 200 controls the direct current voltage conversion circuit to use one of the PWM control mode and the PFM control mode for direct current voltage conversion. The specific control process of the two control modes is as follows:

[0048] When the current passes through the load 800, a voltage drop proportional to the current size is generated on the current detection resistor 300, which reflects the current size of the load 800. The same-phase input end of the comparator 200 inputs the voltage drop signal from the current detection resistor 300, and the reverse input end of the comparator 200 inputs the reference voltage signal from the reference circuit 400. The comparator 200 compares the two input voltage signals and outputs a high-level or low-level control signal, thereby controlling one of the first control module and the second control module to work. For example, if the high level represents the PWM control signal and the low level represents the PFM control signal, the comparator 200 outputs the high level to control the first control module 110 to work, and the comparator 200 outputs the low level to control the second control module 120 to work.

[0049] When the PWM control signal output by the comparator 200 is received by the current detection end of the first control module 110, the first control module 110 controls the direct current voltage conversion, an output end of the first control module 110 outputs an opening signal to the first switch tube 131, so that the first switch tube 131 is turned on according to the opening signal, an output end of the first switch tube 131 is used as the output end SW of the switching circuit 130, and the first signal after voltage conversion is output, the input end of the voltage dividing unit 500 inputs the first signal after voltage conversion, the first signal after voltage conversion is divided, the feedback voltage after voltage division is obtained, the output end of the voltage dividing unit 500 outputs the feedback voltage, the feedback end FB of the first control module 110 inputs the feedback voltage, and the first control module 110 detects and adjusts the voltage conversion process based on the feedback voltage input by the feedback end FB, so as to adjust the first signal after voltage conversion output, and make it stable at the set value.

[0050] Correspondingly, when the PFM control signal output by the comparator 200 is received by the current detection end of the second control module 120, the second control module 120 controls the direct current voltage conversion, an output end of the second control module 120 outputs an opening signal to the second switch tube 132, so that the second switch tube 132 is turned on according to the opening signal, an output end of the second switch tube 132 is used as the output end SW of the switching circuit 130, and the second signal after voltage conversion is output, the input end of the voltage dividing unit 500 inputs the second signal after voltage conversion, the second signal after voltage conversion is divided, the feedback voltage after voltage division is obtained, the output end of the voltage dividing unit 500 outputs the feedback voltage, the feedback end FB of the second control module 120 inputs the feedback voltage, and the second control module 120 detects and adjusts the voltage conversion process based on the feedback voltage input by the feedback end FB, so as to adjust the second signal after voltage conversion output, and make it stable at the set value.

[0051] The direct current voltage conversion circuit of the embodiment can control one of the first control module based on the PWM control mode and the second control module based on the PFM control mode to work according to different load conditions, compared with the parallel mode of the converter circuit of the traditional different control architecture, the utility model only uses one circuit, simplifies the design of the whole system circuit and realizes the same application demand, that is, on the basis of optimizing the shortcomings of the single circuit control architecture, maintaining the conversion efficiency of the direct current voltage conversion circuit under different load conditions, further simplifying the circuit design complexity and reducing the design cost.

[0052] In an embodiment, as Figure 1As shown, the direct current voltage conversion circuit further comprises a comparator 200;

[0053] The output end of the comparator 200 is connected with the current detection end of the first control module 110 and the current detection end of the second control module 120 respectively, for outputting the PWM control signal or the PFM control signal.

[0054] The non-inverting input end of the comparator 200 receives the voltage or current signal from the current detection resistor 300, and the inverting input end of the comparator 200 receives the reference voltage signal or the reference current signal from the reference circuit 400. By comparing the two input voltage signals or the two input current signals, a high level or low level control signal is outputted to the current detection end of the first control module 110 and the current detection end of the second control module 120, so as to control one of the first control module and the second control module to work. For example, if the high level represents the PWM control signal and the low level represents the PFM control signal, the comparator 200 outputs the high level to control the first control module 110 to work, and the comparator 200 outputs the low level to control the second control module 120 to work.

[0055] The direct current voltage conversion circuit of the present application further comprises a comparator. Through the current detection resistor and the comparator, the load weight is detected, and according to the detection result, the working mode is switched. Either the first control module is controlled to work in the PWM mode, or the second control module is controlled to work in the PFM mode. Compared with the parallel mode of the traditional converter circuit with different control architectures, the utility model uses only one circuit, simplifies the design of the whole system circuit and realizes the same application requirement.

[0056] In an embodiment, as shown in Figure 1 As shown, the direct current voltage conversion circuit further comprises a current detection resistor 300;

[0057] The first end of the current detection resistor 300 is used for connecting the output end of the load 800, and the second end of the current detection resistor 300 is connected with the non-inverting input end of the comparator 200. The inverting input end of the comparator 200 is used for inputting the reference signal.

[0058] When the current passes through the load 800, a voltage drop proportional to the current is generated on the current detection resistor 300, which reflects the current of the load 800, and the voltage drop signal is input to the same phase input end of the comparator 200 through the comparator 200, so that the comparator 200 compares the voltage drop signal with the reference voltage signal input to the opposite phase input end, and outputs a high level or low level control signal, so as to control the first control module or the second control module to work, for example, if the high level represents the PWM control signal and the low level represents the PFM control signal, the comparator 200 outputs the high level, and the first control module 110 is controlled to work, and the comparator 200 outputs the low level, and the second control module 120 is controlled to work.

[0059] The direct current voltage conversion circuit further comprises a current detection resistor, and the load is detected through the current detection resistor and the comparator, and the working mode is switched according to the detection result, so that the first control module is controlled to work in the PWM mode or the second control module is controlled to work in the PFM mode, compared with the parallel mode of the traditional converter circuit with different control architectures, the utility model only uses one circuit, simplifies the design of the whole system circuit and realizes the same application demand.

[0060] In an embodiment, as shown in Figure 1 The direct current voltage conversion circuit further comprises a reference circuit 400.

[0061] The output end of the reference circuit 400 is connected to the opposite phase input end of the comparator 200, and is used for outputting the reference signal.

[0062] The output end of the reference circuit 400 is connected to the opposite phase input end of the comparator 200, and is used for outputting the reference signal.

[0063] The direct current voltage conversion circuit further comprises a reference circuit, and by providing a stable reference voltage or reference current reference point, the comparator can respond to the change of the input signal faster, and output the corresponding control signal, which is helpful to speed up the response speed of the circuit.

[0064] In an embodiment, as shown in Figure 1 The switch circuit 130 comprises a first switch tube 131 and a second switch tube 132.

[0065] The input end of the first switch tube 131 is connected with a power supply, the control end of the first switch tube 132 is connected with the output end of the first control module 110, and the output end of the first switch tube 131 is used as the output end of the switch circuit 130 to output the first signal.

[0066] The input end of the second switch tube 132 is connected with the power supply, the control end of the second switch tube 132 is connected with the output end of the second control module 120, and the output end of the second switch tube 132 is used as the output end of the switch circuit 130 to output the second signal.

[0067] The output end of the first switch tube 131 is connected with the input end of the second switch tube 132, and the output end of the second switch tube 132 is connected with the ground.

[0068] When the current detection end of the first control module 110 receives the PWM control signal output by the comparator 200, an opening signal is sent to the control end of the first switch tube 131, the first switch tube 131 is turned on after receiving the opening signal, the output end of the first switch tube 131 is used as the output end SW of the switch circuit 130, and the first signal after being boosted or reduced is output, when the current detection end of the second control module 120 receives the PFM control signal of the comparator 200, an opening signal is sent to the control end of the second switch tube 132, the second switch tube 132 is turned on after receiving the opening signal, the output end of the second switch tube 132 is used as the output end SW of the switch circuit 130, and the second signal after being boosted or reduced is output.

[0069] The switch circuit of the embodiment comprises a first switch tube and a second switch tube, different signals are output by turning on and off of the two switch tubes, the design of the circuit is simplified, and the realization and maintenance are easy.

[0070] In an embodiment, as shown in Figure 1 The direct-current voltage conversion circuit further comprises a voltage dividing unit 500.

[0071] The input end of the voltage dividing unit 500 is connected with the output end of the switch circuit 130, and the output end of the voltage dividing unit 500 is respectively connected with the feedback end of the first control module 110 and the feedback end of the second control module 120.

[0072] The input end of the voltage dividing unit 500 is connected to the output end SW of the switching circuit 130, and is used to input the first signal after voltage conversion output by the first switch tube 131, and to divide the voltage of the first signal to obtain a feedback voltage. The output end of the voltage dividing unit 500 outputs the feedback voltage, and the feedback end FB of the first control module 110 inputs the feedback voltage. The first control module 110 detects and adjusts the voltage conversion process based on the feedback voltage input by the feedback end FB, so as to adjust the output first signal after voltage conversion to stabilize at a set value.

[0073] Correspondingly, the input end of the voltage dividing unit 500 is connected to the output end SW of the switching circuit 130, and is used to input the second signal after voltage conversion output by the second switch tube 132, and to divide the voltage of the second signal to obtain a feedback voltage. The output end of the voltage dividing unit 500 outputs the feedback voltage, and the feedback end FB of the second control module 120 inputs the feedback voltage. The second control module 120 detects and adjusts the voltage conversion process based on the feedback voltage input by the feedback end FB, so as to adjust the output second signal after voltage conversion to stabilize at a set value.

[0074] The direct current voltage conversion circuit of the embodiment further comprises a voltage dividing unit, which takes a part of the output voltage of the switching circuit as a feedback voltage through voltage dividing principle. The feedback voltage is used to feedback the first control module and the second control module for output voltage adjustment, so as to realize stable voltage output.

[0075] In an embodiment, as shown in FIG. 5, the voltage dividing unit 500 comprises a first voltage dividing resistor 501 and a second voltage dividing resistor 502. Figure 1

[0076] The first end of the first voltage dividing resistor 501 is connected to the output end of the switching circuit 130, and the second end of the first voltage dividing resistor 501 is connected to the feedback end of the first control module 110 and the feedback end of the second control module 120 respectively. The second end of the first voltage dividing resistor 501 is connected to the first end of the second voltage dividing resistor 502, and the second end of the second voltage dividing resistor 502 is connected to the ground.

[0077] The first end of the first voltage dividing resistor 501 inputs the first signal or the second signal after voltage conversion output by the output end SW of the switching circuit 130. The first voltage dividing resistor 501 and the second voltage dividing resistor 502 divide the voltage of the first signal or the second signal to obtain a feedback voltage. The feedback voltage is output through the second end of the first voltage dividing resistor 501, and the feedback end of the first control module 110 or the feedback end of the second control module 120 inputs the feedback voltage. The first control module 110 or the second control module 120 detects and adjusts the voltage conversion process based on the feedback voltage, so as to adjust the output converted voltage to stabilize at a set value. ​

[0078] The first voltage dividing resistor and the second voltage dividing resistor in the voltage dividing unit of the embodiment take out a part of the output voltage of the switching circuit as a feedback voltage through the voltage dividing principle, and the feedback voltage is used to feedback the first control module and the second control module to adjust the output voltage, so as to realize stable voltage output.

[0079] In an embodiment, as shown in Figure 1 The direct current voltage conversion circuit further comprises a voltage stabilizing unit 600.

[0080] The input end of the voltage stabilizing unit 600 is connected to the input end of the voltage dividing unit 500, and the output end of the voltage stabilizing unit 600 is connected to the ground.

[0081] The input end of the voltage stabilizing unit 600 inputs the first signal or the second signal after the voltage boost or voltage reduction of the output end SW of the switching circuit 130, stores energy through the internal energy storage element, provides or absorbs excess energy when the first signal or the second signal after the voltage boost or voltage reduction fluctuates, so as to keep the first signal or the second signal after the voltage boost or voltage reduction at a set value.

[0082] The direct current voltage conversion circuit of the embodiment further comprises a voltage stabilizing unit, which provides or absorbs excess energy when the first signal or the second signal after the voltage boost or voltage reduction fluctuates, so as to keep the first signal or the second signal after the voltage boost or voltage reduction at a set value, thereby improving the voltage conversion effect.

[0083] In an embodiment, as shown in Figure 1 The voltage stabilizing unit comprises a capacitor 601.

[0084] The first end of the capacitor 601 is connected to the input end of the voltage dividing unit 500, and the second end of the capacitor 601 is connected to the ground.

[0085] The input end of the capacitor 601 inputs the first signal or the second signal after the voltage boost or voltage reduction of the output end SW of the switching circuit 130, stores energy through the internal energy storage element, provides or absorbs excess energy when the first signal or the second signal after the voltage boost or voltage reduction fluctuates, so as to keep the first signal or the second signal after the voltage boost or voltage reduction at a set value.

[0086] The voltage stabilizing unit of the embodiment comprises a capacitor, which provides or absorbs excess energy when the first signal or the second signal after the voltage boost or voltage reduction fluctuates, so as to keep the first signal or the second signal after the voltage boost or voltage reduction at a set value, thereby improving the voltage conversion effect.

[0087] In an embodiment, as shown in Figure 1 The direct current voltage conversion circuit further comprises an inductor 700.

[0088] The first end of the inductor 700 is connected to the output end of the switching circuit 130, and the second end of the inductor 700 is connected to the input end of the voltage dividing unit 500.

[0089] The first end of the inductor 700 inputs the first signal or the second signal after boosting or reducing of the output end SW output of the switching circuit 130, hinders the change of the current, and outputs the hindered first signal or second signal from the second end of the inductor 700, and the input end of the voltage dividing module 500 inputs the hindered first signal or second signal.

[0090] The embodiment is based on the hindering effect of the inductor on the current change, so that the current change through the inductor is relatively stable, the sudden change and peak of the current is reduced, and the effect of smooth current is realized.

[0091] The above-described embodiments are only used to illustrate the technical solutions of the present application, but not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that the technical solutions recorded in the foregoing embodiments can be modified, or some technical features can be replaced by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application, and should be included in the protection scope of the present application.

Claims

1. A direct current voltage conversion circuit, characterized by, The direct current voltage conversion circuit comprises: a first control module based on a PWM control mode, a second control module based on a PFM control mode, and a switching circuit; an input end of the first control module is used for inputting a PWM control signal, an output end of the first control module is connected to an input end of the switching circuit, and an output end of the switching circuit is used for outputting a first signal; an input end of the second control module is used for inputting a PFM control signal, an output end of the second control module is connected to an input end of the switching circuit, and an output end of the switching circuit is used for outputting a second signal; the direct current voltage conversion circuit further comprises a comparator; an output end of the comparator is connected to a current detection end of the first control module and a current detection end of the second control module respectively, and is used for outputting the PWM control signal or the PFM control signal; the switching circuit comprises a first switch tube and a second switch tube; an input end of the first switch tube is connected to a power supply, a control end of the first switch tube is connected to an output end of the first control module, and an output end of the first switch tube is used as an output end of the switching circuit to output the first signal; an input end of the second switch tube is connected to the power supply, a control end of the second switch tube is connected to an output end of the second control module, and an output end of the second switch tube is used as the output end of the switching circuit to output the second signal; an output end of the first switch tube is connected to an input end of the second switch tube, and an output end of the second switch tube is connected to a ground.

2. The direct-current voltage conversion circuit according to claim 1, characterized in that the direct current voltage conversion circuit further comprises a current detection resistor; a first end of the current detection resistor is used for connecting an output end of a load, a second end of the current detection resistor is connected to a non-inverting input end of the comparator, and an inverting input end of the comparator is used for inputting a reference signal.

3. The direct-current voltage conversion circuit according to claim 2, characterized in that the direct current voltage conversion circuit further comprises a reference circuit; an output end of the reference circuit is connected to the inverting input end of the comparator, and is used for outputting the reference signal.

4. The direct-current voltage conversion circuit according to claim 1, characterized in that the direct current voltage conversion circuit further comprises a voltage division unit; an input end of the voltage division unit is used for connecting an output end of the switching circuit, and an output end of the voltage division unit is used for connecting a feedback end of the first control module and a feedback end of the second control module respectively.

5. The direct voltage conversion circuit of claim 4, characterized in that the voltage division unit comprises a first voltage division resistor and a second voltage division resistor; a first end of the first voltage division resistor is used for connecting the output end of the switching circuit, a second end of the first voltage division resistor is used for connecting the feedback end of the first control module and the feedback end of the second control module respectively, the second end of the first voltage division resistor is connected to a first end of the second voltage division resistor, and a second end of the second voltage division resistor is connected to a ground.

6. The direct-current voltage conversion circuit according to claim 4, characterized in that the direct current voltage conversion circuit further comprises a voltage stabilizing unit; an input end of the voltage stabilizing unit is connected to an input end of the voltage division unit, and an output end of the voltage stabilizing unit is connected to a ground.

7. The direct voltage conversion circuit of claim 6, characterized by the voltage stabilizing unit comprises a capacitor; a first end of the capacitor is connected to the input end of the voltage division unit, and a second end of the capacitor is connected to a ground.

8. The direct-current voltage conversion circuit according to claim 4, characterized in that the direct current voltage conversion circuit further comprises an inductor; a first end of the inductor is connected to an output end of the switching circuit, and a second end of the inductor is connected to an input end of the voltage division unit.

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