Power circuit and power adapter

Abstract

The invention relates to the technical field of electronics, in particular to a power supply circuit and a power adapter, and the power supply circuit comprises a transformation rectification module, a first feedback module and a control module; the first feedback module is connected with the output end of the voltage transformation and rectification module and used for detecting the magnitude relation between the voltage transformation signal output by the voltage transformation and rectification module and the reference output voltage signal and generating a feedback signal; and the control module is respectively connected with the first feedback module and the voltage transformation and rectification module, and is used for controlling the conduction of a switching device in the voltage transformation and rectification module according to the feedback signal so as to reduce the difference value between the variable voltage signal and the reference output voltage signal, so that the output variable voltage is stabilized at the reference voltage. The beneficial effects of improving the conversion efficiency and improving the voltage stabilization performance on the basis of the output voltage of the power supply circuit can be realized.

Description

Technical Field

[0001] The present application relates to the field of electronic technology, and in particular to a power supply circuit and a power supply adapter. Background Art

[0002] A power adapter is a device that converts AC power into DC power. It is widely used in various electronic products. With the development of science and technology, the requirements for power circuits are getting higher and higher. It is not only required to be able to efficiently convert and regulate voltage, but also to have good stability and reliability.

[0003] For traditional power supply circuits, most of them use front and rear two-stage circuits to realize power conversion and transmission and achieve output voltage regulation. However, this type of circuit often has many components, complex circuit structure, and low conversion efficiency. How to simplify the circuit structure based on the output voltage of the power supply circuit and improve the conversion efficiency and voltage regulation performance is a technical problem that needs to be solved urgently. Summary of the invention

[0004] The present application provides a power supply circuit and a power supply adapter, which can achieve the beneficial effect of improving conversion efficiency and improving voltage stabilization performance based on the output voltage of the power supply circuit.

[0005] In a first aspect of the present application, a power supply circuit is provided, comprising: A transformer and rectifier module, used for receiving an input voltage signal, and rectifying and transforming the input voltage signal to obtain a transformed voltage signal; a first feedback module, connected to the output end of the transformer and rectifier module, for obtaining the variable voltage signal and the reference output voltage signal, and generating a first feedback signal according to the variable voltage signal and the reference output voltage signal, wherein the first feedback signal is used to express the magnitude relationship between the variable voltage signal and the reference output voltage signal; a control module, connected to the first feedback module and the transformer and rectifier module respectively, configured to receive the first feedback signal and generate a first control signal according to the first feedback signal; The transformer and rectifier module is further used to receive the first control signal and control the conduction of the switch device according to the first control signal to reduce the difference between the transformed voltage signal and the reference output voltage signal.

[0006] By adopting the above technical solution, the first feedback module determines the magnitude relationship between the input voltage signal and the transformer voltage signal according to the input voltage and the voltage output by the transformer-rectifier module, thereby obtaining a corresponding first feedback signal, and the control module generates a first control signal according to the first feedback signal, thereby controlling the conduction of the switching device in the transformer-rectifier module, adaptively adjusting the conduction of the switching device, thereby outputting a stable output voltage.

[0007] Optionally, the control module includes: A comparator, connected to the first feedback module, for receiving the first feedback signal and determining whether the voltage value of the variable voltage signal is greater than the voltage value of the reference output voltage signal according to the first feedback signal; A processor, connected to the comparator, for obtaining the input voltage signal, the variable voltage signal, and the reference output voltage signal when the voltage value of the variable voltage signal is greater than the voltage value of the reference output voltage signal, and generating a first control signal according to the input voltage signal, the variable voltage signal, and the reference output voltage signal.

[0008] By adopting the above technical solution, the control module of the power supply circuit adopts the structure of a comparator and a processor. Through the collaborative work of the two, the situation of the output voltage can be accurately judged. If the voltage value of the variable voltage signal is greater than the voltage value of the reference output voltage signal, the processor generates a first control signal according to the input voltage signal, the variable voltage signal, and the reference output voltage signal, further adjusting the working state of the voltage conversion and rectification module, thereby reducing the difference between the variable voltage signal and the reference output voltage signal, and improving the reliability and overall performance of the power supply circuit.

[0009] Optionally, the processor is used for Determining the boost duty ratio and the buck duty ratio according to the input voltage signal and the variable voltage signal; If the boost duty ratio is greater than or equal to the buck duty ratio, determining to perform buck control on the input voltage signal according to the variable voltage signal, the reference output voltage signal, and the boost and buck duty ratios; If the boost duty ratio is less than the buck duty ratio, determining to perform boost control on the input voltage signal according to the variable voltage signal, the reference output voltage signal, and the boost and buck duty ratios.

[0010] By adopting the above technical solution, the processor can accurately calculate the duty ratios required for boosting and bucking according to the analysis of the input voltage signal and the variable voltage signal. When the boost duty ratio is greater than or equal to the buck duty ratio, a buck control strategy is selected. On the contrary, when the boost duty ratio is less than the buck duty ratio, a boost control strategy is selected, so as to obtain the required output voltage.

[0011] Optionally, the processor is used for Determining the maximum value and the minimum value of the variable voltage signal according to the variable voltage signal; Respectively determining a new boost duty ratio according to the maximum value and the minimum value of the variable voltage signal, the boost duty ratio, and the reference output voltage signal; Generate the first control signal according to the new boost ratio.

[0012] By adopting the above technical solution, the processor can dynamically adjust the boost ratio according to the maximum and minimum values of the variable voltage signal and the existing boost ratio, so as to ensure that the output voltage is always close to the reference output voltage signal, reduce voltage fluctuations, and improve the stability and efficiency of the power supply circuit.

[0013] Optionally, the processor is used to, Determine a new boost duration and a new buck duration within a preset time period according to the new boost ratio; Generate the first control signal according to the boost duration and the buck duration.

[0014] By adopting the above technical solution, after the processor determines the new boost ratio, it can calculate the boost duration within a preset time period, and then determine the buck duration. By calculating and controlling the boost and buck durations, the on and off of the switching device can be effectively controlled, preventing overly frequent switching, reducing the voltage fluctuation range, and thus improving the voltage regulation performance.

[0015] Optionally, the voltage transformation and rectification module includes a transformer and a synchronous rectification unit; The second input terminal and the second output terminal of the transformer are respectively connected to the control module, and the three output terminals of the transformer are connected to the input terminal and the output terminal of the synchronous rectification unit; The first input terminal of the transformer is used to receive the input voltage signal; The second output terminal of the transformer is used to output the variable voltage signal.

[0016] By adopting the above technical solution, when the power adapter works, the transformer receives the input voltage signal and outputs a variable voltage signal through electromagnetic induction. Combining with the synchronous rectification module, the variable voltage output by the transformer is subjected to ripple rectification processing to reduce harmonic interference and make the final variable voltage more stable.

[0017] Optionally, the voltage transformation and rectification module further includes: an auxiliary winding, a first MOS transistor, a first diode, and a first triode; One end of the auxiliary winding is connected to the first input terminal of the transformer, the other end of the auxiliary winding is connected to the collector of the first triode, the base of the first triode is connected to the control module, the emitter of the first triode is connected to the cathode of the first diode, and the anode of the first diode is connected to the connection between the control module and the first triode; The gate of the first MOS transistor is connected to the connection point of the control module, the first triode, and the first diode. The source of the first MOS transistor is connected to the connection point of the first triode and the auxiliary winding. The drain of the first MOS transistor is used to receive the input voltage signal.

[0018] By adopting the above technical solution, when receiving the input voltage signal, the first MOS transistor can adapt to the change of the input voltage under the drive of the control module. At the same time, with the help of the first diode and the first triode, the energy stored in the transformer can be released when the first MOS transistor is turned off, preventing the circuit from being damaged by excessive reverse voltage, and improving the safety and reliability of the circuit.

[0019] Optionally, the voltage transformation and rectification module further includes a second MOS transistor, a second diode, and a second triode. The other end of the auxiliary winding is connected to the drain of the second MOS transistor. The gate of the second MOS transistor is connected to the emitter of the second triode. The base of the second triode is connected to the control module. The source of the second MOS transistor and the collector of the second triode are grounded. The anode of the second diode is connected to the connection point of the second triode and the control module. The cathode of the second diode is connected to the connection point of the second MOS transistor and the second triode.

[0020] By adopting the above technical solution, when receiving the input voltage signal, with the help of the second diode and the second triode, the detection of the control module is realized, which is convenient for the subsequent output of the voltage transformation and rectification module.

[0021] Optionally, the power supply circuit further includes: a noise voltage suppression module. The input end of the noise voltage suppression module is connected to the externally connected alternating current, and is used to determine a voltage suppression signal according to the voltage of the alternating current. The output end of the noise voltage suppression module is connected to the drain of the first MOS transistor, and is used to determine the input voltage signal according to the voltage suppression signal.

[0022] By adopting the above technical solution, the noise voltage suppression module obtains a voltage suppression signal according to the externally connected alternating current, thereby performing noise voltage suppression, filtering out the common-mode interference signals in the alternating current, avoiding these interference signals from affecting the normal operation of the subsequent circuit, making the input voltage more stable, and then improving the conversion efficiency and output accuracy of the voltage transformation and rectification module, and enhancing the overall anti-interference ability of the power supply circuit.

[0023] In the second aspect of the present application, a power adapter is provided, including the power supply circuit as described above.

[0024] In summary, the present application includes at least one of the following beneficial technical effects: 1. The first feedback module determines the magnitude relationship between the input voltage signal and the transformed voltage signal based on the input voltage and the voltage output by the transformer-rectifier module, thereby obtaining a corresponding first feedback signal. Then, the control module generates a first control signal according to the first feedback signal, and controls the conduction of the switching device in the transformer-rectifier module, adaptively adjusting the conduction situation of the switching device, so as to output a stable output voltage; 2. The noise voltage suppression module obtains a voltage suppression signal based on the externally connected alternating current, thereby performing noise voltage suppression, filtering out the common-mode interference signals in the alternating current, avoiding these interference signals from affecting the normal operation of the subsequent circuit, making the input voltage more stable, and further improving the conversion efficiency and output accuracy of the transformer-rectifier module, and enhancing the overall anti-interference ability of the power supply circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 is a module connection diagram of a power supply circuit provided by an embodiment of the present application; Figure 2 is a circuit schematic diagram of a power supply circuit provided by an embodiment of the present application; Figure 3 is a module connection diagram of another power supply circuit provided by an embodiment of the present application; Figure 4 is a circuit schematic diagram of the noise voltage suppression module provided by an embodiment of the present application. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0026] In order to enable those skilled in the art to better understand the technical solutions in this specification, the technical solutions in the embodiments of this specification will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of this specification. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all of the embodiments.

[0027] In the description of the embodiments of the present application, words such as "for example" or "for illustration" are used to indicate examples, illustrations or explanations. Any embodiment or design solution described as "for example" or "for illustration" in the embodiments of the present application should not be construed as being more preferred or having more advantages than other embodiments or design solutions. Rather, the use of words such as "for example" or "for illustration" is intended to present related concepts in a specific manner.

[0028] In the description of the embodiments of the present application, the term "a plurality" means two or more. For example, a plurality of systems means two or more systems, and a plurality of screen terminals means two or more screen terminals. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance or implicitly specifying the technical features indicated. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. The terms "comprise", "include", "have" and their variants all mean "including but not limited to", unless otherwise specifically emphasized in other ways.

[0029] The present invention will be described in more detail below with reference to the accompanying drawings. In the respective drawings, the same elements are denoted by like reference numerals. For the sake of clarity, the various parts in the drawings are not drawn to scale. In addition, some well-known parts may not be shown in the figures.

[0030] Refer to Figure 1 , which is a module connection diagram of the power supply circuit provided by the embodiment of the present application, including a step-down rectification module 1, a first feedback module 2 and a control module 3. Among them, the first feedback module 2 is connected to the output terminal of the step-down rectification module 1, and the control module 3 is respectively connected to the first feedback module 2 and the step-down rectification module 1.

[0031] The step-down rectification module 1 is used to receive an input voltage signal and rectify and transform the input voltage signal to obtain a transformed voltage signal.

[0032] The first feedback module 2 is used to obtain the transformed voltage signal and the reference output voltage signal, and generate a first feedback signal according to the transformed voltage signal and the reference output voltage signal. The first feedback signal is used to represent the magnitude relationship between the transformed voltage signal and the reference output voltage signal; The control module 3 is used to receive the first feedback signal and generate a first control signal according to the first feedback signal; The step-down rectification module 1 is further used to receive the first control signal and control the conduction of the switching device in the power supply circuit according to the first control signal to reduce the difference between the transformed voltage signal and the reference output voltage signal.

[0033] Among them, the first feedback module 2 is connected to the step-down rectification module 1, and is used to detect the magnitude relationship between the transformed voltage and the reference output voltage, and generate a first feedback signal for representing the magnitude relationship. The control module 3 is connected to the first feedback module 2 and the step-down rectification module 1, and is used to control the conduction of the switching device in the power supply circuit according to the first feedback signal to realize the rise and fall of the voltage.

[0034] Specifically, the step-down rectification module 1 receives the input voltage signal Vi, can convert the input voltage signal Vi into a variable voltage signal Vo, and the output voltage Vo it provides meets the current limiting requirement and the power limiting source requirement. The first feedback module 2 will continuously monitor the magnitude relationship between the variable voltage signal Vo and the reference voltage signal Vs. If Vo is greater than Vs, the first feedback signal takes a logic level, otherwise it takes another logic level. After receiving the first feedback signal, the control module 3 can determine whether the transformer output voltage signal Vo is greater than the reference output voltage Vr.

[0035] Furthermore, the control module 3 will collect Vi, Vo, and Vr, calculate and generate corresponding first control signals according to their relationships to control the conduction of the switching device, so that the variable voltage Vo can be stabilized near Vr as much as possible. If Vo is too high, the control signal will increase the off time of the switching device in the circuit; if Vo is too low, the control signal will increase the on time of the switching device in the circuit. Through the above closed-loop control, the voltage output is realized.

[0036] Based on the above embodiments, as an optional embodiment, as Figure 2 shown, Figure 2 shows a circuit schematic diagram of a power supply circuit. The step-down rectification module 1 may include a transformer and a synchronous rectification unit. The second input terminal and the second output terminal of the transformer are respectively connected to the control module 3. The three output terminals of the transformer are connected to the input terminal and the output terminal of the synchronous rectification unit; the first input terminal of the transformer is used to receive the input voltage signal; the second output terminal of the transformer is used to output the variable voltage signal.

[0037] Regarding the voltage transformation and rectification module 1: The voltage transformation and rectification module 1 includes a transformer and a synchronous rectification unit. The transformer has two primary windings and three secondary windings. The primary windings are used as input terminals, and the secondary windings are used as output terminals, that is, the transformer has two input terminals and three output terminals. One input terminal of the transformer is used to receive an input voltage signal, and the other end is connected to the control module 3 to receive a first control signal. The synchronous rectification unit includes a synchronous rectification chip and a rectification switch tube. The rectification switch tube is connected to the third output terminal of the transformer and is used to rectify the voltage converted and output by the transformer according to the drive signal Vg, and the drive signal Vg is provided by the synchronous rectification chip. The first end of the synchronous rectification chip is connected to one end of the rectification switch tube, and the other end of the rectification switch tube is connected to the third output terminal of the transformer. The synchronous rectification chip detects based on the voltage output by the transformer through a detection circuit. When the synchronous rectification chip detects the voltage output by the transformer, it outputs the drive signal Vg to turn on the rectification switch tube. Among them, the switch tube can be a MOS tube, or other switching control devices such as a triode or an IGBT; the synchronous rectification chip can be TEA2095T, or other rectification controllers. In addition, to determine the accuracy of the first control signal, the embodiments of the present application also have the following designs: The voltage transformation and rectification module 1 further includes: an auxiliary winding LK, a first MOS tube M1, a first diode D1, and a first triode Q1; one end of the auxiliary winding LK is connected to the first input terminal of the transformer, the other end of the auxiliary winding LK is connected to the collector of the first triode Q1, the base of the first triode Q1 is connected to the control module 3, the emitter of the first triode Q1 is connected to the cathode of the first diode D1, and the anode of the first diode D1 is connected to the connection between the control module 3 and the first triode Q1; the gate of the first MOS tube M1 is connected to the connection between the control module 3, the first triode Q1, and the first diode D1, and the source of the first MOS tube M1 is connected to the connection between the first triode Q1 and the auxiliary winding LK; the drain of the first MOS tube M1 is used to receive the input voltage signal.

[0038] Further, the embodiments of the present application also have the following designs: The voltage transformation and rectification module 1 further includes a second MOS tube M2, a second diode D2, and a second triode Q2; the other end of the auxiliary winding LK is connected to the drain of the second MOS tube M2, the gate of the second MOS tube M2 is connected to the emitter of the second triode Q2, the base of the second triode Q2 is connected to the control module 3, and the source of the second MOS tube M2 and the collector of the second triode Q2 are grounded; the anode of the second diode D2 is connected to the connection between the second triode Q2 and the control module 3, and the cathode of the second diode D2 is connected to the connection between the second MOS tube M2 and the second triode Q2.

[0039] Regarding control module 3: Control module 3 includes a control chip, which is provided with a detection input terminal, and controls the on and off of the first MOS transistor M1 according to the input voltage signal output based on the power supply access by the detection input circuit and the transformed voltage signal after rectification of the transformer output. Among them, the control chip can choose TEA2016AAT for control, or it can also be other digital controllers for power supplies.

[0040] Specifically, when the first MOS transistor M1 is turned on, the input voltage passes through the first MOS transistor M1 and the auxiliary winding LK to form an energized loop. At this time, the first primary winding is in the energized loop and is in a charging state. At the same time, when the second MOS transistor M2 is turned on, a high and low side drive loop is formed. If the first MOS transistor M1 is turned off, the first primary winding is not in the loop, and at this time, the first primary winding is in a discharging state.

[0041] Furthermore, to eliminate the noise interference caused by the continuous conduction of the switching device and improve the stability of the input voltage, the present application also provides a circuit connection method for an embodiment. Refer to Figures 3 - 4 , Figure 3 which is the module connection diagram of another power supply circuit provided by the embodiment of the present application, Figure 4 and is the circuit schematic diagram of the noise voltage suppression module provided by the embodiment of the present application. Specific description is made in combination with Figures 3 - 4 as follows: The power supply circuit further includes: a noise voltage suppression module; the input end of the noise voltage suppression module is connected to the externally connected alternating current, and is used to determine a voltage suppression signal according to the voltage of the alternating current. The output end of the noise voltage suppression module is connected to the drain of the first MOS transistor M1, and is used to determine an input voltage signal according to the voltage suppression signal.

[0042] Regarding the noise voltage suppression module: The noise voltage suppression module includes several common-mode inductors, capacitors, and resistors. After the externally connected alternating current passes through the fuse, it is connected in parallel with three common-mode inductors and then connected to a rectifier bridge formed by four diodes, and then connected to the first MOS transistor M1 to output the input voltage signal entering the first MOS transistor M1. That is, the first voltage terminal in the three-phase power is connected to one end of the fuse, and the other end of the fuse is connected to the first end of the first common-mode inductor LF1. The third end of the first common-mode inductor LF1 is connected to the first end of the second common-mode inductor LF2. The third end of the second common-mode inductor LF2 is connected to the first end of the third common-mode inductor. The third end of the third common-mode inductor is connected to the drain of the first MOS transistor M1. The third voltage terminal in the three-phase power is connected to the second end of the first common-mode inductor LF1. The fourth end of the first common-mode inductor LF1 is connected to the second end of the second common-mode inductor LF2. The fourth end of the second common-mode inductor LF2 is connected to the second end of the third common-mode inductor. The fourth end of the third common-mode inductor is connected to the drain of the first MOS transistor M1. Among them, a first capacitor CX1 is connected at the connection between the first common-mode inductor LF1 and the second common-mode inductor LF2, and a second capacitor CX3 and a group of parallel resistors are connected at the connection between the second common-mode inductor LF2 and the third common-mode inductor.

[0043] Specifically, during the operation of the power supply circuit, the continuous on and off of the switching device will cause a common-mode noise voltage in the circuit. If this common-mode noise voltage is not eliminated, it will affect the stability of the output voltage of the power supply circuit. Therefore, the common-mode suppression module suppresses the voltage according to the externally connected alternating current. The inductor and resistor can filter out the differential-mode signal of the alternating current, and the common-mode inductor can effectively filter out the common-mode signal in the alternating current, so as to effectively filter out the interference signals generated by the common-mode and differential-mode in the alternating current, output a high-precision input voltage signal, and improve the overall anti-interference ability of the power supply circuit.

[0044] In a feasible implementation manner, the control module 3 includes: A comparator, connected to the first feedback module 2, for receiving the first feedback signal and determining whether the voltage value of the variable voltage signal is greater than the voltage value of the reference output voltage signal according to the first feedback signal; A processor, connected to the comparator, for obtaining the input voltage signal, the variable voltage signal, and the reference output voltage signal when the voltage value of the variable voltage signal is greater than the voltage value of the reference output voltage signal, and generating a first control signal according to the input voltage signal, the variable voltage signal, and the reference output voltage signal.

[0045] Specifically, setting the first feedback module 2 can further improve the accuracy of voltage control. The first feedback module 2 detects the error between the variable voltage signal Vo and the reference output voltage signal Vr in real time, generates a first feedback signal and feeds it back to the control module 3. The comparator in the control module 3 is connected to the first feedback module 2 and can compare the voltage value of the received variable voltage signal with the reference output voltage to determine whether the variable voltage signal is greater than the reference output voltage signal.

[0046] Further, when the comparator detects that the variable voltage signal is greater than the reference output voltage signal, it notifies the processor. The processor will obtain the input voltage Vi, the variable voltage Vo, and the set reference output voltage Vr. According to the relationship between Vi, Vo, and Vr, the processor will calculate and generate a first control signal, send the first control signal to the voltage conversion and rectification module 1, and precisely control the on and off of the internal MOS transistors therein, so as to obtain a stable output voltage and achieve a stable voltage output.

[0047] Based on the above embodiments, as an alternative embodiment, the processor is configured to determine the boost ratio and the buck ratio according to the input voltage signal and the variable voltage signal; if the boost ratio is greater than or equal to the buck ratio, then determine to perform buck control on the input voltage signal according to the variable voltage signal, the reference output voltage signal, and the boost and buck ratios; if the boost ratio is less than the buck ratio, then determine to perform boost control on the input voltage signal according to the variable voltage signal, the reference output voltage signal, and the boost and buck ratios.

[0048] Specifically, when it is detected that the variable voltage signal is greater than the reference output voltage signal, it indicates that the voltage output by the transformer is not the required voltage. At this time, in order to obtain the required voltage, it is necessary to adjust the voltage conversion and rectification module 1. The processor calculates the corresponding boost ratio and buck ratio according to the input voltage Vi and the output voltage Vo. This is because the magnitude relationship between Vi and Vo determines the degree of boost or buck required. Then, the processor compares the magnitude relationship between the boost ratio and the buck ratio. If it is detected at this time that the boost ratio is greater than the buck ratio, it indicates that more buck is needed to reduce the output voltage. In this case, it means that the current input voltage is already relatively high and does not need to be further increased, but should be reduced to an appropriate level to avoid damage to the device or other adverse effects caused by too high an output voltage.

[0049] Based on the above embodiments, as an alternative embodiment, the processor is configured to determine the maximum value and the minimum value of the variable voltage signal according to the variable voltage signal; respectively determine a new boost ratio according to the maximum value and the minimum value of the variable voltage signal, the boost, and the reference output voltage signal; and generate a first control signal according to the new boost ratio.

[0050] Optionally, the processor is configured to determine a new boost duration and a new buck duration according to the new boost duty ratio; and generate a first control signal according to the boost duration and the buck duration.

[0051] Specifically, the processor calculates the new boost duty ratio based on the maximum value and the minimum value of the variable voltage signal, the boost duty ratio, and the reference output voltage signal, so as to obtain the new duty ratio, generate the first control signal, and control the on and off of the switching device in the variable voltage rectification module 1 according to the duty ratio, thereby achieving the purpose of regulating the output voltage.

[0052] For example, the higher the boost duty ratio, the longer its duration. The duty ratio is proportional to the duration. The duration determines the actual working time of each mode. The processor precisely controls the switching of the switching device according to the calculated duration, thereby regulating the output voltage.

[0053] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present application, and should all be included in the protection scope of the present application.

Claims

1. A power supply circuit, characterized in that: include: A transformer and rectifier module, used for receiving an input voltage signal, and rectifying and transforming the input voltage signal to obtain a transformed voltage signal; a first feedback module, connected to the output end of the transformer and rectifier module, for obtaining the variable voltage signal and the reference output voltage signal, and generating a first feedback signal according to the variable voltage signal and the reference output voltage signal, wherein the first feedback signal is used to express the magnitude relationship between the variable voltage signal and the reference output voltage signal; a control module, connected to the first feedback module and the transformer and rectifier module respectively, configured to receive the first feedback signal and generate a first control signal according to the first feedback signal; The transformer and rectifier module is further used to receive the first control signal and control the conduction of the switch device according to the first control signal to reduce the difference between the transformed voltage signal and the reference output voltage signal.

2. The power supply circuit according to claim 1, characterized in that: The control module comprises: a comparator, connected to the first feedback module, configured to receive the first feedback signal, and determine whether the voltage value of the variable voltage signal is greater than the voltage value of the reference output voltage signal according to the first feedback signal; A processor is connected to the comparator and is used to obtain the input voltage signal, the variable voltage signal and the reference output voltage signal when the voltage value of the variable voltage signal is greater than the voltage value of the reference output voltage signal, and generate a first control signal according to the input voltage signal, the variable voltage signal and the reference output voltage signal.

3. The power supply circuit according to claim 2, characterized in that: The processor is used to, Determine a voltage step-up ratio and a voltage step-down ratio according to the input voltage signal and the variable voltage signal; If the voltage-boosting ratio is greater than or equal to the voltage-dropping ratio, determining to perform voltage-dropping control on the input voltage signal according to the variable voltage signal, the reference output voltage signal, and the voltage-boosting and voltage-dropping ratios; If the voltage-boosting ratio is less than the voltage-dropping ratio, the voltage-boosting control of the input voltage signal is determined according to the variable voltage signal, the reference output voltage signal, and the voltage-boosting and voltage-dropping ratios.

4. The power supply circuit according to claim 3, characterized in that: The processor is used to, Determining a maximum value and a minimum value of the variable voltage signal according to the variable voltage signal; Determining a new voltage boost ratio according to the maximum value and the minimum value of the variable voltage signal, the voltage boost ratio and the reference output voltage signal respectively; The first control signal is generated according to the new voltage boost ratio.

5. The power supply circuit according to claim 4, characterized in that: The processor is used to, Determining a new boost duration and a new buck duration within a preset time period according to the new boost ratio; The first control signal is generated according to the boost duration and the drop duration.

6. The power supply circuit according to claim 1, characterized in that: The transformer and rectifier module includes a transformer and a synchronous rectifier unit; The second input terminal and the second output terminal of the transformer are connected to the control module respectively, and the three output terminals of the transformer are connected to the input terminal and the output terminal of the synchronous rectification unit; The first input terminal of the transformer is used to receive the input voltage signal; The second output terminal of the transformer is used to output a variable voltage signal.

7. The power supply circuit according to claim 6, characterized in that: The transformer and rectifier module further includes: an auxiliary winding, a first MOS tube, a first diode and a first transistor; One end of the auxiliary winding is connected to the first input end of the transformer, the other end of the auxiliary winding is connected to the collector of the first transistor, the base of the first transistor is connected to the control module, the emitter of the first transistor is connected to the cathode of the first diode, and the anode of the first diode is connected to the connection between the control module and the first transistor; The connection point between the control module, the first transistor and the first diode is connected to the gate of the first MOS transistor, and the source of the first MOS transistor is connected to the connection point between the first transistor and the auxiliary winding; The drain of the first MOS tube is used to receive the input voltage signal.

8. The power supply circuit according to claim 7, characterized in that: The transformer and rectifier module also includes a second MOS tube, a second diode and a second triode; The other end of the auxiliary winding is connected to the drain of the second MOS tube, the gate of the second MOS tube is connected to the emitter of the second transistor, the base of the second transistor is connected to the control module, and the source of the second MOS tube and the collector of the second transistor are grounded; The anode of the second diode is connected to the connection point between the second transistor and the control module, and the cathode of the second diode is connected to the connection point between the second MOS tube and the second transistor.

9. The power supply circuit according to claim 7, characterized in that: The power supply circuit also includes: a noise voltage suppression module; The input end of the noise voltage suppression module is connected to the externally connected alternating current, and is used to determine the voltage suppression signal according to the voltage of the alternating current. The output end of the noise voltage suppression module is connected to the drain of the first MOS tube, and is used to determine the input voltage signal according to the voltage suppression signal.

10. A power adapter, characterized in that: The method comprises a power supply circuit as claimed in any one of claims 1 to 9.

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