Power supply circuit and device

Abstract

The utility model provides a power supply circuit and device. The power supply circuit comprises a primary side input module, a transformer, a first voltage output module, a second voltage output module and a voltage sampling module. The primary side input module is respectively connected with a power supply and the transformer, the first voltage output module is respectively connected with the transformer and the voltage sampling module, and the second voltage output module is respectively connected with the transformer and the voltage sampling module; the primary side input module is used for acquiring input voltage from a power supply and transmitting the input voltage to the transformer; the transformer converts an input voltage into a first voltage; the first voltage output module outputs a first target voltage according to the first voltage; the second voltage output module is used for outputting second target voltage according to the first voltage; the voltage sampling module is used for collecting a first target voltage and a second target voltage, and calculating a voltage value of the input voltage according to the first target voltage and the second target voltage. The input voltage can be accurately calculated, and the circuit structure is relatively simple.

Description

Technical Field

[0001] This application belongs to the field of power electronics technology, and particularly relates to a power supply circuit and device. Background Art

[0002] In products using an isolating switch converter as an auxiliary power supply, an MCU (Microcontroller Unit) is usually placed on the secondary side as the main controller, which is convenient for providing drive signals to the load and sampling the voltage signal and current signal of the load. When the MCU is placed on the secondary side, it is necessary to sample the input voltage of the primary side and perform corresponding overvoltage protection or undervoltage protection operations according to the input voltage.

[0003] Currently, there are usually two methods for detecting the input voltage of the primary side of a flyback switching power supply. The first method is to use an isolation chip. By using an isolation chip, the voltage signal of the primary side is directly transmitted to the secondary side MCU for detection. However, the first method requires the use of an isolation chip, which not only occupies area but also increases the cost. The second method is to add a forward winding on the secondary side of the transformer. By adding a forward winding on the secondary side of the transformer, the relationship between the voltage on the forward winding and the input voltage of the primary side of the transformer is the same as the turns ratio. However, the additional forward winding in the second method makes the design of the transformer and the winding process of the coil more complex. When there are multiple windings on the secondary side of the transformer, the manufacturing of the transformer becomes more complex, and the cost is also increased. Summary of the Utility Model

[0004] The embodiments of this application provide a power supply circuit and device, which can accurately calculate the input voltage and have a relatively simple circuit structure.

[0005] In a first aspect, the embodiments of this application provide a power supply circuit, including: a primary input module, a transformer, a first voltage output module, a second voltage output module, and a voltage sampling module; the primary input module is respectively connected to a power supply and the transformer, the first voltage output module is respectively connected to the transformer and the voltage sampling module, and the second voltage output module is respectively connected to the transformer and the voltage sampling module; the primary input module is configured to obtain an input voltage from the power supply and transmit the input voltage to the transformer; the transformer is configured to convert the input voltage into a first voltage; the first voltage output module is configured to output a first target voltage according to the first voltage; the second voltage output module is configured to output a second target voltage according to the first voltage; the voltage sampling module is configured to collect the first target voltage and the second target voltage, and calculate the voltage value of the input voltage according to the first target voltage and the second target voltage.

[0006] In some embodiments, the transformer includes a primary winding and a first secondary winding; the same-name terminal of the primary winding is connected to the power supply through the primary input module, the different-name terminal of the primary winding is connected to the equipotential terminal through the primary input module, the same-name terminal of the first secondary winding is connected to the voltage sampling module through the second voltage output module, and the different-name terminal of the first secondary winding is connected to the voltage sampling module through the first voltage output module; the primary winding is configured to generate an alternating magnetic flux according to the input voltage; the first secondary winding is configured to obtain electrical energy from the primary winding through the alternating magnetic flux to output the first voltage.

[0007] In some embodiments, the first voltage output module includes a diode D3 and a capacitor EC2; the positive electrode of the diode D3 is connected to the different-name terminal of the first secondary winding, the negative electrode of the diode D3 is connected to both the positive electrode of the capacitor EC2 and the voltage sampling module, and the negative electrode of the capacitor EC2 is connected to the equipotential terminal.

[0008] In some embodiments, the second voltage output module includes a diode D4 and a capacitor C3; the positive electrode of the diode D4 is connected to the same-name terminal of the first secondary winding, the negative electrode of the diode D4 is connected to both the first terminal of the capacitor C3 and the voltage sampling module, and the second terminal of the capacitor C3 is connected to the equipotential terminal.

[0009] In some embodiments, the voltage sampling module includes a resistor R5, a resistor R6, a resistor R7, a resistor R8, and a controller; the first terminal of the resistor R5 is connected to the second voltage output module, the second terminal of the resistor R5 is connected to both the first terminal of the resistor R6 and the controller, the first terminal of the resistor R7 is connected to the first voltage output module, the second terminal of the resistor R7 is connected to both the first terminal of the resistor R8 and the controller, and the second terminals of the resistor R6 and the resistor R8 are respectively connected to the equipotential terminal.

[0010] In some embodiments, the primary input module includes a switching transistor Q1, a diode D2, a resistor R1, a capacitor C1, and a capacitor EC1; the positive electrode of the diode D1 is connected to the power supply, the negative electrode of the diode D1 is connected to the positive electrode of the capacitor EC1, the first terminal of the resistor R1, the first terminal of the capacitor C1, and the same-name terminal of the primary winding, the different-name terminal of the primary winding is connected to the positive electrode of the diode D2 and the second terminal of the switching transistor Q1, the negative electrode of the diode D2 is connected to the second terminal of the resistor R1 and the second terminal of the capacitor C1, the control terminal of the switching transistor Q1 is connected to a second power supply, and the third terminal of the switching transistor Q1 and the negative electrode of the capacitor EC1 are respectively connected to the equipotential terminal.

[0011] In some embodiments, the transformer further includes a second secondary winding; the same-name end of the second secondary winding is connected to the same-name end of the first secondary winding; the second secondary winding is configured to obtain electrical energy from the primary winding through the alternating magnetic flux to output a second voltage.

[0012] In some embodiments, the power supply circuit further includes a third voltage output module; the third voltage output module is connected to the second secondary winding; the third voltage output module is configured to output a third target voltage according to the second voltage to supply electrical energy to a load.

[0013] In some embodiments, the third voltage output module includes a diode D5, a diode D6, a resistor R4, a capacitor EC3, and a capacitor C4; the positive electrode of the diode D5 is connected to the different-name end of the second secondary winding, the negative electrode of the diode D5 is connected to the positive electrode of the capacitor EC3, the first end of the capacitor C4, and the first end of the resistor R4, the second end of the resistor R4, the second end of the capacitor C4, the negative electrode of the capacitor EC3, and the positive electrode of the diode D6 are connected and connected to the equipotential end, and the negative electrode of the diode D6 is connected to the same-name end of the second secondary winding.

[0014] In a second aspect, an embodiment of the present application provides a power supply device including the power supply circuit as described above.

[0015] Distinct from the prior art, the embodiments of the present application provide a power supply circuit and a device. Among them, the power supply circuit includes: a primary input module, a transformer, a first voltage output module, a second voltage output module, and a voltage sampling module; the primary input module is respectively connected to a power supply and the transformer, the first voltage output module is respectively connected to the transformer and the voltage sampling module, and the second voltage output module is respectively connected to the transformer and the voltage sampling module; the primary input module is configured to obtain an input voltage from the power supply and transmit the input voltage to the transformer; the transformer is configured to convert the input voltage into a first voltage; the first voltage output module is configured to output a first target voltage according to the first voltage; the second voltage output module is configured to output a second target voltage according to the first voltage; the voltage sampling module is configured to collect the first target voltage and the second target voltage, and calculate the voltage value of the input voltage according to the first target voltage and the second target voltage. In the power supply circuit and device of the embodiments of the present application, firstly, by collecting and using the first target voltage and the second target voltage to calculate the voltage value of the input voltage, multiple voltage information can be comprehensively analyzed and calculated, reducing the error that may be brought by single voltage measurement, thereby significantly improving the accuracy and precision of voltage detection. Compared with some complex multi-module series or parallel voltage detection schemes, this centralized power supply circuit structure is relatively simple. Secondly, through reasonable module division of labor and collaborative work, unnecessary circuit components and connections are reduced, thereby simplifying the circuit design to a certain extent and reducing the hardware cost and design complexity. Moreover, the compact circuit design and fewer component numbers contribute to the integration and miniaturization of the system. This is particularly important in electronic devices with limited space, such as portable devices, micro control systems, etc., which can reduce the volume of the device without sacrificing performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] One or more embodiments are exemplarily illustrated by corresponding drawings. These exemplary illustrations do not constitute limitations on the embodiments. Elements with the same reference numerals in the drawings represent similar elements, unless otherwise stated, and the drawings in the figures do not constitute a proportional limitation.

[0017] Figure 1 is a block diagram of the power supply circuit provided by an embodiment of the present application;

[0018] Figure 2 is a block diagram of the power supply circuit provided by another embodiment of the present application;

[0019] Figure 3 is a schematic diagram of the circuit structure of the power supply circuit provided by an embodiment of the present application. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0020] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the following will clearly and detailedly describe the technical solutions in the embodiments of this application with reference to the accompanying drawings in the embodiments of this application. Obviously, the described embodiments are some, but not all, of the embodiments of this application. It should be understood that the specific embodiments described herein are only used to explain this application and are not used to limit this application.

[0021] The technical features involved in the various embodiments of this application described below do not conflict with each other and can be combined with each other.

[0022] When an element is described as "connected to" another element, it can be directly connected to the other element, or there can be one or more intermediate elements therebetween.

[0023] The terms "first", "second", etc. in the description and claims of this application are used to distinguish similar objects and are not used to describe a specific order or sequence. It should be understood that such data can be interchanged under appropriate circumstances so that the embodiments of this application can be implemented in an order other than those illustrated or described herein, and the objects distinguished by "first", "second", etc. are usually of the same category and do not limit the number of objects. For example, the first object can be one or multiple.

[0024] In products using an isolation switch converter as an auxiliary power supply, placing the MCU on the secondary side as the main control has certain advantages. However, when detecting the primary input voltage, there are respective problems with the two common existing methods.

[0025] For the method using an isolation chip, although it can achieve the transmission of the primary voltage signal to the secondary MCU, the isolation chip not only occupies a large circuit board area but also significantly increases the cost of the product. This is disadvantageous for product designs that pursue miniaturization and cost control. For example, in some portable devices with limited space, the additional area occupied by the isolation chip may cause difficulties in the overall layout; in mass production, the increased cost of the isolation chip may weaken the price competitiveness of the product in the market.

[0026] As for the method of adding a forward winding on the secondary side of the transformer, although the voltage on the forward winding has a turn ratio relationship with the primary input voltage and can be used to detect the primary voltage, this method will complicate the design of the transformer and the coil winding process. Especially when there are multiple windings on the secondary side of the transformer, the complexity is further exacerbated. This not only increases the design difficulty and time cost but also may lead to a reduction in the yield rate during the production process. For example, in the complex transformer winding process, problems such as inaccurate winding turns and inconsistent distributed capacitance are likely to occur, thus affecting the performance and reliability of the transformer. At the same time, the complex transformer design and manufacturing also increase the cost.

[0027] Based on this, please refer to Figure 1 , Figure 1 which is a structural block diagram of a power supply circuit 100 provided by an embodiment of the present application.

[0028] The power supply circuit 100 provided by the present application includes: a primary input module 10, a transformer 20, a first voltage output module 30, a second voltage output module 40, and a voltage sampling module 50.

[0029] Among them, the primary input module 10 is respectively connected to the power supply 200 and the transformer 20, the first voltage output module 30 is respectively connected to the transformer 20 and the voltage sampling module 50, and the second voltage output module 40 is respectively connected to the transformer 20 and the voltage sampling module 50.

[0030] Specifically, the primary input module 10 is used to obtain the input voltage VCC from the power supply 200 and transmit the input voltage VCC to the transformer 20; the transformer 20 is used to convert the input voltage VCC into a first voltage; the first voltage output module 30 is used to output a first target voltage VDD1 according to the first voltage; the second voltage output module 40 is used to output a second target voltage VIN according to the first voltage; the voltage sampling module 50 is used to collect the first target voltage VDD1 and the second target voltage VIN, and calculate the voltage value of the input voltage VCC according to the first target voltage VDD1 and the second target voltage VIN.

[0031] Among them, the power supply 200 is a DC power supply or an AC power supply.

[0032] Among them, the voltage value of the first voltage is related to the turns ratio of the primary and secondary sides of the transformer 20 and the input voltage VCC. The voltage value of the first target voltage VDD1 is related to the components in the first voltage output module 30. The voltage value of the second target voltage VIN is related to the components in the second voltage output module 40. Here, no specific limitations are made.

[0033] In this embodiment, after the primary input module 10 obtains the input voltage VCC from the power supply 200, it transmits the input voltage VCC to the transformer 20. The transformer 20 transforms the input voltage VCC to obtain a first voltage. The first voltage output module 30 receives the first voltage and converts it into a first target voltage VDD1 and outputs it based on specific circuit characteristics and component parameters. At the same time, the second voltage output module 40 also receives the first voltage, and after its own processing and conversion, outputs a second target voltage VIN. The voltage sampling module 50 respectively samples the first target voltage VDD1 output by the first voltage output module 30 and the second target voltage VIN output by the second voltage output module 40. Then, the voltage sampling module 50 uses the values of the first target voltage VDD1 and the second target voltage VIN collected and their known relationships with the input voltage VCC (such as proportional relationships, functional relationships, etc. determined through circuit design) to perform calculations and analyses, and finally obtains the accurate voltage value of the input voltage VCC. Generally speaking, this circuit realizes the detection and measurement of the input voltage VCC through the voltage transformation of the transformer and the processing, sampling and calculation of each module.

[0034] Please refer to Figure 2 , Figure 2 which is a structural block diagram of the power supply circuit 100 provided in another embodiment of the present application.

[0035] In some embodiments, the transformer 20 is further configured to convert the input voltage VCC into a second voltage, and the power supply circuit 100 further includes a third voltage output module 60.

[0036] Among them, the third voltage output module 60 is connected to the transformer 20.

[0037] Specifically, the third voltage output module 60 is configured to output a third target voltage VDD2 according to the second voltage to provide electrical energy for the load 300.

[0038] Among them, the voltage value of the second voltage is related to the turns ratio of the primary and secondary windings of the transformer 20 and the input voltage VCC. The voltage value of the third target voltage VDD2 is related to the components in the third voltage output module 60. Here, no specific limitations are made.

[0039] Please refer to Figure 3 , Figure 3 which is a schematic circuit diagram of the power supply circuit provided in an embodiment of the present application.

[0040] In some embodiments, as Figure 3 shown, the transformer 20 includes a primary winding Np and a first secondary winding Ns1.

[0041] Among them, the primary winding Np and the first secondary winding Ns1 are coupled through an iron core (not shown in the figure). The same-name end of the primary winding Np is connected to the power supply 200 through the primary input module 10, and the different-name end of the primary winding Np is connected to the equipotential end through the primary input module 10. The same-name end of the first secondary winding Ns1 is connected to the voltage sampling module 50 through the second voltage output module 40, and the different-name end of the first secondary winding Ns1 is connected to the voltage sampling module 50 through the first voltage output module 30.

[0042] Specifically, the primary winding Np is used to generate an alternating magnetic flux in the iron core according to the input voltage VCC. The first secondary winding Ns1 is used to obtain electrical energy from the primary winding Np through the alternating magnetic flux to output a first voltage.

[0043] In some embodiments, the transformer 20 further includes a second secondary winding Ns2. Among them, as Figure 3 shown, the same-name end of the second secondary winding Ns2 is connected to the same-name end of the first secondary winding Ns1. The second secondary winding Ns2 is used to obtain electrical energy from the primary winding Np through the alternating magnetic flux to output a second voltage.

[0044] In some embodiments, the power supply circuit 100 further includes a third voltage output module 60. The third voltage output module 60 is connected to the second secondary winding Ns2. The third voltage output module is used to output a third target voltage VDD2 according to the second voltage to provide electrical energy for the load 300.

[0045] In some embodiments, the first voltage output module 30 includes a diode D3 and a capacitor EC2.

[0046] In some embodiments, the first voltage output module 30 further includes a capacitor C5.

[0047] Among them, the positive electrode of the diode D3 is connected to the different-name end of the first secondary winding Ns1, the negative electrode of the diode D3 is connected to the positive electrode of the capacitor EC2, the first end of the capacitor C5, and the voltage sampling module 50. The negative electrode of the capacitor EC2 and the second end of the capacitor C5 are both connected to the equipotential end.

[0048] In some embodiments, the second voltage output module 40 includes a diode D4 and a capacitor C3.

[0049] Among them, the positive electrode of the diode D4 is connected to the same-name end of the first secondary winding Ns1, the negative electrode of the diode D4 is connected to the first end of the capacitor C3 and the voltage sampling module 50. The second end of the capacitor C3 is connected to the equipotential end.

[0050] In some embodiments, the second voltage output module 40 further includes a resistor R2 and a capacitor C2.

[0051] Among them, the first end of resistor R2 is connected to the first end of capacitor C2 and the opposite-named end of the first secondary winding Ns1, and the second end of resistor R2 is connected to the second end of capacitor C2 and the cathode of diode D4.

[0052] In some embodiments, the voltage sampling module 50 includes resistor R5, resistor R6, resistor R7, resistor R8, and a controller.

[0053] Among them, the first end of resistor R5 is connected to the second voltage output module 40, the second end of resistor R5 is connected to the first end of resistor R6 and the controller, the first end of resistor R7 is connected to the first voltage output module 30, the second end of resistor R7 is connected to the first end of resistor R8 and the controller, and the second ends of resistor R6 and resistor R8 are respectively connected to an equipotential end.

[0054] Specifically, the controller can be an MCU or other device capable of calculating the input voltage VCC.

[0055] In some embodiments, the primary input module 10 includes switching transistor Q1, diode D2, resistor R1, capacitor C1, and capacitor EC1.

[0056] Among them, the anode of diode D1 is connected to the power supply 200, the cathode of diode D1 is connected to the anode of capacitor EC1, the first end of resistor R1, the first end of capacitor C1, and the same-named end of the primary winding Np. The opposite-named end of the primary winding Np is connected to the anode of diode D2 and the second end of switching transistor Q1. The cathode of diode D2 is connected to the second end of resistor R1 and the second end of capacitor C1. The control end of switching transistor Q1 is connected to the second power supply, and the third end of switching transistor Q1 and the cathode of capacitor EC1 are respectively connected to an equipotential end.

[0057] Among them, in this embodiment, switching transistor Q1 is an NMOS transistor. Specifically, the control end of switching transistor Q1 is the gate of the NMOS transistor, the second end of switching transistor Q1 is the drain of the NMOS transistor, and the third end of switching transistor Q1 is the source of the NMOS transistor.

[0058] In addition, switching transistor Q1 can be any controllable switch, for example, an insulated gate bipolar transistor (IGBT) device, an integrated gate-commutated thyristor (IGCT) device, a gate turn-off thyristor (GTO) device, a silicon controlled rectifier (SCR) device, a junction gate field effect transistor (JFET) device, etc.

[0059] Among them, the second power supply 200 is used to drive switching transistor Q1 to conduct and turn off. Specifically, the second power supply 200 can be a power supply chip.

[0060] In some embodiments, the third voltage output module 60 includes diode D5, diode D6, resistor R4, capacitor EC3, and capacitor C4.

[0061] Among them, the positive electrode of the diode D5 is connected to the opposite-named end of the second secondary winding Ns2, the negative electrode of the diode D5 is connected to the positive electrode of the capacitor EC3, the first end of the capacitor C4, and the first end of the resistor R4. The second end of the resistor R4, the second end of the capacitor C4, the negative electrode of the capacitor EC3, and the positive electrode of the diode D6 are connected and connected to the equipotential end, and the negative electrode of the diode D6 is connected to the same-named end of the second secondary winding Ns2.

[0062] The following combines Figure 3 to illustrate the working principle of the power supply circuit 100 in the embodiment of the present application.

[0063] It should be noted that the switching transistor Q1 switches between conduction and cut-off at a certain frequency.

[0064] When the switching transistor Q1 is conducting, the voltage on the primary winding Np of the transformer T1 is VNp and the polarity is positive at the top and negative at the bottom. According to the direction of the same-named ends of the transformer, the first secondary winding Ns1 obtains a voltage with positive at the bottom and negative at the top (i.e., the first voltage). At this time, the diode D4 is conducting, and the diodes D3, D5, and D6 are all cut off. The second target voltage VIN is output from the same-named end of the first secondary winding Ns1. After the second target voltage VIN is divided by the resistors R5 and R6, the voltage at point A1 is sent into the MCU (controller). And, the capacitor EC2 discharges to generate the first target voltage VDD1. At the same time, after the first target voltage VDD1 is divided by the resistors R7 and R8, the voltage at point A2 is sent into the MCU (controller).

[0065] In this embodiment, assume that the forward conduction voltage drops of the diodes D1, D3, and D4 are Vd, the turns ratio Np / Ns1 = k, R6 / (R5 + R6) = n, and R8 / (R7 + R8) = m. Then, the voltage value VIN of the second target voltage VIN = UA1 / n, where UA1 is Figure 3 the voltage value at point A1 in Figure 3 . At the same time, the voltage value VDD1 of the first target voltage VDD1 = UA2 / m, where UA2 is

[0066] At this time, it can be known that the voltage value of the first voltage on the first secondary winding Ns1 is:

[0067] V Ns1 =(VIN + V d )-(V DD1 + V d ) = U A1 / n - U A2 / m;

[0068] Since the voltage ratio on the primary and secondary windings of transformer T1 is equal to the turn ratio, that is, the voltage value on the primary winding Np is:

[0069] V Np = k * V NS1 ;

[0070] It can be obtained that the voltage value of the input voltage VCC is:

[0071] VCC = k * (U A1 / n - U A2 / m) + V d .

[0072] When the switching transistor Q1 is turned off, the voltage polarity on the primary winding Np of the transformer T1 is negative at the top and positive at the bottom. According to the direction of the same-name terminals of the transformer, the voltage polarities on the first secondary winding NS1 and the second secondary winding Ns2 are negative at the bottom and positive at the top. At this time, the diodes D3, D5, and D6 are conducting, and the diode D4 is cut off. At this time, the first secondary winding NS1 and the second secondary winding NS2 respectively output the first target voltage VDD1 and the second target voltage VDD2 to the backend load 300.

[0073] In the embodiment of the present application, the voltage input to the primary side of the power supply circuit 100 is a DC voltage, that is, the input DC voltage can be detected. Moreover, calculating the input voltage using one of the secondary windings will not affect the output voltages of other windings.

[0074] In the power supply circuit 100 of the embodiment of the present application, first, by collecting and using the first target voltage and the second target voltage to calculate the voltage value of the input voltage, multiple voltage information can be comprehensively analyzed and calculated, reducing the error that may be brought by single voltage measurement, thereby significantly improving the accuracy and precision of voltage detection. Compared with some complex multi-module series or parallel voltage detection schemes, this centralized power supply circuit structure is relatively simple. Secondly, through reasonable module division of labor and collaborative work, unnecessary circuit elements and connections are reduced, thereby simplifying the circuit design to a certain extent and reducing the hardware cost and design complexity. Moreover, the compact circuit design and fewer component numbers contribute to the integration and miniaturization of the system. This is particularly important for electronic devices with limited space, such as portable devices, micro control systems, etc., which can reduce the volume of the device without sacrificing performance.

[0075] The embodiment of the present application also provides a power supply device, including the power supply circuit 100 as described above.

[0076] This power supply device is connected to the power supply and is used to detect the voltage value of the input voltage of the power supply.

[0077] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than limiting it; under the idea of the present invention, the technical features in the above embodiments or different embodiments can also be combined, and there are many other variations in different aspects of the present invention as described above. For the sake of brevity, they are not provided in detail; although the present invention 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 make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A power supply circuit, characterized in that, Comprising: A primary input module, a transformer, a first voltage output module, a second voltage output module, and a voltage sampling module; The primary input module is respectively connected to a power supply and the transformer, the first voltage output module is respectively connected to the transformer and the voltage sampling module, and the second voltage output module is respectively connected to the transformer and the voltage sampling module; The primary input module is configured to obtain an input voltage from the power supply and transmit the input voltage to the transformer; The transformer is configured to convert the input voltage into a first voltage; The first voltage output module is configured to output a first target voltage according to the first voltage; The second voltage output module is configured to output a second target voltage according to the first voltage; The voltage sampling module is configured to collect the first target voltage and the second target voltage and calculate the voltage value of the input voltage according to the first target voltage and the second target voltage.

2. The power supply circuit according to claim 1, characterized in that, The transformer includes a primary winding and a first secondary winding; The same-name end of the primary winding is connected to the power supply through the primary input module, the different-name end of the primary winding is connected to an equipotential end through the primary input module, the same-name end of the first secondary winding is connected to the voltage sampling module through the second voltage output module, and the different-name end of the first secondary winding is connected to the voltage sampling module through the first voltage output module; The primary winding is configured to generate an alternating magnetic flux according to the input voltage; The first secondary winding is configured to obtain electrical energy from the primary winding through the alternating magnetic flux to output the first voltage.

3. The power supply circuit according to claim 2, wherein The first voltage output module includes a diode D3 and a capacitor EC2; The positive electrode of the diode D3 is connected to the different-name end of the first secondary winding, the negative electrode of the diode D3 is connected to both the positive electrode of the capacitor EC2 and the voltage sampling module, and the negative electrode of the capacitor EC2 is connected to the equipotential end.

4. The power supply circuit according to claim 2, wherein The second voltage output module includes a diode D4 and a capacitor C3; The positive electrode of the diode D4 is connected to the same-name end of the first secondary winding, the negative electrode of the diode D4 is connected to both the first end of the capacitor C3 and the voltage sampling module, and the second end of the capacitor C3 is connected to the equipotential end.

5. The power supply circuit according to claim 2, wherein The voltage sampling module includes a resistor R5, a resistor R6, a resistor R7, a resistor R8, and a controller; The first end of the resistor R5 is connected to the second voltage output module, the second end of the resistor R5 is connected to both the first end of the resistor R6 and the controller, the first end of the resistor R7 is connected to the first voltage output module, the second end of the resistor R7 is connected to both the first end of the resistor R8 and the controller, and the second ends of the resistor R6 and the resistor R8 are respectively connected to the equipotential end.

6. The power supply circuit according to claim 2, wherein The primary input module includes a switching transistor Q1, a diode D2, a resistor R1, a capacitor C1, and a capacitor EC1; The positive electrode of the diode D1 is connected to the power supply, the negative electrode of the diode D1 is connected to the positive electrode of the capacitor EC1, the first end of the resistor R1, the first end of the capacitor C1 and the homonymous end of the primary winding, the non-homonymous end of the primary winding is connected to the positive electrode of the diode D2 and the second end of the switching transistor Q1, the negative electrode of the diode D2 is connected to the second end of the resistor R1 and the second end of the capacitor C1, the control end of the switching transistor Q1 is connected to the second power supply, and the third end of the switching transistor Q1 and the negative electrode of the capacitor EC1 are respectively connected to the equipotential end.

7. The power supply circuit according to any one of claims 2-6, characterized in that, The transformer further includes a second secondary winding; The homonymous end of the second secondary winding is connected to the homonymous end of the first secondary winding; The second secondary winding is used to obtain electrical energy from the primary winding through the alternating magnetic flux to output a second voltage.

8. The power supply circuit according to claim 7, characterized in that, The power supply circuit further includes a third voltage output module; The third voltage output module is connected to the second secondary winding; The third voltage output module is used to output a third target voltage according to the second voltage to provide electrical energy for the load.

9. The power supply circuit according to claim 8, wherein, The third voltage output module includes a diode D5, a diode D6, a resistor R4, a capacitor EC3 and a capacitor C4; The positive electrode of the diode D5 is connected to the non-homonymous end of the second secondary winding, the negative electrode of the diode D5 is connected to the positive electrode of the capacitor EC3, the first end of the capacitor C4 and the first end of the resistor R4, the second end of the resistor R4, the second end of the capacitor C4, the negative electrode of the capacitor EC3 and the positive electrode of the diode D6 are connected and connected to the equipotential end, and the negative electrode of the diode D6 is connected to the homonymous end of the second secondary winding.

10. A power supply device, characterized in that, Comprising the power supply circuit according to any one of claims 1-9.

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