Wide voltage input automatic switching circuit

Abstract

The utility model relates to a wide voltage input automatic switching circuit, the input end of wide control circuit is externally connected with power supply, the output end of wide control circuit is connected with the control end of wide constant voltage circuit, the power input end of wide constant voltage circuit is externally connected with power supply, the output end of wide constant voltage circuit is connected with load after passing through the isolation anti -backfill circuit, the input end of low control circuit is connected with the output end of wide constant voltage circuit, the power input end of low control circuit is externally connected with power supply, the output end of low control circuit is connected with the control end of low switch circuit, the power input end of low switch circuit is externally connected with power supply, the output end of low switch circuit is connected with load, the utility model discloses through automatic switching low voltage low amplitude channel and high voltage wide channel, make product can adapt more extensive voltage range, solved the equipment of market different voltage output to cause the problem of inadaptation.

Description

Technical Field

[0001] This utility model relates to an automatic switching circuit, and more particularly to a wide-range voltage input automatic switching circuit, belonging to the field of power supply circuit technology. Background Technology

[0002] With the diversification of electronic devices, different devices have different power supply voltage requirements. In order to adapt to different DC voltage output power supplies on the market, traditional electronic devices such as cooling fans need to design a variety of power adapter solutions. Therefore, in order to achieve the purpose of adaptation, the mechanism is often quite complex, which will increase the production cost. Moreover, the current power adapter circuit also determines its scope of use. Once it is incompatible, it cannot be used, thus limiting the versatility of the product and reducing its scope of use.

[0003] Therefore, developing a circuit that can automatically switch between wide voltage input and output a stable low voltage is of great significance for improving product versatility and reducing costs. Utility Model Content

[0004] The purpose of this invention is to provide a wide-range voltage input automatic switching circuit. By automatically switching between low-voltage and high-voltage power supply paths, the product can adapt to a wider voltage range, solving the problem of equipment incompatibility caused by different voltage outputs on the market. It eliminates the need to design multiple power supply adapters for different voltage devices, reduces costs, improves production efficiency, and makes the product suitable for more types of power supply environments, thereby enhancing the product's versatility and market competitiveness.

[0005] To achieve the above objectives, the main technical solutions adopted by this utility model include:

[0006] A wide-range voltage input automatic switching circuit includes: a wide-range control circuit, a wide-range constant voltage circuit, an isolation anti-backflow circuit, a low-range control circuit, and a low-range switching circuit;

[0007] The input terminal of the wide-range control circuit is connected to an external power supply, the output terminal of the wide-range control circuit is connected to the control terminal of the wide-range constant voltage circuit, the power input terminal of the wide-range constant voltage circuit is connected to an external power supply, and the output terminal of the wide-range constant voltage circuit is connected to the load after passing through the isolation anti-backflow circuit.

[0008] The input terminal of the low-amplitude control circuit is connected to the output terminal of the wide-amplitude constant voltage circuit; the power input terminal of the low-amplitude control circuit is connected to an external power supply; the output terminal of the low-amplitude control circuit is connected to the control terminal of the low-amplitude switching circuit; the power input terminal of the low-amplitude switching circuit is connected to an external power supply; and the output terminal of the low-amplitude switching circuit is connected to a load.

[0009] In one embodiment, the wide-range constant voltage circuit includes a DC-DC step-down unit U1;

[0010] The wide-range control circuit includes resistors R8 and R9, which form a voltage divider circuit. The input of the voltage divider circuit is connected to an external power supply, and the output is connected to the enable terminal EN of the DC-DC step-down unit U1. The power input terminal IN of the DC-DC step-down unit U1 is connected to an external power supply.

[0011] In one embodiment, the wide-range constant voltage circuit further includes: resistors R6, R7, and R10, capacitor C6, and inductor L1; the BS pin of the DC-DC step-down unit U1 is connected in series with resistor R10 and capacitor C6 and then connected to the LX pin of the DC-DC step-down unit U1; the LX pin of the DC-DC step-down unit U1 is also connected in series with inductor L1 and serves as the output terminal of the wide-range constant voltage circuit.

[0012] The resistors R6 and R7 form a voltage sampling circuit that samples the voltage at the output of the wide-range constant voltage circuit and feeds it back to the FB pin of the DC-DC step-down unit U1.

[0013] In one embodiment, the low-amplitude control circuit includes: resistors R1, R2, R3, R4, R5, and R6; an NPN transistor Q1; and a PNP transistor Q2. Resistors R1 and R2 form a voltage sampling circuit that samples the output of the wide-range constant-voltage circuit and connects it to the base of the NPN transistor Q1. The emitter of the NPN transistor Q1 is grounded, and its collector is connected in series with resistor R3 and then to an external power supply. The collector of the NPN transistor Q1 is also connected in series with resistor R6 and then to the base of the PNP transistor Q2. The emitter of the PNP transistor Q2 is connected in series with resistor R4 and then to an external power supply. The collector of the PNP transistor Q2 is connected in series with resistor R5 and then grounded. The collector of the PNP transistor Q2 also serves as the output of the low-amplitude control circuit and is connected to the control terminal of the low-amplitude switching circuit.

[0014] In one embodiment, the low-amplitude switching circuit includes: capacitor C3, PMOS transistor Q3, and PMOS transistor Q4; the gates of PMOS transistor Q3 and PMOS transistor Q4 are both connected to the output terminal of the low-amplitude control circuit; the gate of PMOS transistor Q3 is also connected to ground via series with capacitor C3; the source of PMOS transistor Q3 is connected to the source of PMOS transistor Q4; the drain of PMOS transistor Q3 is connected to an external power supply; and the drain of PMOS transistor Q4 serves as the output terminal of the low-amplitude switching circuit, connected to a load.

[0015] In one embodiment, the isolation anti-backflow circuit includes a diode D2, and the output terminal of the wide-range constant voltage circuit is connected in series with the diode D2 and then connected to the load.

[0016] In one embodiment, the wide-range voltage input automatic switching circuit further includes an isolation input circuit, through which the power supply is connected to the power input terminal of the low-range control circuit and the power input terminal of the low-range control circuit, respectively. Specifically, the isolation input circuit includes a diode D1.

[0017] In one embodiment, the wide-range voltage input automatic switching circuit further includes a power supply filtering circuit. The power supply, after being filtered by the power supply filtering circuit, supplies power to the wide-range control circuit, the wide-range constant voltage circuit, the low-range control circuit, and the low-range switching circuit. Specifically, the power supply filtering circuit includes a capacitor C1, one end of which is connected to the external power supply, and the other end is grounded.

[0018] In one embodiment, the wide-range voltage input automatic switching circuit further includes a constant-voltage output filter circuit. The output of the wide-range constant-voltage circuit is filtered by the constant-voltage output filter circuit and then connected to the load. The constant-voltage output filter circuit includes a capacitor C2. One end of the capacitor C2 is connected to the output of the wide-range constant-voltage circuit, and the other end is grounded.

[0019] In one embodiment, the wide-range voltage input automatic switching circuit further includes a first output filter circuit, and the output of the low-range switching circuit is filtered by the first output filter circuit before being connected to the load. Specifically, the first output filter circuit includes capacitors C4 and C5, which are connected in parallel.

[0020] This utility model has at least the following beneficial effects:

[0021] By automatically switching between low-voltage and high-voltage power supply paths, the product can adapt to a wider range of voltages, solving the problem of equipment incompatibility caused by different voltage outputs on the market. It eliminates the need to design multiple power adapter solutions for different voltage devices, reducing costs, improving production efficiency, and enabling the product to be used in more types of power environments, thereby enhancing its versatility and market competitiveness. Attached Figure Description

[0022] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments of this application and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings:

[0023] Figure 1 This is a schematic diagram of Embodiment 1 of the present utility model;

[0024] Figure 2 This is a schematic diagram of Embodiment 2 of the present invention;

[0025] Figure 3 This is a circuit diagram of Embodiment 2 of the present invention;

[0026] Among them, 100 is the wide-range control circuit; 200 is the wide-range constant voltage circuit; 300 is the isolation anti-backflow circuit; 400 is the low-range control circuit; 500 is the low-range switching circuit; 600 is the isolation input circuit; 700 is the power supply filter circuit; 800 is the constant voltage output filter circuit; 900 is the first output filter circuit; 10 is the power supply; and 20 is the load. Detailed Implementation

[0027] The following will describe in detail the implementation of this application with reference to the accompanying drawings and embodiments, so that the implementation process of how this application uses technical means to solve technical problems and achieve technical effects can be fully understood and implemented accordingly.

[0028] Example 1

[0029] like Figure 1 As shown, a wide-range voltage input automatic switching circuit includes: a wide-range control circuit 100, a wide-range constant voltage circuit 200, an isolation anti-backflow circuit 300, a low-range control circuit 400, and a low-range switching circuit 500. The input terminal of the wide-range control circuit 100 is connected to an external power supply 10, and the output terminal of the wide-range control circuit 100 is connected to the control terminal of the wide-range constant voltage circuit 200. The power input terminal of the wide-range constant voltage circuit 200 is also connected to the external power supply 10, and the output terminal of the wide-range constant voltage circuit 200 is connected to a load 20 after passing through the isolation anti-backflow circuit 300.

[0030] The input terminal of the low-amplitude control circuit is connected to the output terminal of the wide-amplitude constant voltage circuit; the power input terminal of the low-amplitude control circuit is connected to an external power supply; the output terminal of the low-amplitude control circuit is connected to the control terminal of the low-amplitude switching circuit; the power input terminal of the low-amplitude switching circuit is connected to an external power supply; and the output terminal of the low-amplitude switching circuit is connected to the load.

[0031] Example 2

[0032] like Figure 2 As shown, a wide-range voltage input automatic switching circuit includes: a wide-range control circuit 100, a wide-range constant voltage circuit 200, an isolation anti-backflow circuit 300, a low-range control circuit 400, a low-range switching circuit 500, an isolation input circuit 600, a power supply filter circuit 700, a constant voltage output filter circuit 800, and a first output filter circuit 900.

[0033] like Figure 2As shown, the power supply 10, after being filtered by the power supply filter circuit 700, supplies power to the wide-range control circuit 100 and the wide-range constant voltage circuit 200. The power supply 10, after being filtered by the power supply filter circuit 700 and isolated by the isolation input circuit 600, supplies power to the low-range control circuit 400 and the low-range switching circuit 500, respectively. Figure 3 As shown, the power supply filter circuit 700 includes a capacitor C1, one end of which is connected to an external power supply 10, and the other end is grounded. Of course, in other embodiments, the power supply filter circuit 700 can be implemented by two or more capacitors connected in parallel. The isolation input circuit 600 includes a diode D1. The anode of diode D1 is connected to the output terminal of the power supply filter circuit 700, and the cathode is connected to the input terminal of the low-amplitude control circuit 400 and the input terminal of the low-amplitude switching circuit 500.

[0034] like Figure 2 As shown, the output terminal of the wide-range control circuit 100 is connected to the control terminal of the wide-range constant voltage circuit 200. The output terminal of the wide-range constant voltage circuit 200 is filtered sequentially by the constant voltage output filter circuit 800, isolated by the isolation anti-backflow circuit 300, and filtered by the first output filter circuit 900 before being connected to the load 20. The input terminal of the low-range control circuit 400 is connected to the output terminal of the wide-range constant voltage circuit 200; the output terminal of the low-range control circuit 400 is connected to the control terminal of the low-range switching circuit 500; the output terminal of the low-range switching circuit 500 is filtered by the first output filter circuit 900 before being connected to the load 20.

[0035] like Figure 3 As shown, the isolation anti-backflow circuit 300 includes a diode D2, and the output terminal of the wide-range constant voltage circuit 200 is connected to the load 20 after the diode D2 is connected in series. The constant voltage output filter circuit 800 includes a capacitor C2. Of course, in other embodiments, the constant voltage output filter circuit 800 can be implemented by two or more capacitors connected in parallel.

[0036] like Figure 3 As shown, the wide-range constant voltage circuit 200 includes a DC-DC step-down unit U1. The wide-range control circuit 100 includes resistors R8 and R9, which form a voltage divider circuit. The input terminal of the voltage divider circuit is connected to the output terminal of the power supply filter circuit 700, and the output terminal of the voltage divider circuit is connected to the enable terminal EN of the DC-DC step-down unit U1. The power input terminal IN of the DC-DC step-down unit U1 is connected to the output terminal of the power supply filter circuit 700.

[0037] like Figure 3As shown, the wide-range constant voltage circuit 200 also includes resistors R6, R7, and R10, capacitor C6, and inductor L1. The BS pin of the DC-DC step-down unit U1 is connected to the LX pin of the DC-DC step-down unit U1 via resistor R10 and capacitor C6 in series. The LX pin of the DC-DC step-down unit U1 is also connected to the LX pin via inductor L1 in series, serving as the output terminal of the wide-range constant voltage circuit 200 and connected to the input terminal of the constant voltage output filter circuit 800. Resistors R6 and R7 form a voltage sampling circuit to sample the voltage at the output terminal of the wide-range constant voltage circuit 200 and feed it back to the FB pin of the DC-DC step-down unit U1. It should be noted that the resistor R10, capacitor C6, and inductor L1 of the wide-range constant voltage circuit 200 can form a high-pass filter. The capacitor C6 presents a high impedance to low-frequency signals, while the resistor R10 restricts the passage of low-frequency signals, thereby filtering out low-frequency noise and retaining high-frequency signals. The series combination of capacitor C6 and resistor R10 can be used to adjust the input or output impedance of the circuit to match it with the preceding and following stage circuits, thereby reducing signal reflection and power loss.

[0038] like Figure 3 As shown, the low-amplitude control circuit 400 includes: resistors R1, R2, R3, R4, R5, and R6; an NPN transistor Q1; and a PNP transistor Q2. Resistors R1 and R2 form a voltage sampling circuit that samples the voltage at the output of the constant-voltage output filter circuit 800 and connects it to the base of the NPN transistor Q1. The emitter of the NPN transistor Q1 is grounded, and its collector is connected in series with resistor R3 to the cathode of diode D1. The collector of the NPN transistor Q1 is also connected in series with resistor R6 to the base of the PNP transistor Q2, and the emitter of the PNP transistor Q2 is connected in series with resistor R4 to the cathode of diode D1. The collector of the PNP transistor Q2 is connected in series with resistor R5 to ground. The collector of the PNP transistor Q2 also serves as the output of the low-amplitude control circuit 400 and is connected to the control terminal of the low-amplitude switching circuit 500.

[0039] like Figure 3 As shown, the low-amplitude switching circuit 500 includes: capacitor C3, PMOS transistor Q3, and PMOS transistor Q4; the gates of PMOS transistor Q3 and PMOS transistor Q4 are both connected to the output terminal of the low-amplitude control circuit, that is, the gates of PMOS transistor Q3 and PMOS transistor Q4 are both connected to the collector of PNP transistor Q2; the gate of PMOS transistor Q3 is also connected to ground after being connected in series with capacitor C3; the source of PMOS transistor Q3 is connected to the source of PMOS transistor Q4; the drain of PMOS transistor Q3 is connected to the negative terminal of diode D1; the drain of PMOS transistor Q4 serves as the output terminal of the low-amplitude switching circuit 500 and is connected to the input terminal of the first output filter circuit 900.

[0040] like Figure 3As shown, the first output filter circuit 900 includes capacitors C4 and C5, which are connected in parallel. Of course, in other embodiments, the first output filter circuit 900 may also include only one capacitor or three or more capacitors connected in parallel.

[0041] Combination Figure 1 , Figure 2 and Figure 3 The working principle of the wide-range voltage input automatic switching circuit of this utility model is explained as follows:

[0042] When the supply voltage of power supply 10 is 5V or lower (the supply voltage is generally between 2V and 5V (inclusive)), the power supply, after being filtered by capacitor C1, supplies power to the IN pin of the DC-DC step-down unit U1. Simultaneously, after being divided by resistors R8 and R9, the power supply supplies power to the EN pin of the DC-DC step-down unit U1. At this time, the voltage divided by resistors R8 and R9 is lower than the threshold voltage of the DC-DC step-down unit U1, therefore the DC-DC step-down unit U1 does not work; thus, the wide-range constant voltage circuit does not work. At the same time, the power supply, after being filtered by capacitor C1, supplies power to the positive terminal of diode D1, and then to the drain of resistors R3 and R4 and the PMOS transistor Q3 via diode D1. Due to the wide-range constant voltage circuit... The amplitude constant voltage circuit is not working, so the input terminal of resistor R1 is at a low voltage. At this time, NPN transistor Q1 is cut off and PNP transistor Q2 is turned on. The voltage flows through resistor R4 and the emitter of PNP transistor Q2 to the collector of PNP transistor Q2. The voltage is then divided by resistor R5 and supplied to the gate of PMOS transistor Q3 and the gate of PMOS transistor Q4. At this time, both PMOS transistors Q3 and Q4 are turned on and output voltage to supply power to the load. It should be noted that when the low amplitude control circuit 400 and the low amplitude switching circuit 500 are working, the output voltage of the low amplitude switching circuit 500 forms a following relationship with the supply voltage of the power supply 10 (but this following relationship is not a 1:1 following ratio).

[0043] When the supply voltage of power supply 10 is higher than 5V (the supply voltage is generally between 5V (excluding 5V) and 48V), the power supply is filtered by capacitor C1 and then supplied to the IN pin of DC-DC step-down unit U1. At the same time, it is supplied to the EN pin of DC-DC step-down unit U1 after being divided by resistors R8 and R9. At this time, the voltage of resistors R8 and R9 is higher than the threshold voltage of DC-DC step-down unit U1, so DC-DC step-down unit U1 works. The output voltage of DC-DC step-down unit U1 is output through the internal circuit and external circuit (resistor R10, capacitor C6 and inductor L1). At this time, the voltage is divided by resistors R6 and R7 and then fed back to the FB pin of DC-DC step-down unit U1, thereby locking the output voltage to 4.5V or the preset voltage value. This 4.5V voltage or the preset voltage value is filtered by capacitor C2, isolated by diode D2 to prevent backflow, and then filtered by capacitors C5 and C4 before supplying power to the load.

[0044] When the supply voltage of power supply 10 is higher than 5V, the supply voltage is supplied to the drain of PMOS transistor Q3 through diode D1. Because the wide-range constant voltage circuit 200 outputs 4.5V or a preset voltage value, this 4.5V or preset voltage is filtered by capacitor C1 and then divided by resistors R1 and R2 before being supplied to the base of NPN transistor Q1. NPN transistor Q1 is turned on. At this time, the voltage is pulled down by resistor R3 and NPN transistor Q1, thus turning off PNP transistor Q2. Consequently, PMOS transistors Q3 and Q4 are also turned off. That is, the low-range switching circuit is not turned on, and the voltage can only supply power to the load through the wide-range constant voltage circuit, thereby realizing automatic switching.

[0045] This invention enables the product to adapt to a wider range of voltages by automatically switching between low-voltage, low-amplitude channels and high-voltage, wide-amplitude channels, thus solving the problem of equipment incompatibility caused by different voltage outputs on the market.

[0046] Therefore, this utility model eliminates the need to design multiple power adapter schemes for devices with different voltages, reducing costs and improving production efficiency. With the addition of this circuit, the product can be applied to more types of power environments, improving the product's versatility and market competitiveness.

[0047] If certain terms are used in the specification and claims to refer to specific components, those skilled in the art will understand that hardware manufacturers may use different names to refer to the same component. This specification and claims do not distinguish components based on differences in name, but rather on differences in function. The term "comprising" as used throughout the specification and claims is an open-ended term and should be interpreted as "comprising but not limited to." "Approximately" means that within an acceptable margin of error, those skilled in the art can solve the technical problem and substantially achieve the technical effect within a certain margin of error.

[0048] It should be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a product or system comprising a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a product or system. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the product or system that includes that element.

[0049] The foregoing description illustrates and describes several preferred embodiments of the present invention. However, as previously stated, it should be understood that the present invention is not limited to the forms disclosed herein and should not be construed as excluding other embodiments. It can be used in various other combinations, modifications, and environments, and can be altered within the scope of the inventive concept described herein through the foregoing teachings or techniques or knowledge in related fields. Any modifications and variations made by those skilled in the art that do not depart from the spirit and scope of the present invention should be within the protection scope of the appended claims.

Claims

1. A wide-range voltage input automatic switching circuit, characterized in that, include: Wide-range control circuit, wide-range constant voltage circuit, isolation anti-backflow circuit, low-range control circuit, low-range switching circuit; The input terminal of the wide-range control circuit is connected to an external power supply, the output terminal of the wide-range control circuit is connected to the control terminal of the wide-range constant voltage circuit, the power input terminal of the wide-range constant voltage circuit is connected to an external power supply, and the output terminal of the wide-range constant voltage circuit is connected to the load after passing through the isolation anti-backflow circuit. The input terminal of the low-amplitude control circuit is connected to the output terminal of the wide-amplitude constant voltage circuit, and the power input terminal of the low-amplitude control circuit is connected to an external power supply; the output terminal of the low-amplitude control circuit is connected to the control terminal of the low-amplitude switching circuit. The power input terminal of the low-amplitude switching circuit is connected to an external power supply; the output terminal of the low-amplitude switching circuit is connected to a load.

2. The wide-range voltage input automatic switching circuit according to claim 1, characterized in that, The wide-range constant voltage circuit includes a DC-DC step-down unit U1; The wide-range control circuit includes resistors R8 and R9, which form a voltage divider circuit. The input of the voltage divider circuit is connected to an external power supply, and the output is connected to the enable terminal EN of the DC-DC step-down unit U1. The power input terminal IN of the DC-DC step-down unit U1 is connected to an external power supply.

3. The wide-range voltage input automatic switching circuit according to claim 2, characterized in that, The wide-range constant voltage circuit also includes: resistors R6, R7, and R10, capacitor C6, and inductor L1; the BS pin of the DC-DC step-down unit U1 is connected in series with resistor R10 and capacitor C6 and then connected to the LX pin of the DC-DC step-down unit U1; the LX pin of the DC-DC step-down unit U1 is also connected in series with inductor L1 and serves as the output terminal of the wide-range constant voltage circuit. The resistors R6 and R7 form a voltage sampling circuit that samples the voltage at the output of the wide-range constant voltage circuit and feeds it back to the FB pin of the DC-DC step-down unit U1.

4. The wide-range voltage input automatic switching circuit according to claim 1, characterized in that, The low-amplitude control circuit includes: resistors R1, R2, R3, R4, R5, and R6; an NPN transistor Q1; and a PNP transistor Q2. Resistors R1 and R2 form a voltage sampling circuit that samples the output voltage of the wide-range constant-voltage circuit and connects it to the base of the NPN transistor Q1. The emitter of the NPN transistor Q1 is grounded, and its collector is connected in series with resistor R3 and then to an external power supply. The collector of the NPN transistor Q1 is also connected in series with resistor R6 and then to the base of the PNP transistor Q2. The emitter of the PNP transistor Q2 is connected in series with resistor R4 and then to an external power supply. The collector of the PNP transistor Q2 is connected in series with resistor R5 and then grounded. The collector of the PNP transistor Q2 also serves as the output of the low-amplitude control circuit and is connected to the control terminal of the low-amplitude switching circuit.

5. The wide-range voltage input automatic switching circuit according to claim 4, characterized in that, The low-amplitude switching circuit includes: capacitor C3, PMOS transistor Q3, and PMOS transistor Q4; the gates of PMOS transistor Q3 and PMOS transistor Q4 are both connected to the output terminal of the low-amplitude control circuit; the gate of PMOS transistor Q3 is also connected to ground via series with capacitor C3; the source of PMOS transistor Q3 is connected to the source of PMOS transistor Q4; the drain of PMOS transistor Q3 is connected to an external power supply; the drain of PMOS transistor Q4 serves as the output terminal of the low-amplitude switching circuit and is connected to the load.

6. The wide-range voltage input automatic switching circuit according to claim 1, characterized in that, The isolation anti-backflow circuit includes a diode D2, and the output terminal of the wide-range constant voltage circuit is connected in series with the diode D2 and then connected to the load.

7. The wide-range voltage input automatic switching circuit according to claim 1, characterized in that, It also includes an isolation input circuit, through which the power supply is connected to the power input terminal of the low-amplitude control circuit and the power input terminal of the low-amplitude control circuit, respectively.

8. The wide-range voltage input automatic switching circuit according to claim 1, characterized in that, It also includes a power supply filtering circuit, through which the power supply is filtered to supply power to the wide-range control circuit, the wide-range constant voltage circuit, the low-range control circuit, and the low-range switching circuit.

9. The wide-range voltage input automatic switching circuit according to claim 1, characterized in that, It also includes a constant voltage output filter circuit, and the output terminal of the wide-range constant voltage circuit is connected to the load after being filtered by the constant voltage output filter circuit.

10. The wide-range voltage input automatic switching circuit according to claim 1, characterized in that, It also includes a first output filter circuit, and the output terminal of the low-amplitude switching circuit is filtered by the first output filter circuit and then connected to the load.

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