Power supply circuit

By designing power supply circuits of multiple voltage conversion circuits, the complexity of power supply circuits caused by equipment diversity in facial care instruments is solved, and the effect of reducing design costs and simplifying the circuit structure is achieved.

CN222464422UActive Publication Date: 2025-02-11深圳艾摩米智能科技有限公司
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Patent Information

Application Number
CN202420183328.0
Authority / Receiving Office
CN · China
Patent Type
Utility models(China)
Current Assignee / Owner
Filing Date
2024-01-24
Publication Date
2025-02-11
Estimated Expiration
2034-01-24

AI Technical Summary

Technical Problem

In the prior art, there are too many equipment in facial care instruments, and the power supply voltage required by each equipment is different, resulting in a complex structure of the power supply circuit and a large number of circuit components, which increases the design cost.

Method used

A power supply circuit including multiple voltage conversion circuits is designed, and the voltage provided by the external power supply is gradually converted into the voltage required by different devices through the first voltage conversion circuit, the second voltage conversion circuit, the third voltage conversion circuit, etc., and The circuit components are protected by a protection circuit.

Benefits of technology

The working needs of different equipment can be met through a simple circuit structure, reducing the design cost of power supply circuits and simplifying the circuit structure.

✦ Generated by Eureka AI based on patent content.

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Patent Text Reader

Abstract

The input end of the first voltage conversion circuit is connected with an external power supply, and the output end of the first voltage conversion circuit is connected with the input end of a second voltage conversion circuit and first equipment. The output end of the second voltage conversion circuit is connected with second equipment, and the second voltage conversion circuit is used for receiving the second voltage; the input end of the third voltage conversion circuit is connected with the external power supply, and the output end of the third voltage conversion circuit is connected with third equipment and the input end of the fourth voltage conversion circuit; the output end of the fourth voltage conversion circuit is connected with fourth equipment and the input end of the fifth voltage conversion circuit; and the output end of the fifth voltage conversion circuit is connected with fifth equipment. The working requirements of different devices can be met through a simple circuit structure, and the design cost of the power supply circuit is reduced.
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Description

Technical Field

[0001] The utility model relates to the technical field of power supply, in particular to a power supply circuit. Background Art

[0002] A power supply circuit is a circuit used to provide different power supply voltages for devices. In the prior art, when there are too many devices in a facial care instrument and each device requires a different power supply voltage, the prior art often sets an independent power supply circuit for each device to meet the normal power supply requirements of each device, resulting in a complex structure of the power supply circuit and numerous circuit elements, which increases the design cost of the power supply circuit. Utility Model Content

[0003] Based on this, it is necessary to propose a power supply circuit to address the above problems.

[0004] A power supply circuit, comprising:

[0005] A first voltage conversion circuit, whose input end is connected to an external power supply, and whose output end is connected to an input end of a second voltage conversion circuit and a first device, for receiving a first voltage provided by the external power supply, and converting the first voltage into a second voltage and outputting the converted voltage to the external power supply and the second voltage conversion circuit;

[0006] The second voltage conversion circuit has an output end connected to the second device, and is used to receive the second voltage, and convert the second voltage into a third voltage and then output it to the second device;

[0007] a third voltage conversion circuit, whose input end is connected to the external power supply, and whose output end is connected to the input end of the third device and the fourth voltage conversion circuit, and is used to receive the first voltage provided by the external power supply, and convert the first voltage into a fourth voltage and output it to the third device and the fourth voltage conversion circuit;

[0008] The fourth voltage conversion circuit has an output end connected to the fourth device link and the input end of the fifth voltage conversion circuit, and is used to receive the fourth voltage, and convert the fourth voltage into a fifth voltage and output it to the fourth device link and the fifth voltage conversion circuit;

[0009] The fifth voltage conversion circuit has an output end connected to the fifth device, is used to receive the fifth voltage, and convert the fifth voltage into a sixth voltage and then output it to the fifth device.

[0010] In one embodiment, the power supply circuit further includes:

[0011] A protection circuit, whose input end is connected to the external power supply and whose output end is connected to the input end of the first voltage conversion circuit and the input end of the third voltage conversion circuit, is used to protect the first voltage conversion circuit and the third voltage conversion circuit.

[0012] In one embodiment, the first voltage conversion circuit includes: a first buck regulator, a first inductor, a first diode, a first capacitor, a first resistor, and a second resistor;

[0013] The input end of the first buck regulator is connected to the external power supply, the enable end of the first buck regulator is connected to the external single-chip microcomputer, the switch end of the first buck regulator is connected to one end of the first inductor, and the other end of the first inductor is connected to the input end of the second voltage conversion circuit and the first device; the feedback end of the first buck regulator is connected to one end of the first resistor and one end of the second resistor; the common end of the first buck regulator is grounded;

[0014] The cathode of the first diode is connected to the switch end of the first buck regulator, and the anode of the first diode is grounded;

[0015] One end of the first capacitor is connected to the other end of the first inductor, and the other end of the first capacitor is grounded;

[0016] The other end of the first resistor is connected to the other end of the first inductor;

[0017] The other end of the second resistor is grounded.

[0018] In one embodiment, the first voltage conversion circuit further includes: a third resistor, a second capacitor and a third capacitor;

[0019] One end of the second capacitor is connected to the common end of the first buck regulator, and the other end is connected to one end of the third resistor, and the other end of the third resistor is grounded;

[0020] One end of the third capacitor is connected to the common end of the first buck regulator, and the other end is grounded.

[0021] In one embodiment, the third voltage conversion circuit includes: a second buck regulator, a second inductor, a second diode, a fourth capacitor, a fourth resistor and a fifth resistor;

[0022] The input terminal of the second buck regulator is connected to the external power supply, the enable terminal EN of the second buck regulator is connected to the external single-chip microcomputer, the switch terminal of the second buck regulator is connected to one end of the second inductor, and the other end of the second inductor is connected to the third device and the input terminal of the fourth voltage conversion circuit; the feedback terminal of the second buck regulator is connected to one end of the fourth resistor and one end of the fifth resistor; the common terminal of the second buck regulator is grounded;

[0023] The cathode of the second diode is connected to the switch terminal SW of the second buck regulator, and the anode of the second diode is grounded;

[0024] One end of the fourth capacitor is connected to the other end of the second inductor, and the other end of the fourth capacitor is grounded;

[0025] The other end of the fourth resistor is connected to the other end of the second inductor;

[0026] The other end of the fifth resistor is grounded.

[0027] In one embodiment, the third voltage conversion circuit further includes: a sixth resistor, a fifth capacitor and a sixth capacitor;

[0028] One end of the fifth capacitor is connected to the common end of the second buck regulator, and the other end is connected to one end of the sixth resistor, and the other end of the sixth resistor is grounded;

[0029] One end of the sixth capacitor is connected to the common end of the second buck regulator, and the other end is grounded.

[0030] In one embodiment, the second voltage conversion circuit includes: a first linear regulator, a seventh capacitor, an eighth capacitor and a ninth capacitor;

[0031] The input end of the first linear regulator is connected to the other end of the first inductor, the output end of the first linear regulator is connected to the second device, and the ground end of the first linear regulator is grounded;

[0032] One end of the seventh capacitor is connected to the input end of the first linear regulator, and the other end is grounded;

[0033] One end of the eighth capacitor is connected to the output end of the first linear regulator, and the other end is grounded;

[0034] The ninth capacitor is connected in parallel with the eighth capacitor.

[0035] In one embodiment, the fourth voltage conversion circuit includes: a second linear regulator, a tenth capacitor, an eleventh capacitor, and an eleventh capacitor;

[0036] The input end of the second linear regulator is connected to the other end of the second inductor, the output end of the second linear regulator is connected to the fourth device and the fifth voltage conversion circuit, and the ground end of the second linear regulator is grounded;

[0037] One end of the tenth capacitor is connected to the input end of the second linear regulator, and the other end is grounded;

[0038] One end of the eleventh capacitor is connected to the output end of the second linear regulator, and the other end is grounded;

[0039] The eleventh capacitor is connected in parallel with the eleventh capacitor.

[0040] In one embodiment, the fifth voltage conversion circuit includes: an isolated power supply, a third inductor, a fourth inductor, a twelfth capacitor and a thirteenth capacitor;

[0041] The positive input terminal in+ of the isolated power supply is connected to one end of the third inductor, and the other end of the third inductor is connected to the output end of the second linear regulator; the negative input terminal in- of the isolated power supply is connected to one end of the twelfth capacitor and grounded, and the other end of the twelfth capacitor is connected to the other end of the third inductor; the positive output terminal of the isolated power supply is connected to one end of the fourth inductor, and the other end of the fourth inductor is connected to the fifth device; the negative output terminal - of the isolated power supply is connected to one end of the thirteenth capacitor and grounded, and the other end of the thirteenth capacitor is connected to the other end of the fourth inductor.

[0042] In one embodiment, the protection circuit includes: a fuse, a third diode and a fourth diode;

[0043] One end of the fuse is connected to the external power supply, the other end of the fuse is connected to the anode of the fourth diode, and the cathode of the fourth diode is connected to the input end of the first voltage conversion circuit and the input end of the third voltage conversion circuit;

[0044] A cathode of the third diode is connected to the other end of the fuse, and an anode of the third diode is grounded.

[0045] Implementing the embodiments of the present utility model will have the following beneficial effects:

[0046] The present application receives the first voltage provided by the external power supply through the first voltage conversion circuit, and converts the first voltage into the second voltage and outputs it to the external power supply and the second voltage conversion circuit; the second voltage conversion circuit receives the second voltage, and converts the second voltage into the third voltage and outputs it to the second device; the third voltage conversion circuit receives the first voltage provided by the external power supply, and converts the first voltage into the fourth voltage and outputs it to the third device and the fourth voltage conversion circuit; the fourth voltage conversion circuit receives the fourth voltage, and converts the fourth voltage into the fifth voltage and outputs it to the fourth device and the fifth voltage conversion circuit; the fifth voltage conversion circuit receives the fifth voltage, and converts the fifth voltage into the sixth voltage and outputs it to the fifth device. The working requirements of different devices can be met through a simple circuit structure, which reduces the design cost of the power supply circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0048] in:

[0049] Figure 1 is a structural block diagram of a power supply circuit in one embodiment;

[0050] Figure 2 is a structural block diagram of a power supply circuit in another embodiment;

[0051] Figure 3 is a circuit diagram of a first voltage conversion circuit, a third voltage conversion circuit and a protection circuit in one embodiment;

[0052] Figure 4 is a circuit diagram of a second voltage conversion circuit in one embodiment;

[0053] Figure 5 is a circuit diagram of a fourth voltage conversion circuit in one embodiment;

[0054] Figure 6 FIG. 4 is a circuit diagram of a fifth voltage conversion circuit in an embodiment. DETAILED DESCRIPTION

[0055] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0056] A power supply circuit is a circuit used to provide different power supply voltages for devices. In the prior art, when there are too many devices in a facial care instrument and each device requires a different power supply voltage, the prior art often sets an independent power supply circuit for each device to meet the normal power supply requirements of each device, resulting in a complex structure of the power supply circuit and numerous circuit elements, which increases the design cost of the power supply circuit. In order to solve the above technical problems, the present application provides a power supply circuit such as Figure 1As shown, it includes: a first voltage conversion circuit 10, a second voltage conversion circuit 20, a third voltage conversion circuit 30, a fourth voltage conversion circuit 40 and a fifth voltage conversion circuit 50, wherein the input end of the first voltage conversion circuit 10 is connected to an external power supply, and the output end is connected to the input end of the second voltage conversion circuit 20 and a first device, for receiving a first voltage provided by the external power supply, and converting the first voltage into a second voltage and outputting it to the external power supply and the second voltage conversion circuit 20; the output end of the second voltage conversion circuit 20 is connected to a second device, for receiving the second voltage, and converting the second voltage into a third voltage and outputting it to the second device; the input end of the third voltage conversion circuit 30 is connected to the input end of the second voltage conversion circuit 20 and the first device, and the output ... The input end is connected to the external power supply, and the output end is connected to the third device and the input end of the fourth voltage conversion circuit 40, for receiving the first voltage provided by the external power supply, and converting the first voltage into a fourth voltage and outputting it to the third device and the fourth voltage conversion circuit 40; the output end of the fourth voltage conversion circuit 40 is connected to the fourth device and the input end of the fifth voltage conversion circuit 50, for receiving the fourth voltage, and converting the fourth voltage into a fifth voltage and outputting it to the fourth device and the fifth voltage conversion circuit 50; the output end of the fifth voltage conversion circuit 50 is connected to the fifth device, for receiving the fifth voltage, and converting the fifth voltage into a sixth voltage and outputting it to the fifth device. The present application receives the first voltage provided by the external power supply through the first voltage conversion circuit, and converts the first voltage into the second voltage and outputs it to the external power supply and the second voltage conversion circuit; the second voltage conversion circuit receives the second voltage, and converts the second voltage into the third voltage and outputs it to the second device; the third voltage conversion circuit receives the first voltage provided by the external power supply, and converts the first voltage into the fourth voltage and outputs it to the third device and the fourth voltage conversion circuit; the fourth voltage conversion circuit receives the fourth voltage, and converts the fourth voltage into the fifth voltage and outputs it to the fourth device and the fifth voltage conversion circuit; the fifth voltage conversion circuit receives the fifth voltage, and converts the fifth voltage into the sixth voltage and outputs it to the fifth device. The working requirements of different devices can be met through a simple circuit structure, which reduces the design cost of the power supply circuit.

[0057] In one embodiment, Figure 2 As shown, the power supply circuit also includes: a protection circuit 60, whose input end is connected to the external power supply, and whose output end is connected to the input end of the first voltage conversion circuit 10 and the input end of the third voltage conversion circuit 30, for protecting the first voltage conversion circuit 10 and the third voltage conversion circuit 30.

[0058] In one embodiment, Figure 3 As shown, the first voltage conversion circuit 10 includes: a first buck regulator U3, a first inductor L4, a first diode D4, a first capacitor CE5, a first resistor R68 and a second resistor R70; wherein, the input terminal VIN of the first buck regulator U3 is connected to the external power supply, the enable terminal EN of the first buck regulator U3 is connected to the external microcontroller, the switch terminal SW of the first buck regulator U3 is connected to one end of the first inductor L4, and the other end of the first inductor L4 is connected to the input terminal of the second voltage conversion circuit 20 and the first device; the first buck regulator U3 is connected to the external power supply, the enable terminal EN of the first buck regulator U3 is connected to the external microcontroller, the switch terminal SW of the first buck regulator U3 is connected to one end of the first inductor L4, and the other end of the first inductor L4 is connected to the input terminal of the second voltage conversion circuit 20 and the first device; The feedback terminal FB of the buck regulator U3 is connected to one end of the first resistor R68 and one end of the second resistor R70; the common terminal COMP of the first buck regulator U3 is grounded; the cathode of the first diode D4 is connected to the switch end SW of the first buck regulator U3, and the anode of the first diode D4 is grounded; one end of the first capacitor CE5 is connected to the other end of the first inductor L4, and the other end of the first capacitor CE5 is grounded; the other end of the first resistor R68 is connected to the other end of the first inductor L4; the other end of the second resistor R70 is grounded.

[0059] In one embodiment, Figure 3 As shown, the first voltage conversion circuit 10 also includes: a third resistor R66, a second capacitor C29 and a third capacitor C30; wherein, one end of the second capacitor C29 is connected to the common terminal COMP of the first buck regulator U3, and the other end is connected to one end of the third resistor R66, and the other end of the third resistor R66 is grounded; one end of the third capacitor C30 is connected to the common terminal COMP of the first buck regulator U3, and the other end is grounded.

[0060] In one embodiment, Figure 3As shown, the third voltage conversion circuit 30 includes: a second buck regulator U6, a second inductor L3, a second diode D16, a fourth capacitor CE4, a fourth resistor R230 and a fifth resistor R231; wherein, the input terminal VIN of the second buck regulator U6 is connected to the external power supply, the enable terminal EN of the second buck regulator U6 is connected to the external microcontroller, the switch terminal SW of the second buck regulator U6 is connected to one end of the second inductor L3, and the other end of the second inductor L3 is connected to the third device and the input terminal of the fourth voltage conversion circuit 40; ... the external power supply, and the enable terminal EN of the second buck regulator U6 is connected to the external microcontroller, and the switch terminal SW of the second buck regulator U6 is connected to the external microcontroller, and the switch terminal SW of the second buck regulator U6 is connected to the external microcontroller, and the switch terminal SW of the second buck regulator U6 is connected to the external microcontroller, and the switch terminal SW of the second buck regulator U6 is connected to the external microcontroller, and A feedback terminal FB of the regulator U6 is connected to one end of the fourth resistor R230 and one end of the fifth resistor R231; a common terminal COMP of the second buck regulator U6 is grounded; a cathode of the second diode D16 is connected to the switch terminal SW of the second buck regulator U6, and an anode of the second diode D16 is grounded; one end of the fourth capacitor CE4 is connected to the other end of the second inductor L3, and the other end of the fourth capacitor CE4 is grounded; the other end of the fourth resistor R230 is connected to the other end of the second inductor L3; and the other end of the fifth resistor R231 is grounded.

[0061] In one embodiment, Figure 3 As shown, the third voltage conversion circuit 30 also includes: a sixth resistor R229, a fifth capacitor C130 and a sixth capacitor C131; wherein, one end of the fifth capacitor C130 is connected to the common terminal COMP of the second buck regulator U6, and the other end is connected to one end of the sixth resistor R229, and the other end of the sixth resistor R229 is grounded; one end of the sixth capacitor C131 is connected to the common terminal COMP of the second buck regulator U6, and the other end is grounded.

[0062] In one embodiment, Figure 4 As shown, the second voltage conversion circuit 20 includes: a first linear regulator U5, a seventh capacitor C27, an eighth capacitor C31 and a ninth capacitor CE7; wherein, the input terminal VIN of the first linear regulator U5 is connected to the other end of the first inductor L4, the output terminal VOUT of the first linear regulator U5 is connected to the second device, and the ground terminal GND of the first linear regulator U5 is grounded; one end of the seventh capacitor C27 is connected to the input terminal VIN of the first linear regulator U5, and the other end is grounded; one end of the eighth capacitor C31 is connected to the output terminal VOUT of the first linear regulator U5, and the other end is grounded; the ninth capacitor CE7 is connected in parallel with the eighth capacitor C31.

[0063] In one embodiment, Figure 5As shown, the fourth voltage conversion circuit 40 includes: a second linear regulator U7, a tenth capacitor C35, an eleventh capacitor C34 and an eleventh capacitor CE12; wherein, the input terminal VIN of the second linear regulator U7 is connected to the other end of the second inductor L3, the output terminal VOUT of the second linear regulator U7 is connected to the fourth device and the fifth voltage conversion circuit 50, and the ground terminal GND of the second linear regulator U7 is grounded; one end of the tenth capacitor C35 is connected to the input terminal VIN of the second linear regulator U7, and the other end is grounded; one end of the eleventh capacitor C34 is connected to the output terminal VOUT of the second linear regulator U7, and the other end is grounded; the eleventh capacitor CE12 is connected in parallel with the eleventh capacitor C34.

[0064] In one embodiment, Figure 6 As shown, the fifth voltage conversion circuit 50 includes: an isolated power supply U8, a third inductor L6, a fourth inductor L7, a twelfth capacitor C36 and a thirteenth capacitor C37; wherein, the positive input terminal in+ of the isolated power supply U8 is connected to one end of the third inductor L6, and the other end of the third inductor L6 is connected to the output terminal VOUT of the second linear regulator U7; the negative input terminal in- of the isolated power supply U8 is connected to one end of the twelfth capacitor C36 and grounded, and the other end of the twelfth capacitor C36 is connected to the other end of the third inductor L6; the positive output terminal out+ of the isolated power supply U8 is connected to one end of the fourth inductor L7, and the other end of the fourth inductor L7 is connected to the fifth device; the negative output terminal out- of the isolated power supply U8 is connected to one end of the thirteenth capacitor C37 and grounded, and the other end of the thirteenth capacitor C37 is connected to the other end of the fourth inductor L7.

[0065] In one embodiment, Figure 3 As shown, the protection circuit 60 includes: a fuse F1, a third diode ZD1 and a fourth diode D3; wherein, one end of the fuse F1 is connected to the external power supply, the other end of the fuse F1 is connected to the anode of the fourth diode D3, and the cathode of the fourth diode D3 is connected to the input end of the first voltage conversion circuit 10 and the input end of the third voltage conversion circuit 30; the cathode of the third diode ZD1 is connected to the other end of the fuse F1, and the anode of the third diode ZD1 is grounded.

[0066] The present application receives the first voltage provided by the external power supply through the first voltage conversion circuit, and converts the first voltage into the second voltage and outputs it to the external power supply and the second voltage conversion circuit; the second voltage conversion circuit receives the second voltage, and converts the second voltage into the third voltage and outputs it to the second device; the third voltage conversion circuit receives the first voltage provided by the external power supply, and converts the first voltage into the fourth voltage and outputs it to the third device and the fourth voltage conversion circuit; the fourth voltage conversion circuit receives the fourth voltage, and converts the fourth voltage into the fifth voltage and outputs it to the fourth device and the fifth voltage conversion circuit; the fifth voltage conversion circuit receives the fifth voltage, and converts the fifth voltage into the sixth voltage and outputs it to the fifth device. The working requirements of different devices can be met through a simple circuit structure, which reduces the design cost of the power supply circuit.

[0067] The above disclosure is only a preferred embodiment of the present invention, and certainly cannot be used to limit the scope of rights of the present invention. Therefore, equivalent changes made according to the claims of the present invention are still within the scope covered by the present invention.

Claims

1. A power supply circuit, characterized in that: include: A first voltage conversion circuit, whose input end is connected to an external power supply, and whose output end is connected to an input end of a second voltage conversion circuit and a first device, for receiving a first voltage provided by the external power supply, and converting the first voltage into a second voltage and outputting the converted voltage to the external power supply and the second voltage conversion circuit; The second voltage conversion circuit has an output end connected to the second device, and is used to receive the second voltage, and convert the second voltage into a third voltage and then output it to the second device; a third voltage conversion circuit, whose input end is connected to the external power supply, and whose output end is connected to the input end of the third device and the fourth voltage conversion circuit, and is used for receiving the first voltage provided by the external power supply, and converting the first voltage into a fourth voltage and outputting it to the third device and the fourth voltage conversion circuit; The fourth voltage conversion circuit, whose output end is connected to the fourth device link and the input end of the fifth voltage conversion circuit, is used to receive the fourth voltage, and convert the fourth voltage into a fifth voltage and output it to the fourth device link and the fifth voltage conversion circuit; The fifth voltage conversion circuit has an output end connected to the fifth device, is used to receive the fifth voltage, and convert the fifth voltage into a sixth voltage and then output it to the fifth device.

2. The power supply circuit according to claim 1, characterized in that: Also includes: A protection circuit, whose input end is connected to the external power supply and whose output end is connected to the input end of the first voltage conversion circuit and the input end of the third voltage conversion circuit, is used to protect the first voltage conversion circuit and the third voltage conversion circuit.

3. The power supply circuit according to claim 1, characterized in that: The first voltage conversion circuit includes: a first buck regulator, a first inductor, a first diode, a first capacitor, a first resistor and a second resistor; The input end of the first buck regulator is connected to the external power supply, the enable end of the first buck regulator is connected to the external single-chip microcomputer, the switch end of the first buck regulator is connected to one end of the first inductor, and the other end of the first inductor is connected to the input end of the second voltage conversion circuit and the first device; the feedback end of the first buck regulator is connected to one end of the first resistor and one end of the second resistor; the common end of the first buck regulator is grounded; The cathode of the first diode is connected to the switch terminal SW of the first buck regulator, and the anode of the first diode is grounded; One end of the first capacitor is connected to the other end of the first inductor, and the other end of the first capacitor is grounded; The other end of the first resistor is connected to the other end of the first inductor; The other end of the second resistor is grounded.

4. The power supply circuit according to claim 3, characterized in that: The first voltage conversion circuit further includes: a third resistor, a second capacitor and a third capacitor; One end of the second capacitor is connected to the common end of the first buck regulator, and the other end is connected to one end of the third resistor, and the other end of the third resistor is grounded; One end of the third capacitor is connected to the common end of the first buck regulator, and the other end is grounded.

5. The power supply circuit according to claim 1, characterized in that: The third voltage conversion circuit includes: a second buck regulator, a second inductor, a second diode, a fourth capacitor, a fourth resistor and a fifth resistor; The input terminal of the second buck regulator is connected to the external power supply, the enable terminal EN of the second buck regulator is connected to the external single-chip microcomputer, the switch terminal of the second buck regulator is connected to one end of the second inductor, and the other end of the second inductor is connected to the third device and the input terminal of the fourth voltage conversion circuit; the feedback terminal of the second buck regulator is connected to one end of the fourth resistor and one end of the fifth resistor; the common terminal of the second buck regulator is grounded; The cathode of the second diode is connected to the switch terminal of the second buck regulator, and the anode of the second diode is grounded; One end of the fourth capacitor is connected to the other end of the second inductor, and the other end of the fourth capacitor is grounded; The other end of the fourth resistor is connected to the other end of the second inductor; The other end of the fifth resistor is grounded.

6. The power supply circuit according to claim 5, characterized in that: The third voltage conversion circuit further includes: a sixth resistor, a fifth capacitor and a sixth capacitor; One end of the fifth capacitor is connected to the common end of the second buck regulator, and the other end is connected to one end of the sixth resistor, and the other end of the sixth resistor is grounded; One end of the sixth capacitor is connected to the common end of the second buck regulator, and the other end is grounded.

7. The power supply circuit according to claim 3, characterized in that: The second voltage conversion circuit includes: a first linear regulator, a seventh capacitor, an eighth capacitor and a ninth capacitor; The input end of the first linear regulator is connected to the other end of the first inductor, the output end of the first linear regulator is connected to the second device, and the ground end of the first linear regulator is grounded; One end of the seventh capacitor is connected to the input end of the first linear regulator, and the other end is grounded; One end of the eighth capacitor is connected to the output end of the first linear regulator, and the other end is grounded; The ninth capacitor is connected in parallel with the eighth capacitor.

8. The power supply circuit according to claim 6, characterized in that: The fourth voltage conversion circuit includes: a second linear regulator, a tenth capacitor, an eleventh capacitor and an eleventh capacitor; The input end of the second linear regulator is connected to the other end of the second inductor, the output end of the second linear regulator is connected to the fourth device and the fifth voltage conversion circuit, and the ground end of the second linear regulator is grounded; One end of the tenth capacitor is connected to the input end of the second linear regulator, and the other end is grounded; One end of the eleventh capacitor is connected to the output end of the second linear regulator, and the other end is grounded; The eleventh capacitor is connected in parallel with the eleventh capacitor.

9. The power supply circuit according to claim 8, characterized in that: The fifth voltage conversion circuit comprises: an isolated power supply, a third inductor, a fourth inductor, a twelfth capacitor and a thirteenth capacitor; The positive input terminal in+ of the isolated power supply is connected to one end of the third inductor, and the other end of the third inductor is connected to the output end of the second linear regulator; the negative input terminal in- of the isolated power supply is connected to one end of the twelfth capacitor and grounded, and the other end of the twelfth capacitor is connected to the other end of the third inductor; the positive output terminal of the isolated power supply is connected to one end of the fourth inductor, and the other end of the fourth inductor is connected to the fifth device; the negative output terminal - of the isolated power supply is connected to one end of the thirteenth capacitor and grounded, and the other end of the thirteenth capacitor is connected to the other end of the fourth inductor.

10. The power supply circuit according to claim 2, characterized in that: The protection circuit comprises: a fuse, a third diode and a fourth diode; One end of the fuse is connected to the external power supply, the other end of the fuse is connected to the anode of the fourth diode, and the cathode of the fourth diode is connected to the input end of the first voltage conversion circuit and the input end of the third voltage conversion circuit; A cathode of the third diode is connected to the other end of the fuse, and an anode of the third diode is grounded.