Overvoltage protection circuit, solar power supply system and electronic equipment

Abstract

The utility model discloses an overvoltage protection circuit, a solar power supply system and an electronic device, and relates to the technical field of power management, the overvoltage protection circuit is applied to the solar power supply system, the solar power supply system comprises a solar panel, a battery and a main control chip, the overvoltage protection circuit comprises a current limiting circuit, an overvoltage protection circuit and an overvoltage protection circuit, the current limiting module is used for limiting the current output by the solar panel or the current output by the battery; the negative end of the voltage-regulator tube circuit is connected with the output end of the current limiting circuit and the power supply end of the main control chip, and the positive end of the voltage-regulator tube circuit is connected with the grounding end of the main control chip and is grounded; and the voltage-regulator tube circuit is used for stabilizing the power supply voltage output to the main control chip by the solar panel. According to the technical scheme of the utility model, the output voltage of the solar panel can be effectively stabilized, and the main control chip is prevented from being damaged under the condition of high illumination.

Description

Technical Field

[0001] The utility model relates to the technical field of power management, and in particular to an overvoltage protection circuit, a solar power supply system and electronic equipment. Background Art

[0002] In a solar power system, core components include solar panels, batteries, and a main control chip, which work together to achieve energy conversion, storage, and management. Solar panels, as energy harvesting devices, are responsible for converting solar energy into electricity, which is primarily used to charge the battery. Batteries, as energy storage devices, store the electricity from the solar panels for later use. The main control chip plays a crucial role in monitoring the solar panel output voltage, distinguishing between daytime and nighttime, and controlling load output. Its power source can be either batteries or directly from the solar panels.

[0003] However, in practice, the output voltage of solar panels is not constant but fluctuates with changing solar conditions. Especially at noon, when solar radiation intensity reaches its peak, the voltage generated by the solar panels can rise significantly, even exceeding the operating voltage range of the main control chip. If this voltage overshoot is not effectively controlled, it will directly threaten the safe operation of the main control chip, potentially causing chip breakdown and further damage to the entire circuit, seriously affecting the stability and reliability of the solar power system.

[0004] Therefore, how to effectively stabilize the output voltage of the solar panel to prevent it from damaging the main control chip under high light conditions has become a key issue in the design of solar power supply systems. Utility Model Content

[0005] The main purpose of this utility model is to propose an overvoltage protection circuit, a solar power supply system and an electronic device, aiming to solve the problem of how to effectively stabilize the output voltage of the solar panel to prevent it from damaging the main control chip under high light conditions.

[0006] To achieve the above objectives, the overvoltage protection circuit proposed in the present invention is applied to a solar power supply system, wherein the solar power supply system includes a solar panel, a battery, and a main control chip. The overvoltage protection circuit includes:

[0007] a current limiting circuit, wherein an input end of the current limiting circuit is interconnected with the positive electrode of the solar panel and the positive electrode of the battery, and the current limiting circuit is used to limit the current output by the solar panel or the current output by the battery;

[0008] A voltage regulator circuit, wherein the negative end of the voltage regulator circuit is interconnected with the output end of the current limiting circuit and the power supply end of the main control chip, the positive end of the voltage regulator circuit is connected to the ground end of the main control chip and is grounded, and the voltage regulator circuit is used to stabilize the power supply voltage output by the solar panel to the main control chip.

[0009] In one embodiment, the voltage regulator circuit includes a first voltage regulator, the cathode of the first voltage regulator is the negative end of the voltage regulator circuit, and the anode of the first voltage regulator is the positive end of the voltage regulator circuit.

[0010] In one embodiment, the voltage-stabilizing diode circuit further includes a first voltage-stabilizing capacitor, and the first voltage-stabilizing capacitor is arranged in parallel with the first voltage-stabilizing diode.

[0011] In one embodiment, the current limiting circuit includes a first current limiting resistor, a first end of the first current limiting resistor is an input end of the current limiting circuit, and a second end of the first current limiting resistor is an output end of the current limiting circuit.

[0012] In one embodiment, the overvoltage protection circuit further includes:

[0013] A battery protection circuit is arranged in series between the negative electrode of the battery and the ground. The detection end of the battery protection circuit is connected to the positive electrode of the battery and the positive electrode of the solar panel. The battery protection circuit is used to disconnect the path between the negative electrode of the battery and the ground when the battery is over-voltage when detected by the output voltage of the battery.

[0014] In one embodiment, the battery protection circuit includes a battery protection chip, a second current-limiting resistor, and a second voltage-stabilizing capacitor. The first end of the second current-limiting resistor serves as a detection end of the battery protection circuit. The second end of the second current-limiting resistor is connected to the first end of the second voltage-stabilizing capacitor and the detection end of the battery protection chip. The second end of the second voltage-stabilizing capacitor is interconnected with the control end of the battery protection chip and the negative electrode of the battery. The ground end of the battery protection chip is grounded.

[0015] In one embodiment, the overvoltage protection circuit further includes:

[0016] A unidirectional conducting circuit is provided in series with the positive electrode of the solar panel, and is used to prevent the electric energy of the battery from flowing back to the solar panel.

[0017] In one embodiment, the unidirectional conduction circuit includes a plurality of first diodes arranged in parallel, wherein the anodes of the plurality of first diodes are interconnected with the positive electrode of the solar panel, and the cathodes of the plurality of first diodes are interconnected with the positive electrode of the battery and the input end of the current limiting circuit.

[0018] The present invention further provides a solar power supply system, which includes a solar panel, a battery, a main control chip, and the overvoltage protection circuit described above.

[0019] The present invention also provides an electronic device, comprising the overvoltage protection circuit as described above;

[0020] Alternatively, it includes a solar power supply system as described above.

[0021] The technical solution of the present invention adopts an overvoltage protection circuit and sets a voltage-stabilizing tube circuit in parallel in front of the main control chip, so that under strong light conditions, when the power supply voltage of the solar panel exceeds the breakdown voltage of the voltage-stabilizing tube circuit, the voltage-stabilizing tube circuit maintains the voltage drop at both ends at the breakdown voltage, so that the voltage at both ends of the parallel main control chip is also maintained at the breakdown voltage. The breakdown voltage of the voltage-stabilizing tube circuit is within the operating voltage of the main control chip, so that the voltage at both ends of the main control chip is stabilized within the operating voltage, protecting the main control chip from breakdown and damage. A current limiting circuit is set in series between the main control chip and the power supply input to limit the current output by the solar panel or the current output by the battery, preventing excessive current from damaging the voltage-stabilizing tube circuit, thereby affecting the voltage stabilization function. In summary, the technical solution of the present invention can effectively stabilize the output voltage of the solar panel and prevent it from damaging the main control chip under high light conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0023] Figure 1 A schematic diagram of the module structure of an embodiment of an overvoltage protection circuit provided by the present utility model;

[0024] Figure 2 A schematic diagram of the module structure of an embodiment of an overvoltage protection circuit provided by the present utility model;

[0025] Figure 3 A schematic diagram of the module structure of an embodiment of an overvoltage protection circuit provided by the present utility model;

[0026] Figure 4 This is a circuit structure diagram of an embodiment of the overvoltage protection circuit provided by the utility model.

[0027] Description of Figure Numbers:

[0028] 10. Current-limiting circuit; R1, first current-limiting resistor; 20. Zener diode circuit; ZD1, first Zener diode; C1, first voltage-stabilizing capacitor; 30. Battery protection circuit; U2, battery protection chip; R2, second current-limiting resistor; C2, second voltage-stabilizing capacitor; 40. Unidirectional conduction circuit; D1, first Schottky diode; D2, second Schottky diode; D3, third Schottky diode; D4, fourth Schottky diode;

[0029] U1, main control chip.

[0030] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0031] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0032] It should be noted that if the embodiments of the present invention involve directional indications (such as up, down, left, right, front, back, etc.), the directional indications are only used to explain the relative position relationship, movement status, etc. between the components in a certain specific posture. If the specific posture changes, the directional indications will also change accordingly.

[0033] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features limited to "first" and "second" may explicitly or implicitly include at least one of such features. In addition, if "and / or" or "and / or" appears in the full text, its meaning includes three parallel schemes. Taking "A and / or B" as an example, it includes scheme A, or scheme B, or a scheme in which A and B are satisfied at the same time. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the ability of ordinary technicians in this field to implement. When the combination of technical solutions is mutually contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0034] In a solar power system, core components include solar panels, batteries, and a main control chip, which work together to achieve energy conversion, storage, and management. Solar panels, as energy harvesting devices, are responsible for converting solar energy into electricity, which is primarily used to charge the battery. Batteries, as energy storage devices, store the electricity from the solar panels for later use. The main control chip plays a crucial role in monitoring the solar panel output voltage, distinguishing between daytime and nighttime, and controlling load output. Its power source can be either batteries or directly from the solar panels.

[0035] However, in practice, the output voltage of solar panels is not constant but fluctuates with changing solar conditions. Especially at noon, when solar radiation intensity reaches its peak, the voltage generated by the solar panels can rise significantly, even exceeding the operating voltage range of the main control chip. If this voltage overshoot is not effectively controlled, it will directly threaten the safe operation of the main control chip, potentially causing chip breakdown and further damage to the entire circuit, seriously affecting the stability and reliability of the solar power system.

[0036] Therefore, how to effectively stabilize the output voltage of the solar panel to prevent it from damaging the main control chip under high light conditions has become a key issue in the design of solar power supply systems.

[0037] Based on this, the present invention proposes an overvoltage protection circuit, which is applied to a solar power supply system. The solar power supply system includes a solar panel, a battery, and a main control chip.

[0038] It should be noted that the output voltage of the solar panel in the solar power supply system is higher than the voltage of the battery. The battery can be a rechargeable battery such as a lithium battery or a lithium iron battery, and the supply voltage of the battery needs to be less than the output voltage of the solar panel. This embodiment does not specifically limit the specific selection of the battery. The main control chip can be an MCU (Microcontroller Unit) chip, an FPGA (Field-Programmable Gate Array) chip, an STM32 chip, an STM chip, an ARM (Advanced RISC Machines, Advanced Reduced Instruction Set Processor 31) chip, or other chips with control capabilities. This embodiment does not specifically limit this.

[0039] See also Figure 1 In one embodiment of the present invention, the overvoltage protection circuit includes:

[0040] a current limiting circuit 10, wherein the input end of the current limiting circuit 10 is interconnected with the positive electrode of the solar panel and the positive electrode of the battery, and the current limiting circuit 10 is used to limit the current output by the solar panel or the current output by the battery;

[0041] The voltage-stabilizing tube circuit 20 has a negative end interconnected with the output end of the current-limiting circuit 10 and the power supply end of the main control chip U1, and a positive end connected to the ground end of the main control chip U1 and grounded. The voltage-stabilizing tube circuit 20 is used to stabilize the power supply voltage output by the solar panel to the main control chip U1.

[0042] It should be noted that the current limiting circuit 10 can be a circuit composed of a current limiting resistor, which is arranged in series between the power supply terminals of the solar panel and the battery and the main control chip U1. By setting the current limiting circuit 10, the current output by the solar panel or the current output by the battery can be limited to within the maximum operating current of the voltage regulator circuit 20, thereby ensuring that the voltage regulator circuit 20 is not damaged due to excessive input current, affecting the voltage stabilization function.

[0043] The Zener diode circuit 20 can be a circuit composed of a Zener diode and a Zener capacitor. The negative end of the Zener diode circuit 20 is connected to the output voltage of the solar panel or the output voltage of the battery, and the positive end of the Zener diode circuit 20 is grounded. When the voltage connected to the negative end of the Zener diode circuit 20 is greater than the breakdown voltage of the Zener diode in the Zener diode circuit 20, the Zener diode in the Zener diode circuit 20 is broken down, so that the Zener diode circuit 20 can maintain the voltage across its two ends at the Zener diode breakdown voltage, thereby making the voltage across the main control chip U1 connected in parallel with the Zener diode circuit 20 also stable at the Zener diode breakdown voltage, and the Zener diode breakdown voltage is less than the maximum operating voltage of the main control chip U1.

[0044] The solar panel can power both the main control chip and the battery. When the battery is not fully charged, the main control chip is still powered by the battery voltage. The maximum battery voltage can be set to 4.2V. When the main control chip U1 is powered by the lithium battery, its supply voltage is lower than the breakdown voltage of the Zener diode, rendering the diode inoperative. When the battery is fully charged, the chip's supply voltage switches from the battery voltage to the solar panel voltage. When powered by the solar panel, if the solar panel output voltage is too high, the Zener diode breaks down, stabilizing the voltage across the diode to a voltage range acceptable to the main control chip, protecting the main control chip U1 from damage caused by the solar panel output voltage. For example, if the solar panel voltage exceeds 5.1V, the voltage is stabilized at 5.1V, protecting the chip from overvoltage breakdown.

[0045] The technical solution of the present invention adopts an overvoltage protection circuit and sets a voltage regulator circuit 20 in parallel in front of the main control chip U1. When the supply voltage of the solar panel exceeds the breakdown voltage of the voltage regulator circuit 20 under strong light conditions, the voltage regulator circuit 20 maintains the voltage drop at both ends at the breakdown voltage, thereby keeping the voltage at both ends of the parallel main control chip U1 at the breakdown voltage. The breakdown voltage of the voltage regulator circuit 20 is within the operating voltage of the main control chip U1. Therefore, the voltage at both ends of the main control chip U1 is stabilized within the operating voltage, protecting the main control chip U1 from breakdown and damage. A current limiting circuit 10 is set in series between the main control chip U1 and the power input to limit the current output by the solar panel or the battery, preventing excessive current from damaging the voltage regulator circuit 20 and affecting the voltage stabilization function. In summary, the technical solution of the present invention can effectively stabilize the output voltage of the solar panel and prevent it from damaging the main control chip U1 under high light conditions.

[0046] See also Figure 4 In one embodiment of the present invention, the voltage-stabilizing tube circuit 20 includes a first voltage-stabilizing tube ZD1, the cathode of the first voltage-stabilizing tube ZD1 is the negative end of the voltage-stabilizing tube circuit 20, and the anode of the first voltage-stabilizing tube ZD1 is the positive end of the voltage-stabilizing tube circuit 20.

[0047] It should be noted that the first voltage-stabilizing diode ZD1 is a voltage-stabilizing diode, and its breakdown voltage should be set to be less than the maximum operating voltage of the main control chip U1. Its specific parameters and specifications should be determined according to the specific circuit design and are not specifically limited in this embodiment. The first voltage-stabilizing diode ZD1 is arranged in parallel with the main control chip U1. The output voltage of the solar panel or the output voltage of the battery is connected to the negative electrode of the first voltage-stabilizing diode ZD1. When the negative electrode input voltage of the first voltage-stabilizing diode ZD1 is greater than a first preset voltage, the first voltage-stabilizing diode ZD1 is broken down, causing the first voltage-stabilizing diode ZD1 to maintain the voltage across its terminals at the voltage-stabilizing diode breakdown voltage. As a result, the voltage across the main control chip U1 connected in parallel with the first voltage-stabilizing diode ZD1 is also stabilized at the voltage-stabilizing diode breakdown voltage, and the voltage across the main control chip U1 is less than the maximum operating voltage of the main control chip U1.

[0048] In this embodiment, the input voltage of the solar panel is stabilized by the first voltage-stabilizing diode ZD1. Under high light conditions, when the output voltage of the solar panel is greater than the breakdown voltage of the first voltage-stabilizing diode ZD1, the first voltage-stabilizing diode ZD1 is broken down, thereby maintaining the voltage across the first voltage-stabilizing diode ZD1 at the breakdown voltage, thereby stabilizing the voltage across the main control chip U1 at the breakdown voltage, thereby effectively stabilizing the output voltage of the solar panel and preventing damage to the main control chip U1 under high light conditions.

[0049] In addition, the first voltage-stabilizing diode ZD1 will only work when the voltage connected to the negative electrode is higher than the breakdown voltage, which will not increase the standby power consumption and can increase the service life of the first voltage-stabilizing diode ZD1. The circuit design is simple and practical, and is cheaper than using voltage-stabilizing devices such as low-voltage linear regulators, which can save product costs.

[0050] See also Figure 4 In one embodiment of the present invention, the voltage-stabilizing tube circuit 20 further includes a first voltage-stabilizing capacitor C1 , and the first voltage-stabilizing capacitor C1 is connected in parallel with the first voltage-stabilizing tube ZD1 .

[0051] It should be noted that the specific parameters and specifications of the first voltage-stabilizing capacitor C1 should be determined based on the specific circuit design and are not specifically limited in this embodiment. The first voltage-stabilizing diode ZD1 is arranged in parallel with the first voltage-stabilizing capacitor C1, and the first voltage-stabilizing diode ZD1 is arranged in parallel with the main control chip U1. The first voltage-stabilizing capacitor C1 is connected in parallel between the first voltage-stabilizing diode ZD1 and the main control chip U1. When the voltage output by the solar panel or the voltage output by the battery changes, the first voltage-stabilizing capacitor C1 releases or stores electrical energy based on the change trend, slowing the change rate to maintain circuit stability. This helps prevent malfunction or damage to the main control chip U1 caused by power supply voltage fluctuations.

[0052] In this embodiment, by providing the first voltage-stabilizing capacitor C1 in parallel with the first voltage-stabilizing diode ZD1, the speed of change of the power supply voltage across the main control chip U1 can be slowed down to maintain circuit stability, which helps prevent failure or damage of the main control chip U1 caused by power supply voltage fluctuations.

[0053] See also Figure 4 In one embodiment of the present utility model, the current limiting circuit 10 includes a first current limiting resistor R1, the first end of the first current limiting resistor R1 is the input end of the current limiting circuit 10, and the second end of the first current limiting resistor R1 is the output end of the current limiting circuit 10.

[0054] It should be noted that the resistance setting of the first current limiting resistor R1 should be determined according to the specific circuit design so that the current in the overvoltage protection circuit does not exceed the maximum operating current of the voltage regulator circuit 20, and the resistance value of the first current limiting resistor R1 can be adjusted according to the current required by the subsequent stage of the main control chip U1. This embodiment does not make specific restrictions on this.

[0055] In this embodiment, by setting the first current limiting resistor R1, the current in the overvoltage protection circuit can be kept within the first preset current. The first preset current is the maximum operating current of the Zener diode circuit 20, thereby ensuring that the Zener diode circuit 20 is not damaged due to excessive input current.

[0056] See also Figure 2In one embodiment of the present invention, the overvoltage protection circuit further includes:

[0057] A battery protection circuit 30 is provided in series between the negative electrode of the battery and the ground. The detection end of the battery protection circuit 30 is connected to the positive electrode of the battery and the positive electrode of the solar panel. The battery protection circuit 30 is used to disconnect the path between the negative electrode of the battery and the ground when the battery is over-voltage when detected by the output voltage of the battery.

[0058] It should be noted that the battery protection circuit 30 can be composed of a battery protection chip U2, a resistor, and a capacitor. The battery protection circuit 30 is used to protect the battery from overcharge. The battery's output voltage can reflect the battery's charge level. When an overvoltage condition is detected, it indicates that the battery is fully charged and the charging circuit needs to be disconnected to prevent overcharging. After the battery is disconnected, the solar panel stops charging the battery, and the main control chip U1 is directly powered by the solar panel.

[0059] In this embodiment, the battery protection circuit 30 monitors the output voltage of the battery to obtain the battery power information through the output voltage of the battery. When the battery is overvoltage, that is, when the battery is fully charged, the battery is powered off, thereby achieving overcharge protection of the battery.

[0060] See also Figure 4 In one embodiment of the present utility model, the battery protection circuit 30 includes a battery protection chip U2, a second current-limiting resistor R2, and a second voltage-stabilizing capacitor C2. The first end of the second current-limiting resistor R2 serves as a detection end of the battery protection circuit 30. The second end of the second current-limiting resistor R2 is connected to the first end of the second voltage-stabilizing capacitor C2 and the detection end of the battery protection chip U2. The second end of the second voltage-stabilizing capacitor C2 is interconnected with the control end of the battery protection chip U2 and the negative electrode of the battery. The ground end of the battery protection chip U2 is grounded.

[0061] It should be noted that the battery protection chip U2 can be a battery protection IC with battery voltage monitoring and overcharge protection functions. The specific specifications and parameters of the second current limiting resistor R2 and the second voltage stabilizing capacitor C2 should be determined according to the specific circuit design, and this embodiment does not specifically limit this.

[0062] In this embodiment, the battery protection chip U2 monitors the battery's output voltage and obtains battery charge information from the battery's output voltage. When the battery is fully charged, the battery is disconnected from the ground line, automatically shutting off power when fully charged, thereby achieving overcharge protection. Furthermore, the second current-limiting resistor R2 is provided to protect the battery protection chip U2 from overcurrent, and the second voltage-stabilizing capacitor C2 is provided to improve the stability of the battery protection circuit 30 and the detection accuracy of the battery protection chip U2.

[0063] See also Figure 2 In one embodiment of the present invention, the overvoltage protection circuit further includes:

[0064] A unidirectional conducting circuit 40 is connected in series to the positive electrode of the solar panel. The unidirectional conducting circuit 40 is used to prevent the electric energy of the battery from flowing back to the solar panel.

[0065] It should be noted that the unidirectional conduction circuit 40 can be a circuit with a unidirectional conduction function composed of multiple diodes. The unidirectional conduction characteristics of the diodes are used to make the solar panel only output electrical energy to the outside, and the battery cannot output electrical energy to the solar panel. Therefore, when the lighting conditions are poor and the output voltage of the solar panel is reduced, the battery will not output electrical energy to the solar panel, thereby effectively preventing the battery's electrical energy from flowing back to the solar panel.

[0066] See also Figure 4 In one embodiment of the present invention, the unidirectional conduction circuit 40 includes a plurality of first diodes arranged in parallel, the positive poles of the plurality of first diodes are interconnected with the positive pole of the solar panel, and the negative poles of the plurality of first diodes are interconnected with the positive pole of the battery and the input end of the current limiting circuit 10.

[0067] It should be noted that the multiple first diodes are Schottky diodes. In this embodiment, by providing multiple first diodes in parallel at the positive electrode of the solar panel, the solar panel can only output electrical energy to the outside through the unidirectional conduction circuit 40, and the battery cannot output electrical energy to the solar panel. This effectively prevents the battery's electrical energy from flowing back to the solar panel when the lighting conditions are poor and the output voltage of the solar panel is reduced. In addition, by providing multiple first diodes to shunt the output current of the solar panel, it is prevented that the output current of the solar panel is too large and causes damage to the first diodes. The specific number of first diodes needs to be determined based on the current-carrying performance of the selected Schottky diode and the maximum output current of the solar panel. This embodiment does not impose any specific restrictions on this.

[0068] For example, in order to help understand the technical concept or technical principle of the overvoltage protection circuit after combining the above embodiments, please refer to Figure 4 , Figure 4A circuit structure schematic diagram of an overvoltage protection circuit is provided, which is as follows: the maximum output voltage of the solar panel is 7V, the supply voltage of the battery is 3.7V to 4.2V, the maximum withstand voltage value (maximum operating voltage) of the selected main control chip U1 is 5.5V, the first voltage-stabilizing diode ZD1 uses a voltage-stabilizing diode with a breakdown voltage of 5.1V, the first voltage-stabilizing capacitor C1 uses a 22uF capacitor, the second voltage-stabilizing capacitor C2 uses a 100nF capacitor, four first diodes are provided, namely, the first Schottky diode D1 to the fourth Schottky diode D4, all of which use Schottky diodes with a voltage drop of 0.2V, and the first current-limiting resistor R1 and the second current-limiting resistor R2 use current-limiting resistors with a resistance of 330R.

[0069] When the main control chip U1 is powered by a lithium battery, its supply voltage is lower than the breakdown voltage of the Zener diode, and the Zener diode does not work. When powered by a solar panel, under high light conditions, the maximum output voltage of the solar panel can reach 7V, which is 6.8V after a 0.2V voltage drop across the Schottky diode of the unidirectional conduction circuit 40, still higher than the breakdown voltage of the Zener diode. At this time, the Zener diode is broken down, and the voltage across the Zener diode is stabilized at its breakdown voltage of 5.1V, protecting the main control chip U1 from damage due to overvoltage breakdown.

[0070] Among them, when the lithium battery is fully charged, the battery protection chip U2 detects battery overvoltage, disconnects the path between the battery negative electrode and the ground wire, and cuts off the power to the lithium battery, thereby achieving overcharge protection for the lithium battery.

[0071] The present utility model also proposes a solar power supply system, which includes a solar panel, a battery, a main control chip and an overvoltage protection circuit as described in the above embodiments. The specific structure of the overvoltage protection circuit refers to the above embodiments. Since the present solar power supply system adopts all the technical solutions of all the above embodiments, it has at least all the beneficial effects brought by the technical solutions of the above embodiments, which will not be described one by one here.

[0072] The present invention further provides an electronic device, which includes: the overvoltage protection circuit as described in any one of the above embodiments; or the solar power supply system as described in the above embodiments.

[0073] It should be noted that the electronic device can be a solar street light, and the main control chip is the main control MCU of the solar street light. It is used to detect the voltage of the solar panel and distinguish between day and night based on the voltage of the solar panel. During the day, the solar panel outputs a high voltage, and the main control chip outputs a low-level control signal to control the solar street light to not light up. At night, when the solar panel outputs a low voltage, the main control chip outputs a high-level control signal to control the solar street light to light up. During the day, the main control chip is powered by the solar panel and the battery. When the battery is fully charged, the main control chip is powered directly by the solar panel.

[0074] The specific structure of the electronic device refers to the above embodiments. Since the electronic device adopts all the technical solutions of all the above embodiments, it has at least all the beneficial effects brought by the technical solutions of the above embodiments, which will not be described one by one here.

[0075] The above description is merely an exemplary embodiment of the present invention and does not limit the patent scope of the present invention. All equivalent structural transformations made using the contents of the present invention specification and drawings under the technical concept of the present invention, or direct / indirect application in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. An overvoltage protection circuit, characterized in that: Applied to a solar power supply system, the solar power supply system includes a solar panel, a battery and a main control chip, and the overvoltage protection circuit includes: a current limiting circuit, wherein an input end of the current limiting circuit is interconnected with the positive electrode of the solar panel and the positive electrode of the battery, and the current limiting circuit is used to limit the current output by the solar panel or the current output by the battery; A voltage regulator circuit, wherein the negative end of the voltage regulator circuit is interconnected with the output end of the current limiting circuit and the power supply end of the main control chip, the positive end of the voltage regulator circuit is connected to the ground end of the main control chip and is grounded, and the voltage regulator circuit is used to stabilize the power supply voltage output by the solar panel to the main control chip.

2. The overvoltage protection circuit according to claim 1, wherein: The voltage-stabilizing tube circuit includes a first voltage-stabilizing tube, wherein the cathode of the first voltage-stabilizing tube is the negative end of the voltage-stabilizing tube circuit, and the anode of the first voltage-stabilizing tube is the positive end of the voltage-stabilizing tube circuit.

3. The overvoltage protection circuit according to claim 2, wherein: The voltage-stabilizing tube circuit further includes a first voltage-stabilizing capacitor, which is arranged in parallel with the first voltage-stabilizing tube.

4. The overvoltage protection circuit according to claim 1, wherein: The current limiting circuit includes a first current limiting resistor, a first end of the first current limiting resistor is an input end of the current limiting circuit, and a second end of the first current limiting resistor is an output end of the current limiting circuit.

5. The overvoltage protection circuit according to claim 1, wherein: The overvoltage protection circuit further includes: A battery protection circuit is arranged in series between the negative electrode of the battery and the ground. The detection end of the battery protection circuit is connected to the positive electrode of the battery and the positive electrode of the solar panel. The battery protection circuit is used to disconnect the path between the negative electrode of the battery and the ground when the battery is over-voltage when detected by the output voltage of the battery.

6. The overvoltage protection circuit according to claim 5, wherein: The battery protection circuit includes a battery protection chip, a second current-limiting resistor, and a second voltage-stabilizing capacitor. The first end of the second current-limiting resistor serves as a detection end of the battery protection circuit. The second end of the second current-limiting resistor is connected to the first end of the second voltage-stabilizing capacitor and the detection end of the battery protection chip. The second end of the second voltage-stabilizing capacitor is interconnected with the control end of the battery protection chip and the negative electrode of the battery. The ground end of the battery protection chip is grounded.

7. The overvoltage protection circuit according to claim 1, wherein: The overvoltage protection circuit further includes: A unidirectional conducting circuit is provided in series with the positive electrode of the solar panel, and is used to prevent the electric energy of the battery from flowing back to the solar panel.

8. The overvoltage protection circuit according to claim 7, wherein: The unidirectional conduction circuit includes a plurality of first diodes arranged in parallel, wherein the anodes of the plurality of first diodes are interconnected with the anode of the solar panel, and the cathodes of the plurality of first diodes are interconnected with the anode of the battery and the input end of the current limiting circuit.

9. A solar power supply system, characterized in that: The solar power supply system includes a solar panel, a battery, a main control chip and the overvoltage protection circuit according to any one of claims 1 to 8.

10. An electronic device, characterized in that: The electronic device comprises the overvoltage protection circuit according to any one of claims 1 to 8; Alternatively, it comprises the solar power supply system as claimed in claim 9.

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