Charging circuit, circuit board and device

Abstract

The embodiment of the utility model provides a charging circuit, a circuit board and a device, and the charging circuit comprises a protection unit which comprises a first resistor, a second resistor and a voltage stabilizing diode, the second end of the first resistor, the second resistor and the negative electrode of the voltage stabilizing diode are sequentially connected in series, and the protection unit is used for outputting a protection signal when the voltage stabilizing diode is reversely conducted; a first charging interface; a charging unit; the first switch unit is respectively connected with the first charging interface, the charging unit, the first end of the first resistor and the positive electrode of the voltage stabilizing diode; and the second switch unit is respectively connected with the series connection point of the first resistor and the second resistor, the positive electrode of the voltage stabilizing diode, the first switch unit and the first charging interface, and is used for triggering a protection signal of which the current value is not less than a preset value, so that the first switch unit cuts off the connection between the first charging interface and the charging unit. The charging voltage is divided through the first resistor and the second resistor, so that the current in the protection unit is suppressed to a certain extent, and the utilization rate of overvoltage tolerance is improved.

Description

Technical Field

[0001] The present application relates to the field of charging technology, and in particular to a charging circuit, a circuit board and a device. Background Art

[0002] At present, with the development of the trend of portability, more and more electronic products have appeared in portable versions. For portable electronic products, in order to ensure their sustainable use, these electronic products must be equipped with rechargeable batteries and corresponding charging circuits.

[0003] For the charging circuit, a protection circuit is generally provided. The protection circuit needs to make a voltage judgment on the battery charging voltage, and will perform a protection action when the voltage exceeds a certain threshold. These protection circuits are divided into software protection circuits and hardware protection circuits. The software protection circuit includes a control integrated circuit (IC). The control IC can make a certain logical judgment on the voltage, thereby driving the protection circuit to perform a protection action. The hardware protection circuit only includes non-logical electronic components, so that the hardware protection circuit can only perform protection actions based on the characteristics of the components.

[0004] For rechargeable batteries, in order to cope with the fluctuation of charging voltage, a certain overvoltage tolerance is designed for these batteries at the beginning of their design. For software protection circuits, since the control IC can use judgment logic, the software protection circuit can make good use of the battery's overvoltage tolerance. For hardware protection circuits, due to the fixed characteristics of the components, the utilization rate of the battery's overvoltage tolerance is not high, resulting in the protection circuit being prone to erroneous execution of protection actions within the actual overvoltage tolerance range, which prolongs the charging time. Utility Model Content

[0005] In view of the deficiencies in the prior art, the present application proposes a charging circuit, a circuit board and a device, aiming to improve the utilization rate of the charging circuit's tolerance to overvoltage.

[0006] To achieve the above object, the first aspect of the present application provides a charging circuit, the circuit comprising:

[0007] A protection unit, comprising a first resistor, a second resistor and a voltage-stabilizing diode, wherein the second end of the first resistor, the second resistor and the cathode of the voltage-stabilizing diode are sequentially connected in series, and the protection unit is used to output a protection signal when the voltage-stabilizing diode is reversely conducted;

[0008] A first charging interface;

[0009] Charging unit;

[0010] a first switch unit, connected to the first charging interface, the charging unit, the first end of the first resistor, and the positive electrode of the voltage stabilizing diode respectively;

[0011] The second switch unit is respectively connected to the series point of the first resistor and the second resistor, the positive electrode of the voltage regulator diode, the first switch unit and the first charging interface. The second switch unit is used to trigger the protection signal when the current value is not less than a preset value, so that the first switch unit cuts off the connection between the first charging interface and the charging unit.

[0012] In some possible embodiments of the present application, the second switch unit includes:

[0013] a first switch device, wherein a first end of the first switch device is connected to the first charging interface, a second end of the first switch device is connected to the first switch unit, and a third end of the first switch device is connected to a series connection point of the first resistor and the second resistor;

[0014] A pull-up resistor is connected between the second end of the first switch device and the anode of the voltage stabilizing diode.

[0015] In some possible embodiments of the present application, the first switch unit includes:

[0016] A second switch device, wherein a first end of the second switch device is connected to the first charging interface, a second end of the second switch device is connected to the charging unit, and a third end of the second switch device is connected to the second end of the first switch device.

[0017] In some possible embodiments of the present application, the protection unit further includes:

[0018] A unidirectional module is used to connect the first charging interface to at least one of the first switch unit, the second switch unit and the first resistor.

[0019] In some possible embodiments of the present application, the circuit further includes:

[0020] A filter unit is connected between the first switch unit and the charging unit, and is used for filtering the voltage input to the charging unit.

[0021] In some possible embodiments of the present application, the circuit further includes:

[0022] The first indication module is connected to the first switch unit and connected in parallel with the filter unit relative to the first switch unit. The first indication module is used to send a charging indication signal according to the voltage input to the charging unit.

[0023] In some possible embodiments of the present application, the circuit further includes:

[0024] The second charging interface is connected to the filter unit and is connected in parallel with the first switch unit relative to the filter unit.

[0025] In some possible embodiments of the present application, the circuit further includes:

[0026] The second indication module is connected to a connection point between the first switch unit and the second switch unit, and is used to trigger the first switch unit to enter an off state and send an overvoltage signal.

[0027] To achieve the above-mentioned purpose, the second aspect of the present application provides a circuit board, and the circuit board includes the charging circuit as described in the first aspect above.

[0028] To achieve the above objective, a third aspect of the present application provides a device, which includes the circuit board as described in the second aspect.

[0029] An embodiment of the present application provides a charging circuit, a circuit board and a device, wherein the charging circuit includes: a protection unit, including a first resistor, a second resistor and a voltage-stabilizing diode, wherein the second end of the first resistor, the second resistor and the negative electrode of the voltage-stabilizing diode are connected in series in sequence, and the protection unit is used to output a protection signal when the voltage-stabilizing diode is reversely conducted; a first charging interface; a charging unit; a first switch unit, respectively connected to the first charging interface, the charging unit, the first end of the first resistor and the positive electrode of the voltage-stabilizing diode; a second switch unit, respectively connected to the series connection point of the first resistor and the second resistor, the positive electrode of the voltage-stabilizing diode, the first switch unit and the first charging interface, and the second switch unit is used to trigger the protection signal when the current value is not less than a preset value, so that the first switch unit cuts off the connection between the first charging interface and the charging unit. By dividing the charging voltage by the first resistor and the second resistor, the current in the protection unit can be suppressed to a certain extent, thereby increasing the action threshold of the protection unit, and further reducing the conflict between the voltage fluctuation of the charging voltage within the overvoltage tolerance range and the reverse breakdown voltage of the Zener diode, thereby improving the utilization rate of the overvoltage tolerance, so that the charging circuit can continuously charge the battery with the charging voltage with a voltage fluctuation within the overvoltage tolerance range, thereby keeping the charging process smooth, thereby reducing the charging time and improving the user's charging experience. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 is a circuit diagram of a charging circuit provided by an embodiment of the present application;

[0031] Figure 2 is a circuit diagram of a charging circuit provided in another embodiment of the present application;

[0032] Figure 3 is a circuit diagram of a charging circuit provided in another embodiment of the present application;

[0033] Figure 4 is a circuit diagram of a charging circuit provided in another embodiment of the present application;

[0034] Figure 5 is a circuit diagram of a charging circuit provided in another embodiment of the present application;

[0035] Figure 6 is a circuit diagram of a charging circuit provided in another embodiment of the present application.

[0036] Reference numerals:

[0037] Charging circuit 1, protection unit 11, first resistor 111, second resistor 112, Zener diode 113, unidirectional module 114, first charging interface 12, charging unit 13, first switch unit 14, second switch device 141, second switch unit 15, first switch device 151, pull-up resistor 152, filtering unit 16, first indication module 17, first indication device 171, fourth resistor 172, second charging interface 18, second indication module 19, second indication device 191, fifth resistor 192. DETAILED DESCRIPTION

[0038] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0039] It should be noted that, unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein are only for the purpose of describing the embodiments of this application and are not intended to limit this application.

[0040] At present, with the development of the trend of portability, more and more electronic products have appeared in portable versions. For portable electronic products, in order to ensure their sustainable use, these electronic products must be equipped with rechargeable batteries and corresponding charging circuits.

[0041] For the charging circuit, a protection circuit is generally provided. The protection circuit needs to make a voltage judgment on the battery charging voltage, and will perform a protection action when the voltage exceeds a certain threshold. These protection circuits are divided into software protection circuits and hardware protection circuits. The software protection circuit includes a control IC, which can make a certain logical judgment on the voltage, thereby driving the protection circuit to perform a protection action, while the hardware protection circuit only includes non-logical electronic components, so that the hardware protection circuit can only perform protection actions based on the characteristics of the components.

[0042] For rechargeable batteries, in order to cope with the fluctuation of charging voltage, a certain overvoltage tolerance is designed for these batteries at the beginning of their design. For software protection circuits, since the control IC can use judgment logic, the software protection circuit can make good use of the battery's overvoltage tolerance. For hardware protection circuits, due to the fixed characteristics of the components, the utilization rate of the battery's overvoltage tolerance is not high, resulting in the protection circuit being prone to erroneous execution of protection actions within the actual overvoltage tolerance range, which prolongs the charging time.

[0043] Based on this, the embodiments of the present application provide a charging circuit, a circuit board, and a device, aiming to improve the utilization rate of the charging circuit's tolerance to overvoltage.

[0044] Before describing the embodiments of the present application, for the convenience of description, definitions are made here to define the pins of all capacitors, resistors, diodes, switching devices and other devices that appear in the present application. From left to right of the circuit in the accompanying drawings, for devices with pins distributed in the horizontal direction, the first end is the left pin of the device, and the second end is the right pin of the device; for devices with pins distributed in the vertical direction, the first end is the upper pin of the device, and the second end is the lower pin of the device; for devices with pins distributed in all directions, the first end is the upper left pin of the device, and the second end is the next pin of the first end along the clockwise direction of the device.

[0045] The charging circuit, circuit board and device provided in the embodiments of the present application are specifically described through the following embodiments. First, the charging circuit in the embodiments of the present application is described.

[0046] Reference Figure 1 As shown, in this embodiment, the charging circuit 1 may include, but is not limited to, a protection unit 11 , a first charging interface 12 , a charging unit 13 , a first switch unit 14 , and a second switch unit 15 .

[0047] The protection unit 11 may include but is not limited to a first resistor 111 (at Figure 1 R1), a second resistor 112 (in Figure 1R2) and the Zener diode 113 are shown in the figure. The second end of the first resistor 111, the second resistor 112 and the cathode of the Zener diode 113 are connected in series in sequence. The protection unit 11 can be but is not limited to being used to output a protection signal when the Zener diode 113 is reversely conducted.

[0048] The first switch unit 14 is respectively connected to the first charging interface 12, the charging unit 13, the first end of the first resistor 111 and the positive electrode of the Zener diode 113; the second switch unit 15 is respectively connected to the series point of the first resistor 111 and the second resistor 112, the positive electrode of the Zener diode 113, the first switch unit 14 and the first charging interface 12. The second switch unit 15 can be used to trigger when the current value is not less than the protection signal, so that the first switch unit 14 cuts off the voltage transmission between the first charging interface 12 and the charging unit 13.

[0049] Specifically, when the first charging interface 12 is inserted into the charging line, the first charging interface 12 can obtain the charging voltage through the inserted charging line. For the first switch unit 14 and the second switch unit 15, the first charging interface 12 transmits the charging voltage to the first end of the first switch unit 14 and the first end of the second switch unit 15. For the protection unit 11, the charging voltage passes through the first resistor 111, the second resistor 112 and the voltage regulator diode 113. At this time, since the voltage regulator diode 113 is reversely connected in series, when the charging voltage is less than the reverse breakdown voltage of the voltage regulator diode 113, the voltage regulator diode 113 is not turned on. At this time, no current flows through the protection unit 11, so there is no voltage difference between the first resistor 111 and the second resistor 112. The potential difference at the series connection point of the first resistor 111 and the second resistor 112 is 0, so that the protection unit 11 cannot send a protection signal to the second switch unit 15. In this case, even if a charging voltage is applied to the first end of the second switch unit 15, the second switch unit 15 cannot obtain the charging voltage, so that the second switch unit 15 cannot output a shutdown signal to the first switch unit 14. At this time, the first switch unit 14 will be in an on state, so that the first switch unit 14 can transmit the charging voltage to the charging unit 13, so that the charging unit 13 can be charged.

[0050] When the charging voltage is greater than or equal to the reverse breakdown voltage of the Zener diode 113, the Zener diode 113 can be reversely conducted. At this time, a current will be generated in the protection unit 11. The current can cause a certain voltage to be generated at both ends of the first resistor 111 and the second resistor 112, and the sum of the two voltages is the difference between the charging voltage and the reverse breakdown voltage, that is, the difference voltage. In other words, the first resistor 111 and the second resistor 112 divide the difference voltage, and the series connection point of the first resistor 111 and the second resistor 112 will output a protection signal to the second switch unit 15 due to the voltage division. At this time, there are two situations. When the difference voltage is less than a certain value, the value of the current flowing through the first resistor 111 and the second resistor 112 will be less than a value (i.e., a preset value) that cannot drive the second switch unit 15 to conduct. In this case, even if the voltage-stabilizing diode 113 has been reversely conducted, the output protection signal still cannot turn on the second switch unit 15. Since the second switch unit 15 still cannot be turned on, the second switch unit 15 still cannot output a shutdown signal to the first switch unit 14, and the first switch unit 14 can still transmit the charging voltage to Charging unit 13; when the differential voltage is greater than or equal to a certain value, the value of the current flowing through the first resistor 111 and the second resistor 112 will be greater than or equal to a preset value. At this time, the output protection signal can cause the output protection signal to output a shutdown signal to the first switch unit 14. The first switch unit 14 is triggered by the shutdown signal and enters an off state. At this time, since the first switch unit 14 is turned off, the transmission path between the first charging interface 12 and the charging unit 13 is disconnected, so that the charging unit 13 cannot obtain a charging voltage from the first charging interface 12.

[0051] Since the first resistor 111 and the second resistor 112 can be used for voltage division, when the charging voltage fluctuates, if the voltage value of the fluctuating charging voltage is higher than or equal to a certain value, the current value corresponding to the current flowing through the first resistor 111 and the second resistor 112 will be greater than or equal to a preset value. At this time, the current fluctuating charging voltage has exceeded the overvoltage tolerance of the rechargeable battery, and the second switch unit 15 is required to turn off the first switch unit 14 to interrupt the charging process of the charging unit 13, so as to protect the battery charged by the charging unit 13; if the voltage value of the charging voltage is lower than a certain value, the current value corresponding to the current flowing through the first resistor 111 and the second resistor 112 will be less than the preset value. At this time, the current fluctuating charging voltage has not exceeded the overvoltage tolerance of the rechargeable battery, and the first switch unit 14 can be allowed to remain turned on, so as to maintain the continuity of the charging of the battery by the charging unit 13.

[0052] The embodiment of the present application divides the charging voltage by the first resistor and the second resistor, which can suppress the current in the protection unit to a certain extent, thereby increasing the action threshold of the protection unit, and further reducing the conflict between the voltage fluctuation of the charging voltage within the overvoltage tolerance range and the reverse breakdown voltage of the Zener diode, thereby improving the utilization rate of the overvoltage tolerance, so that the charging circuit can continuously charge the battery with the charging voltage with a voltage fluctuation within the overvoltage tolerance range, thereby keeping the charging process smooth, thereby reducing the charging time and improving the user's charging experience.

[0053] in, Figure 1 The charging circuit 1 shown includes at least a first resistor 111 and a second resistor 112 to achieve a voltage division effect, but the charging circuit 1 can also include but is not limited to multiple resistors. These resistors are connected in series with the first resistor 111 and the second resistor 112 to achieve the same voltage division effect, which is not specifically limited here.

[0054] The first charging interface 12 may be a USB interface, a DC 5.5mm interface, etc., which is not specifically limited here. In addition, the charging unit 13 may include a charging control IC, or a charging control IC and its peripheral circuits, etc., which is not specifically limited here.

[0055] In one embodiment, the first switch unit 14 may include only one switch device, or may include a switch device and an external circuit of the switch device, which is not specifically limited here; the second switch unit 15 may include only one switch device, or may include a switch device and an external circuit of the switch device, which is not specifically limited here.

[0056] For example, the second switch unit 15 may, but is not limited to, include a first switch device 151 and a pull-up resistor 152, wherein the first end of the first switch device 151 is connected to the first charging interface 12, the second end of the first switch device 151 is connected to the first switch unit 14, the third end of the first switch device 151 is connected to the series point of the first resistor 111 and the second resistor 112, and the pull-up resistor 152 is connected between the second end of the first switch device 151 and the positive electrode of the Zener diode 113. When the current value corresponding to the current flowing through the first resistor 111 and the second resistor 112 is greater than or equal to the preset value, the protection signal output by the protection unit 11 can turn on the first switch device 151. At this time, the first switch device 151 will output the conducting current. Therefore, the pull-up resistor can generate a pull-up voltage with the current, so that the second switch unit 15 can output a shutdown signal to the first switch unit 14; when the current value corresponding to the current flowing through the first resistor 111 and the second resistor 112 is less than the preset value, the first switch device 151 remains in the off state, and the pull-up resistor 152 cannot obtain the current output by the first switch device 151, thereby making it impossible for the second switch unit 15 to output a shutdown signal, so that the first switch unit 14 can remain in the on state. Among them, the first switch device 151 can be a controllable diode, a triode, a MOS tube, or a JFET tube, etc., which is not specifically limited here. Among them, the pull-up resistor 152 can be one or more, which is not specifically limited here.

[0057] For example, the first switch unit 14 may include, but is not limited to, a second switch device 141, a first end of the second switch device 141 may be connected to the first charging interface 12, a second end of the second switch device 141 may be connected to the charging unit 13, and a third end of the second switch device 141 may be connected to the second end of the first switch device 151. After the first switch device 151 outputs a shutdown signal at the second end of the first switch device 151 through the pull-up resistor 152, the third end of the second switch device 141 receives the shutdown signal, and when the current value of the shutdown signal is greater than or equal to a preset value, the second switch device 141 may shut off the connection between the first charging interface 12 and the charging unit 13 according to the shutdown signal; when the current value corresponding to the current flowing through the first resistor 111 and the second resistor 112 is less than the preset value, the first switch device 151 cannot output a shutdown signal at the second end of the first switch device 151 through the pull-up resistor 152, and at this time, the second switch device 141 will remain on and transmit the charging voltage input from the first charging interface 12 to the charging unit 13. The second switch device 141 may be a MOS tube, or a JFET tube or other switch devices, which is not specifically limited here.

[0058] For example, the first switch unit 14 may include, but is not limited to, a third switch device and a NOT gate circuit, the positive electrode of the third switch device is connected to the first charging interface 12, the negative electrode of the third switch device is connected to the charging unit 13, the control electrode of the third switch device is connected to the output end of the NOT gate circuit, and the input end of the NOT gate circuit is connected to the second end of the first switch device 151. When the first switch device 151 is pulled up by the pull-up resistor 152, the NOT gate circuit performs a logic conversion on the pull-up voltage to obtain a shutdown signal. When the current value of the shutdown signal is greater than or equal to the preset value, the third switch device can shut down the connection between the first charging interface 12 and the charging unit 13 according to the shutdown signal.

[0059] In one embodiment, the protection unit 11 may also include but is not limited to a unidirectional module 114. The unidirectional module 114 may be used to connect the first charging interface 12 to at least one of the first switch unit 14, the second switch unit 15 and the first resistor 111. Since the charging circuit 1 involves at least the first switch unit 14 and the second switch unit 15, both of which include switching devices. Generally speaking, except for voltage stabilizing devices, the reverse current tolerance of the switching devices is low. When an abnormality occurs inside the charging circuit 1 or the charging line is reversely connected to the power supply, current backflow may occur, thereby causing damage to the first switch unit 14 and / or the second switch unit 15. Therefore, it is necessary to add a unidirectional module 114 to limit the direction of the current, so that the charging current can be kept in the positive direction, thereby reducing the damage to the first switch unit 14 and the second switch unit 15 caused by the reverse current. Among them, the unidirectional module 114 can be as follows Figure 2 As shown, it includes a diode, and can also be a bridge circuit, etc., which is not specifically limited here.

[0060] In one embodiment, the charging circuit 1 may also include, but is not limited to, a filtering unit 16. The filtering unit 16 is connected to the first switch unit 14 and the charging unit 13, respectively. The filtering unit 16 may be, but is not limited to, used for filtering the voltage input to the charging unit. Specifically, when the second switch unit 15 has not yet turned off the first switch unit 14, the charging voltage will be transmitted to the filtering unit 16 through the first switch unit 14. The filtering unit 16 filters the voltage output by the first switch unit 14 to filter out the noise in the voltage. Since the voltage output by the first switch unit 14 is filtered, when the charging unit 13 is charged according to the voltage, the impact of the charging voltage containing noise on the battery being charged can be reduced, thereby improving the charging life of the battery and reducing the impact of noise on the charging IC. Among them, the filtering unit 16 can be as follows: Figure 3 As shown, it is an RC parallel circuit, and it can also be a filter IC such as UAF42AU, BFCN-4800, etc., which is not specifically limited here.

[0061] Reference Figure 4 As shown, the charging circuit 1 also includes but is not limited to a first indication module 17, the first indication module 17 is connected to the first switch unit 14, and is connected in parallel with the filter unit 16 relative to the first switch unit 14, and the first switch unit 14 can be but is not limited to being used to send a charging indication signal according to the unit input by the charging unit 13. When the current value corresponding to the current flowing through the first resistor 111 and the second resistor 112 is less than the preset value, the protection signal output by the protection unit 11 cannot turn on the second switch unit 15, so that the second switch unit 15 cannot turn off the first switch unit 14. At this time, since the first switch unit 14 can transmit the charging voltage to the charging unit 13, the first indication module 17 is also the same as the charging unit 13, and can obtain the charging voltage by connecting with the first switch unit 14, so that the charging indication signal can be sent out according to the charging voltage. Since the first indication module 17 can send a charging indication signal, when a user uses a device including the charging circuit 1 of the embodiment of the present application, he can know that the device is charging through the charging indication signal, thereby improving the user's convenience. Among them, the first indication module 17 may include only an indication device, or may include but not be limited to the indication device and its peripheral circuits. In addition, the indication device may be a light-emitting device such as an LED, or a sound-emitting device such as a buzzer, etc. Correspondingly, the charging indication signal may be a light signal or a sound signal, which is not specifically limited here.

[0062] For example, Figure 4 As shown, the first indication module 17 may include a first indication device 171 and a fourth resistor 172 , the fourth resistor 172 is connected to the first switch unit 14 , and the first indication device 171 is connected to the fourth resistor 172 .

[0063] Reference Figure 5 As shown, in one embodiment, the charging circuit 1 also includes but is not limited to a second charging interface 18, which is connected to the filter unit 16 and connected in parallel with the first switch unit 14 relative to the filter unit 16. The second charging interface 18 is not connected to the protection unit 11 relative to the first charging interface 12. When the charging cable is inserted into the second charging interface 18, the battery can be charged without being restricted by the protection unit 11. On this basis, when the protection unit 11 or the first charging interface 12 is unable to work, the second charging interface 18 can be used as a backup charging interface, so as to achieve emergency charging, thereby improving the user's convenience. Among them, the second charging interface 18 can be a USB interface, a DC5.5mm interface, etc., which is not specifically limited here.

[0064] Reference Figure 6As shown, the charging circuit 1 also includes but is not limited to a second indication module 19, which is connected to the connection point between the first switch unit 14 and the second switch unit 15. The first switch unit 14 can be but is not limited to being used to trigger the first switch unit 14 to enter the off state and send out an overvoltage signal. When the current value corresponding to the current flowing through the first resistor 111 and the second resistor 112 is less than the preset value, the protection signal output by the protection unit 11 cannot turn on the second switch unit 15, so that the second switch unit 15 cannot output the off signal to turn off the first switch unit 14. At this time, the second indication module 19 cannot obtain the off signal and cannot send out the overvoltage signal; when the current value corresponding to the current flowing through the first resistor 111 and the second resistor 112 is greater than or equal to the preset value, the protection signal output by the protection unit 11 can turn on the second switch unit 15, so that the second switch unit 15 can turn off the first switch unit 14. At this time, the second indication module 19 can send out an overvoltage signal according to the off signal. Since the second indication module 19 can send out an overvoltage signal, when a user uses a device including the charging circuit 1 of the embodiment of the present application, the user can know that the current charging voltage is abnormal through the overvoltage signal, so that the user can stop charging, thereby reducing the damage to the battery caused by the charging voltage exceeding the battery overvoltage tolerance. Among them, the second indication module 19 can only include an indication device, and can also include but not be limited to the indication device and its peripheral circuits. In addition, the indication device can be a light-emitting device such as an LED, or a sound-emitting device such as a buzzer, etc., which is not specifically limited here.

[0065] For example, Figure 6 As shown, the second indication module 19 may include a second indication device 191 and a fifth resistor 192 , the fifth resistor 192 is connected to the second switch unit 15 , and the second indication device 191 is connected to the fifth resistor 192 .

[0066] To achieve the above objectives, an embodiment of the present application further provides a circuit board, which includes the charging circuit 1 in each of the above examples.

[0067] To achieve the above purpose, the present application also provides a device, which includes the circuit board provided by each of the above embodiments.

[0068] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0069] In the embodiments of the present application, "at least one" refers to one or more, and "more than one" refers to two or more. "And / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can represent the situation where A exists alone, A and B exist at the same time, and B exists alone. Among them, A and B can be singular or plural. The character " / " generally indicates that the objects associated before and after are in an "or" relationship. "At least one of the following" and similar expressions refer to any combination of these items, including any combination of singular or plural items. For example, at least one of a, b and c can mean: a exists alone, b exists alone, c exists alone, a and b exist at the same time, a and c exist at the same time, b and c exist at the same time, or a, b and c exist at the same time, wherein a, b, c can be single or multiple.

[0070] In the embodiments of the present application, "indication" may include direct indication and indirect indication, and may also include explicit indication and implicit indication. The information indicated by a certain information is called information to be indicated. In the specific implementation process, there may be many ways to indicate the information to be indicated, such as but not limited to, the information to be indicated may be directly indicated, such as indicating the information to be indicated itself or the index of the information to be indicated. The information to be indicated may also be indirectly indicated by indicating other information, wherein the other information has an association relationship with the information to be indicated. It is also possible to indicate only a part of the information to be indicated, while the other parts of the information to be indicated are known or agreed in advance. For example, the indication of specific information may also be achieved by means of the arrangement order of each information agreed in advance (for example, specified by the protocol), thereby reducing the indication overhead to a certain extent.

[0071] In the embodiments of the present application, each term and English abbreviation is provided for the convenience of description and shall not constitute any limitation to the present application. The present application does not exclude the possibility of defining other terms that can achieve the same or similar functions in existing or future protocols.

[0072] In the embodiments of the present application, the terms "first", "second", and "third" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, a feature defined as "first", "second", and "third" may explicitly or implicitly include one or more of the features.

[0073] The above-mentioned embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the present application. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application.

Claims

1. A charging circuit, characterized in that: The circuit comprises: A protection unit, comprising a first resistor, a second resistor and a voltage-stabilizing diode, wherein the second end of the first resistor, the second resistor and the cathode of the voltage-stabilizing diode are sequentially connected in series, and the protection unit is used to output a protection signal when the voltage-stabilizing diode is reversely conducted; A first charging interface; Charging unit; a first switch unit, connected to the first charging interface, the charging unit, the first end of the first resistor, and the positive electrode of the voltage stabilizing diode respectively; The second switch unit is respectively connected to the series point of the first resistor and the second resistor, the positive electrode of the voltage regulator diode, the first switch unit and the first charging interface. The second switch unit is used to trigger the protection signal when the current value is not less than a preset value, so that the first switch unit cuts off the connection between the first charging interface and the charging unit.

2. The circuit according to claim 1, characterized in that The second switch unit comprises: a first switch device, wherein a first end of the first switch device is connected to the first charging interface, a second end of the first switch device is connected to the first switch unit, and a third end of the first switch device is connected to a series connection point of the first resistor and the second resistor; A pull-up resistor is connected between the second end of the first switch device and the anode of the voltage stabilizing diode.

3. The circuit according to claim 2, characterized in that The first switch unit comprises: A second switch device, wherein a first end of the second switch device is connected to the first charging interface, a second end of the second switch device is connected to the charging unit, and a third end of the second switch device is connected to the second end of the first switch device.

4. The circuit according to claim 1, characterized in that The protection unit also includes: A unidirectional module is used to connect the first charging interface to at least one of the first switch unit, the second switch unit and the first resistor.

5. The circuit according to claim 1, characterized in that The circuit further comprises: A filter unit is connected between the first switch unit and the charging unit, and is used for filtering the voltage input to the charging unit.

6. The circuit according to claim 5, characterized in that The circuit further comprises: The first indication module is connected to the first switch unit and connected in parallel with the filter unit relative to the first switch unit. The first indication module is used to send a charging indication signal according to the voltage input to the charging unit.

7. The circuit according to claim 5, characterized in that The circuit further comprises: The second charging interface is connected to the filter unit and is connected in parallel with the first switch unit relative to the filter unit.

8. The circuit according to claim 1, characterized in that The circuit further comprises: The second indication module is connected to a connection point between the first switch unit and the second switch unit, and is used to trigger the first switch unit to enter an off state and send an overvoltage signal.

9. A circuit board, characterized in that: The circuit board comprises the circuit according to any one of claims 1 to 8.

10. A device, characterized in that: The device comprises the circuit board as claimed in claim 9.

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