Charging circuit for electric equipment and electric equipment

Abstract

The present application relates to a charging circuit, and in particular to a charging circuit for an electrical device, wherein the electrical device includes a switching power supply, a battery pack and a load, and the charging circuit includes a DC plug and a step-down circuit; the step-down circuit converts the voltage input by the DC plug into a target voltage; the step-down circuit includes a transistor and a voltage stabilizing component, and the voltage stabilizing component includes a parallel voltage regulator and a voltage dividing branch, the collector of the transistor is connected to the positive pole of the DC plug, the cathode of the parallel voltage regulator is connected to the base of the transistor, the anode of the parallel voltage regulator is connected to the negative pole of the DC plug, the reference end of the parallel voltage regulator is connected to the voltage dividing point of the voltage dividing branch, one end of the voltage dividing branch is connected to the emitter of the transistor, and the other end is connected to the negative pole of the DC plug, and the emitter of the transistor is connected to the positive pole of the switching power supply for outputting the target voltage; wherein the size of the target voltage is suitable for charging the battery pack. The present application can convert the voltage input by the DC plug into a target voltage suitable for charging the battery pack.

Description

Technical Field

[0001] The present application relates to a charging circuit, and in particular to a charging circuit for an electrical device and the electrical device. Background Art

[0002] In the related art, many fans on the market are 16-inch and 18-inch in specifications. The fans include a built-in switching power supply and a battery. The fans mainly work through the voltage provided by the switching power supply. When the switching power supply is not used, the fans can work through the voltage provided by the battery. In addition to the built-in switching power supply and battery, fans sold in some areas also provide a DC charging plug for charging lithium batteries. However, most DC plugs are currently 12V in specifications, and a few are 15V in specifications. The voltage specifications of the batteries are also varied, including 6V lead-acid batteries, 7.4V lithium batteries, and 11.1V lithium batteries. It is difficult to match the voltage specifications of the DC charging plug and the battery. Therefore, there is often a problem that the built-in lithium battery cannot be charged directly using the DC plug. If the DC plug is used directly to charge the lithium battery, the circuit current will be too large or the circuit temperature will be too high, which poses certain safety hazards. At the same time, it will damage the lithium battery and affect the service life of the lithium battery. Summary of the invention

[0003] The present application aims to solve at least one of the technical problems existing in the prior art. To this end, the present application provides a charging circuit and an electric device for an electric device, which can convert the voltage input by a DC plug into a target voltage suitable for charging a battery pack.

[0004] In a first aspect, an embodiment of the present application provides a charging circuit for an electric device, wherein the electric device includes a switching power supply, a battery pack, and a load, wherein the positive electrode of the switching power supply is connected to the positive electrode of the battery pack, and the switching power supply and the battery pack are both connected to the load for power supply, and the charging circuit includes:

[0005] DC plug;

[0006] A step-down circuit, used for converting the voltage input by the DC plug into a target voltage; the step-down circuit includes a transistor and a voltage stabilizing component, the voltage stabilizing component includes a shunt regulator and a voltage dividing branch, the collector of the transistor is connected to the positive electrode of the DC plug, the cathode of the shunt regulator is connected to the base of the transistor, the anode of the shunt regulator is connected to the negative electrode of the DC plug, the reference end of the shunt regulator is connected to the voltage dividing point of the voltage dividing branch, one end of the voltage dividing branch is connected to the emitter of the transistor, and the other end is connected to the negative electrode of the DC plug, the emitter of the transistor is connected to the positive electrode of the switching power supply, and is used for outputting the target voltage;

[0007] The target voltage is suitable for charging the battery pack.

[0008] The technical solution of the first aspect of the embodiment of the present application has at least one of the following advantages or beneficial effects: the positive electrode of the DC plug is connected to the collector of the transistor, so that the voltage input by the DC plug flows through the transistor to put the transistor in a conducting state, one end of the voltage-dividing branch is connected to the emitter of the transistor, and the other end is connected to the negative electrode of the DC plug, the reference end of the shunt regulator is connected to the voltage-dividing point of the voltage-dividing branch, the base of the transistor is connected to the cathode of the shunt regulator, and the voltage output by the emitter of the transistor provides a voltage suitable for the reference end of the shunt regulator through the voltage-dividing branch, so that the shunt regulator is in a working state of regulated output, thereby being able to convert the input voltage of the DC plug into a stable target voltage, and output the target voltage to the switching power supply through the emitter of the transistor, that is, the battery pack is charged through the target voltage, thereby realizing the step-down circuit to convert the input voltage of the DC plug into the target voltage. Therefore, the present application can output the target voltage through the parallel regulator for different voltages input by the DC plug. The parallel regulator will not cause the output voltage to be high due to the high voltage input of the DC plug with different voltage specifications, and it plays a constant voltage output role, thereby improving the stability of the charging circuit. Since the size of the target voltage is suitable for charging the battery pack, it can effectively avoid the current and voltage of the charging circuit being too large to cause the circuit to heat up, thereby improving the safety and reliability of the charging circuit.

[0009] According to some embodiments of the present application, the voltage dividing branch includes a first resistor and a second resistor, the first resistor and the second resistor are connected in series, and the reference end of the parallel regulator is connected between the first resistor and the second resistor.

[0010] According to some embodiments of the present application, the step-down circuit further includes a first current limiting component and a first diode, the DC plug is connected to one end of the first current limiting component through the first diode, and the other end of the first current limiting component is connected to the collector of the transistor.

[0011] According to some embodiments of the present application, the step-down circuit also includes a third resistor, a fourth resistor and a capacitor, one end of the third resistor is connected to the cathode of the first diode, the other end of the third resistor is connected to the cathode of the parallel regulator, one end of the fourth resistor is connected to the base of the transistor, the other end of the fourth resistor is connected to the cathode of the parallel regulator, and the capacitor is connected in parallel with the parallel regulator.

[0012] According to some embodiments of the present application, the parallel regulator is a TL431 voltage regulator device.

[0013] According to some embodiments of the present application, it also includes a second current limiting component and a second diode, one end of the second current limiting component is connected to the positive electrode of the switching power supply, the other end of the second current limiting component is connected to the positive electrode of the second diode, and the negative electrode of the second diode is connected to the positive electrode of the battery pack.

[0014] According to some embodiments of the present application, a third diode and a fourth diode are also included, wherein the anode of the third diode is connected to the emitter of the transistor, the cathode of the third diode is connected to the anode of the switching power supply, the anode of the fourth diode is connected to the anode of the switching power supply, and the cathode of the fourth diode is connected to the load.

[0015] According to some embodiments of the present application, a fifth resistor and a fuse are further included, wherein the fifth resistor is connected in parallel with the battery pack, one end of the fuse is connected to the cathode of the second diode, and the other end of the fuse is connected to the anode of the battery pack.

[0016] According to some embodiments of the present application, a fifth diode is further included, wherein an anode of the fifth diode is connected to a cathode of the second diode, and a cathode of the fifth diode is connected to the load.

[0017] In a second aspect, an embodiment of the present application provides an electrical device, comprising the charging circuit described in the technical solution of the first aspect.

[0018] Other features and advantages of the present application will be described in the following description, and partly become apparent from the description, or understood by practicing the present application. The purpose and other advantages of the present application can be realized and obtained by the structures specifically pointed out in the description, claims and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 is a circuit diagram of a charging circuit of an electric device provided in an embodiment of the present application;

[0020] Figure 2 is a circuit diagram of another charging circuit of an electric device provided in an embodiment of the present application;

[0021] Figure 3 This is a circuit diagram of a charging circuit for another electrical device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0022] In order to make the purpose, technical solutions and advantages of the present application clearer, the present application is further described in detail below in conjunction with the accompanying drawings and examples. It should be understood that the specific embodiments described herein are only used to explain the present application and are not intended to limit the present application. In addition, the characteristics, operations or features described in the specification can be combined in any appropriate manner to form various implementation methods. At the same time, the steps or actions in the method description can also be replaced or adjusted in order in a manner that is obvious to those skilled in the art. Therefore, the various sequences in the specification and the accompanying drawings are only for the purpose of clearly describing a certain embodiment and are not meant to be a necessary sequence, unless otherwise specified that a certain sequence must be followed.

[0023] In the description of this application, "several" means one or more, "more" means more than two, "greater than", "less than", "exceed", etc. are understood to exclude the number itself, and "above", "below", "within", etc. are understood to include the number itself. If there is a description of "first" or "second", it is only used for the purpose of distinguishing technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.

[0024] The serial numbers of the components in this document, such as "first", "second", etc., are only used to distinguish the objects described and do not have any order or technical meaning. The "connection" and "coupling" mentioned in this application, unless otherwise specified, include direct and indirect connections (couplings).

[0025] In the related art, many fans on the market are 16-inch and 18-inch in size. The fans include a built-in switching power supply and a battery. The fans mainly work through the voltage provided by the switching power supply. When the switching power supply is not used, the fans can work through the voltage provided by the battery. In addition to the built-in switching power supply and battery, fans sold in some areas also provide a DC charging plug for charging lithium batteries. However, most DC plugs are currently 12V in size, and a few are 15V in size. The voltage specifications of the batteries are also varied, including 6V lead-acid batteries, 7.4V lithium batteries, and 11.1V lithium batteries. It is difficult to match the voltage of the DC charging plug with the voltage rules of the battery. Therefore, there is often a problem that the built-in lithium battery cannot be charged directly using the DC plug. If the DC plug is used directly to charge the lithium battery, the circuit current will be too large or the circuit temperature will be too high, which poses certain safety hazards. At the same time, it will damage the lithium battery and affect the service life of the lithium battery.

[0026] Based on this, the embodiments of the present application provide a charging circuit for an electric device and an electric device, which can convert the voltage input by a DC plug into a target voltage suitable for charging a battery pack.

[0027] The embodiments of the present application are further described below in conjunction with the accompanying drawings.

[0028] Reference Figure 1 , Figure 1 This is a circuit diagram of a charging circuit of an electric device provided in an embodiment of the present application. The electric device includes a switching power supply, a battery pack and a load. The positive electrode of the switching power supply is connected to the positive electrode of the battery pack. The switching power supply and the battery pack are both connected to the load for power supply. The charging circuit includes:

[0029] DC plug;

[0030] A step-down circuit is used to convert the voltage input by a DC plug into a target voltage; the step-down circuit includes a transistor Q and a voltage stabilizing component 100, the voltage stabilizing component 100 includes a parallel regulator 110 and a voltage dividing branch, the collector of the transistor Q is connected to the positive electrode of the DC plug, the cathode of the parallel regulator 110 is connected to the base of the transistor Q, the anode of the parallel regulator 110 is connected to the negative electrode of the DC plug, the reference end of the parallel regulator 110 is connected to the voltage dividing point of the voltage dividing branch, one end of the voltage dividing branch is connected to the emitter of the transistor Q, and the other end is connected to the negative electrode of the DC plug, the emitter of the transistor Q is connected to the positive electrode of the switching power supply, and is used to output the target voltage; wherein the magnitude of the target voltage is suitable for charging the battery pack.

[0031] The positive electrode of the DC plug is connected to the collector of the transistor Q, so that the voltage input by the DC plug flows through the transistor Q to put the transistor Q in a conducting state. One end of the voltage-dividing branch is connected to the emitter of the transistor Q, and the other end is connected to the negative electrode of the DC plug. The reference end of the parallel regulator 110 is connected to the voltage-dividing point of the voltage-dividing branch. The base of the transistor Q is connected to the cathode of the parallel regulator 110. The voltage output by the emitter of the transistor Q provides a voltage suitable for the reference end of the parallel regulator 110 through the voltage-dividing branch, so that the parallel regulator 110 is in a working state of regulated output, so that the input voltage of the DC plug can be converted into a stable target voltage, and the target voltage is output to the switching power supply through the emitter of the transistor Q, that is, the battery pack is charged through the target voltage, thereby realizing that the step-down circuit converts the input voltage of the DC plug into the target voltage. Therefore, the present application can output a target voltage through the parallel regulator 110 for different voltages input by the DC plug. The parallel regulator 110 will not cause a high output voltage due to the high voltage input of the DC plug with different voltage specifications, and it plays a constant voltage output role, thereby improving the stability of the charging circuit. Since the size of the target voltage is suitable for charging the battery pack, it can effectively avoid the current and voltage of the charging circuit being too large to cause the circuit to heat up, thereby improving the safety and reliability of the charging circuit.

[0032] In some embodiments of the present application, the voltage stabilizing component 100 includes a parallel regulator 110 and a voltage divider branch, the parallel regulator 110 is a TL431 voltage stabilizing device, one end of the voltage divider branch is connected to the emitter of the transistor Q, and the other end is connected to the negative pole of the DC plug; the voltage divider branch includes a first resistor R1 and a second resistor R2, the first resistor R1 and the second resistor R2 are connected in series, and the reference end of the parallel regulator 110 is connected between the first resistor R1 and the second resistor R2.

[0033] The voltage input by the DC plug flows through the transistor Q and flows through the voltage divider circuit through the emitter of the transistor Q. Since the reference end of the TL431 voltage stabilizer is connected between the first resistor R1 and the second resistor R2, that is, the reference end of the TL431 voltage stabilizer is connected to the voltage dividing point of the voltage dividing branch, by selecting the first resistor R1 and the second resistor R2 with preset resistance values, the voltage dividing point of the voltage dividing branch provides a voltage suitable for the reference end of the TL431 voltage stabilizer, so that the TL431 voltage stabilizer is in a working state of voltage stabilization output, so that the emitter of the transistor Q can output a target voltage suitable for charging the battery pack to the positive electrode of the switching power supply.

[0034] In some embodiments of the present application, the resistance of the first resistor R1 is 4.7KΩ, and the resistance of the second resistor R2 is 1.8KΩ. By setting the resistance of the first resistor R1 to 4.7KΩ and the resistance of the second resistor R2 to 1.8KΩ, the voltage given to the reference terminal of the TL431 voltage regulator is greater than the internal reference voltage 2.5V, so that the TL431 voltage regulator is in a working state of voltage stabilization output. The output voltage is calculated by the working state characteristics of the TL431 voltage regulator. Specifically, the output voltage of the TL431 voltage regulator is calculated as follows:

[0035]

[0036] Wherein, V0 is the output voltage of TL431 voltage regulator, R1 is the resistance value of the first resistor R1, R2 is the resistance value of the second resistor R2, V r It is the reference voltage of the TL431 voltage regulator.

[0037] Set R1 to 4.7KΩ, R2 to 1.8KΩ, V r Substituting 2.5V into the above formula, the voltage output by the emitter of transistor Q is 9.03V. Since the emitter of transistor Q is connected to the positive electrode of the switching power supply, the emitter of transistor Q outputs 9.03V to the positive electrode of the switching power supply, thereby reducing the voltage output by the DC plug to the same voltage as the output of the switching power supply, thereby converting the output voltage of the DC plug into a stable target voltage. It should be noted that the target voltage is suitable for charging the battery pack.

[0038] Reference Figure 2 , Figure 2 It is a circuit diagram of another charging circuit of an electric device provided in an embodiment of the present application, wherein the step-down circuit further includes a first current limiting component 200 and a first diode D1, wherein the DC plug is connected to one end of the first current limiting component 200 through the first diode D1, and the other end of the first current limiting component 200 is connected to the collector of the transistor Q. The step-down circuit further includes a third resistor R3, a fourth resistor R4 and a capacitor C, wherein one end of the third resistor R3 is connected to the cathode of the first diode D1, the other end of the third resistor R3 is connected to the cathode of the parallel regulator 110, one end of the fourth resistor R4 is connected to the base of the transistor Q, the other end of the fourth resistor R4 is connected to the cathode of the parallel regulator 110, and the capacitor C is connected in parallel to the parallel regulator 110. The voltage input by the DC plug passes through the first diode D1 and the first current limiting component 200 to the collector of the transistor Q, and then passes through the third resistor R3 to the cathode of the TL431 voltage regulator. When the voltage input by the DC plug passes through the collector of the transistor Q and the base of the transistor Q to the fourth resistor R4 and then to the compensation capacitor C, the transistor Q is turned on, so that the reference end of the TL431 voltage regulator is greater than the internal reference voltage, so that the TL431 voltage regulator is in a working state of voltage stabilization output, so that the input voltage of the DC plug can be converted into a stable target voltage, and the target voltage is output to the switching power supply through the emitter of the transistor Q, that is, the battery pack is charged by the target voltage, thereby realizing the step-down circuit to convert the input voltage of the DC plug into the target voltage.

[0039] It should be noted that the first current limiting component 200 includes a sixth resistor R6 and a seventh resistor R7, and the sixth resistor R6 and the seventh resistor R7 are connected in parallel. The first current limiting component 200 may also include two or more current limiting resistors in parallel. The embodiment of the present application does not limit the composition of the first current limiting component 200, and technicians in this field can set the first current limiting component 200 according to actual conditions.

[0040] In some embodiments of the present application, a second current limiting component 300 and a second diode D2 are further included, one end of the second current limiting component 300 is connected to the positive electrode of the switching power supply, the other end of the second current limiting component 300 is connected to the positive electrode of the second diode D2, and the negative electrode of the second diode D2 is connected to the positive electrode of the battery pack. By arranging the second current limiting component 300 and the second diode D2 between the positive electrode of the switching power supply and the battery pack, the current output by the switching power supply can flow through the second current limiting component 300, avoiding the switching power supply from directly charging the battery pack, effectively avoiding the current and voltage of the charging circuit from being too large to damage the battery pack, and improving the safety and reliability of the charging circuit.

[0041] It should be noted that the second current limiting component 300 includes an eighth resistor R8 and a ninth resistor R9, and the eighth resistor R8 and the ninth resistor R9 are connected in parallel. The second current limiting component 300 can also be two or more current limiting resistors in parallel. The embodiment of the present application does not limit the composition of the second current limiting component 300, and technicians in this field can set the second current limiting component 300 according to actual conditions.

[0042] In some embodiments of the present application, the charging circuit further includes a third diode D3 and a fourth diode D4, the anode of the third diode D3 is connected to the emitter of the transistor Q, the cathode of the third diode D3 is connected to the anode of the switching power supply, the anode of the fourth diode D4 is connected to the anode of the switching power supply, and the cathode of the fourth diode D4 is connected to the load. It can be understood that the third diode D3 plays a role in voltage stabilization, the third diode D3 is arranged between the transistor Q and the switching power supply, and the voltage output by the emitter of the transistor Q can be stably transmitted to the switching power supply. Similarly, the third diode D3 plays a role in voltage stabilization, the fourth diode D4 is arranged between the switching power supply and the load, and the voltage output by the switching power supply can be stably transmitted to the load. The third diode D3 plays a role in voltage stabilization, which improves the safety and reliability of the charging circuit.

[0043] In some embodiments of the present application, the charging circuit further includes a fifth resistor R5 and a fuse 400, the fifth resistor R5 is connected in parallel with the battery pack, one end of the fuse 400 is connected to the negative electrode of the second diode D2, and the other end of the fuse 400 is connected to the positive electrode of the battery pack. By setting the fuse 400 and the battery pack in series, the current output by the switching power supply passes through the second current limiting component 300 and the second diode D2, and then flows through the fuse 400 to the battery pack. The fuse 400 can avoid overcharging, overdischarging and excessive current, play a role in protecting the charging circuit, and improve the safety and reliability of the charging circuit. By setting the fifth resistor R5 and the battery pack in parallel, a part of the voltage output by the positive electrode of the switching power supply passes through the fifth resistor R5 and returns to the negative electrode of the switching power supply, and the other part of the voltage passes through the second current limiting component 300 and the second diode D2 to the battery pack. Therefore, the fifth resistor R5 and the battery pack are connected in parallel to play a voltage dividing role, so that the voltage output by the switching power supply to the battery pack is suitable for charging the battery pack.

[0044] It should be noted that, in some embodiments of the present application, the battery pack includes two lithium batteries connected in series, and the voltage specification of each lithium battery is 3.7V, so the specification of the battery pack is 7.4V. Since the voltage of about 9.03V outputted from the emitter of the transistor Q is to the positive pole of the switching voltage, in order to allow the switching power supply to provide a suitable voltage to charge the battery pack, a fifth resistor R5 is set to be connected in parallel with the battery pack. By setting the fifth resistor R5 to 2KΩ, the voltage delivered to the battery pack by the switching power supply can be 7.4V.

[0045] In some embodiments of the present application, the charging circuit further includes a fifth diode D5, the anode of the fifth diode D5 is connected to the cathode of the second diode D2, the anode of the fifth diode D5 is also connected to the anode of the battery pack, and the cathode of the fifth diode D5 is connected to the load. It can be understood that the fifth diode D5 plays a voltage stabilizing role, and by setting the anode of the fifth diode D5 to be connected to the anode of the battery pack, the voltage output by the battery pack can be stably output to the load to power the load.

[0046] In some embodiments of the present application, the charging circuit also includes a sixth diode D6, the anode of the sixth diode D6 is connected to the anode of the DC plug, the cathode of the sixth diode D6 is connected to the load, a portion of the voltage input by the DC plug flows through the first diode D1 and the first current limiting component 200 to the transistor Q, and another portion of the voltage directly powers the load through the sixth diode D6, thereby providing a variety of power supply modes for the load.

[0047] The present application is described below by means of an embodiment.

[0048] Reference Figure 2 and 3 , Figure 3 : is a circuit diagram of a charging circuit of another electrical device provided in an embodiment of the present application. The electrical device includes a switching power supply, a battery pack and a load. The positive electrode of the switching power supply is connected to the positive electrode of the battery pack. The switching power supply and the battery pack are both connected to the load for power supply. The charging circuit includes:

[0049] DC plug and step-down circuit; the step-down circuit is used to convert the voltage input by the DC plug into a target voltage, the step-down circuit includes a transistor Q and a voltage stabilizing component, the voltage stabilizing component includes a parallel regulator 110 and a voltage dividing branch, the collector of the transistor Q is connected to the positive electrode of the DC plug, the cathode of the parallel regulator 110 is connected to the base of the transistor Q, the anode of the parallel regulator 110 is connected to the negative electrode of the DC plug, the reference end of the parallel regulator 110 is connected to the voltage dividing point of the voltage dividing branch, one end of the voltage dividing branch is connected to the emitter of the transistor Q, and the other end is connected to the negative electrode of the DC plug, the emitter of the transistor Q is connected to the positive electrode of the switching power supply, and is used to output the target voltage; wherein the size of the target voltage is suitable for charging the battery pack. The voltage dividing branch includes a first resistor R1 and a second resistor R2, the first resistor R1 and the second resistor R2 are connected in series, and the reference end of the parallel regulator 110 is connected between the first resistor R1 and the second resistor R2. By selecting the first resistor R1 and the second resistor R2 with preset resistance values, the voltage dividing point of the voltage dividing branch provides a voltage suitable for the reference end of the TL431 voltage regulator, so that the TL431 voltage regulator is in a working state of voltage regulation output, so that the emitter of the transistor Q can output a target voltage suitable for charging the battery pack to the positive electrode of the switching power supply.

[0050] The output voltage is calculated by the working state characteristics of the TL431 voltage regulator. Specifically, the output voltage of the TL431 voltage regulator is calculated as follows:

[0051]

[0052] Wherein, V0 is the output voltage of TL431 voltage regulator, R1 is the resistance value of the first resistor R1, R2 is the resistance value of the second resistor R2, V r It is the reference voltage of the TL431 voltage regulator.

[0053] The resistance value of the first resistor R1 is selected to be 4.7KΩ, and the resistance value of the second resistor R2 is selected to be 1.8KΩ. By setting the resistance value of the first resistor R1 to 4.7KΩ and the resistance value of the second resistor R2 to 1.8Ω, the voltage given to the reference end of the TL431 voltage regulator is greater than the internal reference voltage of 2.5V, so that the TL431 voltage regulator is in a working state of voltage regulation output, so that the stable output voltage of the TL431 voltage regulator is 9.03V. Since the cathode of the TL431 voltage regulator is connected to the base of the transistor Q, the emitter of the transistor Q outputs a voltage of 9.03V, and outputs a voltage of 9.03V to the switching power supply through the emitter of the transistor Q, thereby realizing the step-down circuit to convert the input voltage of the DC plug into a target voltage suitable for charging the battery pack. The positive electrode of the switching power supply outputs the target voltage, and part of the voltage outputted by the positive electrode of the switching power supply returns to the negative electrode of the switching power supply through the fifth resistor R5, and the other part of the voltage passes through the second current limiting component 300, the second diode D2, and the fuse 400 to the battery pack to provide power for charging the battery pack, and the voltage inputted by the DC plug can be converted into a target voltage suitable for charging the battery pack. In addition, the fuse 400 and the battery pack are connected in series to avoid overcharging, overdischarging and excessive current, play a role in protecting the charging circuit, and improve the safety and reliability of the charging circuit.

[0054] The step-down circuit also includes a third resistor R3, a fourth resistor R4 and a capacitor C. The voltage input by the DC plug passes through the first diode D1 and the first current limiting component 200 to the collector of the transistor Q, and then passes through the third resistor R3 to the cathode of the TL431 voltage regulator. When the voltage input by the DC plug passes through the collector of the transistor Q and the base of the transistor Q to the fourth resistor R4 and then to the compensation capacitor C, the transistor Q is in a conducting state, so that the reference end of the TL431 voltage regulator is greater than the internal reference voltage, so that the TL431 voltage regulator is in a working state of voltage stabilization output, so that the input voltage of the DC plug can be converted into a stable target voltage, and the target voltage is output to the switching power supply through the emitter of the transistor Q, that is, the battery pack is charged by the target voltage, thereby realizing that the step-down circuit converts the input voltage of the DC plug into the target voltage to charge the battery pack.

[0055] The charging circuit also includes a fifth resistor R5 and a fuse 400, the fifth resistor R5 is connected in parallel with the battery pack, one end of the fuse 400 is connected to the negative electrode of the second diode D2, and the other end of the fuse 400 is connected to the positive electrode of the battery pack. By setting the fuse 400 and the battery pack in series, the current output by the switching power supply passes through the second current limiting component 300 and the second diode D2, and then flows through the fuse 400 to the battery pack. The fuse 400 can avoid overcharging, overdischarging and excessive current, play a role in protecting the charging circuit, and improve the safety and reliability of the charging circuit. By setting the fifth resistor R5 and the battery pack in parallel, a part of the voltage output by the positive electrode of the switching power supply passes through the fifth resistor R5 and returns to the negative electrode of the switching power supply, and the other part of the voltage passes through the second current limiting component 300 and the second diode D2 to the battery pack. Therefore, the fifth resistor R5 and the battery pack are connected in parallel to play a voltage dividing role, so that the voltage output by the switching power supply to the battery pack is suitable for charging the battery pack. The charging circuit also includes a sixth diode D6, the anode of the sixth diode D6 is connected to the anode of the DC plug, the cathode of the sixth diode D6 is connected to the load, a part of the voltage input by the DC plug flows through the first diode D1 and the first current limiting component 200 to the transistor Q, and another part of the voltage directly supplies power to the load through the sixth diode D6, thereby providing a variety of power supply modes for the load.

[0056] In addition, it should be noted that the present application can output a target voltage through the parallel regulator 110 for different voltages input by the DC plug. Since the output end of the TL431 regulator is limited to 9.03V output, the parallel regulator 110 in the present application will not cause a high output voltage due to the high voltage input of the DC plug with different voltage specifications, and it plays a constant voltage output role, thereby improving the stability of the charging circuit. Since the size of the target voltage is suitable for charging the battery pack, it can effectively avoid the current and voltage of the charging circuit being too large to cause the circuit to heat up, thereby improving the safety and reliability of the charging circuit.

[0057] The embodiment of the present application also provides an electric device, which includes a switching power supply, a battery pack, a load and a charging circuit provided in the above embodiment. The positive electrode of the switching power supply is connected to the positive electrode of the battery pack, and the switching power supply and the battery pack are both connected to the load for power supply. The charging circuit makes the output of the emitter of the triode output a stable target voltage through a parallel regulator, and then connects the target voltage to the positive electrode of the switching power supply through a third diode. The charging circuit converts the input voltage of the DC plug into a stable target voltage, and charges the battery pack through the target voltage. The switching power supply and the battery pack are both connected to the load and power the load. In addition, in the electric device of the present application, the target voltage can be output through the parallel regulator for different voltages input by the DC plug. The parallel regulator will not cause the output voltage to be high due to the high voltage input of the DC plug with different voltage specifications, and plays a constant voltage output role, which improves the stability of the charging circuit. Since the size of the target voltage is suitable for charging the battery pack, it effectively avoids the current and voltage of the charging circuit from being too large, which causes the circuit to heat up, and improves the safety and reliability of the charging circuit.

[0058] The above is a specific description of the preferred implementation of the present application, but the present application is not limited to the above-mentioned implementation mode. Technical personnel familiar with the field can also make various equivalent deformations or substitutions without violating the spirit of the present application. These equivalent deformations or substitutions are all included in the scope defined by the claims of the present application.

Claims

1. A charging circuit for an electric device, characterized in that: The electrical equipment comprises a switching power supply, a battery pack and a load, the positive electrode of the switching power supply is connected to the positive electrode of the battery pack, the switching power supply and the battery pack are both connected to the load for power supply, and the charging circuit comprises: DC plug; A step-down circuit, used for converting the voltage input by the DC plug into a target voltage; the step-down circuit includes a transistor and a voltage stabilizing component, the voltage stabilizing component includes a shunt regulator and a voltage dividing branch, the collector of the transistor is connected to the positive electrode of the DC plug, the cathode of the shunt regulator is connected to the base of the transistor, the anode of the shunt regulator is connected to the negative electrode of the DC plug, the reference end of the shunt regulator is connected to the voltage dividing point of the voltage dividing branch, one end of the voltage dividing branch is connected to the emitter of the transistor, and the other end is connected to the negative electrode of the DC plug, the emitter of the transistor is connected to the positive electrode of the switching power supply, and is used for outputting the target voltage; The target voltage is suitable for charging the battery pack.

2. The charging circuit of the electric device according to claim 1, characterized in that: include: The voltage dividing branch includes a first resistor and a second resistor, the first resistor and the second resistor are connected in series, and the reference end of the parallel regulator is connected between the first resistor and the second resistor.

3. The charging circuit of the electric device according to claim 1, characterized in that: The step-down circuit further includes a first current limiting component and a first diode. The DC plug is connected to one end of the first current limiting component through the first diode, and the other end of the first current limiting component is connected to the collector of the transistor.

4. The charging circuit of the electric device according to claim 3, characterized in that: The step-down circuit also includes a third resistor, a fourth resistor and a capacitor, one end of the third resistor is connected to the cathode of the first diode, the other end of the third resistor is connected to the cathode of the parallel regulator, one end of the fourth resistor is connected to the base of the transistor, the other end of the fourth resistor is connected to the cathode of the parallel regulator, and the capacitor is connected in parallel with the parallel regulator.

5. The charging circuit of the electric device according to claim 1 or 2, characterized in that: The shunt regulator is a TL431 voltage regulator.

6. The charging circuit of the electric device according to claim 1, characterized in that: It also includes a second current limiting component and a second diode, one end of the second current limiting component is connected to the positive electrode of the switching power supply, the other end of the second current limiting component is connected to the positive electrode of the second diode, and the negative electrode of the second diode is connected to the positive electrode of the battery pack.

7. The charging circuit of the electric device according to claim 1, characterized in that: It also includes a third diode and a fourth diode, wherein the anode of the third diode is connected to the emitter of the transistor, the cathode of the third diode is connected to the anode of the switching power supply, the anode of the fourth diode is connected to the anode of the switching power supply, and the cathode of the fourth diode is connected to the load.

8. The charging circuit of the electric device according to claim 6, characterized in that: It also includes a fifth resistor and a fuse, wherein the fifth resistor is connected in parallel with the battery pack, one end of the fuse is connected to the cathode of the second diode, and the other end of the fuse is connected to the anode of the battery pack.

9. The charging circuit of the electric device according to claim 8, characterized in that: It also includes a fifth diode, wherein the anode of the fifth diode is connected to the cathode of the second diode, and the cathode of the fifth diode is connected to the load.

10. An electrical device, characterized in that: The charging circuit comprises the charging circuit as claimed in any one of claims 1 to 9.

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