Charging indication circuit and charger

Abstract

The utility model relates to a charging indication circuit and a charger. The charging indication circuit comprises a sampling module, a detection module, a switch switching module and an indication module. The sampling module is used for accessing a bus, the detection module is respectively connected with the sampling module and the switch switching module, and the switch switching module is also connected with the indication module; the sampling module is used for sampling a current signal of a bus and converting the current signal into a voltage signal; the detection module is used for outputting a first control signal to the switch switching module when the voltage signal is smaller than a first preset threshold value, and outputting a second control signal to the switch switching module when the voltage signal is larger than or equal to the first preset threshold value; the switch switching module is used for being switched on to control the indication module to be in a first indication state when receiving the first control signal, and is switched off to control the indication module to be in a second indication state when receiving the second control signal. Pin resources of the single-chip microcomputer are not used, so that the pin resources of the unit machine are saved.

Description

Technical Field

[0001] The present application relates to the field of power electronics technology, and in particular to a charging indication circuit and a charger. Background Art

[0002] With the increasing demand for travel and outdoor activities and the booming portable energy storage power market, the demand for portable energy storage power chargers has also grown. Portable energy storage power chargers usually have a small and lightweight design, which is easy to carry and use.

[0003] The charger usually needs two colors of LED (light-emitting diode) to indicate the status of the charger, which includes the loaded state and the unloaded state. Usually, two microcontroller pins are used to control the two LEDs respectively. Utility Model Content

[0004] The embodiments of the present application provide a charging indication circuit and a charger, which can indicate whether the charger is loaded and have a relatively simple structure.

[0005] In a first aspect, an embodiment of the present application provides a charging indication circuit, comprising: a sampling module, a detection module, a switch switching module and an indication module; the sampling module is used to access a bus, the detection module is connected to the sampling module and the switch switching module respectively, and the switch switching module is also connected to the indication module; the sampling module is used to sample the current signal of the bus and convert the current signal into a voltage signal; the detection module is used to output a first control signal to the switch switching module when the voltage signal is less than a first preset threshold, and output a second control signal to the switch switching module when the voltage signal is greater than or equal to the first preset threshold; the switch switching module is used to turn on when receiving the first control signal to control the indication module to be in a first indication state, and turn off when receiving the second control signal to control the indication module to be in a second indication state.

[0006] In some embodiments, the detection module includes: a comparison unit and a feedback unit; the first input end of the comparison unit is used to connect to a first power supply, the second input end of the comparison unit is connected to the sampling module, the input end of the feedback unit is connected to the first input end of the comparison unit, the output end of the feedback unit is connected to the output end of the comparison unit, and the output end of the comparison unit is connected to the switch switching module; the comparison unit is used to output a first control signal to the switch switching module when the voltage signal is less than a first preset threshold, and output a second control signal to the switch switching module when the voltage signal is greater than or equal to the first preset threshold; the feedback unit is used to pull down the voltage of the first input end of the comparison unit when the voltage signal is greater than or equal to the first preset threshold, so that the comparison unit outputs the first control signal when the voltage signal is less than the second preset threshold; wherein the second preset threshold is less than the first preset threshold.

[0007] In some embodiments, the comparison unit includes: a comparator U2A, a resistor R6, a resistor R7, a resistor R11, a resistor R13, a capacitor C3, and a capacitor C5; the first end of the resistor R7 is used to connect to the first power supply, the first end of the resistor R6 is connected to the sampling module, the second end of the resistor R7 is connected to the first end of the resistor R11 and the first end of the resistor R13, the second end of the resistor R11 is connected to the in-phase input end of the comparator U2A, the first end of the capacitor C3, and the input end of the feedback unit, the inverting input end of the comparator U2A is connected to the second end of the resistor R6 and the first end of the capacitor C5, the second end of the capacitor C5, the second end of the resistor R13, and the second end of the capacitor C3 are all grounded, and the output end of the comparator U2A is connected to the output end of the feedback unit and the switch switching module.

[0008] In some embodiments, the feedback unit includes: a resistor R5 and a diode D1; the first end of the resistor R5 is connected to the first input end of the comparison unit, the second end of the resistor R5 is connected to the anode of the diode D1, and the cathode of the diode D1 is connected to the output end of the comparison unit.

[0009] In some embodiments, the indication module includes: a light-emitting unit, a resistor R8, a resistor R9, and a resistor R10; the input end of the light-emitting unit and the first end of the resistor R8 are both connected to a second power supply, the second end of the resistor R8 is connected to the switch switching module, the first output end of the light-emitting unit is connected to the switch switching module through the resistor R9, and the second output end of the light-emitting unit is connected to the switch switching module through the resistor R10.

[0010] In some embodiments, the light-emitting unit includes: a first LED and a second LED; the anode of the first LED is connected to the anode of the second LED and the second power supply respectively, the cathode of the first LED is connected to the switch switching module through the resistor R9, and the cathode of the second LED is connected to the switch switching module through the resistor R10.

[0011] In some embodiments, the sampling module includes: an amplifier U1A, a resistor R1, a resistor R2, a resistor R3, a resistor R4, and a capacitor C1; the first end of the resistor R1 and the first end of the resistor R2 are both connected to the bus, the second end of the resistor R2 is grounded, the second end of the resistor R1 is connected to the first end of the capacitor C1 and the in-phase input end of the amplifier U1A, the inverting input end of the amplifier U1A is connected to the first end of the resistor R3 and the first end of the resistor R4, the second end of the resistor R3 is connected to the output end of the amplifier U1A, the second end of the capacitor C1 and the second end of the resistor R4 are both grounded, and the output end of the amplifier U1A is connected to the detection module.

[0012] In some embodiments, the switch switching module is a switch tube Q1; the gate of the switch tube Q1 is respectively connected to the detection module and the indication module, the drain of the switch tube Q1 is connected to the indication module, and the source of the switch tube Q1 is grounded.

[0013] In some embodiments, the switch switching module includes: a switch tube Q1 and a resistor R12; the gate of the switch tube Q1 is connected to the first end of the resistor R12, the detection module, and the indication module, the drain of the switch tube Q1 is connected to the indication module, and the source of the switch tube Q1 is connected to the second end of the resistor R12 and grounded.

[0014] In some embodiments, the switch tube Q1 is an NMOS tube.

[0015] In a second aspect, an embodiment of the present application provides a charger, comprising a battery and a charging indication circuit as described above; the negative pole of the battery is connected to the charging indication circuit; the battery is used to be connected to a load to power the load and generate a current signal; the charging indication circuit is used to control an indication module of the charging indication circuit to be in a first indication state or a second indication state according to the current signal.

[0016] The embodiment of the present application provides a charging indication circuit and a charger, and the charging indication circuit includes: a sampling module, a detection module, a switch switching module and an indication module; the sampling module is used to access the bus, the detection module is connected to the sampling module and the switch switching module respectively, and the switch switching module is also connected to the indication module; the current signal of the bus is sampled by the sampling module, and the current signal is converted into a voltage signal, and then the switch switching module is controlled to be turned on by the detection module when the voltage signal is less than the first preset threshold value so that the indication module is in the first indication state, and the switch switching module is controlled to be turned off by the detection module when the voltage signal is greater than or equal to the first preset threshold value so that the indication module is in the second indication state. Thus, the state of the charger is indicated by the first indication state and the second indication state. The charging indication circuit of the embodiment of the present application does not use the pin resources of the single-chip microcomputer, thereby saving the pin resources of the unit machine. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] One or more embodiments are exemplarily described by corresponding drawings, which do not constitute limitations on the embodiments. Elements with the same reference numerals in the drawings represent similar elements, and the figures in the drawings do not constitute proportional limitations unless otherwise stated.

[0018] Figure 1 is a structural block diagram of a charger provided in an embodiment of the present application;

[0019] Figure 2 is a structural block diagram of a charging indication circuit provided in an embodiment of the present application;

[0020] Figure 3 is a schematic diagram of the circuit structure of a sampling module provided in an embodiment of the present application;

[0021] Figure 4 is a structural block diagram of a sampling module provided in an embodiment of the present application;

[0022] Figure 5 It is a schematic diagram of the circuit structure of a detection module, a switch switching module and an indication module provided in an embodiment of the present application. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme in the embodiments of the present application will be described clearly and in detail in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the 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.

[0024] The technical features involved in the various embodiments of the present application described below do not conflict with each other and can be combined with each other.

[0025] When an element is referred to as being “connected to” another element, it can be directly connected to the other element, or one or more intervening elements may be present therebetween.

[0026] The terms "first", "second", etc. in the specification and claims of this application are used to distinguish similar objects, and are not used to describe a specific order or sequence. It should be understood that the terms used in this way can be interchangeable under appropriate circumstances, so that the embodiments of the present application can be implemented in an order other than those illustrated or described here, and the objects distinguished by "first", "second", etc. are generally of the same type, and the number of objects is not limited. For example, the first object can be one or more.

[0027] See also Figure 1 , Figure 1 It is a structural block diagram of a charger 1000 provided in an embodiment of the present application.

[0028] The charger 1000 provided in the present application includes a battery 200 and a charging indication circuit 100. The negative electrode of the battery 200 is connected to the charging indication circuit 100. The battery 200 can be connected to the load 2000 through a bus bar.

[0029] When the battery 200 is connected to the load 2000, the battery 200 can supply power to the load 2000 and generate a current signal in the bus. The charging indication circuit 100 controls the indication module 40 of the charging indication circuit 100 to be in the first indication state or the second indication state according to the current signal.

[0030] The first indication state is used to indicate that the state of the battery 200 is an unloaded state or a low-load state, and the second indication state is used to indicate that the state of the battery 200 is a loaded state.

[0031] See also Figure 2 , Figure 2 1 is a structural block diagram of a charging indication circuit 100 provided in an embodiment of the present application.

[0032] like Figure 2As shown, the charging indication circuit 100 includes: a sampling module 10, a detection module 20, a switch switching module 30 and an indication module 40. Specifically, the sampling module 10 is used to access the bus, the detection module 20 is connected to the sampling module 10 and the switch switching module 30 respectively, and the switch switching module 30 is also connected to the indication module 40. Among them, the sampling module 10 can sample the current signal of the bus and convert the current signal into a voltage signal; when the voltage signal is less than the first preset threshold, the detection module 20 outputs a first control signal to the switch switching module 30, and when the voltage signal is greater than or equal to the first preset threshold, the detection module 20 outputs a second control signal to the switch switching module 30; when the first control signal is received, the switch switching module 30 is turned on to control the indication module 40 to be in the first indication state, and when the second control signal is received, the switch switching module 30 is turned off to control the indication module 40 to be in the second indication state.

[0033] When the indication module 40 is in the first indication state, it indicates that the battery 200 is in an unloaded state or a low-load state, where unload means that the battery 200 is not connected to a load, and low-load means that the battery 200 is connected to a load with relatively low power. When the indication module 40 is in the second indication state, it indicates that the battery 200 is in a loaded state, where loaded means that the battery 200 is connected to a load with sufficiently high power.

[0034] It should be noted that the first preset threshold is determined by the connection relationship between the components of the circuit and the components, and is not specifically limited here. In addition, the first control signal is used to control the switch switching module 30 to be turned on, and the second control signal is used to control the switch switching module 30 to be turned off. In some embodiments, the first control signal is a high level signal, and the second control signal is a low level signal.

[0035] See also Figure 3 , Figure 3 Schematic diagram of the circuit structure of the sampling module 10 provided in one embodiment of the present application.

[0036] In some embodiments, the sampling module 10 includes: an amplifier U1A, a resistor R1, a resistor R2, a resistor R3, a resistor R4, and a capacitor C1. Specifically, the first end of the resistor R1 and the first end of the resistor R2 are both connected to the bus, the second end of the resistor R2 is grounded, the second end of the resistor R1 is connected to the first end of the capacitor C1 and the in-phase input end of the amplifier U1A, the inverting input end of the amplifier U1A is connected to the first end of the resistor R3 and the first end of the resistor R4, the second end of the resistor R3 is connected to the output end of the amplifier U1A, the second end of the capacitor C1 and the second end of the resistor R4 are both grounded, and the output end of the amplifier U1A is connected to the detection module 20.

[0037] In this embodiment, the current signal on the busbar forms an initial voltage signal on the resistor R2, and the amplifier U1A amplifies the initial voltage signal to form a voltage signal.

[0038] See also Figure 4 , Figure 4 It is a structural block diagram of a sampling module provided in an embodiment of the present application.

[0039] In some embodiments, Figure 4 As shown, the detection module 20 includes: a comparison unit 201 and a feedback unit 202. Specifically, the first input end of the comparison unit 201 is used to connect to the first power supply 300, the second input end of the comparison unit 201 is connected to the sampling module 10, the input end of the feedback unit 202 is connected to the first input end of the comparison unit 201, the output end of the feedback unit 202 is connected to the output end of the comparison unit 201, and the output end of the comparison unit 201 is connected to the switch switching module 30.

[0040] In this embodiment, when the voltage signal is less than the first preset threshold, the comparison unit 201 outputs a first control signal to the switch switching module 30, and when the voltage signal is greater than or equal to the first preset threshold, the comparison unit 201 outputs a second control signal to the switch switching module 30; when the voltage signal is greater than or equal to the first preset threshold, the feedback unit 202 pulls down the voltage of the first input terminal of the comparison unit 201, so that the comparison unit 201 outputs the first control signal when the voltage signal is less than the second preset threshold.

[0041] Among them, the second preset threshold is less than the first preset threshold. It should be noted that the first preset threshold and the second preset threshold are determined by the connection relationship between the components of the circuit and the components, and are not specifically limited here. The first control signal is used to control the switch switching module 30 to be turned on, and the second control signal is used to control the switch switching module 30 to be turned off. In some embodiments, the first control signal is a high-level signal, and the second control signal is a low-level signal.

[0042] See also Figure 5 , Figure 5 It is a schematic diagram of the circuit structure of the detection module 20, the switch switching module 30 and the indication module 40 provided in one embodiment of the present application.

[0043] In some embodiments, Figure 5As shown, the comparison unit 201 includes: a comparator U2A, a resistor R6, a resistor R7, a resistor R11, a resistor R13, a capacitor C3, and a capacitor C5. Specifically, the first end of the resistor R7 is used to connect to the first power supply 300, the first end of the resistor R6 is connected to the sampling module 10, the second end of the resistor R7 is connected to the first end of the resistor R11 and the first end of the resistor R13, the second end of the resistor R11 is connected to the in-phase input end of the comparator U2A, the first end of the capacitor C3, and the input end of the feedback unit 202, the inverting input end of the comparator U2A is connected to the second end of the resistor R6 and the first end of the capacitor C5, the second end of the capacitor C5, the second end of the resistor R13, and the second end of the capacitor C3 are all grounded, and the output end of the comparator U2A is connected to the output end of the feedback unit 202 and the switch switching module 30.

[0044] The feedback unit 202 includes a resistor R5 and a diode D1. Specifically, the first end of the resistor R5 is connected to the first input end of the comparison unit 201, the second end of the resistor R5 is connected to the anode of the diode D1, and the cathode of the diode D1 is connected to the output end of the comparison unit 201.

[0045] The switch switching module 30 includes: a switch tube Q1 and a resistor R12. Specifically, the gate of the switch tube Q1 is connected to the first end of the resistor R12, the detection module 20, and the indication module 40, the drain of the switch tube Q1 is connected to the indication module 40, and the source of the switch tube Q1 is connected to the second end of the resistor R12 and grounded. In some embodiments, the switch tube Q1 is an NMOS tube.

[0046] The indicating module 40 includes: a light emitting unit, a resistor R8, a resistor R9, and a resistor R10. Specifically, the input end of the light emitting unit and the first end of the resistor R8 are connected to the second power supply, the second end of the resistor R8 is connected to the switch switching module 30, the first output end of the light emitting unit is connected to the switch switching module 30 through the resistor R9, and the second output end of the light emitting unit is connected to the switch switching module 30 through the resistor R10.

[0047] In some embodiments, the light emitting unit includes: a first LED and a second LED. Specifically, the anode of the first LED is connected to the anode of the second LED and the second power supply respectively, the cathode of the first LED is connected to the switch switching module 30 through the resistor R9, and the cathode of the second LED is connected to the switch switching module 30 through the resistor R10. Figure 5 As shown, the first LED is LED1 and the second LED is LED2. In some embodiments, the light emitting colors of LED1 and LED2 are different, for example, LED1 may be a red light emitting diode and LED2 may be a green light emitting diode. In some embodiments, the light emitting unit may be a two-color common anode diode having one anode and two cathodes.

[0048] It should be noted that if Figure 3 and Figure 4 As shown, by setting the resistance values ​​of resistors R1 , R3 , R7 , and R8 , the first preset threshold value and the second preset threshold value can be set.

[0049] Specifically, when the voltage signal is less than the first preset threshold, the voltage at the inverting input terminal of the comparator U2A is less than the voltage at the non-inverting input terminal, and the comparator U2A outputs a high level, i.e., a first control signal. The NMOS tube Q1 is connected to the power supply through the pull-up resistor R8 and the comparator U2A outputs a high level, at which time the NMOS tube is turned on to control LED2 to light up and LED1 not to light up, i.e., the indication module is in the first indication state, indicating that the battery is in a no-load state or a low-load state.

[0050] When the voltage signal is greater than or equal to the first preset threshold, the voltage at the inverting input terminal of the comparator U2A is less than the voltage at the inverting input terminal, and the comparator U2A outputs a low level, i.e., the second control signal. The NMOS tube is turned off because the gate voltage is grounded, so the control LED1 is lit and LED2 is not lit, i.e., the indication module is in the second indication state, indicating that the battery is in the loaded state. At the same time, the feedback unit 202 composed of the resistor R5 and the diode D1 pulls down the voltage at the inverting input terminal of the comparator U2A, so that the voltage at the inverting input terminal of the comparator U2A, i.e., the voltage signal, must be reduced to less than the second preset threshold before the output of the comparator U2A will be converted back to a high level, thereby forming a hysteresis window. By setting the detection module 20 as a hysteresis comparator, the phenomenon of the first LED and the second LED switching back and forth when the current of the load fluctuates can be avoided. The freewheeling diode D1 is set in the feedback unit 202 to prevent the high current on the NMOS tube Q1 and LED1 side from affecting the voltage at the inverting input terminal of the comparator U2A as a reference, thereby improving the stability of the output of the comparator U2A.

[0051] The embodiment of the present application provides a charging indication circuit 100, comprising: a sampling module 10, a detection module 20, a switch switching module 30 and an indication module 40. The sampling module 10 is used to access the bus, the detection module 20 is connected to the sampling module 10 and the switch switching module 30 respectively, and the switch switching module 30 is also connected to the indication module 40. The current signal of the bus is sampled by the sampling module 10, and the current signal is converted into a voltage signal. Then, when the voltage signal is less than the first preset threshold, the switch switching module 30 is controlled to be turned on by the detection module 20 so that the indication module 40 is in the first indication state, and when the voltage signal is greater than or equal to the first preset threshold, the switch switching module 30 is controlled to be turned off by the detection module 20 so that the indication module 40 is in the second indication state. Thus, the state of the charger is indicated by the first indication state and the second indication state. The charging indication circuit 100 of the embodiment of the present application does not use the pin resources of the single-chip microcomputer, thereby saving the pin resources of the unit machine.

[0052] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Based on the idea of ​​the present application, the technical features in the above embodiments or different embodiments may also be combined, and there are many other changes in different aspects of the present application as described above, which are not provided in detail for the sake of simplicity. Although the present application has been described in detail with reference to the aforementioned embodiments, a person of ordinary skill in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A charging indication circuit, It is characterized in that include: Sampling module, detection module, switch module and indication module; The sampling module is used to access the bus, the detection module is connected to the sampling module and the switch module respectively, and the switch module is also connected to the indication module; The sampling module is used to sample the current signal of the bus and convert the current signal into a voltage signal; The detection module is used to output a first control signal to the switch switching module when the voltage signal is less than a first preset threshold, and output a second control signal to the switch switching module when the voltage signal is greater than or equal to the first preset threshold; The switch switching module is used to be turned on when receiving the first control signal to control the indication module to be in a first indication state, and to be turned off when receiving the second control signal to control the indication module to be in a second indication state.

2. The charging indication circuit according to claim 1, It is characterized in that The detection module includes: a comparison unit and a feedback unit; The first input end of the comparison unit is used to connect to the first power supply, the second input end of the comparison unit is connected to the sampling module, the input end of the feedback unit is connected to the first input end of the comparison unit, the output end of the feedback unit is connected to the output end of the comparison unit, and the output end of the comparison unit is connected to the switch switching module; The comparison unit is used to output a first control signal to the switch switching module when the voltage signal is less than a first preset threshold, and output a second control signal to the switch switching module when the voltage signal is greater than or equal to the first preset threshold; The feedback unit is used to pull down the voltage of the first input terminal of the comparison unit when the voltage signal is greater than or equal to a first preset threshold, so that the comparison unit outputs the first control signal when the voltage signal is less than a second preset threshold; wherein the second preset threshold is less than the first preset threshold.

3. The charging indication circuit according to claim 2, It is characterized in that The comparison unit includes: a comparator U2A, a resistor R6, a resistor R7, a resistor R11, a resistor R13, a capacitor C3, and a capacitor C5; The first end of the resistor R7 is used to connect to the first power supply, the first end of the resistor R6 is connected to the sampling module, the second end of the resistor R7 is connected to the first end of the resistor R11 and the first end of the resistor R13, the second end of the resistor R11 is connected to the non-inverting input end of the comparator U2A, the first end of the capacitor C3 and the input end of the feedback unit, the inverting input end of the comparator U2A is connected to the second end of the resistor R6 and the first end of the capacitor C5, the second end of the capacitor C5, the second end of the resistor R13 and the second end of the capacitor C3 are all grounded, and the output end of the comparator U2A is connected to the output end of the feedback unit and the switch switching module.

4. The charging indication circuit according to claim 2, It is characterized in that The feedback unit includes: a resistor R5 and a diode D1; The first end of the resistor R5 is connected to the first input end of the comparison unit, the second end of the resistor R5 is connected to the anode of the diode D1, and the cathode of the diode D1 is connected to the output end of the comparison unit.

5. The charging indication circuit according to claim 1, It is characterized in that The indication module includes: a light emitting unit, a resistor R8, a resistor R9, and a resistor R10; The input end of the light-emitting unit and the first end of the resistor R8 are both connected to the second power supply, the second end of the resistor R8 is connected to the switch switching module, the first output end of the light-emitting unit is connected to the switch switching module through the resistor R9, and the second output end of the light-emitting unit is connected to the switch switching module through the resistor R10.

6. The charging indication circuit according to claim 5, It is characterized in that The light emitting unit comprises: a first LED and a second LED; The anode of the first LED is connected to the anode of the second LED and the second power supply respectively, the cathode of the first LED is connected to the switch module through the resistor R9, and the cathode of the second LED is connected to the switch module through the resistor R10.

7. The charging indication circuit according to claim 1, It is characterized in that The sampling module includes: an amplifier U1A, a resistor R1, a resistor R2, a resistor R3, a resistor R4, and a capacitor C1; The first end of the resistor R1 and the first end of the resistor R2 are both connected to the bus, the second end of the resistor R2 is grounded, the second end of the resistor R1 is connected to the first end of the capacitor C1 and the non-inverting input end of the amplifier U1A, the inverting input end of the amplifier U1A is connected to the first end of the resistor R3 and the first end of the resistor R4, the second end of the resistor R3 is connected to the output end of the amplifier U1A, the second end of the capacitor C1 and the second end of the resistor R4 are both grounded, and the output end of the amplifier U1A is connected to the detection module.

8. The charging indication circuit according to claim 1, It is characterized in that The switch switching module includes: a switch tube Q1 and a resistor R12; The gate of the switch tube Q1 is connected to the first end of the resistor R12, the detection module and the indication module, the drain of the switch tube Q1 is connected to the indication module, and the source of the switch tube Q1 is connected to the second end of the resistor R12 and grounded.

9. The charging indication circuit according to claim 8, It is characterized in that The switch tube Q1 is an NMOS tube.

10. A charger, It is characterized in that The charger comprises a battery and a charging indication circuit as claimed in any one of claims 1 to 9; The negative electrode of the battery is connected to the charging indication circuit; The battery is used to be connected to a load to supply power to the load and generate a current signal; The charging indication circuit is used to control the indication module of the charging indication circuit to be in the first indication state or the second indication state according to the current signal.

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