Charging circuit and electric toothbrush

Abstract

The utility model discloses a charging circuit and an electric toothbrush, the charging circuit comprises a power supply input end, the power supply input end is used for accessing a power supply; the switching circuit is connected in series between the power supply input end and the positive electrode of the battery; the detection end of the electric quantity detection circuit is electrically connected with the positive electrode of the battery, and the electric quantity detection circuit is used for detecting the residual electric quantity output to the battery and outputting a corresponding electric quantity detection signal; the main control circuit is electrically connected with the controlled end of the switching circuit and the electric quantity detection circuit, and the main control circuit is used for controlling the switching circuit to be switched off to stop charging the battery when it is detected that the residual electric quantity of the battery reaches a preset electric quantity threshold value according to the electric quantity detection signal; the utility model aims to avoid accelerated aging and shortened service life of the battery in a floating charge state after the battery is fully charged.

Description

Technical Field

[0001] This utility model relates to the field of electric toothbrush technology, and in particular to a charging circuit and an electric toothbrush. Background Technology

[0002] With the increasing popularity of personal care devices, electric toothbrushes, as an oral cleaning tool, are gaining popularity among consumers due to their efficiency and convenience.

[0003] Most electric toothbrushes on the market currently use lithium-ion or nickel-metal hydride batteries as their power source, and are powered by a charging circuit. During the charging process, to ensure that the battery is always fully charged and ready for use, many electric toothbrushes enter a "float charging" state after the battery is fully charged.

[0004] Although float charging can ensure that the battery is always fully charged to a certain extent, long-term float charging will have a significant negative impact on the battery's lifespan and performance, such as accelerating battery aging and shortening the battery's lifespan. Utility Model Content

[0005] The main purpose of this invention is to provide a charging circuit and an electric toothbrush that aims to prevent the battery from aging faster and its lifespan from being in a float charging state after it is fully charged.

[0006] To achieve the above objectives, this utility model proposes a charging circuit for use in an electric toothbrush, the electric toothbrush including a battery, comprising:

[0007] A power input terminal, which is used to connect to a power supply;

[0008] A switching circuit, wherein the switching circuit is connected in series between the power input terminal and the positive terminal of the battery;

[0009] A power detection circuit, wherein the detection terminal of the power detection circuit is electrically connected to the positive terminal of the battery, the power detection circuit is used to detect the remaining power output to the battery and output a corresponding power detection signal;

[0010] The main control circuit is electrically connected to the controlled terminal of the switch circuit and the power detection circuit. The main control circuit is used to control the switch circuit to turn off when it detects that the remaining power of the battery has reached a preset power threshold based on the power detection signal, so as to stop charging the battery.

[0011] In one embodiment, the switching circuit includes:

[0012] The main switch circuit and the drive circuit are provided, wherein the input terminal of the main switch circuit is connected to the power input terminal, and the output terminal of the main switch circuit is connected to the positive terminal of the battery.

[0013] The input terminal of the drive circuit is electrically connected to the main control circuit, and the output terminal of the drive circuit is connected to the controlled terminal of the main switch circuit.

[0014] In one embodiment, the main switching circuit includes:

[0015] A first switching transistor and a first resistor, wherein the input terminal of the first switching transistor is connected to the power input terminal, the output terminal of the first switching transistor is connected to the positive terminal of the battery, and the controlled terminal of the first switching transistor is electrically connected to the drive circuit;

[0016] The first end of the first resistor is connected to the input terminal of the first switching transistor, and the second end of the first resistor is connected to the controlled terminal of the first switching transistor.

[0017] In one embodiment, the driving circuit includes:

[0018] The circuit consists of a second switch, a first diode, a second resistor, and a third resistor. The input terminal of the second switch is connected to the controlled terminal of the main switch circuit, the output terminal of the second switch is grounded, and the controlled terminal of the second switch is electrically connected to the main control circuit.

[0019] The anode of the first diode is connected to the power input terminal, the cathode of the first diode is connected to the first end of the second resistor, the second end of the second resistor is connected to the controlled terminal of the second switch, the first end of the third resistor is connected to the controlled terminal of the second switch, and the second end of the third resistor is grounded.

[0020] In one embodiment, the power detection circuit includes:

[0021] The system includes a fourth resistor, a fifth resistor, and a first capacitor. The first end of the fourth resistor is electrically connected to the positive terminal of the battery. The second end of the fourth resistor is connected to the first end of the fifth resistor. The second end of the fifth resistor is grounded. The first end of the first capacitor and the main control circuit are both connected to the first end of the fifth resistor. The second end of the first capacitor is grounded.

[0022] In one embodiment, the charging circuit further includes:

[0023] The current acquisition circuit and indicator light are provided. The acquisition terminal of the current acquisition circuit is connected to the power input terminal, and the output terminal of the current acquisition circuit is electrically connected to the main control circuit. The current acquisition circuit is used to output a current acquisition signal when current is acquired.

[0024] The indicator light is electrically connected to the main control circuit, which controls the indicator light to illuminate when it receives the current detection signal.

[0025] In one embodiment, the current acquisition circuit includes:

[0026] The circuit includes a sixth resistor, a seventh resistor, and a third switching transistor. The input terminal of the third switching transistor is electrically connected to the main control circuit, the output terminal of the third switching transistor is grounded, and the controlled terminal of the third switching transistor is connected to the second terminal of the sixth resistor.

[0027] The first end of the sixth resistor is connected to the power input terminal, the first end of the seventh resistor is connected to the controlled terminal of the third switching transistor, and the second end of the seventh resistor is grounded.

[0028] In one embodiment, the charging circuit further includes:

[0029] A clamping circuit is electrically connected to the positive terminal of the battery, and the clamping circuit is used to limit the voltage output to the battery within a preset voltage threshold.

[0030] In one embodiment, the clamping circuit includes:

[0031] A Zener diode, wherein the cathode of the Zener diode is electrically connected to the positive terminal of the battery, and the anode of the Zener diode is grounded.

[0032] This utility model also proposes an electric toothbrush, including a battery and a charging circuit as described in any of the above claims; wherein the battery is electrically connected to the charging circuit.

[0033] This utility model's charging circuit includes a power input terminal, a switching circuit, a power detection circuit, and a main control circuit. The switching circuit is connected in series between the power input terminal and the positive terminal of the battery. The detection terminal of the power detection circuit is electrically connected to the positive terminal of the battery. The power detection circuit is used to detect the remaining power output to the battery and output a corresponding power detection signal. The main control circuit is electrically connected to the controlled terminal of the switching circuit and the power detection circuit. When the remaining power in the electric field detects that the power detection signal has reached a preset power threshold, the main control circuit controls the switching circuit to turn off, thereby stopping the charging of the battery. With this configuration, in practical applications, the preset power threshold can be set to 100% power, so that charging stops when the battery reaches 100%, thus avoiding the battery being in a float charging state. By avoiding the battery being in a float charging state, excessive internal chemical reactions can be reduced, and the battery aging process can be slowed down. For users, there is no need to worry about forgetting to unplug the charger and causing the battery to float charge for a long time, improving the user experience. Attached Figure Description

[0034] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0035] Figure 1 This is a schematic diagram of a module according to an embodiment of the present invention;

[0036] Figure 2 This is a schematic diagram of a module according to another embodiment of the present invention;

[0037] Figure 3 This is a schematic diagram of the circuit structure of an embodiment of the present invention;

[0038] Figure 4 This is a schematic diagram of the circuit structure of another embodiment of the present utility model;

[0039] Figure 5 This is a schematic diagram of a module according to another embodiment of the present invention;

[0040] Figure 6 This is a schematic diagram of the circuit structure of another embodiment of the present invention;

[0041] Figure 7 This is a schematic diagram of a module according to another embodiment of the present invention;

[0042] Figure 8 This is a schematic diagram of the circuit structure of another embodiment of the present invention.

[0043] Explanation of icon numbers:

[0044] 10. Battery; 20. Switching circuit; 21. Main switching circuit; 22. Drive circuit; 30. Power detection circuit; 40. Main control circuit; 50. Current acquisition circuit; 60. Indicator light; 70. Clamping circuit.

[0045] The realization of the purpose, functional features and advantages of this utility model will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0046] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0047] It should be noted that if the embodiments of this utility model involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of the components in a specific posture. If the specific posture changes, the directional indicators will also change accordingly.

[0048] Furthermore, if the embodiments of this utility model involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the use of "and / or" or "and / or" throughout the text includes three parallel solutions. For example, "A and / or B" includes solution A, solution B, or a solution where both A and B are satisfied simultaneously. Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this utility model.

[0049] With the increasing popularity of personal care devices, electric toothbrushes, as an oral cleaning tool, are gaining popularity among consumers due to their efficiency and convenience.

[0050] Most electric toothbrushes on the market currently use lithium-ion or nickel-metal hydride batteries as their power source, and are powered by a charging circuit. During the charging process, to ensure that the battery is always fully charged and ready for use, many electric toothbrushes enter a "float charging" state after the battery is fully charged.

[0051] Although float charging can ensure that the battery is always fully charged to a certain extent, long-term float charging will have a significant negative impact on the battery's lifespan and performance, such as accelerating battery aging and shortening the battery's lifespan.

[0052] Therefore, this utility model proposes a charging circuit and an electric toothbrush, aiming to avoid the battery aging and shortening its lifespan caused by the battery being in a float charging state after being fully charged. In one embodiment of this utility model, refer to... Figure 1 The charging circuit includes:

[0053] A power input terminal, which is used to connect to a power supply;

[0054] A switching circuit 20 is connected in series between the power input terminal and the positive terminal of the battery 10.

[0055] A power detection circuit 30 is provided, the detection terminal of which is electrically connected to the positive terminal of the battery 10. The power detection circuit 30 is used to detect the remaining power output to the battery 10 and output a corresponding power detection signal.

[0056] The main control circuit 40 is electrically connected to the controlled terminal of the switch circuit 20 and the power detection circuit 30 respectively. The main control circuit 40 is used to control the switch circuit 20 to turn off when the remaining power of the battery 10 reaches a preset power threshold according to the power detection signal, so as to stop charging the battery 10.

[0057] In this embodiment, the power detection circuit 30 can detect the voltage of the battery 10 and output a corresponding voltage detection signal. The main control circuit 40 determines the voltage of the battery 10 based on the voltage detection signal and compares the voltage of the battery 10 with pre-stored voltage-power mapping data to confirm the remaining power of the battery 10. The power detection circuit 30 can use a voltage divider circuit to detect the voltage of the battery 10, for example, referring to... Figure 4 The power detection circuit 30 includes:

[0058] The fourth resistor R4, the fifth resistor R5, and the first capacitor C1 are configured such that the first end of the fourth resistor R4 is electrically connected to the positive terminal of the battery 10, the second end of the fourth resistor R4 is connected to the first end of the fifth resistor R5, the second end of the fifth resistor R5 is grounded, the first end of the first capacitor C1 and the main control circuit 40 are both connected to the first end of the fifth resistor R5, and the second end of the first capacitor C1 is grounded.

[0059] The fourth resistor R4 and the fifth resistor R5 are used to divide the voltage of the battery 10. The main control circuit 40 can calculate the voltage of the battery 10 based on the voltage of the fifth resistor R5 and the resistance ratio of the fourth resistor R4 and the fifth resistor R5. The first capacitor C1 is used as a filter capacitor to smooth the voltage signal of the fifth resistor R5 sampled by the main control circuit 40, so as to reduce the interference of high-frequency noise on the sampling of the main control circuit 40.

[0060] In addition, the power detection circuit 30 can also be implemented using a voltage sensor, such as a Hall effect voltage sensor or a voltage transformer, without limitation.

[0061] In this embodiment, the main control circuit 40 can be implemented using a main controller, such as an MCU (Microcontroller Unit), a DSP (Digital Signal Processor), an FPGA (Field Programmable Gate Array), or a SOC (System On Chip).

[0062] In this embodiment, optionally, refer to Figure 2 The switching circuit 20 includes:

[0063] The main switch circuit 21 and the drive circuit 22 are provided. The input terminal of the main switch circuit 21 is connected to the power input terminal, and the output terminal of the main switch circuit 21 is connected to the positive terminal of the battery 10.

[0064] The input terminal of the drive circuit 22 is electrically connected to the main control circuit 40, and the output terminal of the drive circuit 22 is connected to the controlled terminal of the main switch circuit 21.

[0065] The main switch circuit 21 is used to control the on / off state of the charging current input at the power input terminal, and the driving circuit 22 is used to convert the logic signal of the main control circuit 40 into a level or current suitable for driving the main switch circuit 21.

[0066] The main switching circuit 21 can be implemented using at least one switching transistor, such as a MOSFET, IGBT, thyristor, transistor, or power transistor, and / or using at least one switching device, such as a contactor, circuit breaker, or relay. For example, see reference... Figure 3 The main switching circuit 21 includes:

[0067] A first switch Q1 and a first resistor R1 are connected. The input terminal of the first switch Q1 is connected to the power input terminal, the output terminal of the first switch Q1 is connected to the positive terminal of the battery 10, and the controlled terminal of the first switch Q1 is electrically connected to the drive circuit 22.

[0068] The first end of the first resistor R1 is connected to the input terminal of the first switch Q1, and the second end of the first resistor R1 is connected to the controlled terminal of the first switch Q1.

[0069] Wherein, the first switch Q1 is a PMOS transistor, and the first resistor R1 is used to pull up the controlled terminal voltage of the first switch Q1 when the first switch Q1 is in the off state, so as to ensure that the first switch Q1 is completely turned off; the first resistor R1 is also used to limit the current input to the first switch Q1 from the power input terminal when the first switch Q1 is in the on state, so as to avoid excessive transient current damaging the first switch Q1.

[0070] The drive circuit 22 can be implemented using MOSFETs, for example, see reference. Figure 3 The driving circuit 22 includes:

[0071] The circuit consists of a second switch Q2, a first diode D1, a second resistor R2, and a third resistor R3. The input terminal of the second switch Q2 is connected to the controlled terminal of the main switch circuit 21, the output terminal of the second switch Q2 is grounded, and the controlled terminal of the second switch Q2 is electrically connected to the main control circuit 40.

[0072] The anode of the first diode D1 is connected to the power input terminal, the cathode of the first diode D1 is connected to the first end of the second resistor R2, the second end of the second resistor R2 is connected to the controlled terminal of the second switch Q2, the first end of the third resistor R3 is connected to the controlled terminal of the second switch Q2, and the second end of the third resistor R3 is grounded.

[0073] In this circuit, the second switch Q2 is an NMOS transistor. The second resistor R2 and the third resistor R3 are used to divide the voltage at the power input terminal. With the second resistor R2 and the third resistor R3 set to reasonable resistance values, the voltage of the third resistor R3 can turn on the second switch Q2 after dividing the voltage at the power input terminal. When the second switch Q2 is turned on, it pulls down the controlled terminal voltage of the main switch circuit 21, so that the main switch circuit 21 is turned on. With this setting, in practical applications, when the electric toothbrush is connected to the power supply, the main switch circuit 21 can be turned on immediately so that the charging current can charge the battery 10 in the first time.

[0074] When the main control circuit 40 detects that the battery 10 has reached the preset power threshold, it outputs a low-level signal to the second switch Q2 to control the second switch Q2 to turn off, thereby raising the controlled terminal voltage of the main switch circuit 21, so as to indirectly control the main switch circuit 21 to cut off the charging circuit of the battery 10 and prevent the battery 10 from being in a floating charging state.

[0075] In addition, the switching circuit 20 can also be implemented using at least one switching transistor, such as a MOSFET, IGBT, thyristor, transistor, power transistor, etc., and / or using at least one switching device, such as a contactor, circuit breaker, and relay. The main control circuit 40 is used to control the switching transistor / switching assembly to cut off the charging circuit of the battery 10 when the battery 10's charge level reaches a preset charge threshold; the main control circuit 40 is also used to control the switching transistor / switching assembly to turn on the charging circuit of the battery 10 when the battery 10's charge level is less than the preset charge threshold, without limitation.

[0076] In this embodiment, the preset power threshold can be set to 100% or close to 100%, so that when the main control circuit 40 detects that the power of the battery 10 reaches 100% or close to 100%, it controls the switch circuit 20 to disconnect the charging circuit of the battery 10, thereby preventing the battery 10 from being in a floating charging state.

[0077] This utility model's charging circuit includes a power input terminal, a switching circuit 20, a power detection circuit 30, and a main control circuit. The switching circuit 20 is connected in series between the power input terminal and the positive terminal of the battery 10. The detection terminal of the power detection circuit 30 is electrically connected to the positive terminal of the battery 10. The power detection circuit 30 is used to detect the remaining power output to the battery 10 and output a corresponding power detection signal. The main control circuit 40 is electrically connected to the controlled terminal of the switching circuit 20 and the power detection circuit 30. When the remaining power in the electric field is detected by the power detection signal and reaches a preset power threshold, the main control circuit 40 controls the switching circuit 20 to turn off, thereby stopping the charging of the battery 10. With this configuration, in practical applications, the preset power threshold can be set to 100% power, so that charging of the battery 10 stops when the power reaches 100%, thus avoiding the battery 10 being in a float charging state. By avoiding the battery 10 being in a float charging state, excessive chemical reactions inside the battery 10 can be reduced, and the aging process of the battery 10 can be slowed down. For users, there is no need to worry about forgetting to unplug the charger and causing the battery to float for a long time, which improves the user experience.

[0078] In one embodiment of this utility model, reference is made to Figure 5 The charging circuit further includes:

[0079] The current acquisition circuit 50 and the indicator light 60 are provided. The acquisition terminal of the current acquisition circuit 50 is connected to the power input terminal, and the output terminal of the current acquisition circuit 50 is electrically connected to the main control circuit 40. The current acquisition circuit 50 is used to output a current acquisition signal when current is acquired.

[0080] The indicator light 60 is electrically connected to the main control circuit 40, and the main control circuit 40 is used to control the indicator light 60 to light up when it receives the current detection signal.

[0081] With the above settings, in practical applications, when the electric toothbrush is plugged into the charger and the charging current charges the battery 10 through the power input terminal of the charger box, the indicator light 60 will light up to intuitively remind the user that the electric toothbrush is in the charging state.

[0082] When the electric toothbrush is plugged into the charger and no charging current flows through the power input terminal to charge the battery 10, the indicator light 60 does not light up, to visually indicate to the user that the electric toothbrush is not charging properly (it may be due to a faulty charger, poor contact, or a problem with the battery 10).

[0083] For users, simply observing the status of indicator light 60 is enough to understand the charging status of the electric toothbrush; no additional operation or professional knowledge is required.

[0084] In this embodiment, optionally, the current acquisition circuit 50 can be implemented based on the resistor voltage divider method, for example, referring to... Figure 6 The current acquisition circuit 50 includes:

[0085] The circuit consists of a sixth resistor R6, a seventh resistor R7, and a third switch Q3. The input terminal of the third switch Q3 is electrically connected to the main control circuit 40, the output terminal of the third switch Q3 is grounded, and the controlled terminal of the third switch Q3 is connected to the second terminal of the sixth resistor R6.

[0086] The first end of the sixth resistor R6 is connected to the power input terminal, the first end of the seventh resistor R7 is connected to the controlled terminal of the third switch Q3, and the second end of the seventh resistor R7 is grounded.

[0087] The third switch Q3 can be an NMOS transistor. When current flows to the battery 10 through the power input terminal, some current flows to the sixth resistor R6 and the seventh resistor R7, causing the voltage of the sixth resistor R6 and the seventh resistor R7 to rise. When the voltage of the seventh resistor R7 rises to the conduction threshold of the third switch Q3, the third switch Q3 turns on. After the third switch Q3 turns on, it pulls down the voltage of the port connected to the input terminal of the third switch Q3 in the main control circuit 40, so that the main control circuit 40 detects a low-level signal. When the main control circuit 40 detects a low-level signal, the control indicator 60 lights up to indicate to the user that the electric toothbrush is in charging mode.

[0088] When current is not input to battery 10 through the power input terminal, the voltage of the sixth resistor R6 and the seventh resistor R7 is basically 0, the third switch Q3 remains off, and the voltage of the port of the main control circuit 40 connected to the input terminal of the third switch Q3 is maintained at a high level. At this time, the main control circuit 40 controls the indicator light 60 to turn off, so as to intuitively remind the user that the electric toothbrush has not been charged properly.

[0089] In addition, the current acquisition circuit 50 can also be implemented using a current sensor, such as a Hall effect sensor or a current transformer, without limitation.

[0090] Rechargeable batteries 10, such as lithium batteries 10 or nickel-metal hydride batteries 10, are very sensitive to charging voltage. If the input voltage at the power input terminal exceeds the maximum allowable voltage of the battery 10 (for example, 4.2V for a single lithium battery 10 cell), it may cause the battery 10 to be overcharged, which may lead to serious problems such as bulging, leakage, or even fire and explosion.

[0091] In one embodiment of this utility model, reference is made to... Figure 7 The charging circuit further includes:

[0092] A clamping circuit 70 is electrically connected to the positive terminal of the battery 10. The clamping circuit 70 is used to limit the voltage output to the battery 10 within a preset voltage threshold.

[0093] In this embodiment, the clamping circuit 70 can be implemented using a Zener diode, see reference. Figure 8 The clamping circuit 70 includes:

[0094] A Zener diode is included, with its cathode electrically connected to the positive terminal of the battery 10 and its anode grounded. The Zener diode exhibits reverse breakdown characteristics; when the voltage exceeds its breakdown voltage, the Zener diode conducts and clamps the voltage to the breakdown voltage value, preventing damage to the battery 10 due to overvoltage.

[0095] In addition, the clamping circuit 70 can also be implemented using a linear regulator. A linear regulator can stabilize the input voltage at a set voltage value to prevent the battery 10 from being damaged due to overvoltage. No restrictions are imposed here.

[0096] With the above settings, the clamping circuit 70 limits the voltage input to the battery 10 to within a preset voltage threshold (the threshold set according to the specifications of the battery 10), which can effectively prevent the battery 10 from being damaged due to overvoltage, thereby extending the battery 10's lifespan and improving safety.

[0097] This utility model also proposes an electric toothbrush, including a battery 10 and a charging circuit as described above.

[0098] It is worth noting that since the electric toothbrush of this utility model is based on the above-mentioned charging circuit, the embodiments of the electric toothbrush of this utility model include all the technical solutions of all the embodiments of the above-mentioned charging circuit, and the technical effects achieved are exactly the same, so they will not be repeated here.

[0099] The above description is merely an exemplary embodiment of the present utility model and does not limit the patent scope of the present utility model. Any equivalent structural transformations made based on the technical concept of the present utility model and the contents of the present utility model specification and drawings, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present utility model.

Claims

1. A charging circuit for use in an electric toothbrush, the electric toothbrush comprising a battery, characterized in that, include: A power input terminal, which is used to connect to a power supply; A switching circuit, wherein the switching circuit is connected in series between the power input terminal and the positive terminal of the battery; A power detection circuit, wherein the detection terminal of the power detection circuit is electrically connected to the positive terminal of the battery, and the power detection circuit is used to detect the remaining power output to the battery and output a corresponding power detection signal; The main control circuit is electrically connected to the controlled terminal of the switch circuit and the power detection circuit. The main control circuit is used to control the switch circuit to turn off when it detects that the remaining power of the battery has reached a preset power threshold based on the power detection signal, so as to stop charging the battery.

2. The charging circuit as described in claim 1, characterized in that, The switching circuit includes: The main switch circuit and the drive circuit are provided, wherein the input terminal of the main switch circuit is connected to the power input terminal, and the output terminal of the main switch circuit is connected to the positive terminal of the battery. The input terminal of the drive circuit is electrically connected to the main control circuit, and the output terminal of the drive circuit is connected to the controlled terminal of the main switch circuit.

3. The charging circuit as described in claim 2, characterized in that, The main switching circuit includes: A first switching transistor and a first resistor, wherein the input terminal of the first switching transistor is connected to the power input terminal, the output terminal of the first switching transistor is connected to the positive terminal of the battery, and the controlled terminal of the first switching transistor is electrically connected to the drive circuit; The first end of the first resistor is connected to the input terminal of the first switching transistor, and the second end of the first resistor is connected to the controlled terminal of the first switching transistor.

4. The charging circuit as described in claim 2, characterized in that, The driving circuit includes: The circuit consists of a second switch, a first diode, a second resistor, and a third resistor. The input terminal of the second switch is connected to the controlled terminal of the main switch circuit, the output terminal of the second switch is grounded, and the controlled terminal of the second switch is electrically connected to the main control circuit. The anode of the first diode is connected to the power input terminal, the cathode of the first diode is connected to the first end of the second resistor, the second end of the second resistor is connected to the controlled terminal of the second switch, the first end of the third resistor is connected to the controlled terminal of the second switch, and the second end of the third resistor is grounded.

5. The charging circuit as described in claim 1, characterized in that, The power detection circuit includes: The system includes a fourth resistor, a fifth resistor, and a first capacitor. The first end of the fourth resistor is electrically connected to the positive terminal of the battery. The second end of the fourth resistor is connected to the first end of the fifth resistor. The second end of the fifth resistor is grounded. The first end of the first capacitor and the main control circuit are both connected to the first end of the fifth resistor. The second end of the first capacitor is grounded.

6. The charging circuit according to any one of claims 1 to 5, characterized in that, The charging circuit also includes: The current acquisition circuit and indicator light are provided. The acquisition terminal of the current acquisition circuit is connected to the power input terminal, and the output terminal of the current acquisition circuit is electrically connected to the main control circuit. The current acquisition circuit is used to output a current acquisition signal when current is acquired. The indicator light is electrically connected to the main control circuit, which controls the indicator light to illuminate when it receives the current detection signal.

7. The charging circuit as described in claim 6, characterized in that, The current acquisition circuit includes: The circuit includes a sixth resistor, a seventh resistor, and a third switching transistor. The input terminal of the third switching transistor is electrically connected to the main control circuit, the output terminal of the third switching transistor is grounded, and the controlled terminal of the third switching transistor is connected to the second terminal of the sixth resistor. The first end of the sixth resistor is connected to the power input terminal, the first end of the seventh resistor is connected to the controlled terminal of the third switching transistor, and the second end of the seventh resistor is grounded.

8. The charging circuit according to any one of claims 1 to 5, characterized in that, The charging circuit also includes: A clamping circuit is electrically connected to the positive terminal of the battery, and the clamping circuit is used to limit the voltage output to the battery within a preset voltage threshold.

9. The charging circuit as described in claim 8, characterized in that, The clamping circuit includes: A Zener diode, wherein the cathode of the Zener diode is electrically connected to the positive terminal of the battery, and the anode of the Zener diode is grounded.

10. An electric toothbrush, characterized in that, It includes a battery and a charging circuit as described in any one of claims 1 to 9; wherein the battery is electrically connected to the charging circuit.

Images