Control circuit and electric toothbrush

Abstract

The control circuit comprises a charging loop composed of an external power supply, a universal serial bus (USB) interface circuit, a charging management circuit and a battery, a driving circuit and a main control circuit, the main control circuit detects the state of the charging loop in real time, and when the external power supply is connected and the charging loop is formed, the driving circuit drives the charging management circuit to charge the charging loop. And the trigger protection logic actively outputs a prohibition signal to the driving circuit, and a transmission path of a motor driving signal is forcibly blocked, so that the problems of battery overload, device temperature rise and the like caused by superposition of charging and driving current are fundamentally avoided, and the safety of the charging process is remarkably improved. And meanwhile, the fault risks of poor contact, short circuit and the like caused by misoperation or cable pulling are reduced. In addition, a standardized USB interface circuit is adopted to replace special charging equipment, a mainstream charging power supply is compatible, the burden of a user carrying accessories outdoors is reduced, and the multi-scene charging requirement is met.

Description

Technical Field

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

[0002] With the increasing demand for intelligent oral care, electric toothbrushes have gradually evolved from simple mechanical vibrations into intelligent products with multi-mode sonic vibration functions. Traditional electric toothbrushes mostly use a charging solution with a dedicated charging base and a separate power adapter, which suffers from poor device compatibility and limited charging scenarios, making it difficult to meet the rigid demand of modern users for portable charging. This design has obvious limitations in practical use: users need to carry a dedicated charging base when going out, and if it is lost or damaged, they cannot charge; wireless charging solutions simplify operation, but suffer from low charging efficiency and high heat generation.

[0003] In recent years, some manufacturers have attempted to improve portability by using direct charging via USB interfaces. However, this has led to new technical challenges. Due to the length limitations of USB charging cables, users may accidentally activate the toothbrush during charging. In this case, the motor's operation will cause current to be superimposed between the charging and drive circuits. This can not only cause battery overload and overheating, shortening device lifespan, but also potentially lead to poor interface contact due to cable pulling, resulting in charging interruption or short circuit risks. Utility Model Content

[0004] The main purpose of this invention is to propose a control circuit and an electric toothbrush, which aims to solve the problems of current superposition, battery overload and interface safety hazards caused by accidental motor start-up during the charging process of traditional electric toothbrushes.

[0005] To achieve the above objectives, this application proposes a control circuit for use in an electric toothbrush, the electric toothbrush comprising a motor and a battery, characterized in that the control circuit comprises:

[0006] The USB interface circuit has its input end connected to an external power source for connecting to an external power supply.

[0007] The charging management circuit has its input terminal connected to the output terminal of the interface circuit and its output terminal connected to the battery interface. It is used to process the external power supply and charge the battery.

[0008] The external power supply, USB interface circuit, charging management circuit and battery form a charging circuit;

[0009] The drive circuit is used to drive the motor to work;

[0010] The main control circuit is connected to the interface circuit and the drive circuit. When a charging circuit is detected to be formed, the main control circuit outputs a control signal to the drive circuit to stop the motor from working.

[0011] In one embodiment, the charging management circuit includes:

[0012] The battery charging circuit has its input terminal connected to the output terminal of the interface circuit and its output terminal connected to the interface of the battery, and is used to dynamically adjust the charging current output to the battery according to the battery voltage.

[0013] The power sampling circuit has its input terminal connected to the output terminal of the interface circuit and its output terminal connected to the first sampling terminal of the main control circuit. It is used to collect the voltage of the external power supply and output the charging voltage signal to the main control circuit.

[0014] The main control circuit is also used to output a stop signal to the drive circuit when it receives the charging voltage signal from the power sampling circuit, so as to stop the motor from working.

[0015] In one embodiment, the charging management circuit includes:

[0016] A temperature detection circuit, whose output is connected to the battery charging circuit, is used to output a temperature abnormality signal to the battery charging circuit when a temperature abnormality is detected during the charging process.

[0017] A water ingress detection circuit, with its output terminal connected to the battery charging circuit, is used to output a water ingress signal to the battery charging circuit when water ingress is detected during the charging process.

[0018] The battery charging circuit is also used to stop working when it receives an abnormal temperature signal or a water ingress signal.

[0019] In one embodiment, the temperature detection circuit and the battery charging circuit are integrated into the same chip.

[0020] In one embodiment, the power sampling circuit includes a first resistor and a second resistor. One end of the first resistor is connected to the USB interface circuit, and the other end is connected to one end of the second resistor and the first sampling terminal of the main control circuit. The other end of the second resistor is grounded.

[0021] In one embodiment, the control circuit further includes:

[0022] A battery protection circuit is provided, in which a discharge circuit is formed between the battery, the battery protection circuit and the motor. The battery protection circuit is used to cut off the discharge circuit when it detects an abnormal voltage in the battery.

[0023] The battery sampling circuit has its input terminal connected to the interface of the battery and its output terminal connected to the second sampling terminal of the main control circuit. It is used to collect the battery voltage and output the discharge voltage signal to the main control circuit.

[0024] In one embodiment, it further includes:

[0025] Indicator light circuit is used to display the charging or power status of the electric toothbrush;

[0026] The main control circuit input terminal is connected to the battery charging circuit and the battery sampling circuit, and the output terminal is connected to the indicator light circuit. When the main control circuit receives the full charge signal output by the battery charging circuit, it drives the corresponding LED in the indicator light circuit to work, so as to indicate that the electric toothbrush is fully charged.

[0027] The main control circuit is also used to drive the corresponding LED in the indicator circuit to work when the discharge voltage signal output by the battery sampling circuit is lower than the preset voltage value, so as to indicate that the electric toothbrush is in a low power state.

[0028] In one embodiment, it further includes:

[0029] A power switch circuit, connected to the main control circuit, is used to output corresponding electrical signals to the main control circuit when operated by the user.

[0030] The main control circuit is used to receive and control the motor to work according to the electrical signal output by the power switch circuit.

[0031] In addition, to achieve the above objectives, this application proposes an electric toothbrush, including a battery, a motor, and a control circuit as described above.

[0032] In one embodiment of an electric toothbrush, a handle and a toothbrush head disposed at one end of the handle are also included;

[0033] The control circuit, battery, and motor are housed inside the handle, which is equipped with a USB interface. The USB interface circuit is connected to an external power source via the USB interface.

[0034] This application includes a charging circuit, a drive circuit, and a main control circuit, consisting of an external power supply, a USB interface circuit, a charging management circuit, and a battery. The main control circuit monitors the charging circuit status in real time. When an external power supply is connected and a charging circuit is formed, it triggers protection logic to actively output a prohibition signal to the drive circuit, forcibly blocking the transmission path of the motor drive signal. This fundamentally avoids battery overload and device temperature rise caused by the superposition of charging and drive currents, significantly improving the safety of the charging process. Simultaneously, it reduces the risk of malfunctions such as poor contact and short circuits caused by misoperation or cable pulling. Furthermore, this application uses a standardized USB interface circuit instead of dedicated charging equipment, ensuring compatibility with mainstream charging power supplies, reducing the burden on users carrying accessories, and meeting charging needs in various scenarios. Attached Figure Description

[0035] 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.

[0036] Figure 1 This is a structural diagram of a control circuit according to the present invention.

[0037] Figure 2 This is a structural diagram of an embodiment of the control circuit of this utility model;

[0038] Figure 3 This is a circuit diagram of one embodiment of the control circuit of this utility model.

[0039] Reference numerals: USB interface circuit 01, charging management circuit 02, battery charging circuit 21, power sampling circuit 22, drive circuit 03, main control circuit 04, battery protection circuit 51, battery sampling circuit 52, indicator light circuit 06, power switch circuit 07.

[0040] 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

[0041] 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.

[0042] 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 certain specific posture (as shown in the figure). If the specific posture changes, the directional indicators will also change accordingly.

[0043] 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, features defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, if the word "and / or" appears throughout the text, it means including three parallel solutions; for example, "A and / or B" includes solution A, solution B, or a solution that simultaneously satisfies A and B. 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.

[0044] This application proposes a control circuit, such as Figure 1 As shown, an electric toothbrush is used in an electric toothbrush, the electric toothbrush including a motor and a battery, characterized in that the control circuit includes:

[0045] USB interface circuit 01, the input end is connected to an external power supply, for connecting to an external power supply;

[0046] The charging management circuit 02 has its input terminal connected to the output terminal of the interface circuit and its output terminal connected to the battery interface. It is used to process the external power supply and charge the battery.

[0047] The external power supply, USB interface circuit 01, and charging management circuit 02 form a charging circuit with the battery.

[0048] Drive circuit 03 is used to drive the motor to work;

[0049] The main control circuit 04 is connected to the interface circuit and the drive circuit 03. The main control circuit 04 is used to output a control signal to the drive circuit 03 to stop the motor from working when a charging circuit is detected.

[0050] Specifically, with the upgrading of intelligent oral care needs, electric toothbrushes are evolving from single mechanical vibration to multimodal sonic cleaning. Traditional charging solutions rely on a combination of dedicated charging bases and customized adapters. While this achieves basic charging functionality, it has significant limitations in terms of application scenarios: the strong binding relationship between dedicated charging bases and specific power sources leads to insufficient device compatibility, and users in mobile scenarios are easily trapped in a charging dilemma due to the lack of accessories. Although the introduction of wireless charging technology simplifies the operation process, its inherent defects, such as low energy conversion efficiency and high heat generation during charging, limit its practical application value.

[0051] In recent years, the industry has shifted towards USB direct charging technology to improve portability, but new technical challenges have emerged: when users charge via USB cable, due to cable length limitations or operational habits, they are prone to accidentally activating the toothbrush switch while plugged in. At this time, the device will simultaneously operate two circuits: charging and driving. The charging current and motor driving current will have a superposition effect at the battery end. This is because the traditional circuit architecture lacks a dynamic isolation mechanism between the charging and driving circuits, allowing the two systems to operate in parallel while powered on. This current superposition not only poses safety hazards such as battery overload and accelerated temperature rise of power devices, but also may cause transient poor contact at the USB interface due to cable tension, leading to charging interruption or port short circuit risks.

[0052] Current technological improvements mostly focus on physical isolation at the hardware level, such as adding charging status recognition switches or improving the mechanical structure of USB interfaces. However, such solutions often lead to increased costs or affect the waterproof performance of devices. Compared to toothbrushes, which generally use charging docks for contact charging or wireless charging, this application uses USB interface charging, which saves on charging docks and makes it convenient for users to charge in different situations. However, USB interface charging generally uses a USB charging cable of a certain length, and users may subconsciously pick up the toothbrush to brush their teeth while charging (because of the cable, they won't pull on it or stop the charging). Therefore, to prevent users from using the toothbrush during charging, which could cause unstable operation or high temperature and lead to a poor user experience, this application proposes a control circuit. The solution lies in building an intelligent dynamic control system: the main control chip monitors the power supply status in real time, and when an external power source is detected, it immediately cuts off the drive signal transmission path, realizing mutual exclusion locking between charging mode and working mode at the system level. This solution retains the advantages of universal USB charging while eliminating the risk of current superposition caused by accidental touches through circuit control logic reconstruction, establishing a dynamic balance mechanism between portability and safety.

[0053] The USB interface circuit 01 serves as the system power input port, consisting of a Micro-USB standard interface and its accompanying filtering circuit, responsible for establishing the physical connection path between the external power supply and the device. Internally, it integrates polarity protection, overvoltage protection, and ESD electrostatic protection modules, automatically performing power polarity correction and interference suppression when the charging cable is connected, ensuring stable external power input. The interface circuit and charging management circuit 02 are electrically connected via PCB traces, forming the primary energy transmission channel. The charging management circuit 02, as the core of power conversion, is composed of a charging control chip. When external power is input via the USB interface, the charging chip dynamically adjusts the charging mode based on the current battery voltage, sequentially executing a three-stage charging strategy: trickle pre-charging, constant current fast charging, and constant voltage replenishment. Simultaneously, a temperature sensor provides real-time feedback on the battery status. The circuit output is directly connected to the battery pack via metal contacts or flexible wiring, forming a complete charging energy transmission link.

[0054] The drive circuit 03 drives the motor. The PWM speed control signal output by the main control circuit 04 is converted into a power signal with a corresponding duty cycle by the drive chip. By controlling the direction and intensity of the motor winding current, the vibration mode switching and intensity adjustment are achieved. The main control circuit 04, as the system control center, integrates a microcontroller, a power detection module, and a logic interlock unit. The microcontroller continuously monitors the voltage signal of the USB interface through the ADC channel. When a valid VBUS voltage is detected, the charging status flag is immediately triggered. At this time, the logic interlock unit outputs a high-impedance control signal to the drive circuit 03, forcibly shutting down the enable terminal of the drive circuit 03, thus physically isolating the electrical path between the drive circuit 03 and the motor. This interlock mechanism, through hardware-level signal blocking and a software state machine, ensures that even accidental touches of function buttons during charging cannot activate the motor. When the system is working, the main control circuit 04 switches operating modes by polling the USB interface status in real time: when an external power source is connected, the charging circuit priority is automatically increased, and the output of the drive circuit 03 is forcibly locked; after the external power source is removed, the main control circuit 04 immediately releases the drive enable signal, restoring the motor control function. This state-detection-based dynamic isolation mechanism fundamentally decouples the runtime sequence of the two major functional modules of charging and driving, avoiding the risk of current superposition caused by the parallel operation of the two circuits.

[0055] This application includes a charging circuit consisting of an external power supply, a USB interface circuit 01, a charging management circuit 02, and a battery; a drive circuit 03; and a main control circuit 04. The main control circuit 04 monitors the charging circuit status in real time. When an external power supply is connected and a charging circuit is formed, it triggers protection logic to actively output a prohibition signal to the drive circuit 03, forcibly blocking the transmission path of the motor drive signal. This fundamentally avoids battery overload and device temperature rise caused by the superposition of charging and drive currents, significantly improving the safety of the charging process. Simultaneously, it reduces the risk of faults such as poor contact and short circuits caused by misoperation or cable pulling. Furthermore, this application uses a standardized USB interface circuit 01 instead of dedicated charging equipment, ensuring compatibility with mainstream charging power supplies, reducing the burden on users carrying accessories, and meeting charging needs in various scenarios.

[0056] In one embodiment, such as Figure 2 As shown, the charging management circuit 02 includes:

[0057] The battery charging circuit 21 has its input terminal connected to the output terminal of the interface circuit and its output terminal connected to the interface of the battery. It is used to dynamically adjust the charging current output to the battery according to the battery voltage.

[0058] The power sampling circuit 22 has its input terminal connected to the output terminal of the interface circuit and its output terminal connected to the first sampling terminal of the main control circuit 04. It is used to collect the voltage of the external power supply and output a charging voltage signal to the main control circuit 04. The main control circuit 04 is also used to output a stop signal to the drive circuit 03 when it receives the charging voltage signal from the power sampling circuit 22, so as to stop the motor from working.

[0059] In this embodiment, the charging management circuit 02, through the coordinated operation of the battery charging circuit 21 and the power sampling circuit 22, constructs a complete power management and safety control system. The battery charging circuit 21, as the core energy transmission channel, integrates an intelligent charging control chip and peripheral voltage regulating components. The charging control chip automatically switches charging stages by monitoring the battery terminal voltage in real time: when the battery is detected to be in a deep discharge state, it prioritizes pre-charging with a small current to repair the battery polarization effect; as the voltage rises to a safe threshold, it switches to constant current mode for rapid energy replenishment; when approaching full charge, it automatically switches to constant voltage mode for refined trickle charging. The circuit also includes an over-temperature protection module, which collects temperature data in real time using a thermistor attached to the battery surface and dynamically adjusts the charging power to prevent thermal runaway.

[0060] The power sampling circuit 22, serving as the charging status sensing unit, employs a combined architecture of a precision resistor voltage divider network and a signal conditioning module. The voltage divider network attenuates the DC high voltage input from the USB interface at a fixed ratio, generating an analog signal adapted to the input range of the main control chip's ADC. The signal conditioning module eliminates high-frequency interference through a low-pass filter circuit and incorporates a voltage follower to enhance signal driving capability, ensuring stable and reliable sampling values. When the USB cable is connected, this circuit continuously converts the effective voltage value of the external power supply into a linearly changing electrical signal, providing charging status criteria for the main control system. When the charging voltage signal output by the power sampling circuit 22 reaches a preset threshold, the main control chip immediately triggers an interrupt service routine: on the one hand, it cuts off the clock source of the PWM signal generator through digital logic circuitry, causing the motor drive signal to lose its modulation reference; on the other hand, it directly outputs a low-level hard reset signal to the enable pin of the drive chip, forcibly shutting down the gate drive of the power switch transistor. This dual blocking mechanism completely cuts off the current loop of the motor windings at the hardware level, ensuring that the drive system remains in an absolutely silent state even if the user accidentally presses a physical button or the program malfunctions.

[0061] In one embodiment, the charging management circuit 02 includes:

[0062] The temperature detection circuit, whose output terminal is connected to the battery charging circuit 21, is used to output a temperature abnormality signal to the battery charging circuit 21 when a temperature abnormality is detected during the charging process.

[0063] The water ingress detection circuit is connected to the battery charging circuit 21 at its output terminal. When water ingress is detected during the charging process, it outputs a water ingress signal to the battery charging circuit 21. The battery charging circuit 21 is also used to stop working when it receives a temperature abnormality signal or a water ingress signal.

[0064] In this embodiment, the temperature detection circuit consists of a thermistor. The thermistor is tightly attached to the battery surface, and its resistance changes non-linearly with temperature. A voltage divider circuit converts the temperature change into a voltage signal. A threshold comparison unit presets a safe temperature range. When the amplified temperature signal exceeds the preset range, a temperature anomaly signal is immediately triggered. This circuit effectively prevents the risk of thermal runaway caused by overcharging or environmental overheating through real-time thermal state monitoring. The water ingress detection circuit employs a collaborative design of a contact sensor and an impedance analysis module. The contact sensor consists of two sets of staggered metal electrodes. When liquid seeps into the charging interface area, the impedance between the electrodes decreases significantly due to the liquid's conductivity. The impedance analysis module monitors the change in the equivalent impedance modulus between the electrodes in real time by injecting a high-frequency micro-current signal. Combined with an adaptive baseline calibration algorithm, it can effectively distinguish between ambient humidity fluctuations and substantial water ingress events. When the detected impedance value remains below the safe threshold, the circuit outputs a logic signal characterizing water ingress. This design accurately identifies liquid intrusion into the charging port, avoiding electrolyte corrosion or short-circuit risks.

[0065] Upon receiving a temperature anomaly or water ingress signal, the protection logic unit immediately cuts off the control signal path to the charging power transistor, disconnecting the charging circuit. Simultaneously, it activates a fault latch mechanism to ensure that the non-volatile memory records the abnormal event until the system performs a manual reset. This dual protection strategy achieves seamless integration from anomaly detection to charging termination, ensuring the absolute safety of the battery in extreme environments.

[0066] In one embodiment, the temperature detection circuit and the battery charging circuit 21 are integrated into the same chip. In this integrated implementation, the temperature detection function and the battery charging control module are integrated into a single chip through semiconductor technology, forming a highly collaborative thermal management subsystem. An embedded temperature sensing unit is used inside the chip, forming a direct thermal coupling path with the battery's physical contact surface through a heat diffusion layer. The output current of the temperature detection circuit changes linearly with the chip's core temperature, generating a digital temperature characterization value via an on-chip analog-to-digital converter. In the chip architecture, the temperature sensing data bus interacts with the charging control logic unit through a direct hardware connection channel. The charging state machine reads the temperature data stream in real time and compares it with preset multi-level temperature thresholds. When the detected temperature value exceeds the primary warning line, the charging algorithm automatically enters a dynamic adjustment mode to reduce the charging current; if the temperature continues to rise and reaches the safety threshold, the protection circuit immediately cuts off the loop to ensure charging safety. This closed-loop control from detection to protection is completed entirely within the chip, without the need for an external microcontroller. This ensures safety while improving the space utilization and anti-interference capability of the charging system.

[0067] In one embodiment, such as Figure 3As shown, the power sampling circuit 22 includes a first resistor and a second resistor. One end of the first resistor is connected to the USB interface circuit 01, and the other end is connected to one end of the second resistor and the first sampling terminal of the main control circuit 04. The other end of the second resistor is grounded.

[0068] In this embodiment, the power sampling circuit 22 constructs a voltage detection channel based on the principle of resistor voltage division to achieve accurate sensing of the external power supply status. This circuit consists of a voltage divider network formed by a first resistor and a second resistor connected in series, creating a complete current path from the USB interface to ground. The first resistor acts as a pull-up element, with one end directly connected to the positive terminal of the USB power supply, bearing the main voltage drop. The second resistor acts as a pull-down element, its resistance value determining the voltage division ratio, converting the high-voltage signal into a detection voltage compatible with the input range of the main control chip's analog-to-digital converter (ADC). The connection point of the two resistors constitutes a voltage sampling node, whose potential value is determined by the ratio of the USB power supply voltage to the resistance. When the circuit is working, if the USB interface is connected to an external power supply, the 5V standard voltage forms a current path through the first resistor, generating an intermediate voltage at the sampling node that is inversely proportional to the resistance values ​​of the two resistors. Assuming the first resistor has a resistance of R3 and the second resistor has a resistance of R12, the sampling voltage V_sample = 5V × R12 / (R3 + R12). This voltage signal is transmitted to the dedicated sampling pin of the main control chip and converted into a digital quantity by the built-in ADC. The main control firmware periodically reads this value to determine the USB power connection status and power quality in real time. When the sampled voltage continuously exceeds a preset threshold, the system confirms a valid power connection and triggers the subsequent charging management process.

[0069] At the electrical protection level, the voltage divider network limits potential surge currents to a safe range through resistor current limiting, preventing high-voltage signals from directly impacting the sensitive input ports of the main control chip. Simultaneously, the power dissipation characteristics of the resistors suppress transient voltage fluctuations, enhancing the system's anti-interference capability. In signal processing, by precisely matching the resistance ratio of the two resistors, the USB standard voltage can be accurately mapped to the optimal measurement range of the main control chip's ADC (e.g., 0-3.3V), fully utilizing the ADC's resolution while avoiding measurement distortion caused by signal exceeding the range. This simple yet reliable design provides the charging management system with accurate power status judgment.

[0070] In one embodiment, such as Figure 2 and Figure 3 As shown, the control circuit further includes:

[0071] A battery protection circuit 51 is provided, which forms a discharge circuit between the battery, the battery protection circuit 51 and the motor. The battery protection circuit 51 is used to cut off the discharge circuit when it detects an abnormal voltage in the battery.

[0072] The battery sampling circuit 52 has its input end connected to the interface of the battery and its output end connected to the second sampling end of the main control circuit 04. It is used to collect the battery voltage and output the discharge voltage signal to the main control circuit 04.

[0073] The battery protection circuit 51 monitors the electrical status of the battery pack in real time. When abnormal conditions such as overvoltage, undervoltage, or overcurrent are detected, it immediately cuts off the power supply circuit to the motor to prevent permanent damage to the battery due to deep discharge or overload. By continuously comparing the battery terminal voltage with a preset threshold, when any monitored parameter exceeds the safe range, the logic control unit disconnects the main circuit and triggers a state latching mechanism to maintain the open circuit state until the system restarts or the fault is cleared. The battery sampling circuit 52 is responsible for converting the real-time voltage information of the battery into a standardized signal that can be processed by the main control chip. Its main structure consists of a voltage divider composed of a precision resistor network, which proportionally attenuates the battery voltage to a suitable input range for analog-to-digital conversion through high-precision resistors configured in series. Parallel filter capacitors at the voltage divider nodes eliminate high-frequency interference and ensure the stability of signal transmission. The analog voltage signal output by this circuit is sent to the ADC pin of the main control chip through a dedicated channel. After digital processing, the main control system can accurately calculate the remaining power, assess the battery health status, and dynamically adjust the motor power output or charging strategy. The sampling circuit and the protection circuit form a dual monitoring mechanism. The former provides data support for proactive and refined management, while the latter serves as the last line of defense for passive emergency protection. Together, they ensure that the battery system operates efficiently within a safe range.

[0074] In one embodiment, such as Figure 2 As shown, it also includes:

[0075] Indicator light circuit 06 is used to display the charging or power status of the electric toothbrush.

[0076] The main control circuit 04 has its input terminal connected to the battery charging circuit 21 and the battery sampling circuit 52, and its output terminal connected to the indicator light circuit 06. When the main control circuit 04 receives a full charge signal from the battery charging circuit 21, it drives the corresponding LED in the indicator light circuit 06 to work, indicating that the electric toothbrush is fully charged. The main control circuit 04 is also used to drive the corresponding LED in the indicator light circuit 06 to work when the discharge voltage signal output by the battery sampling circuit 52 is lower than a preset voltage value, indicating that the electric toothbrush is in a low battery state.

[0077] The indicator light circuit 06 is a crucial medium for human-machine interaction, clearly conveying device energy status information through visual feedback. This circuit consists of a multi-color LED array, with different LEDs connected in parallel via independent branches, each with a dedicated control node. The main control chip outputs differentiated drive signals based on the system status: when a full-charge flag signal from the charging management chip is detected, its corresponding GPIO port outputs a high level, activating the LED branch corresponding to the fully charged state via the main control circuit 04; when the battery voltage is detected to be below a preset threshold, another set of I / O ports triggers an intermittent flashing mode for the LED corresponding to the low-charge state.

[0078] In essence, during charging, when the battery is detected to be fully saturated, the battery charging circuit 21 sends a signal to the main control chip. The main control chip then wakes up the corresponding command, causing a specific pin to output a stable current, driving the emerald green LED to continuously emit light, forming an intuitive visual confirmation of full charge. During daily use of the toothbrush, the battery sampling circuit 52 continuously tracks the battery capacity through precise voltage division measurements. When the voltage value is detected to be approaching a preset warning threshold, the main control chip immediately activates the warning mechanism. At this time, the corresponding control port will output a regularly changing electrical signal according to a preset program. This warning flashing mode utilizes the sensitivity of human vision to dynamic light sources to ensure that users can promptly detect the low battery status.

[0079] In one embodiment, it further includes:

[0080] The power switch circuit 07 is connected to the main control circuit 04 and is used to output corresponding electrical signals to the main control circuit 04 when operated by the user; wherein, the main control circuit 04 is used to receive and control the motor to work according to the electrical signals output by the power switch circuit 07.

[0081] During system operation, the raw electrical signals generated by user operations are input to the pins of the main control chip, triggering a preset edge detection mechanism. The main control chip captures the switching action in real time through an interrupt service routine, and distinguishes between different operation types such as short presses and long presses using a timer module. Upon confirmation of a valid operation, the main control chip switches the operating mode according to the current system state: an initial short press activates the basic motor cleaning mode, a second short press switches to the sensitive care mode, and a long press triggers a stop command. During mode switching, the main control chip synchronously adjusts the PWM output parameters, precisely controlling the motor's vibration frequency and amplitude through the drive circuit 03, forming a complete closed-loop control chain. The entire system achieves a balance between "rapid response" and "precise execution" through a layered processing mechanism, completing the entire chain from user operation to motor response within milliseconds, resulting in a seamless interactive experience.

[0082] Furthermore, to achieve the above objectives, this application proposes an electric toothbrush, including a battery, a motor, and a control circuit as described above. The control circuit includes a USB interface circuit 01, with its input connected to an external power source for receiving external power; a charging management circuit 02, with its input connected to the output of the interface circuit and its output connected to the battery interface, for processing the received external power and charging the battery; the external power source, USB interface circuit 01, charging management circuit 02, and battery form a charging loop; a drive circuit 03 for driving the motor; and a main control circuit 04 connected to the interface circuit and drive circuit 03, wherein the main control circuit 04 outputs a control signal to the drive circuit 03 to stop the motor from operating when a charging loop is detected.

[0083] This application includes a charging circuit consisting of an external power supply, a USB interface circuit 01, a charging management circuit 02, and a battery; a drive circuit 03; and a main control circuit 04. The main control circuit 04 monitors the charging circuit status in real time. When an external power supply is connected and a charging circuit is formed, it triggers protection logic to actively output a prohibition signal to the drive circuit 03, forcibly blocking the transmission path of the motor drive signal. This fundamentally avoids battery overload and device temperature rise caused by the superposition of charging and drive currents, significantly improving the safety of the charging process. Simultaneously, it reduces the risk of faults such as poor contact and short circuits caused by misoperation or cable pulling. Furthermore, this application uses a standardized USB interface circuit 01 instead of dedicated charging equipment, ensuring compatibility with mainstream charging power supplies, reducing the burden on users carrying accessories, and meeting charging needs in various scenarios.

[0084] In one embodiment of an electric toothbrush, a handle and a toothbrush head disposed at one end of the handle are also included;

[0085] The control circuit, battery, and motor are housed within the handle, which employs a modular stacked design. A micro vibration motor is mounted at the bottom, and high-frequency vibrations are isolated by shock-absorbing rubber pads. A lithium battery pack is housed in the central cylindrical cavity, while the upper circuit compartment integrates the control board and sensor components. The handle features a USB interface, through which the USB interface circuit 01 connects to an external power source. The USB interface, serving as the energy input channel, is embedded in a recess at the bottom of the handle. Its metal contacts are gold-plated for corrosion resistance, and an internal flexible PCB extends to the charging management circuit 02. A liquid silicone waterproof ring surrounds the interface, forming a 360-degree sealing ring, which, together with the internal drainage channels of the handle housing, constitutes a double waterproof barrier. When an external charger is inserted, the elastic contacts deform under pressure to ensure stable contact. The charging management IC automatically identifies the power type and initiates a constant current-constant voltage charging process. Simultaneously, a Hall element detects the closed state of the interface cover to activate the sleep mode. The entire structure achieves IPX7 waterproofing through ultrasonic welding, and the vibration transmission system uses a three-axis stabilization structure to reduce lateral sway and ensure efficient energy transfer to the brush tips.

[0086] The above embodiments are merely preferred embodiments of this utility model and do not limit the patent scope of this utility model. Any equivalent structural or procedural transformations made based on the content of this utility model specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this utility model.

Claims

1. A control circuit for use in an electric toothbrush, the electric toothbrush comprising a motor and a battery, characterized in that, The control circuit includes: The USB interface circuit has its input end connected to an external power source for connecting to an external power supply. The charging management circuit has its input terminal connected to the output terminal of the interface circuit and its output terminal connected to the battery interface. It is used to process the external power supply and charge the battery. The external power supply, USB interface circuit, charging management circuit and battery form a charging circuit; The drive circuit is used to drive the motor to work; The main control circuit is connected to the interface circuit and the drive circuit. When a charging circuit is detected to be formed, the main control circuit outputs a control signal to the drive circuit to stop the motor from working.

2. The control circuit as described in claim 1, characterized in that, The charging management circuit includes: The battery charging circuit has its input terminal connected to the output terminal of the interface circuit and its output terminal connected to the interface of the battery, and is used to dynamically adjust the charging current output to the battery according to the battery voltage. The power sampling circuit has its input terminal connected to the output terminal of the interface circuit and its output terminal connected to the first sampling terminal of the main control circuit. It is used to collect the voltage of the external power supply and output the charging voltage signal to the main control circuit. The main control circuit is also used to output a stop signal to the drive circuit when it receives the charging voltage signal from the power sampling circuit, so as to stop the motor from working.

3. The control circuit as described in claim 2, characterized in that, The charging management circuit includes: A temperature detection circuit, whose output is connected to the battery charging circuit, is used to output a temperature abnormality signal to the battery charging circuit when a temperature abnormality is detected during the charging process. A water ingress detection circuit, with its output terminal connected to the battery charging circuit, is used to output a water ingress signal to the battery charging circuit when water ingress is detected during the charging process. The battery charging circuit is also used to stop working when it receives an abnormal temperature signal or a water ingress signal.

4. The control circuit as described in claim 3, characterized in that, The temperature detection circuit and the battery charging circuit are integrated into the same chip.

5. The control circuit as described in claim 3, characterized in that, The power sampling circuit includes a first resistor and a second resistor. One end of the first resistor is connected to the USB interface circuit, and the other end is connected to one end of the second resistor and the first sampling terminal of the main control circuit. The other end of the second resistor is grounded.

6. The control circuit as described in claim 2, characterized in that, The control circuit also includes: A battery protection circuit is provided, in which a discharge circuit is formed between the battery, the battery protection circuit and the motor. The battery protection circuit is used to cut off the discharge circuit when it detects an abnormal voltage in the battery. The battery sampling circuit has its input terminal connected to the interface of the battery and its output terminal connected to the second sampling terminal of the main control circuit. It is used to collect the battery voltage and output the discharge voltage signal to the main control circuit.

7. The control circuit as described in claim 2, characterized in that, Also includes: Indicator light circuit is used to display the charging or power status of the electric toothbrush; The main control circuit input terminal is connected to the battery charging circuit and the battery sampling circuit, and the output terminal is connected to the indicator light circuit. When the main control circuit receives the full charge signal output by the battery charging circuit, it drives the corresponding LED in the indicator light circuit to work, so as to indicate that the electric toothbrush is fully charged. The main control circuit is also used to drive the corresponding LED in the indicator circuit to work when the discharge voltage signal output by the battery sampling circuit is lower than the preset voltage value, so as to indicate that the electric toothbrush is in a low power state.

8. The control circuit as described in claim 7, characterized in that, Also includes: A power switch circuit, connected to the main control circuit, is used to output corresponding electrical signals to the main control circuit when operated by the user. The main control circuit is used to receive and control the motor to work according to the electrical signal output by the power switch circuit.

9. An electric toothbrush, characterized in that, Includes a battery, a motor, and a control circuit as described in any one of claims 1-8.

10. The electric toothbrush as described in claim 9, characterized in that, It also includes a handle and a toothbrush head located at one end of the handle; The control circuit, battery, and motor are housed inside the handle, which is equipped with a USB interface. The USB interface circuit is connected to an external power source via the USB interface.

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