The control circuit of the smart door lock, the smart door lock and the door

Abstract

This utility model discloses a control circuit for a smart door lock, a smart door lock, and a door. The control circuit includes a USB interface, a charging circuit, and a control unit. The USB interface includes a charging port and a communication port. The charging port is connected to the charging circuit, and the communication port is connected to the control unit. When the charging port is connected to a solar panel, the solar panel charges the smart door lock. When the communication port is connected to a testing device, the testing device tests the smart door lock. This technical solution, by setting up a USB interface with both a charging port and a communication port, allows the smart door lock to be functionally tested without disassembling the outer casing. This effectively avoids the risk of dust and moisture entering the control board and causing short circuits during testing, improving the convenience of testing and the reliability of the equipment.

Description

Technical Field

[0001] This utility model relates to the field of smart door lock technology, and in particular to a control circuit for a smart door lock, a smart door lock and a door. Background Technology

[0002] In the manufacturing and functional testing of smart locks, it is usually necessary to verify the functionality of the lock's internal control circuit and test its communication interface. A common practice is to temporarily disassemble the lock casing and directly connect it to the control circuit using additional testing equipment to input test commands and read test results. However, in practice, the lock control board is exposed to the air, posing a risk of dust, moisture, and other foreign matter intrusion, especially in high humidity or dusty environments, which may cause short circuits, corrosion, and other problems, reducing product reliability. Furthermore, disassembling the lock assembly not only increases testing time and labor costs but also easily causes wear and tear on structural components or installation deviations. Utility Model Content

[0003] This utility model provides a control circuit for an intelligent door lock, an intelligent door lock, and a door to solve the above-mentioned technical problems.

[0004] The first aspect of this utility model provides a control circuit for a smart door lock, including: a USB interface, a charging circuit, and a control unit. The USB interface includes a charging port and a communication port. The charging port is connected to the charging circuit, and the communication port is connected to the control unit.

[0005] When the charging port is connected to a solar panel, the solar panel charges the smart door lock;

[0006] When the communication port is connected to the testing device, the testing device tests the smart door lock.

[0007] In this embodiment, a USB interface including a charging port and a communication port is provided to achieve an efficient power supply connection between the solar panel and the door lock body. Simultaneously, test equipment can be connected to the smart door lock via the communication port. When the communication port is connected to the test equipment, the control unit receives external test commands and executes functional tests through the communication port. When the charging port is connected to the solar panel, it automatically enters the working state, and the control unit controls the charging circuit to charge the battery according to the battery status, realizing automatic charging management under solar power. This technical solution, by providing a USB interface with both charging and communication ports, allows the smart door lock to be functionally tested without disassembling the outer casing, effectively avoiding the risk of short circuits caused by dust and moisture entering the control board during testing, thus improving the convenience of testing and the reliability of the equipment.

[0008] In some embodiments, the USB interface includes a first power pin, a second power pin, a first ground terminal, a second ground terminal, a first identification pin, and a second identification pin. The first power pin, the second power pin, the first ground terminal, and the second ground terminal constitute the charging port, and the first identification pin and the second identification pin constitute the communication port. The USB interface is a TYPE-C interface.

[0009] In this embodiment, the original dual power supply and identification functions of the Type-C interface are utilized to achieve interface reuse and function expansion. No additional dedicated test port is required, which improves the interface integration and overall structural compactness, making it suitable for smart door lock products with high space and security requirements.

[0010] In some embodiments, the charging circuit includes a charging protection unit and a power management unit. The input terminal of the charging protection unit is connected to the charging port of the USB interface, the voltage output terminal of the charging protection unit is connected to the battery, the signal output terminal of the charging protection unit is connected to the signal acquisition terminal of the power management unit, the first output terminal of the power management unit is connected to the first control terminal of the charging protection unit, and the second output terminal of the power management unit is connected to the control unit.

[0011] In this embodiment, by setting a charging protection unit and a power management unit in the charging circuit, intelligent control and safety protection of the battery charging process are realized. The power management unit dynamically adjusts the output current according to the voltage and current signals collected by the charging protection unit to ensure that the battery is charged stably under constant current and constant voltage conditions. At the same time, the charging status is fed back to the control unit in real time, which is beneficial for charging control and status management, thereby improving charging efficiency, safety and the overall intelligence level of the system.

[0012] In some embodiments, the control unit includes a voltage detection circuit and a control output circuit. The input terminal of the voltage detection circuit is connected to the charging port. The first input terminal of the control output circuit is connected to the second output terminal of the power management unit. The second input terminal of the control output circuit is connected to the output terminal of the voltage detection circuit. The output terminal of the control output circuit is connected to the second control terminal of the charging protection unit.

[0013] In this embodiment, by setting a control terminal in the charging protection unit and having the control unit control its conduction or shutdown in real time according to the USB interface input voltage, dynamic management of the charging path is realized; charging is automatically started when the voltage is normal and immediately shut down when the voltage is abnormal, effectively preventing damage to the battery due to abnormal power supply and improving the charging safety, reliability and environmental adaptability of the system.

[0014] In some embodiments, the charging protection unit includes a first switching unit, a first filtering unit, a sampling unit, an inductor unit, a second switching unit, a second filtering unit, and a feedback unit. One end of the first switching unit is the input terminal of the charging protection unit, and the other end of the first switching unit is connected to one end of the first filtering unit. The control terminal of the first switching unit is the second control terminal of the charging protection unit. The other end of the first filtering unit is connected to one end of the sampling unit and the first signal sampling terminal of the power management unit. The other end of the sampling unit is connected to one end of the inductor unit and the second signal sampling terminal of the power management unit. The other end of the inductor unit is connected to one end of the second switching unit, one end of the feedback unit, and one end of the second filtering unit. The other end of the feedback unit is connected to the third signal sampling terminal of the power management unit. The first output terminal of the power management unit is connected to the control terminal of the second switching unit, and the other end of the second filtering unit is the output terminal of the charging protection unit.

[0015] In this embodiment, by configuring the internal structure of the charging protection unit, a step-down charging path is formed, consisting of switch control, filtering, sampling, inductor energy storage, PWM regulation, output voltage regulation, and feedback acquisition. This not only achieves efficient energy conversion from USB interface input to the battery, but also ensures constant current and constant voltage regulation during the charging process through multi-point signal sampling and feedback control, thereby improving the response speed, stability, and safety of the charging system and adapting to the application requirements of smart door locks in complex power environments.

[0016] In some embodiments, the charging protection unit further includes a maximum power unit, one end of which is connected to the other end of the first filtering unit and one end of the sampling unit; the other end of the maximum power unit is connected to the maximum power acquisition terminal of the power management unit.

[0017] In this embodiment, by introducing a maximum power unit into the charging protection unit, real-time acquisition and dynamic adjustment of solar input power are realized. By jointly sampling voltage and current signals, it is possible to determine whether the current point is at the maximum power point and guide the power management unit to adjust the PWM duty cycle to always maintain the optimal power output state, thereby significantly improving solar energy utilization efficiency and enhancing the system's adaptability and charging stability in low light or light change environments.

[0018] In some embodiments, the control unit further includes a temperature detection unit, the output of which is connected to the temperature acquisition terminal of the power management unit.

[0019] In this embodiment, by introducing a temperature detection unit and linking it with the power management unit, dynamic temperature regulation and over-temperature protection during the charging process can be achieved. This technical solution can not only prevent battery damage caused by high temperature environment or fast charging, but also avoid charging efficiency loss caused by the decline in lithium battery activity under low temperature conditions, thereby significantly improving the charging safety and reliability of the entire smart door lock system.

[0020] In some embodiments, the smart lock further includes a communication protection circuit located between the communication port of the USB interface and the control unit, and the communication protection circuit includes a TVS diode or a Zener diode.

[0021] In this embodiment, a communication protection circuit is set between the communication port of the USB interface and the control unit, which effectively realizes voltage limiting and stabilization protection of the communication signal. In the event of abnormalities such as surges, electromagnetic interference or electrostatic discharge, the unit can quickly clamp the signal voltage to a safe range, prevent the communication pin of the control unit from being damaged or failing due to overvoltage, thereby improving the anti-interference capability and communication stability of the system and ensuring the reliable operation of the smart lock in complex environments.

[0022] A second aspect of this utility model provides a smart door lock, which includes the control circuit, solar panel, and battery described in the first aspect.

[0023] A third aspect of this utility model provides a door, the door including the smart door lock described in the second aspect.

[0024] It is understood that the beneficial effects of the second aspect compared to the third aspect can be found in the relevant description in the first aspect above, and will not be repeated here. Attached Figure Description

[0025] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the description of the embodiments of this utility model 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 these drawings without creative effort.

[0026] Figure 1 This is a schematic diagram of the first structure of the control circuit of an intelligent door lock provided in Embodiment 1 of this utility model;

[0027] Figure 2 This is a schematic diagram of the second structure of the control circuit of an intelligent door lock provided in Embodiment 1 of this utility model;

[0028] Figure 3This is a structural diagram of the USB interface in the control circuit of a smart door lock provided in Embodiment 1 of this utility model;

[0029] Figure 4 This is a schematic diagram of the third structure of the control circuit of an intelligent door lock provided in Embodiment 1 of this utility model;

[0030] Figure 5 This is a schematic diagram of the fourth structure of the control circuit of an intelligent door lock provided in Embodiment 1 of this utility model;

[0031] Figure 6 This is a fifth structural schematic diagram of the control circuit of an intelligent door lock provided in Embodiment 1 of this utility model;

[0032] Figure 7 This is a sixth structural schematic diagram of the control circuit of an intelligent door lock provided in Embodiment 1 of this utility model;

[0033] Figure 8 This is a seventh structural schematic diagram of the control circuit of an intelligent door lock provided in Embodiment 1 of this utility model;

[0034] Figure 9 This is the eighth structural schematic diagram of the control circuit of an intelligent door lock provided in Embodiment 1 of this utility model;

[0035] In the diagram: 101, USB interface; 102, charging circuit; 103, control unit; 104, communication protection circuit; 111, solar panel; 112, battery; 113, testing equipment; 114, temperature detection unit; 121, charging protection unit; 122, power management unit; 201, first switching unit; 202, first filtering unit; 203, sampling unit; 204, inductor unit; 205, second filtering unit; 206, feedback unit; 207, second switching unit; 208, maximum power unit. Detailed Implementation

[0036] 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, not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present utility model.

[0037] It should be understood that this invention can be embodied in various forms and should not be construed as being limited to the embodiments set forth herein. Rather, providing these embodiments will make the disclosure thorough and complete, and will fully convey the scope of this invention to those skilled in the art. In the drawings, for clarity, the dimensions of layers and regions, as well as their relative dimensions, may be exaggerated. The same reference numerals denote the same elements throughout.

[0038] It should be understood that when an element or layer is referred to as "on," "adjacent to," "connected to," or "coupled to" other elements or layers, it may be directly on, adjacent to, connected to, or coupled to other elements or layers, or there may be intervening elements or layers. Conversely, when an element is referred to as "directly on," "directly adjacent to," "directly connected to," or "directly coupled to" other elements or layers, there are no intervening elements or layers. It should be understood that although the terms first, second, third, etc., may be used to describe various elements, components, areas, layers, and / or portions, these elements, components, areas, layers, and / or portions should not be limited by these terms. These terms are only used to distinguish one element, component, area, layer, or portion from another element, component, area, layer, or portion. Therefore, without departing from the teachings of this utility model, the first element, component, area, layer, or portion discussed below may be referred to as the second element, component, area, layer, or portion.

[0039] To fully understand this utility model, detailed structures and steps will be presented in the following description to illustrate the technical solution proposed by this utility model. Preferred embodiments of this utility model are described in detail below; however, in addition to these detailed descriptions, this utility model may have other embodiments.

[0040] Example 1

[0041] This embodiment provides a control circuit for a smart door lock, such as... Figure 1 and Figure 2 As shown, it includes: a USB interface 101, a charging circuit 102, and a control unit 103. The USB interface 101 includes a charging port and a communication port. The charging port is connected to the charging circuit 102, and the communication port is connected to the control unit 103.

[0042] When the charging port is connected to the solar panel 111, the solar panel 111 charges the smart door lock;

[0043] When the communication port is connected to the test device 113, the test device 113 tests the smart door lock.

[0044] The USB interface 101 includes multiple pins, at least constituting a charging port and a communication port. The charging port connects to the solar panel 111 to receive the DC current output from the solar panel 111; the communication port detects whether the test device 113 is connected; the communication port also interacts with the control unit 103; the charging circuit 102 connects to the battery 112, and the charging port charges the battery 112 through the charging circuit 102. Optionally, the USB interface 101 can be a Type-C interface, which has advantages such as small size, reversible insertion, and a large number of pins, making it suitable for space-constrained smart lock devices; stable power supply can be achieved through the VBUS and GND pins of the Type-C interface, communication functions can be implemented using CC1 / CC2 or D+ / D- pins, and auxiliary pins can be used to identify whether the test device 113 is connected. Optionally, the USB interface 101 can also be a Micro-USB interface, which is compact and inexpensive, meeting basic charging and data communication functions, and is suitable for lock models with lower functional requirements. Optionally, the USB interface 101 can also be a customized USB interface. This interface structure can be flexibly configured with the functions of each pin according to the functional requirements of the main control chip, so as to provide power and support the test control of the door lock.

[0045] The charging circuit 102 is used to convert and manage the electrical energy provided by the solar panel 111 connected to the USB interface 101 to stably charge the battery 112. Depending on the application scenario and cost configuration, the charging circuit 102 can adopt the following structures: 1. A linear constant current constant voltage charging structure, including an input filtering unit, a constant current constant voltage linear charging chip, a battery terminal voltage feedback resistor, and an NTC thermistor; the chip status output pin is connected to the control unit 103 to realize full charge detection and fault reporting. 2. A buck intelligent charging structure, where the input voltage comes from the solar panel 111. When the voltage fluctuation range is large (e.g., 6V~18V), the charging circuit 102 preferably uses an intelligent charging chip with buck capability. This structure includes: an input overvoltage protection unit, a Buck-type buck circuit, and a battery terminal voltage divider feedback network; 2 The C-type communication interface connects to the main control MCU for reading charging status and dynamically adjusting the charging strategy. 3. MPPT (Maximum Power Point Tracking) charging structure: In outdoor environments where solar panels are subjected to drastic fluctuations in sunlight, the charging circuit 102 can further integrate MPPT (Maximum Power Point Tracking) functionality to improve solar energy utilization; this includes: an MPPT control unit, a Buck step-down control loop, and a real-time voltage / current detection unit.

[0046] The control unit 103 manages the door lock's operating logic, battery charging, test identification, and communication functions. As the core unit of this technical solution, the control unit 103 works in conjunction with the USB interface 101, charging circuit 102, and battery 112 to achieve intelligent control of the door lock. The control unit 103 includes at least the following functions: 1. Mode recognition and switching function: The control unit 103 detects the communication port status of the USB interface 101 to determine whether an external test device 113 is currently connected; if the test device 113 is detected, it switches to test mode; otherwise, it remains in working mode. 2. Charging management function: In working mode, the control unit 103 acquires information such as battery voltage, current, and temperature, and controls the working state of the charging circuit 102. In abnormal conditions (such as overvoltage or overtemperature), it promptly interrupts charging to protect battery safety. 3. Communication processing function: The control unit 103 connects to the communication pins (such as D+ / D) of the USB interface 101. - (or CC1 / CC2), in test mode, receives test commands from external test equipment 113, executes corresponding functions (such as motor test, LED test, voltage readback, etc.), and returns the test results. 4. Lock body control function: The control unit 103 is also used to execute the daily operation logic of the door lock, such as user authentication, unlocking control, low battery reminder, power consumption management, etc. The control unit 103 is preferably a low-power microcontroller (MCU). The control unit 103 can be directly soldered onto the door lock motherboard, or connected to the main control circuit in unit form via ribbon cable, and the layout can be optimized according to the overall layout.

[0047] The working process of this embodiment is as follows: When the communication port is connected to the test device 113, the test device 113 tests the smart door lock. The communication port of the USB interface 101 is connected to the external test device 113. After the control unit 103 detects this connection, it automatically switches to the test logic path. At this time, the control unit 103 receives test commands from the external test device 113 through the communication port of the USB interface 101, such as LED indicator flashing test, motor action test, battery status reading, etc., and responds and provides feedback in sequence according to the preset test process, which facilitates debugging and verification of the door lock function.

[0048] When the charging port is connected to the solar panel 111, the solar panel 111 charges the smart door lock. At this time, the control unit 103 controls the operation of the charging circuit 102 based on information such as the current battery voltage, current, and temperature. When the battery power is detected to be insufficient or the charging conditions are met, the control unit 103 starts the charging circuit 102 to charge the battery; when the battery is full or an abnormality occurs (such as excessive temperature), charging stops to ensure charging safety and battery life.

[0049] The technical advantages of the solution provided in this embodiment are as follows: By setting a USB interface 101 including a charging port and a communication port, an efficient power supply connection between the solar panel 111 and the door lock body is achieved. At the same time, the test device 113 can be connected to the system for testing through the communication port. When the communication port is connected to the test device 113, the control unit 103 recognizes that the system is in test mode, receives external test commands through the communication port, and executes functional tests. When the charging port is connected to the solar panel 111, it automatically enters the working state. The control unit 103 controls the charging circuit 102 to charge the battery according to the battery status, realizing automatic charging management under solar power. By setting a USB interface with a charging port and a communication port, the smart door lock can be functionally tested without disassembling the outer shell, effectively avoiding the risk of dust and moisture entering the control board and causing short circuits during the test, thus improving the convenience of testing and the reliability of the equipment.

[0050] As one implementation of the USB interface 101, such as Figure 3 As shown, the TYPE-C interface includes a first power pin A9 (VBUS1), a second power pin B9 (VBUS2), a first ground terminal A12 (GND1), a second ground terminal B12 (GND2), a first identification pin A5 (CC1), and a second identification pin B5 (CC2). The first power pin A9 (VBUS1), the second power pin B9 (VBUS2), the first ground terminal A12 (GND1), and the second ground terminal B12 (GND2) constitute a charging port, and the first identification pin A5 (CC1) and the second identification pin B5 (CC2) constitute a communication port. The USB interface 101 is a TYPE-C interface.

[0051] The control circuit of the smart door lock uses a Type-C interface as its external connection interface to realize functions such as solar power supply, charging control, communication interaction, and test status identification. The Type-C interface has a compact structure and abundant pins, capable of simultaneously meeting the requirements of efficient power supply and multi-functional identification. The pins of the Type-C interface have the following functions: the first power pin A9 and the second power pin B9 are used to receive DC power output from the solar panel 111, forming the positive power supply portion. The first ground terminal A12 and the second ground terminal B12 are connected to the system ground, forming a power supply loop to improve current carrying capacity and signal stability. The first identification pin A5 and the second identification pin B5 are the original CC1 and CC2 pins in the Type-C standard, used for cable direction identification and PD negotiation; in this embodiment, they are reused as test identification pins.

[0052] During operation, the control unit 103 determines whether an external test device 113 is currently connected by detecting the level status of the first identification pin A5 and the second identification pin B5. When the identification pin is limited to a specific level or the identification signal of the test device 113 is detected, the control unit 103 automatically enters the test state. When the identification pin is floating or in the default level state, the system remains in the normal working state.

[0053] The technical advantages of this implementation method are as follows: by utilizing the original dual power supply and identification functions of the Type-C interface, interface reuse and function expansion are realized, eliminating the need for additional dedicated test ports, improving interface integration and overall structural compactness, and making it suitable for smart door lock products with high requirements for space and security.

[0054] As one implementation method, such as Figure 4 As shown, the charging circuit 102 includes a charging protection unit 121 and a power management unit 122. The input terminal of the charging protection unit 121 is connected to the charging port of the USB interface 101, the voltage output terminal of the charging protection unit 121 is connected to the battery, the signal output terminal of the charging protection unit 121 is connected to the signal acquisition terminal of the power management unit 122, the first output terminal of the power management unit 122 is connected to the first control terminal of the charging protection unit 121, and the second output terminal of the power management unit 122 is connected to the control unit 103. The power management unit 122 controls the output current of the charging protection unit 121 according to the acquired signal and sends the charging status of the battery to the control unit 103.

[0055] The input terminal of the charging protection unit 121 is connected to the charging port of the USB interface 101 to receive the power supply voltage from the solar panel 111. The charging protection unit 121 has the following functions: 1. Electrical protection function: overvoltage protection and surge suppression of the input voltage; preventing battery damage due to abnormal input voltage or current. 2. Charging control function: regulating the current through internal or external MOSFETs, inductors, and other components; providing constant current / constant voltage output to the battery. 3. Electrical parameter sampling function: transmitting voltage, current, and other information to the power management unit 122 via a sampling network for subsequent feedback control. The charging protection unit 121 includes, but is not limited to, the following structure: a Buck converter consisting of a TVS diode, a current-limiting resistor, an NTC thermistor, and an inductor-capacitor combination; a switching transistor (MOSFET); and a voltage / current sampling network (such as a voltage divider resistor and a sampling resistor).

[0056] The power management unit 122's signal acquisition terminal is connected to the signal output terminal of the charging protection unit 121 to acquire key parameters such as the current charging voltage and current, and to perform the following controls based on these parameters: 1. Closed-loop charging control: The battery charging status is determined based on the sampled values; the first output terminal is controlled to output a control signal (such as a PWM wave or high / low level) to the charging protection unit 121, adjusting the MOSFET switching frequency or duty cycle, thereby adjusting the output current. 2. Status feedback function: The current charging status of the battery (such as charging, fully charged, abnormal temperature, undervoltage input, etc.) is sent to the control unit 103 (MCU) through the second output terminal; this facilitates status display, remote uploading, or strategy adjustment by the main control system. The power management unit 122 can use an integrated power management chip, which internally includes sampling comparison, reference voltage, current setting, and voltage feedback loops; it supports I2C or UART interfaces for communication with the main control unit.

[0057] The working process of this embodiment is as follows: the solar panel 111 inputs electrical energy to the charging protection unit 121 through the USB interface 101; the charging protection unit 121 provides charging current to the battery after filtering and voltage regulation, and outputs voltage and current sampling signals in real time; the power management unit 122 collects these signals and dynamically controls the charging current according to the actual battery status; at the same time, it sends the current charging status back to the control unit 103 to realize linkage control.

[0058] The technical advantages of this embodiment are as follows: by setting a charging protection unit and a power management unit in the charging circuit, intelligent control and safety protection of the battery charging process are realized; the power management unit dynamically adjusts the output current according to the voltage and current signals collected by the charging protection unit to ensure that the battery is charged stably under constant current and constant voltage conditions, and at the same time feeds back the charging status to the control unit in real time, which is conducive to charging control and status management, thereby improving charging efficiency, safety and the overall system intelligence level.

[0059] As one implementation method, such as Figure 5 As shown, the control unit 103 includes a voltage detection circuit 131 and a control output circuit 132. The input terminal of the voltage detection circuit 131 is connected to the charging port, the first input terminal of the control output circuit 132 is connected to the second output terminal of the power management unit 122, and the output terminal of the control output circuit 132 is connected to the second control terminal of the charging protection unit 121.

[0060] The voltage detection circuit 131 is connected to the charging port of the USB interface 101 to collect the USB input voltage value in real time. The voltage detection circuit 131 can be a voltage sampling circuit (e.g., through resistor voltage division and ADC sampling) to determine whether the solar panel 111 is supplying power normally. The control output circuit 132 outputs high and low level signals to the charging protection unit 121 based on the collected voltage value, thereby controlling the on or off state of the charging protection unit 121: when the detected USB input voltage reaches a preset charging level (e.g., greater than 4.5V), indicating normal power supply, the control unit 103 outputs an on control signal to the charging protection unit 121, allowing the charging protection unit 121 to charge the battery; when the input voltage is lower than a set threshold (e.g., less than 3V) or abnormal fluctuations occur, the control unit 103 outputs a off signal to shut down the charging path, preventing damage to the battery from abnormal voltage.

[0061] The technical advantages of this implementation are as follows: by setting a control terminal in the charging protection unit, and having the control unit control its conduction or shutdown in real time according to the USB interface input voltage, dynamic management of the charging path is realized; charging is automatically started when the voltage is normal, and charging is immediately shut down when the voltage is abnormal, effectively preventing damage to the battery due to abnormal power supply, and improving the charging safety, reliability and environmental adaptability of the system.

[0062] As one implementation method, such as Figure 6 As shown, the charging protection unit 121 includes a first switching unit 201, a first filtering unit 202, a sampling unit 203, an inductor unit 204, a second switching unit 207, a second filtering unit 205, and a feedback unit 206. One end of the first switching unit 201 is the input terminal of the charging protection unit 121, and the other end of the first switching unit 201 is connected to one end of the first filtering unit 202. The control terminal of the first switching unit 201 is the control terminal of the charging protection unit 121, and the other end of the first filtering unit 202 is connected to one end of the sampling unit 203 and the power management unit 1. The first signal sampling terminal of 22, the other end of sampling unit 203 is connected to one end of inductor unit 204 and the second signal sampling terminal of power management unit 122 respectively, the other end of inductor unit 204 is connected to one end of second switching unit 207, one end of feedback unit 206 and one end of second filtering unit 205 respectively, the other end of feedback unit 206 is connected to the third signal sampling terminal of power management unit 122, the first output terminal of power management unit 122 is connected to the control terminal of second switching unit 207, and the other end of second filtering unit 205 is the output terminal of charging protection unit 121.

[0063] The first switching unit 201 controls whether the current input from the USB interface is fed into the charging path. Its control terminal is connected to the control unit 103, which opens or closes the charging port based on the input voltage or system status. The first switching unit 201 can be an N-channel MOSFET or a P-MOS + driving circuit combination. The first filtering unit 202 filters out high-frequency noise, power jitter, or spike interference from the USB interface input, protecting the subsequent circuitry for stable operation. The first filtering unit 202 can be composed of a capacitor, inductor, or π-type filter. The sampling unit 203 transmits the input voltage and current signals to the first and second signal sampling terminals of the power management unit 122, facilitating constant current and constant voltage feedback control. The sampling unit 203 can be a resistor divider network, a current sensing resistor, or a Hall current sensor. The inductor unit 204 smooths the current and reduces the voltage under switching control, achieving a stable output of 4.2V from the USB input voltage (e.g., 5V-18V) to the battery terminal. The inductor unit 204 is an inductor L, forming a Buck step-down energy storage unit. The second switching unit 207, together with the inductor unit 204, forms the core of the step-down regulation, controlling the energy transfer rate and achieving output current control under PWM modulation; the second switching unit 207 can be a high-frequency MOSFET. The second filter unit 205 filters out pulse fluctuations generated by the inductor and switching units, outputting a stable DC voltage to the battery; the second filter unit 205 can be a parallel capacitor and an RC low-pass filter network. The feedback unit 206 collects the output voltage (i.e., the battery terminal voltage) and feeds it back to the third signal sampling terminal of the power management unit 122 to determine whether the battery is fully charged, over-voltage, etc. Its structure is a voltage divider resistor network or an operational amplifier buffer circuit.

[0064] The working process of this embodiment is as follows:

[0065] 1. Start-up and input control stage: When the solar panel 111 is powered by the USB interface 101, the control unit 103 collects the input voltage of the USB interface; if the voltage meets the standard, the control unit 103 outputs a high level to turn on the first switching unit 201 and start the charging path; the electrical energy enters the charging path after being filtered by the first filtering unit 202.

[0066] 2. Signal sampling and feedback closed-loop stage: The input voltage / current is transmitted to the first sampling signal terminal and the second sampling signal terminal of the power management unit 122 through the sampling unit 203; the power management unit 122 calculates the required charging current according to the current battery status and the set strategy.

[0067] 3. Buck regulation and energy transfer stage: The power management unit 122 controls the second switching unit 207 (MOS transistor) to perform PWM switching through the first output terminal; it forms a Buck buck path with the inductor unit 204 to achieve constant current / constant voltage output; the output current is filtered by the second filter unit 205 and then stably output to the battery.

[0068] 4. Output feedback and charging status stage: The output voltage is fed back to the third sampling terminal of the power management unit 122 through the feedback unit 206; if the voltage has reached the set cutoff value, the output PWM control signal controls the second switching unit 207 to stop conducting and end the charging; the charging status (charging, full, overvoltage) is sent to the main control unit 103 in real time for reporting or prompting.

[0069] The technical advantages of this implementation are as follows: By setting the internal structure of the charging protection unit, a step-down charging path consisting of switch control, filtering, sampling, inductor energy storage, PWM regulation, output voltage regulation, and feedback acquisition is formed. This not only achieves efficient energy conversion from USB interface input to battery end, but also ensures constant current and constant voltage regulation during the charging process through multi-point signal sampling and feedback control, thereby improving the response speed, stability, and safety of the charging system and adapting to the application needs of smart door locks in complex power environments.

[0070] As one implementation method, such as Figure 7 As shown, the charging protection unit 121 includes a maximum power unit 208. One end of the maximum power unit 208 is connected to the other end of the first filtering unit 202 and one end of the sampling unit 203, respectively. The other end of the maximum power unit 208 is connected to the maximum power acquisition terminal of the power management unit 122.

[0071] The maximum power unit 208 is used to collect and adjust the input power in real time under the power supply condition of the solar panel 111, so that the system always operates close to the maximum power point (MPPT) of the solar panel 111, thereby improving the solar energy utilization efficiency. The maximum power unit 208 is connected between the first filter unit 202 and the sampling unit 203, and can simultaneously acquire the input voltage and current signals of the solar panel 111. The power management unit 122 acquires the current input power value, determines whether the current power is on an increasing or decreasing trend, and adjusts the switching frequency or duty cycle according to the feedback signal to guide the system to approach the maximum power point. The maximum power unit 208 outputs the current maximum power tracking result to the maximum power acquisition terminal of the power management unit 122, which is used to determine whether to adjust the charging control parameters (such as PWM duty cycle) to optimize the energy harvesting efficiency.

[0072] The technical advantages of this implementation are as follows: by introducing a maximum power unit into the charging protection unit, real-time acquisition and dynamic adjustment of solar input power are realized; by jointly sampling voltage and current signals, it is possible to determine whether the current point is at the maximum power point and guide the power management unit to adjust the PWM duty cycle to always maintain the optimal power output state, thereby significantly improving solar energy utilization efficiency and enhancing the system's adaptability and charging stability in low light or light change environments.

[0073] As one implementation method, such as Figure 8 As shown, the control circuit also includes a temperature detection unit 114. The output terminal of the temperature detection unit 114 is connected to the temperature acquisition terminal of the power management unit 122. The power management unit 122 detects the temperature of the battery 112 according to the temperature detection unit 114 and controls the current output by the charging protection unit 121 according to the temperature of the battery 112.

[0074] The temperature detection unit 114 can be an NTC thermistor, a digital temperature sensor, or an integrated temperature sampling chip. Its installation position can be close to the battery or directly attached to the battery casing. The power management unit 114 determines whether the battery is within a safe charging temperature range based on the received temperature value and dynamically controls the current output of the charging protection unit 121 accordingly. Specifically, when the temperature is within the set safe range (e.g., 0℃~45℃), the smart lock charges normally; when the temperature is too high (e.g., >60℃) or too low (e.g., <-10℃), the output current is reduced or charging is paused; charging automatically resumes after the temperature returns to the safe range, ensuring battery life and charging safety.

[0075] The technical advantages of this embodiment are as follows: by introducing a temperature detection unit and linking it with the power management unit, dynamic temperature adjustment and over-temperature protection during the charging process can be achieved. This technical solution can not only prevent battery damage caused by high temperature environment or fast charging, but also avoid charging efficiency loss caused by the decline in lithium battery activity under low temperature conditions, thereby significantly improving the charging safety and reliability of the entire smart door lock system.

[0076] As one implementation method, such as Figure 9 As shown, the smart door lock also includes a communication protection circuit 104, which is located between the communication port of the USB interface 101 and the control unit 103. The communication protection circuit 104 includes a TVS diode or a Zener diode and is used to clamp the voltage output from the communication port to a preset voltage.

[0077] To enhance the electrical safety of the control unit 103 during USB interface communication, the smart lock also includes a communication protection circuit 104. This circuit limits and stabilizes the signal voltage in the communication line to prevent system damage due to abnormal voltage. Specifically, the input of the communication protection circuit 104 is connected to the communication port, and the output is connected to the data communication pins of the control unit 103 (such as the MCU's UART, I2C, GPIO, etc.). The communication protection circuit 104 can be implemented using the following circuit structure:

[0078] TVS (Transient Voltage Suppressor) diodes are used to suppress high-energy transient voltage spikes; Zener diodes are used to clamp signal voltages and protect input logic levels; integrated overvoltage protection chips (such as ESD protection arrays and TVS network ICs) are also used.

[0079] During system operation, if the USB interface experiences transient voltage changes such as surge voltage or electrostatic discharge due to plugging / unplugging, environmental interference, or misconnection of abnormal devices, the communication protection circuit 104 can clamp the signal and control it within the voltage range that the control unit 103 can withstand (e.g., 0-3.3V) to prevent input pin breakdown and ensure the stability of the communication link and the safe operation of the control unit 103.

[0080] The technical advantages of this implementation are as follows: by setting a communication protection circuit between the communication port of the USB interface and the control unit, the voltage limiting and stabilization protection of the communication signal is effectively realized; the unit can quickly clamp the signal voltage to a safe range in the event of abnormalities such as surges, electromagnetic interference or electrostatic discharge, preventing the communication pins of the control unit from being damaged or failing due to overvoltage, thereby improving the anti-interference capability and communication stability of the system and ensuring the reliable operation of the smart lock in complex environments.

[0081] Example 2

[0082] The second aspect of this utility model provides an intelligent door lock, which includes the control circuit, solar panel and battery provided in the first embodiment.

[0083] Example 3

[0084] The third aspect of this utility model provides a door, which includes the smart door lock provided in embodiment two.

[0085] The above embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit it. Although this utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this utility model, and should all be included within the protection scope of this utility model.

Claims

1. A control circuit of an intelligent door lock, characterized by, include: The system includes a USB interface, a charging circuit, and a control unit. The USB interface includes a charging port and a communication port. The charging port is connected to the charging circuit, and the communication port is connected to the control unit. When the charging port is connected to a solar panel, the solar panel charges the smart door lock; When the communication port is connected to the testing device, the testing device tests the smart door lock.

2. The control circuit of claim 1, wherein, The USB interface includes a first power pin, a second power pin, a first ground terminal, a second ground terminal, a first identification pin, and a second identification pin. The first power pin, the second power pin, the first ground terminal, and the second ground terminal constitute the charging port, and the first identification pin and the second identification pin constitute the communication port. The USB interface is a TYPE-C interface.

3. The control circuit of claim 1, wherein, The charging circuit includes a charging protection unit and a power management unit. The input terminal of the charging protection unit is connected to the charging port, the voltage output terminal of the charging protection unit is connected to the battery, the signal output terminal of the charging protection unit is connected to the signal acquisition terminal of the power management unit, the first output terminal of the power management unit is connected to the first control terminal of the charging protection unit, and the second output terminal of the power management unit is connected to the control unit.

4. The control circuit of claim 3, wherein, The control unit includes a voltage detection circuit and a control output circuit. The input terminal of the voltage detection circuit is connected to the charging port. The first input terminal of the control output circuit is connected to the second output terminal of the power management unit. The second input terminal of the control output circuit is connected to the output terminal of the voltage detection circuit. The output terminal of the control output circuit is connected to the second control terminal of the charging protection unit.

5. The control circuit of claim 3, wherein, The charging protection unit includes a first switching unit, a first filtering unit, a sampling unit, an inductor unit, a second switching unit, a second filtering unit, and a feedback unit. One end of the first switching unit is the input terminal of the charging protection unit, and the other end of the first switching unit is connected to one end of the first filtering unit. The control terminal of the first switching unit is the second control terminal of the charging protection unit. The other end of the first filtering unit is connected to one end of the sampling unit and the first signal sampling terminal of the power management unit. The other end of the sampling unit is connected to one end of the inductor unit and the second signal sampling terminal of the power management unit. The other end of the inductor unit is connected to one end of the second switching unit, one end of the feedback unit, and one end of the second filtering unit. The other end of the feedback unit is connected to the third signal sampling terminal of the power management unit. The first output terminal of the power management unit is connected to the control terminal of the second switching unit, and the other end of the second filtering unit is the output terminal of the charging protection unit.

6. The control circuit as described in claim 5, characterized in that, The charging protection unit further includes a maximum power unit, one end of which is connected to the other end of the first filtering unit and one end of the sampling unit; the other end of the maximum power unit is connected to the maximum power acquisition terminal of the power management unit.

7. The control circuit of claim 3, wherein, The control unit also includes a temperature detection unit, the output of which is connected to the temperature acquisition terminal of the power management unit.

8. The control circuit of any one of claims 1 to 7, wherein, It also includes a communication protection circuit, which is located between the communication port of the USB interface and the control unit. The communication protection circuit includes a TVS diode or a Zener diode.

9. A smart door lock, characterized in that, The smart door lock includes the control circuit, solar panel, and battery as described in any one of claims 1 to 8.

10. A door characterized in that, The door includes the smart door lock as described in claim 9.

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