Emergency power supply switching circuit, system and method

Abstract

The invention relates to the technical field of medical instruments, in particular to an emergency power supply switching circuit, system and method, which are used for automatically switching to a storage battery (BAT) to guarantee continuous power supply of a load when the mains supply is cut off. In the circuit, a first transistor (Q11) and a first field effect transistor (Q7) form an on-off control unit of a battery power supply channel, and the on-off control unit is used for controlling whether a storage battery (BAT) is conducted to a load or not. And the second transistor (Q12) is connected with the mains supply input end (VIN) and is used for cutting off the first transistor (Q11) when the mains supply is connected. The first voltage dividing network is connected to the mains supply side and is used for adjusting the conducting state of the second transistor (Q12); the second voltage dividing network is connected to the side of the storage battery (BAT) and used for controlling the first field effect transistor (Q7) to be turned on. The first current-limiting filtering series-parallel network and the second current-limiting filtering series-parallel network realize signal filtering and current limiting, and the switching stability and the electrical safety are improved.

Description

Technical Field

[0001] This invention relates to the field of medical device technology, and in particular to an emergency power switching circuit, system, and method. Background Technology

[0002] During surgical procedures, power outages can lead to malfunctions in surgical equipment or failure of the surgical lighting system, forcing the surgical process to be interrupted and posing a serious threat to the continuity of the procedure and the normal operation of medical equipment. Therefore, operating room lighting systems must be equipped with highly reliable emergency power switching devices to ensure a rapid switch to backup power in the event of a mains power failure. According to the IEC 60364-7-710 standard, medical facilities must ensure a switch to a safe power source within at least 15 seconds in an emergency, while the switching time in the operating room must not exceed 0.5 seconds. This ensures continuous lighting during surgery and prevents surgical procedures from being halted due to power outages.

[0003] In existing technologies, diesel generators are commonly used for emergency power switching. This solution is typically used to provide continuous power for extended periods, with a capacity sufficient to meet the power demands of all high-voltage and low-voltage loads. The diesel generator set must automatically start and supply power within 15 seconds of a mains power outage, and the continuous power supply time must be no less than 24 hours. However, this existing technology has significant drawbacks:

[0004] Environmental pollution issues: Diesel generators produce exhaust gases containing pollutants such as nitrogen oxides (NOx), carbon monoxide (CO), particulate matter (PM), and sulfides (SO2). These exhaust gases negatively impact the environmental quality of medical facilities, especially in areas with stringent air quality requirements such as operating rooms, where emissions from diesel generators may disrupt the cleanliness of the indoor environment.

[0005] Noise interference: The low-frequency noise generated by diesel generators during operation may interfere with the work of medical staff in medical facilities. Although diesel generators are used for short periods and at low frequencies, noise pollution during emergency startup remains a potential problem that cannot be ignored.

[0006] Energy consumption issues: Diesel generators consume a large amount of fuel, especially during long-term operation. Although their fuel consumption is relatively low, frequent starting and running still result in significant fuel consumption, increasing operating costs and raising concerns about fuel storage and supply security.

[0007] Switching efficiency issue: The diesel generator set requires 15 seconds to complete power switching, which is far from meeting the strict requirement of switching within 0.5 seconds in the operating room. This long switching interval may lead to interruption of surgical procedures or malfunction of medical equipment, affecting the stability of the surgical process.

[0008] In summary, existing diesel generator emergency power solutions have significant technical bottlenecks in terms of switching time, environmental friendliness, noise control, and energy consumption, making it difficult to meet the needs of medical facilities such as operating rooms, which have extremely high requirements for power continuity and switching efficiency.

[0009] Therefore, there is an urgent need to develop an emergency power switching method and system that can achieve rapid switching, is environmentally friendly, low-noise, and low-energy consumption, in order to overcome the shortcomings of existing technologies. Summary of the Invention

[0010] The purpose of this invention is to overcome the above-mentioned defects of the prior art, thereby providing an emergency power switching circuit, system and method.

[0011] To solve the above-mentioned technical problems, the emergency power switching circuit provided by the present invention is used to automatically switch to the storage battery BAT to maintain power supply to the load when the mains power fails, including: a first transistor Q11, a second transistor Q12, a first field-effect transistor Q7, a voltage divider network, a first current-limiting filter series-parallel network, and a second current-limiting filter series-parallel network; wherein,

[0012] The base of the first transistor Q11 is connected to the output port of the main control unit through a control signal processing network; its emitter grounding loop forms an on / off control channel; its collector is connected to the gate control terminal of the first field-effect transistor Q7 to control the on or off state of the first field-effect transistor Q7; the first transistor Q11 and the first field-effect transistor Q7 together constitute the on / off control unit of the battery power supply channel.

[0013] The first field-effect transistor Q7 has its source connected to the positive terminal of the battery BAT and its drain connected to the load output port, and is used to control whether the battery BAT is turned on to the load.

[0014] The collector of the second transistor Q12 is connected to the base of the first transistor Q11, its emitter is connected to the ground terminal, and its base is connected to the mains input terminal VIN through a lead wire. When the mains power is connected, it is used to pull down the base potential of the first transistor Q11, so that the first transistor Q11 is turned off.

[0015] The first voltage divider network has its input connected to the mains input terminal VIN and its output connected to the base of the second transistor Q12, and is used to adjust the mains input voltage to control the conduction of the second transistor Q12;

[0016] The second voltage divider network has its input connected to the battery input terminal VBAT and its output connected to the gate of the first field-effect transistor Q7, and is used to adjust the input voltage of the battery BAT to control the conduction of the first field-effect transistor Q7.

[0017] The first current-limiting filter series-parallel network is connected to the first voltage divider network and is used to filter and limit the control signal when the mains power is connected.

[0018] The second current-limiting filter series-parallel network is connected to the on / off control unit port and is used to perform current-limiting filtering on the first transistor Q11.

[0019] As an improvement to the above circuit, the control signal processing network includes a first resistor R92, a first inductor L8 and a switching diode D38 connected in series for filtering, current limiting and backflow protection.

[0020] As an improvement to the above circuit, the first voltage divider network includes a second resistor R97, a third resistor R99, and a transient suppression diode D44. The second resistor R97 and the third resistor R99 are connected in series, and their output terminals are connected to the base of the second transistor Q12. The transient suppression diode D44 is connected in parallel with the third resistor R99 to absorb voltage spikes and provide overvoltage protection. The second voltage divider network includes an eighth resistor R84 and a ninth resistor R88 connected in series. The output terminal of the second voltage divider network is connected to the gate of the first field-effect transistor Q7.

[0021] As an improvement to the above circuit, the circuit further includes a second capacitor C44, which is connected in parallel with a third resistor R99 for filtering the signal.

[0022] As an improvement to the above circuit, the first current-limiting filter series-parallel network is formed by connecting the fourth resistor R98, the second inductor L10, the first capacitor C45 and the fifth resistor R100 in series and parallel.

[0023] As an improvement to the above circuit, the second current-limiting filter series-parallel network is formed by connecting the sixth resistor R95, the seventh resistor R96, and the third capacitor C43 in series and parallel.

[0024] As an improvement to the above circuit, both the first transistor Q11 and the second transistor Q12 are NPN transistors; the first field-effect transistor Q7 is a P-channel MOSFET.

[0025] To achieve another objective of the present invention, the present invention also provides an emergency power switching system, including the above-described emergency power switching circuit, and further comprising:

[0026] The main control unit controls the conduction state of the first transistor Q11 through its output port;

[0027] The power input detection module is used to monitor the mains input terminal VIN in real time. When an interruption of the mains power is detected, an interrupt signal is issued.

[0028] Batteries (BAT) are used to provide backup power during mains power outages.

[0029] Load interface module, used to connect critical load devices; and

[0030] The main control board is used to integrate and install the main control unit, power input detection module, load interface module, and emergency power switching circuit; among them,

[0031] When the power input detection module detects that the mains power is connected, the main control unit controls the second transistor Q12 to turn on, thereby turning off the first transistor Q11 and turning off the first field-effect transistor Q7, disconnecting the battery BAT from the load, and realizing mains power supply.

[0032] When the power input detection module detects a mains power interruption, it sends an interrupt signal to the main control unit, outputs a high level to drive the first transistor Q11 to conduct, and then turns on the first field-effect transistor Q7, so that the battery BAT is connected to the load for power supply.

[0033] As an improvement to the above system, the main control unit also controls the mains power to connect to the battery BAT through the charging circuit when the power input detection module detects that the mains power is connected, so that the battery BAT can be charged.

[0034] To achieve another objective of the present invention, the present invention also provides an emergency power switching method, implemented based on the above-described emergency power switching system, comprising:

[0035] Status detection steps: The voltage status of the mains input terminal VIN is periodically detected by the power input detection module to determine whether the current power supply is mains power.

[0036] Switching control steps: If the mains input terminal VIN is high, it is determined that the mains power is normal. The main control unit outputs a low level to its output port, controlling the first transistor Q11 to turn off, causing the first field-effect transistor Q7 to turn off, disconnecting the power supply path of the battery BAT. The main control unit controls the mains power to charge the battery BAT through the charging circuit. If the mains input terminal VIN is low, it is determined that the mains power is off. The main control unit controls the first transistor Q11 to turn on, causing the first field-effect transistor Q7 to turn on, connecting the power supply path of the battery BAT.

[0037] Compared to existing technologies, the advantages of this invention lie in its rapid response, reliable control, and compact structure in providing an emergency power switching circuit, system, and method. The system employs a hardware and software combined control approach to achieve automatic switching between the mains power supply and the battery (BAT) in less than 0.5 seconds, meeting the emergency power supply response requirements of critical loads such as medical lighting. A controllable on / off control unit is constructed through the collaborative use of transistors and field-effect transistors, along with filtering, current limiting, and overvoltage protection circuits, ensuring electrical safety and system stability during the switching process. The battery (BAT) used features no memory effect, easy maintenance, low cost, and high safety, making it suitable for applications in locations with extremely high requirements for power supply continuity and reliability, such as hospital operating rooms. Furthermore, the system has a charging function, automatically charging the battery when the mains power is normal, improving energy utilization efficiency. The overall solution has clear technical logic, is simple to implement, and possesses good practicality and prospects for widespread application. Attached Figure Description

[0038] Figure 1 This is a schematic diagram of the emergency power switching circuit provided in Embodiment 1 of the present invention;

[0039] Figure 2 This is a schematic diagram of the emergency power switching system provided in Embodiment 2 of the present invention;

[0040] Figure 3 This is a flowchart of the emergency power switching method provided in Embodiment 3 of the present invention. Detailed Implementation

[0041] The technical solutions provided by the present invention will be further illustrated below with reference to the embodiments.

[0042] Example 1

[0043] This embodiment provides an emergency power switching circuit, the core purpose of which is to automatically switch to backup battery power with the shortest possible response time when the mains power fails, ensuring the continuous operation of the load equipment (such as surgical shadowless lamps). Figure 1 As shown, the emergency power switching circuit includes the following structural connections:

[0044] The first transistor Q11 is an NPN transistor, and its base is connected to the main control unit output port Bat_Lamp_ON through a control signal processing network. Specifically, the control signal processing network includes a first resistor R92, a first inductor L8, and a switching diode D38 connected in series for filtering, current limiting, and reverse current protection.

[0045] The emitter-to-ground loop of the first transistor Q11 forms an on / off control channel, and its collector is connected to the gate control terminal of the first field-effect transistor Q7 to control the on or off state of the first field-effect transistor Q7; the first transistor Q11 and the first field-effect transistor Q7 together constitute the on / off control unit of the battery power supply channel.

[0046] The first field-effect transistor Q7 is a P-channel MOSFET. Its source is connected to the positive terminal of the battery BAT, and its drain is connected to the load output port. It is used to control whether the battery BAT is turned on to the load.

[0047] The second transistor Q12 is an NPN transistor. Its collector is connected to the base of the first transistor Q11, its emitter is connected to the ground terminal, and its base is connected to the mains input terminal VIN through a lead. When the mains power is connected, it is used to pull down the base potential of the first transistor Q11, so that the first transistor Q11 is turned off.

[0048] The first voltage divider network, formed by the second resistor R97 and the third resistor R99 connected in series, sets the base voltage of the second transistor Q12. The third resistor R99 is also connected in parallel with a transient suppression diode D44 to absorb voltage spikes and provide overvoltage protection to prevent overvoltage damage to the transistor.

[0049] The eighth resistor R84 and the ninth resistor R88 are connected in series to form a second voltage divider network. The input is connected to the battery input terminal VBAT, and the output is connected to the gate of the first field-effect transistor Q7. This network is used to adjust the input voltage of the battery BAT to control the conduction of the first field-effect transistor Q7.

[0050] The circuit is further configured with a first current-limiting filter series-parallel network formed by the fourth resistor R98, the second inductor L10, the first capacitor C45 and the fifth resistor R100 connected in series and parallel. The first current-limiting filter series-parallel network is connected to the first voltage divider network and is used to filter and limit the control signal when the mains power is connected.

[0051] The second capacitor C44 is connected in parallel with the third resistor R99 to filter and limit the control signal.

[0052] The on / off control unit port is connected to a second current-limiting filter series-parallel network formed by the sixth resistor R95, the seventh resistor R96 and the second capacitor C43 connected in series and parallel. This network is used to perform voltage division and current limiting filtering on the first transistor Q11 to ensure the stability of the switching process.

[0053] Example 2

[0054] This embodiment provides an emergency power switching system, such as Figure 1 As shown, the system includes the emergency power switching circuit provided in Embodiment 1, and further includes:

[0055] Main control unit: Employs a microcontroller (MCU) with ADC sampling and GPIO control capabilities, such as the STM32F030. The main control unit controls the conduction state of the first transistor Q11 through its output port Bat_Lamp_ON;

[0056] Power input detection module: Monitors the mains input terminal VIN in real time, and sends an interrupt signal when an interruption of mains power is detected;

[0057] Battery BAT: Used to provide backup power when the mains power is interrupted. It can be a 12V lead-acid battery BAT or a lithium iron phosphate battery, which has the characteristics of high capacity, low internal resistance and no memory effect. In this embodiment, two battery BATs are used.

[0058] Load interface module: Connects to critical loads such as medical lighting equipment;

[0059] The main control board is used to integrate and install the main control unit, power input detection module, load interface module and emergency power switching circuit.

[0060] like Figure 2 As shown, the system operation process is as follows:

[0061] When the power input detection module detects the connection of mains power (grid power), the main control unit controls the second transistor Q12 to turn on, so that the first transistor Q11 is turned off and the first field-effect transistor Q7 is turned off, thereby disconnecting the connection between the battery BAT and the load and realizing mains power supply.

[0062] When the power input detection module detects a mains power interruption, it sends an interrupt signal to the main control unit, outputting a high level to drive the first transistor Q11 to conduct, which in turn turns on the first field-effect transistor Q7, allowing the battery BAT to be connected to the load for power supply.

[0063] When the power input detection module detects that the mains power is connected, the main control unit controls the mains power to connect to the battery BAT through the charging circuit, so that the battery BAT can be charged.

[0064] Figure 2 In the example, the load is represented by a surgical light.

[0065] This system achieves power path on / off control by forming a controllable connection between the first transistor Q11 and the first field-effect transistor Q7. Simultaneously, the second transistor Q12 forms a structural feedback loop with the mains power voltage signal, enabling automatic control of the first transistor Q11. The switching circuit manages the system's electrical safety through a series of current-limiting, filtering, and overvoltage protection components. All components are physically connected to form a unified and stable emergency power switching control system. This system achieves a switching time of no more than 0.5 seconds, and the entire switching process is fully automatic, requiring no manual operation. The system features a compact structure, clear control logic, and fast switching speed. Furthermore, it ensures system stability through voltage divider protection, inductor filtering, and TVS suppression.

[0066] Example 3

[0067] This embodiment provides an emergency power switching method, implemented based on the emergency power switching system provided in Embodiment 2, such as... Figure 3 As shown, it includes:

[0068] Status detection: The emergency power switching system periodically detects the voltage status of the mains input port VIN to determine whether the current power supply is mains or the mains power is interrupted;

[0069] Switching judgment logic: If the mains input terminal VIN is high, it is judged that the mains power is normal. The main control unit outputs a low level to its output port Bat_Lamp_ON, controls the first transistor Q11 to turn off, and turns off the first field-effect transistor Q7, cutting off the power supply to the battery BAT; if the mains input terminal VIN is low, it is judged that the mains power is off. The main control unit immediately outputs a high level to its output port Bat_Lamp_ON, controls the first transistor Q11 to turn on, and turns on the first field-effect transistor Q7, turning on the power supply to the battery BAT.

[0070] The method also includes: under normal mains power conditions, the main control unit controls the mains power to charge the battery BAT through the charging circuit.

[0071] This method enables the system to achieve rapid and seamless switching between mains power and battery, avoiding load power outages and meeting IEC requirements for a 0.5-second emergency response time for medical lighting.

[0072] The emergency power switching circuit, system, and method provided by this invention are suitable for providing continuous power to the load in the event of a mains power outage. The circuit includes a first transistor Q11, a second transistor Q12, a first field-effect transistor Q7, a first voltage divider network, a second voltage divider network, a first current-limiting filter series-parallel network, and a second current-limiting filter series-parallel network. The first transistor Q11 and the first field-effect transistor Q7 constitute the on / off control unit of the power supply channel of the battery BAT, driving the battery BAT to supply power when the mains power is interrupted; the second transistor Q12 is used to suppress the conduction of the first transistor Q11 when the mains power is connected; the first voltage divider network includes the second resistor R97, the third resistor R99 and the transient suppression diode D44, which is used to adjust the mains input voltage VIN to control the conduction of the second transistor Q12; the second voltage divider network includes the eighth resistor R84 and the ninth resistor R88 connected in series, and the output terminal is connected to the gate of the first field-effect transistor Q7, which is used to adjust the input voltage of the battery BAT to control the conduction of the first field-effect transistor Q7; the first current limiting filter series-parallel network consists of the fourth resistor R98, the second inductor L10, the first capacitor C45 and the fifth resistor R100, which is used to limit the current of the control signal; the second current limiting filter series-parallel network consists of the sixth resistor R95, the seventh resistor R96 and the third capacitor C43, which is used to perform voltage division and current limiting filtering on the first transistor Q11. The system integrates a main control unit, a power input detection module, and a load interface module, enabling automatic switching between the main power supply and the battery (BAT). The method involves real-time detection of the power status and automatic control of the transistor's conduction state to achieve stable power supply to the load.

[0073] As can be seen from the above detailed description of the present invention, the present invention has at least the following advantages:

[0074] Environmental friendliness: BAT batteries do not produce toxic heavy metals during production, use and disposal, making them environmentally friendly and solving the exhaust pollution problem of diesel generators.

[0075] No memory effect: The battery BAT can be charged and discharged at any time without waiting for the power to run out, which is very suitable for the frequent use of emergency lights and improves the availability of the system.

[0076] Easy maintenance: The maintenance of the battery BAT is relatively simple, without the need for a complex management system. In environments such as operating rooms where rapid response is required, this reduces maintenance costs and difficulty, and improves system reliability.

[0077] Rapid switching and high reliability: Through dual hardware and software control, seamless switching in less than 0.5 seconds is achieved, which can quickly provide a stable power supply in the event of a power outage, meet the stringent requirements of IEC standards for operating room power switching time, ensure the continuity of the surgical process, and protect patient safety.

[0078] High cost-effectiveness: As the cheapest secondary battery, the BAT battery costs far less than a diesel generator, giving it a significant economic advantage in medical institutions with limited budgets, while also reducing operating costs.

[0079] High safety: Compared with lithium batteries, the lead-acid batteries used in this solution have a lower risk of thermal runaway and are less likely to explode or catch fire. They are particularly suitable for environments with extremely high safety requirements, such as operating rooms, thus improving the safety and stability of the system.

[0080] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to the embodiments, those skilled in the art should understand that modifications or equivalent substitutions to the technical solutions of the present invention do not depart from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. An emergency power switching circuit for automatically switching to a battery (BAT) to maintain power supply to the load during a mains power outage, characterized in that, include: The system comprises a first transistor (Q11), a second transistor (Q12), a first field-effect transistor (Q7), a first voltage divider network, a second voltage divider network, a first current-limiting filter series-parallel network, and a second current-limiting filter series-parallel network; wherein... The base of the first transistor (Q11) is connected to the output port of the main control unit through a control signal processing network; its emitter grounding loop forms an on / off control channel; its collector is connected to the gate control terminal of the first field-effect transistor (Q7) to control the on or off state of the first field-effect transistor (Q7); the first transistor (Q11) and the first field-effect transistor (Q7) together constitute the on / off control unit of the battery power supply channel; The first field-effect transistor (Q7) has its source connected to the positive terminal of the battery (BAT) and its drain connected to the load output port, and is used to control whether the battery (BAT) is turned on to the load. The collector of the second transistor (Q12) is connected to the base of the first transistor (Q11), its emitter is connected to the ground terminal, and its base is connected to the mains input terminal (VIN) through a lead wire. When the mains power is connected, it is used to pull down the base potential of the first transistor (Q11) and turn off the first transistor (Q11). The first voltage divider network has its input connected to the mains input terminal (VIN) and its output connected to the base of the second transistor (Q12), and is used to adjust the mains input voltage to control the conduction of the second transistor (Q12); The second voltage divider network has its input connected to the battery input terminal (VBAT) and its output connected to the gate of the first field-effect transistor (Q7), and is used to adjust the input voltage of the battery (BAT) to control the conduction of the first field-effect transistor (Q7); The first current-limiting filter series-parallel network is connected to the first voltage divider network and is used to filter and limit the control signal when the mains power is connected. The second current-limiting filter series-parallel network is connected to the on / off control unit port and is used to perform current-limiting filtering on the first transistor (Q11).

2. The emergency power switching circuit according to claim 1, characterized in that, The control signal processing network includes a first resistor (R92), a first inductor (L8), and a switching diode (D38) connected in series for filtering, current limiting, and backflow protection.

3. The emergency power switching circuit according to claim 1, characterized in that, The first voltage divider network includes a second resistor (R97), a third resistor (R99), and a transient voltage suppressor diode (D44). The second resistor (R97) and the third resistor (R99) are connected in series, and their output terminals are connected to the base of the second transistor (Q12). The transient voltage suppressor diode (D44) is connected in parallel with the third resistor (R99) to absorb voltage spikes and provide overvoltage protection. The second voltage divider network includes an eighth resistor (R84) and a ninth resistor (R88) connected in series. The output terminal of the second voltage divider network is connected to the gate of the first field-effect transistor (Q7).

4. The emergency power switching circuit according to claim 3, characterized in that, It also includes a second capacitor (C44), which is connected in parallel with a third resistor (R99) for filtering the signal.

5. The emergency power switching circuit according to claim 1, characterized in that, The first current-limiting filter series-parallel network is formed by connecting the fourth resistor (R98), the second inductor (L10), the first capacitor (C45), and the fifth resistor (R100) in series and parallel.

6. The emergency power switching circuit according to claim 1, characterized in that, The second current-limiting filter series-parallel network is formed by connecting the sixth resistor (R95), the seventh resistor (R96), and the third capacitor (C43) in series and parallel.

7. The emergency power switching circuit according to claim 1, characterized in that, The first transistor (Q11) and the second transistor (Q12) are both NPN transistors; the first field-effect transistor (Q7) is a P-channel MOSFET.

8. An emergency power switching system, comprising the emergency power switching circuit according to any one of claims 1-7, further comprising: The main control unit controls the conduction state of the first transistor (Q11) through its output port; The power input detection module is used to monitor the mains input terminal (VIN) in real time. When an interruption of mains power is detected, an interrupt signal is issued. A battery (BAT) is used to provide backup power when the mains power is interrupted; Load interface module, used to connect critical load devices; and The main control board is used to integrate and install the main control unit, power input detection module, load interface module, and emergency power switching circuit; among them, When the power input detection module detects that the mains power is connected, the main control unit controls the second transistor (Q12) to turn on, thereby turning off the first transistor (Q11), turning off the first field-effect transistor (Q7), disconnecting the battery (BAT) from the load, and realizing mains power supply; When the power input detection module detects a mains power interruption, it sends an interrupt signal to the main control unit, outputs a high level to drive the first transistor (Q11) to turn on, which in turn turns on the first field-effect transistor (Q7), allowing the battery (BAT) to be connected to the load for power supply.

9. The emergency power switching system according to claim 8, characterized in that, The main control unit also controls the mains power to connect to the battery (BAT) through the charging circuit when the power input detection module detects that the mains power is connected, so that the battery (BAT) can be charged.

10. An emergency power switching method, implemented based on the emergency power switching system of claim 7, comprising: Status detection steps: The power input detection module periodically detects the voltage status of the mains input terminal (VIN) to determine whether the current power supply is mains power. Switching control steps: If the mains input terminal (VIN) is high, it is determined that the mains power is normal. The main control unit outputs a low level to its output port, controls the first transistor (Q11) to turn off, turns off the first field-effect transistor (Q7), disconnects the battery (BAT) power supply path, and the main control unit controls the mains power to charge the battery (BAT) through the charging circuit; if the mains input terminal (VIN) is low, it is determined that the mains power is off, controls the first transistor (Q11) to turn on, turns on the first field-effect transistor (Q7), and connects the battery (BAT) power supply path.

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