A dust collector floor brush current detection and short circuit protection circuit

Abstract

The application provides a dust collector floor brush current detection and short circuit protection circuit, which is connected with a control unit of a floor brush host, and comprises a power supply circuit, a first amplifier and a second amplifier. The power supply circuit is composed of a sampling resistor and a switch in series, and a first node is formed on the sampling resistor; the switch is controlled by the control unit to open and close the circuit. The first amplifier is connected with the first node and a signal sampling end of the control unit to form a detection circuit, and is responsible for amplifying the weak voltage signal of the first node, so that even if a control unit with low precision ADC is used, the control unit can also accurately identify the slight current change, and accurate load monitoring and overcurrent judgment are realized. The second amplifier is connected with the first node and a signal protection end of the control unit respectively to form a protection circuit; when the current abnormally rises, the second amplifier directly triggers the control unit to interrupt, and the hardware protection mechanism does not depend on software polling, the response speed is fast, and the hardware burning problem caused by protection delay can be effectively avoided.

Description

Technical Field

[0001] This application relates to the field of vacuum cleaners, and more particularly to a vacuum cleaner floor brush current detection and short-circuit protection circuit. Background Technology

[0002] To achieve precise control of the floor brush motor and ensure safe operation, it is necessary to monitor its operating current in real time and accurately. Currently, a common solution is to use a microcontroller for software monitoring. Specifically, a sampling resistor is usually connected in series in the floor brush motor circuit. The voltage drop across the resistor is directly fed into the analog-to-digital converter (ADC) of the MCU for sampling, and the software calculates the current value. When the software determines that the current exceeds a set threshold, it controls a switching device (such as a MOSFET) to cut off the circuit.

[0003] However, this software-dependent approach has two inherent systemic flaws: The voltage drop signal across the sampling resistor is extremely weak (typically in the millivolt range). For low-precision ADC microcontrollers used in cost-sensitive products, their resolution is insufficient to accurately capture minute current changes. This makes it difficult to implement intelligent functions based on current recognition, and also leads to inaccurate setting of software overcurrent protection points, which can easily cause malfunctions or protection failures.

[0004] Furthermore, short-circuit protection relies entirely on software-based polling, sampling, digital filtering, and calculation processes, resulting in an inherent millisecond-level delay. When faced with sudden, large short-circuit currents, this delay can cause protection actions to lag, failing to cut off the current within the safe time window for power device damage, posing a risk of hardware burnout.

[0005] Therefore, there is a need for a circuit that can accurately detect the current of the vacuum cleaner's floor brush and provide rapid protection. Utility Model Content

[0006] In view of this, it is necessary to provide a circuit that can accurately detect the current of the vacuum cleaner's floor brush and achieve rapid protection in order to solve the above problems.

[0007] An embodiment of this application provides a vacuum cleaner floor brush current detection and short circuit protection circuit, which is connected to the control unit of the floor brush host. The circuit includes: a power supply circuit, a first amplifier, and a second amplifier. The power supply circuit includes a sampling resistor and a switching element. The sampling resistor and the switching element are connected in series in the power supply circuit and form a first node on the sampling resistor. The switching element is connected to the control unit to control the switching element to turn on or off the power supply circuit. The first amplifier connects the first node to the signal sampling terminal of the control unit to form a detection loop that amplifies the voltage signal of the first node; The second amplifier is connected to the signal protection terminal of the first node and the control unit respectively to form a protection loop that triggers the interruption of the control unit.

[0008] In at least one embodiment of this application, the power supply circuit further includes: a current input terminal, a current output terminal, and a ground brush; One end of the ground brush is connected to the current input terminal, and the other end is connected in sequence to the switch, the sampling resistor and the current output terminal.

[0009] In at least one embodiment of this application, the detection circuit includes: a first voltage divider resistor and a second voltage divider resistor; One end of the first voltage divider resistor is connected to the first node, and the other end is connected to one end of the second voltage divider resistor and the inverting input terminal of the first amplifier. The other end of the second voltage divider resistor is connected to the ground terminal of the power supply circuit.

[0010] In at least one embodiment of this application, the detection circuit further includes: a first feedback resistor, a second feedback resistor, and an output resistor; One end of the first feedback resistor is grounded, and the other end is connected to one end of the second feedback resistor and the non-inverting input terminal of the first amplifier. The other end of the second feedback resistor is connected between the output resistor and the output terminal of the first amplifier. The output resistor is connected to the signal sampling terminal of the control unit.

[0011] In at least one embodiment of this application, the first voltage divider resistor has the same resistance value as the first feedback resistor, and the second voltage divider resistor has the same resistance value as the second feedback resistor.

[0012] In at least one embodiment of this application, the protection circuit includes: The third voltage divider resistor and the fourth voltage divider resistor connected in series with the third voltage divider resistor, The first end of the third voltage divider resistor is connected to the power supply voltage, the second end of the fourth voltage divider resistor is grounded, and the connection node between the second end of the third voltage divider resistor and the first end of the fourth voltage divider resistor is connected to the non-inverting input terminal of the second amplifier.

[0013] In at least one embodiment of this application, the protection circuit further includes a first current-limiting resistor, which is connected to the first node and the inverting input terminal of the second amplifier, respectively.

[0014] In at least one embodiment of this application, the protection circuit further includes: a switch trigger branch, one end of which is connected to the output terminal of the second amplifier, and the other end of which is connected to the signal protection terminal of the control unit.

[0015] In at least one embodiment of this application, the switch trigger branch includes a second current-limiting resistor, a switching transistor, and a pull-up resistor; The second current-limiting resistor is connected between the output terminal of the second amplifier and the control electrode of the switching transistor; The pull-up resistor is connected to the power supply voltage and the first terminal of the switching transistor, the second terminal of the switching transistor is grounded, and the first terminal of the switching transistor outputs a short-circuit protection signal to the control unit.

[0016] In at least one embodiment of this application, the first amplifier is a differential operational amplifier and the second amplifier is an operational amplifier.

[0017] The vacuum cleaner floor brush current detection and short-circuit protection circuit described above amplifies the weak voltage signal of the first node of the sampling resistor through the first amplifier, enabling even a low-precision ADC to accurately collect the current, thus solving the problems of unclear identification of minute current changes and inaccurate overcurrent protection; the second amplifier realizes protection by triggering the control unit interrupt, eliminating the need for software polling, resulting in a faster response and solving the problem of short-circuit protection delay that can easily burn out hardware. Attached Figure Description

[0018] Figure 1 This is a circuit diagram of the power supply circuit and the detection circuit in the embodiments of this application; Figure 2 This is a circuit diagram for the protection circuit.

[0019] Explanation of main component symbols 10. Power supply circuit; R1. Sampling resistor; Q1. Switch; DS. First node; 11. Current input terminal; 12. Current output terminal; 13. Ground brush; 20. Detection circuit; U1.2. First amplifier; R2. First voltage divider resistor; R3. Second voltage divider resistor; R4. First feedback resistor; R5. Second feedback resistor; R6. Output resistor; 30. Protection circuit; U1.1. Second amplifier; R9. Third voltage divider resistor; R10. Fourth voltage divider resistor; R7. First current limiting resistor; 40. Switch trigger branch; R11. Second current limiting resistor; Q2. Switch transistor; R12. Pull-up resistor. Detailed Implementation

[0020] The embodiments of this application will now be described with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments.

[0021] It should be noted that when a component is considered to be "connected" to another component, it can be directly connected to the other component or may also have an intervening component. When a component is considered to be "placed" on another component, it can be directly placed on the other component or may also have an intervening component. The terms "top," "bottom," "upper," "lower," "left," "right," "front," "back," and similar expressions used in this article are for illustrative purposes only.

[0022] An embodiment of this application provides a vacuum cleaner floor brush current detection and short circuit protection circuit, which is connected to the control unit of the floor brush host. The circuit includes: a power supply circuit, a first amplifier, and a second amplifier. The power supply circuit includes a sampling resistor and a switching element. The sampling resistor and the switching element are connected in series in the power supply circuit and form a first node on the sampling resistor. The switching element is connected to the control unit to control the switching element to turn on or off the power supply circuit. The first amplifier connects the first node to the signal sampling terminal of the control unit to form a detection loop that amplifies the voltage signal of the first node; The second amplifier is connected to the signal protection terminal of the first node and the control unit respectively to form a protection loop that triggers the interruption of the control unit.

[0023] The vacuum cleaner floor brush current detection and short-circuit protection circuit described above amplifies the weak voltage signal of the first node of the sampling resistor through the first amplifier, enabling even a low-precision ADC to accurately collect the current, thus solving the problems of unclear identification of minute current changes and inaccurate overcurrent protection; the second amplifier realizes protection by triggering the control unit interrupt, eliminating the need for software polling, resulting in a faster response and solving the problem of short-circuit protection delay that can easily burn out hardware.

[0024] The following detailed description of some embodiments of this application is provided in conjunction with the accompanying drawings. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0025] according to Figures 1-2 This application provides a current detection and short-circuit protection circuit for a vacuum cleaner floor brush 13, which is connected to the control unit of the floor brush 13 main unit. The circuit includes: a power supply circuit 10, a first amplifier U1.2, and a second amplifier U1.1.

[0026] The power supply circuit 10 includes a sampling resistor R1 and a switch Q1. The sampling resistor R1 and the switch Q1 are connected in series in the power supply circuit 10, and a first node DS is formed on the sampling resistor R1. The switch Q1 is connected to the control unit to control the switch Q1 to turn on or off the power supply circuit 10.

[0027] The first amplifier U1.2 connects the first node DS and the signal sampling terminal of the control unit to form a detection loop 10 that amplifies the voltage signal of the first node DS.

[0028] The second amplifier U1.1 is connected to the first node DS and the signal protection terminal of the control unit respectively, to form a protection loop 30 that triggers the interruption of the control unit.

[0029] Specifically, the current detection and short-circuit protection circuit of the vacuum cleaner floor brush 13 establishes a communication bridge circuit with the main control unit of the floor brush 13, enabling the current detection and short-circuit protection circuit to interact with the control unit, realize data transmission and receive and execute control commands, thereby facilitating the control unit to obtain current detection information; at the same time, it can also receive control commands from the control unit in a timely manner to control components such as the switch Q1, ensuring the coordinated operation of the entire system.

[0030] Switch Q1 is a switching structure that can quickly disconnect the power supply circuit 10 when an abnormal condition is detected, such as a short circuit, protecting the ground brush 13 motor and other related components from damage by large current, thereby improving the safety and reliability of the system. In this embodiment, switch Q1 is an N-channel MOSFET switch.

[0031] Furthermore, when the power supply circuit 10 is connected, current flows through it and generates a voltage drop across the sampling resistor R1, making the voltage of the first node DS proportional to the current flowing through the ground brush 13. The first amplifier U1.2 and related components connected to the first amplifier U1.2 linearly amplify the weak millivolt-level voltage signal on the first node DS, thereby amplifying the current sampling signal, and then sending the amplified voltage signal to the signal sampling terminal of the control unit.

[0032] The signal protection terminal of the control unit is an external interrupt pin. Unlike the first amplifier U1.2, the second amplifier U1.1 is mainly used for short-circuit protection. When a sudden short-circuit high current occurs, the voltage drop across the sampling resistor R1 will increase rapidly. The second amplifier U1.1 quickly amplifies the signal and triggers the control unit interrupt. Compared with the software polling sampling, digital filtering, and calculation judgment process, this hardware triggering method has almost no delay and can quickly cut off the current within the safe time window for power device damage, effectively avoiding the risk of hardware burnout.

[0033] Furthermore, the second amplifier U1.1 and its peripheral circuitry constitute a voltage comparator and an interrupt trigger circuit, serving as the protection loop 30. The second amplifier U1.1 has a certain reference threshold. When the voltage at the first node DS suddenly rises due to overcurrent or short circuit and exceeds the threshold, the second amplifier U1.1 immediately outputs a trigger signal to the signal protection terminal of the control unit. Based on this, the control unit quickly interrupts the switch Q1, cutting off the power supply loop 10, thereby preventing damage to the ground brush 13 motor or circuit components due to overheating or overload.

[0034] In summary, the control unit turns on the switch Q1, connecting the power supply circuit 10, and the ground brush 13 motor starts working. Current flows through the sampling resistor R1, generating a small voltage drop across R1 that is proportional to the current magnitude. This voltage drop occurs at the first node DS.

[0035] The first amplifier U1.2 amplifies the weak voltage signal of the first node DS and then transmits it to the signal sampling terminal of the control unit. The control unit obtains the current value flowing through the device by sampling and calculating the amplified signal.

[0036] When a sudden short-circuit high current occurs, the voltage drop across the sampling resistor R1 increases rapidly. The second amplifier U1.1 quickly detects this increased voltage drop signal and amplifies it, then triggers an interrupt in the control unit. Upon receiving the interrupt signal, the control unit immediately sends a cut-off command to the switch Q1. The switch Q1 quickly cuts off the power supply circuit 10, preventing the high current from continuing to flow, thereby protecting the ground brush 13 motor and related components from damage.

[0037] In one specific embodiment, the power supply circuit 10 further includes: a current input terminal 11, a current output terminal 12, and a ground brush 13.

[0038] One end of the ground brush 13 is connected to the current input terminal 11, and the other end is connected in sequence to the switch Q1, the sampling resistor R1 and the current output terminal 12.

[0039] Specifically, the connection between the current input terminal 11 and the current output terminal 12 will output the current after passing through the ground brush 13, the switch Q1 and the sampling resistor R1 back to the power supply circuit or connect to other related circuit parts, thus completing the circulation of current in the power supply circuit 10.

[0040] Placing the sampling resistor R1 on the low-voltage side of the circuit near the ground reference point makes the voltage of the first node DS a low positive voltage relative to the common ground, which greatly simplifies the design of the subsequent amplifier circuit.

[0041] The floor brush 13 is the core working component of the vacuum cleaner. Driven by a motor, it rotates or vibrates to clean the floor. In this circuit, it is the main current-consuming load, and changes in its operating state directly affect the current in the power supply circuit 10.

[0042] In one specific embodiment, the detection circuit 10 includes: a first voltage divider resistor R2 and a second voltage divider resistor R3.

[0043] One end of the first voltage divider resistor R2 is connected to the first node DS, and the other end is connected to one end of the second voltage divider resistor R3 and the inverting input terminal of the first amplifier U1.2. The other end of the second voltage divider resistor R3 is connected to the ground terminal of the power supply circuit 10.

[0044] Specifically, in the detection circuit 10, the first voltage divider resistor R2 and the second voltage divider resistor R3 together form a voltage divider circuit. The first voltage divider resistor R2 and the second voltage divider resistor R3 attenuate the higher voltage signal at the first node DS to a lower voltage, so that the voltage input to the inverting input terminal of the first amplifier U1.2 is within a suitable range before processing.

[0045] In one specific embodiment, the detection circuit 10 further includes: a first feedback resistor R4, a second feedback resistor R5, and an output resistor R6.

[0046] One end of the first feedback resistor R4 is grounded, and the other end is connected to one end of the second feedback resistor R5 and the non-inverting input terminal of the first amplifier U1.2. The other end of the second feedback resistor R5 is connected between the output resistor R6 and the output terminal of the first amplifier U1.2. The output resistor R6 is connected to the signal sampling terminal of the control unit.

[0047] Specifically, the first feedback resistor R4 provides a stable reference potential for the non-inverting input of the first amplifier U1.2. The first feedback resistor R4, together with the second feedback resistor R5, forms the amplifier's feedback network, affecting the amplifier's input impedance and voltage gain.

[0048] Furthermore, the output resistor R6 is connected between the output terminal of the first amplifier U1.2 and the signal sampling terminal of the control unit, serving as isolation and impedance matching. It transmits the voltage signal output by the amplifier to the control unit while preventing the control unit from causing excessive load on the amplifier output.

[0049] Furthermore, the voltage signal, after voltage division, is input to the inverting input of the first amplifier U1.2. Simultaneously, the first feedback resistor R4 provides a ground potential reference for the non-inverting input, and the second feedback resistor R5 feeds back the amplifier's output signal to the non-inverting input, forming a negative feedback loop. According to the principle of negative feedback, the amplifier automatically adjusts its gain based on the difference between the feedback signal and the input signal. The inverting input of the first amplifier U1.2 is compared with its non-inverting input, and the first amplifier U1.2 amplifies the difference between the two.

[0050] In one specific embodiment, the first voltage divider resistor R2 has the same resistance value as the first feedback resistor R4, and the second voltage divider resistor R3 has the same resistance value as the second feedback resistor R5.

[0051] Specifically, the first voltage divider resistor R2 has the same resistance value as the first feedback resistor R4, and the second voltage divider resistor R3 has the same resistance value as the second feedback resistor R5. At this time, the circuit can be regarded as a symmetrical differential amplifier structure.

[0052] Assuming the voltage drop across the first node DS of the sampling resistor R1 is Vds, the voltage divider circuit divides Vds and inputs it to the inverting input of the first amplifier U1.2, while the feedback network feeds the output signal back to the non-inverting input. According to the differential amplifier principle, when R2=R4 and R3=R5, the amplifier's output voltage Vo can be expressed as: Vo = (1 + R⁴ / R²) * Vds Furthermore, when the vacuum cleaner's floor brush 13 motor is operating, current I flows through the sampling resistor R1 in the power supply circuit 10. According to Ohm's law V = IR, a small voltage drop Vds at the first node DS is generated across the sampling resistor R1. This Vds is the original signal we use to detect the current. (1 + R4 / R2) in the formula represents the circuit's amplification factor. Since R4 and R2 are known fixed resistances, the amplification factor is a constant. This allows for accurate reading of the current value from the sampling signal.

[0053] In one specific embodiment, the protection circuit 30 includes: a third voltage divider resistor R9 and a fourth voltage divider resistor R10 connected in series with the third voltage divider resistor R9.

[0054] The first terminal of the third voltage divider resistor R9 is connected to the power supply voltage, the second terminal of the fourth voltage divider resistor R10 is grounded, and the connection node between the second terminal of the third voltage divider resistor R9 and the first terminal of the fourth voltage divider resistor R10 is connected to the non-inverting input terminal of the second amplifier U1.1.

[0055] Specifically, in the protection circuit 30, the third voltage dividing resistor R9 and the fourth voltage dividing resistor R10 are connected in series to form a voltage dividing network. The third voltage dividing resistor R9 and the fourth voltage dividing resistor R10 provide a fixed and known voltage threshold V_ref_protect for the second amplifier U1.1, the value of which is determined by the formula V_ref_protect = Vcc × [R10 / (R9 + R10)]. The divided threshold voltage is directly input to the non-inverting terminal of the second amplifier U1.1 to be compared with the voltage at the first node DS.

[0056] The second amplifier U1.1 is configured as a voltage comparator here, and its inverting input terminal is connected to the first node DS on the sampling resistor R1, for monitoring the real-time voltage Vds of the first node DS.

[0057] When the circuit works normally, Vds < V_ref_protect, and the second amplifier U1.1 outputs a low level; once a short circuit or severe overcurrent occurs, Vds will rise sharply and exceed the preset V_ref_protect, the output state of the second amplifier U1.1 immediately flips to a high level or a valid trigger signal, which is sent to the signal protection terminal of the control unit.

[0058] In a specific embodiment, the protection circuit 30 further includes a first current limiting resistor R7, and the first current limiting resistor R7 is respectively connected to the first node DS and the inverting input terminal of the second amplifier U1.1.

[0059] Specifically, the circuit elements connected to the first current limiting resistor R7 jointly form a combined protection and filtering circuit, whose primary function is current limiting. When the power supply circuit 10 generates an abnormally high instantaneous voltage (that is, Vds rises sharply) due to a severe short circuit, the first current limiting resistor R7 can effectively limit the current flowing into the inverting input terminal of the second amplifier U1.1, preventing the excessively high voltage from directly impacting and damaging the precision input-stage transistor inside the amplifier, thereby improving the robustness and survivability of the entire protection circuit.

[0060] Further, the first current limiting resistor R7 and the parasitic capacitance to ground at the inverting input terminal of the second amplifier U1.1 together form a low-pass filtering network. This filter can effectively filter out high-frequency burrs and spike interferences generated by motor carbon brush commutation, switching noise and the like, preventing these interference signals from being misjudged as overcurrent signals by the second amplifier U1.1, thereby greatly reducing the risk of false triggering of the protection circuit.

[0061] In a specific embodiment, the protection circuit 30 further includes: a switch trigger branch 40, one end of the switch trigger branch 40 is connected to the output terminal of the second amplifier U1.1, and the other end is connected to the signal protection terminal of the control unit.

[0062] Specifically, a purely hardware short-circuit trigger link is established between the output of the second amplifier U1.1 and the control unit through the switch trigger branch 40. This solves the problem of short-circuit protection lag caused by software delay, achieves microsecond-level response speed, and ensures that the current is cut off within the safe time window for power devices such as MOSFETs to avoid hardware burnout.

[0063] In one specific embodiment, the switch triggering branch 40 includes a second current-limiting resistor R11, a switching transistor Q2, and a pull-up resistor R12.

[0064] The second current-limiting resistor R11 is connected between the output terminal of the second amplifier U1.1 and the control electrode of the switching transistor Q2.

[0065] The pull-up resistor R12 is connected to the power supply voltage and the first terminal of the switching transistor Q2. The second terminal of the switching transistor Q2 is grounded, and the first terminal of the switching transistor Q2 outputs a short-circuit protection signal to the control unit.

[0066] Specifically, in this embodiment, the switch Q2 is a MOS switch. The control electrode of the switch Q2 is the gate, the first electrode of the switch Q2 is the drain of the MOSFET, and the second electrode of the switch Q2 is the source of the MOSFET.

[0067] The second current-limiting resistor R11 limits the current output from the second amplifier U1.1 to the control stage of the switching transistor Q2, protecting the amplifier and preventing damage to the control stage of Q2 due to overcurrent, thus improving circuit reliability. Under normal operating conditions, the pull-up resistor R12 pulls the first terminal of the switching transistor Q2 to the power supply voltage, ensuring the control unit receives a stable high level. In the event of a short circuit, the switching transistor Q2 conducts, pulling the level low, and the high-to-low level transition precisely triggers the control unit, providing stronger anti-interference capabilities.

[0068] Under normal conditions, the second amplifier U1.1 outputs a low level, preventing the switching transistor Q2 from conducting. At this time, due to the pull-up resistor R12, the first terminal of the switching transistor Q2 is pulled high, and the control unit's signal protection terminal receives a high level, indicating normal operation. Once an overcurrent or short circuit is detected, the voltage across the first node DS surges, and the output of the second amplifier U1.1 flips to a high level. This high level drives the switching transistor Q2 to saturate and conduct through the second current-limiting resistor R11. After Q2 conducts, its first terminal is forcibly pulled low to near ground potential, thereby sending a low-level effective short-circuit protection signal to the control unit's signal protection terminal, immediately triggering an interrupt and quickly cutting off the power supply circuit 10.

[0069] In one specific embodiment, the first amplifier U1.2 is a differential operational amplifier, and the second amplifier U1.1 is an operational amplifier.

[0070] Specifically, the first amplifier U1.2 is a differential operational amplifier. This is because the core task of the detection circuit 10 is to measure the voltage difference across the sampling resistor R1. This difference signal is usually very small and is superimposed on a common-mode voltage that may fluctuate. Differential operational amplifiers inherently possess the characteristics of suppressing common-mode signals and amplifying differential-mode signals, enabling them to accurately extract the true voltage drop across the sampling resistor R1 and effectively offset measurement errors caused by ground noise or power supply fluctuations, thus providing a foundation for achieving high-precision current sampling.

[0071] Furthermore, the second amplifier U1.1 is an operational amplifier, which is actually configured here to function as a voltage comparator. The function of the protection loop 30 is not linear amplification, but rather a yes / no threshold judgment. It only needs to compare the real-time voltage of the first node DS with a fixed reference voltage provided by a voltage divider network; once the threshold is exceeded, its output flips, triggering the protection signal. For this binary logic judgment function, a common operational amplifier is sufficient, and its high gain and fast response characteristics perfectly meet the requirements of fast protection.

[0072] Therefore, the vacuum cleaner floor brush 13 current detection and short circuit protection circuit provided above amplifies the weak voltage signal of the first node DS of the sampling resistor R1 through the first amplifier U1.2, so that even the low-precision ADC can accurately collect the current, solving the problems of unclear identification of small current changes and inaccurate overcurrent protection; the second amplifier U1.1 realizes protection by triggering the control unit interrupt, without the need for software polling, and responds faster, solving the problem of short circuit protection delay that easily burns out hardware.

[0073] The above description is merely an embodiment of this application. It should be noted that those skilled in the art can make improvements without departing from the inventive concept of this application, but these improvements all fall within the protection scope of this application.

Claims

1. A current detection and short-circuit protection circuit for a vacuum cleaner floor brush, connected to the control unit of the floor brush main unit, characterized in that, The circuit includes: a power supply circuit, a first amplifier, and a second amplifier; The power supply circuit includes a sampling resistor and a switching element. The sampling resistor and the switching element are connected in series in the power supply circuit and form a first node on the sampling resistor. The switching element is connected to the control unit to control the switching element to turn on or off the power supply circuit. The first amplifier connects the first node to the signal sampling terminal of the control unit to form a detection loop that amplifies the voltage signal of the first node; The second amplifier is connected to the signal protection terminal of the first node and the control unit respectively to form a protection loop that triggers the interruption of the control unit.

2. The vacuum cleaner floor brush current detection and short-circuit protection circuit according to claim 1, characterized in that, The power supply circuit also includes: a current input terminal, a current output terminal, and a ground brush; One end of the ground brush is connected to the current input terminal, and the other end is connected in sequence to the switch, the sampling resistor and the current output terminal.

3. The vacuum cleaner floor brush current detection and short-circuit protection circuit according to claim 1, characterized in that, The detection circuit includes: a first voltage divider resistor and a second voltage divider resistor; One end of the first voltage divider resistor is connected to the first node, and the other end is connected to one end of the second voltage divider resistor and the inverting input terminal of the first amplifier. The other end of the second voltage divider resistor is connected to the ground terminal of the power supply circuit.

4. The vacuum cleaner floor brush current detection and short-circuit protection circuit according to claim 3, characterized in that, The detection circuit further includes: a first feedback resistor, a second feedback resistor, and an output resistor; One end of the first feedback resistor is grounded, and the other end is connected to one end of the second feedback resistor and the non-inverting input terminal of the first amplifier. The other end of the second feedback resistor is connected between the output resistor and the output terminal of the first amplifier. The output resistor is connected to the signal sampling terminal of the control unit.

5. The vacuum cleaner floor brush current detection and short-circuit protection circuit according to claim 4, characterized in that, The first voltage divider resistor has the same resistance value as the first feedback resistor, and the second voltage divider resistor has the same resistance value as the second feedback resistor.

6. The vacuum cleaner floor brush current detection and short-circuit protection circuit according to claim 1, characterized in that, The protection circuit includes: The third voltage divider resistor and the fourth voltage divider resistor connected in series with the third voltage divider resistor, The first end of the third voltage divider resistor is connected to the power supply voltage, the second end of the fourth voltage divider resistor is grounded, and the connection node between the second end of the third voltage divider resistor and the first end of the fourth voltage divider resistor is connected to the non-inverting input terminal of the second amplifier.

7. The vacuum cleaner floor brush current detection and short-circuit protection circuit according to claim 1, characterized in that, The protection circuit also includes a first current-limiting resistor, which is connected to the first node and the inverting input terminal of the second amplifier, respectively.

8. The vacuum cleaner floor brush current detection and short-circuit protection circuit according to claim 1, characterized in that, The protection circuit further includes a switch trigger branch, one end of which is connected to the output terminal of the second amplifier, and the other end is connected to the signal protection terminal of the control unit.

9. A vacuum cleaner floor brush current detection and short-circuit protection circuit according to claim 8, characterized in that, The switch triggering branch includes a second current-limiting resistor, a switching transistor, and a pull-up resistor; The second current-limiting resistor is connected between the output terminal of the second amplifier and the control electrode of the switching transistor; The pull-up resistor is connected to the power supply voltage and the first terminal of the switching transistor, the second terminal of the switching transistor is grounded, and the first terminal of the switching transistor outputs a short-circuit protection signal to the control unit.

10. A vacuum cleaner floor brush current detection and short-circuit protection circuit according to claim 1, characterized in that, The first amplifier is a differential operational amplifier, and the second amplifier is an operational amplifier.

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