Anti-galloping circuit and electric tool

Abstract

The utility model provides an anti-galloping circuit and an electric tool. The anti-galloping circuit comprises an energy storage module, a voltage dividing module, a first switch module, a second switch module and a control module. The first end of the energy storage module is connected with the first end of the voltage dividing module, the first end of the second switch module and the battery, the second end of the energy storage module is connected with the second end of the voltage dividing module and the first end of the first switch module, and the second end of the first switch module is connected with the first end of the control module. The second end of the second switch module is connected with the second end of the control module, the third end of the control module is connected with the motor, the circuit can prevent the galloping phenomenon, and the use safety of the electric tool is improved.

Description

TECHNICAL FIELD

[0001] Embodiments of the present application relate to the technical field of electronic circuit, in particular to a flywheel prevention circuit and electric tool. BACKGROUND

[0002] For electric tools, especially hand-held electric tools powered by batteries, there may be certain safety hazards during battery replacement. Specifically, when the battery is replaced in the state that the start switch of the electric tool is closed, i.e., when the new battery is connected, the motor in the electric tool will automatically run. Then, if the electric tool is not in a safe position at this time, it is easy to cause danger, and even threaten personal safety. For example, if the electric tool is an electric angle grinder, and the start button of the electric tool remains pressed when the battery is replaced, the angle grinding disc in the angle grinder will rotate at a high speed, which is easy to injure others.

[0003] Among them, the phenomenon that the motor rotates at a high speed in the above state is called flywheel phenomenon, which is a very dangerous situation. Therefore, the flywheel phenomenon should be prevented as much as possible during the use of the electric tool. CONTENT OF THE UTILITY MODEL

[0004] Embodiments of the present application provide a flywheel prevention circuit and electric tool, which can prevent the flywheel phenomenon from occurring and improve the safety of the electric tool during use.

[0005] In a first aspect, embodiments of the present application provide a flywheel prevention circuit, which includes an energy storage module, a voltage division module, a first switch module, a second switch module and a control module. The first end of the energy storage module is connected with the first end of the voltage division module, the first end of the second switch module and a battery, respectively; the second end of the energy storage module is connected with the second end of the voltage division module and the first end of the first switch module, respectively; the second end of the first switch module is connected with the first end of the control module; the second end of the second switch module is connected with the second end of the control module; and the third end of the control module is connected with a motor. The second switch module is configured to be turned on or turned off. The energy storage module is configured to output a first voltage of the battery to the first switch module at the starting moment when the battery is connected with the energy storage module after the second switch module is turned on, so as to turn on the first switch module. The voltage division module is configured to output a voltage division signal to the first switch module based on the first voltage after the time length that the battery is connected with the energy storage module is greater than a first preset time length, so as to turn off the first switch module. The first switch module is configured to output a first level signal when turned on and output a second level signal when turned off. The control module is configured to acquire the level signal output by the first switch module after the second switch module is turned on, and control the motor to stop working when the level signal jumps.

[0006] In one or more embodiments, the first switch module comprises a first switch tube and a first resistor; a first end of the first switch tube is connected with a second end of the energy storage module and a second end of the voltage divider module respectively, a second end of the first switch tube is connected with a first end of the control module and a first end of the first resistor respectively, a second end of the first resistor is connected with a first power supply, and a third end of the first switch tube is grounded.

[0007] In one or more embodiments, the first switch module further comprises a second resistor, a voltage stabilizing diode, a third resistor and a first capacitor; a first end of the second resistor is connected with the second end of the energy storage module and the second end of the voltage divider module respectively, and a second end of the second resistor is connected with the first end of the first switch tube; a cathode of the voltage stabilizing diode is connected with the first end of the first switch tube, and an anode of the voltage stabilizing diode is grounded; a first end of the third resistor is connected with the second end of the first switch tube and the first end of the first resistor respectively, and a second end of the third resistor is connected with the first end of the control module; a first end of the first capacitor is connected with the first end of the control module, and a second end of the first capacitor is grounded.

[0008] In one or more embodiments, the second switch module comprises a first switch unit and a second switch unit; a first end of the second switch unit is connected with a first end of the energy storage module, a first end of the voltage divider module and a battery respectively, a second end of the second switch unit is connected with a power supply end of the control module, a third end of the second switch unit is connected with a first end of the first switch unit and a second end of the control module respectively, and a second end of the first switch unit is grounded; wherein the first switch unit is configured to be turned on or turned off in response to a trigger signal; the second switch unit is configured to be turned on when the first switch unit is turned on, and to supply power to the control unit based on the first voltage, and to be turned off when the first switch unit is turned off.

[0009] In one or more embodiments, the first switch unit comprises a key; a first end of the key is connected with a third end of the second switch unit and a second end of the control module respectively, and a second end of the key is grounded.

[0010] In one or more embodiments, the first switch unit further comprises a first diode and a fourth resistor; a cathode of the first diode is connected with the first end of the key and the third end of the second switch unit respectively, an anode of the first diode is connected with a first power supply and a first end of the fourth resistor respectively, and a second end of the fourth resistor is connected with the second end of the control module.

[0011] In one or more embodiments, the second switch unit comprises a second switch tube, a fifth resistor and a sixth resistor; a first end of the second switch tube is connected with a first end of the fifth resistor, a first end of the energy storage module, a first end of the voltage division module and a battery respectively, a second end of the second switch tube is connected with a power supply end of the control module, a third end of the second switch tube is connected with a second end of the fifth resistor and a first end of the sixth resistor respectively, and a second end of the sixth resistor is connected with the first end of the first switch unit and a second end of the control module respectively.

[0012] In one or more embodiments, the second switch unit further comprises a second diode; an anode of the second diode is connected with the second end of the sixth resistor, and a cathode of the second diode is connected with the first end of the first switch unit and the second end of the control module respectively.

[0013] In one or more embodiments, the voltage division module comprises a first voltage division resistor and a second voltage division resistor; a first end of the first voltage division resistor is connected with a first end of the energy storage module, a first end of the second switch module and a battery respectively, a second end of the first voltage division resistor is connected with a first end of the second voltage division resistor, a second end of the energy storage module and a first end of the first switch module respectively, and a second end of the second voltage division resistor is grounded.

[0014] In a second aspect, the present application provides an electric tool, which comprises a motor and the anti-runaway circuit as any one of the above; the control module in the anti-runaway circuit is connected with the motor.

[0015] The beneficial effects of this application are as follows: This application provides an anti-runaway circuit and power tool, including: an energy storage module, a voltage divider module, a first switch module, a second switch module, and a control module. The first terminal of the energy storage module is connected to the first terminal of the voltage divider module, the first terminal of the second switch module, and a battery. The second terminal of the energy storage module is connected to the second terminal of the voltage divider module and the first terminal of the first switch module. The second terminal of the first switch module is connected to the first terminal of the control module. The second terminal of the second switch module is connected to the second terminal of the control module. The third terminal of the control module is connected to the motor. This circuit can prevent runaway phenomena and improve the safety of power tool use. When the second switch module is in the ON state, if the battery is connected to the energy storage module, at the initial moment of connection, the energy storage module will output the battery's first voltage to the first switch module to turn it on. The first switch module will then output a first-level signal to the control module. Subsequently, after the battery and energy storage module have been connected for a first preset duration, the voltage divider module will output a divided voltage signal to the first switch module based on the first voltage to turn it off. The first switch module will then output a second-level signal to the control module. In this situation, the control module can detect the transition from the first-level signal to the second-level signal. Therefore, the control module determines that the current situation—where the second switch module is turned on first and the battery is connected later—may lead to a runaway motor. Consequently, the control module controls the motor to remain stationary to prevent runaway motoring, thus achieving runaway motor protection. Attached Figure Description

[0016] One or more embodiments are illustrated by way of example with reference numerals in the accompanying drawings. These illustrations do not constitute a limitation on the embodiments. Elements with the same reference numerals in the drawings are denoted as similar elements. Unless otherwise stated, the figures in the drawings are not to be limited by scale.

[0017] Figure 1 This is a structural diagram of an anti-runaway circuit provided in related technologies;

[0018] Figure 2 A structural block diagram of an anti-flying vehicle circuit provided in an embodiment of this application;

[0019] Figure 3 A structural diagram of an anti-flying car circuit provided in an embodiment of this application;

[0020] Figure 4 Provided for the embodiments of this application Figure 3 A waveform diagram of the second end of the energy storage capacitor after the battery is connected;

[0021] Figure 5 Provided for the embodiments of this application Figure 3 A waveform diagram of nodes A and B. Detailed Implementation

[0022] To facilitate understanding of this application, a more detailed description is provided below with reference to the accompanying drawings and specific embodiments. It should be noted that when an element is described as being "fixed to" another element, it can be directly on the other element, or one or more intermediate elements may exist between them. When an element is described as being "electrically connected" to another element, it can be directly connected to the other element, or one or more intermediate elements may exist between them. The terms "upper," "lower," "inner," "outer," "bottom," etc., used in this specification indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. Furthermore, the terms "first," "second," "third," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0023] Unless otherwise defined, all technical and scientific terms used in this specification have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the scope of the application. The term "and / or" as used in this specification includes any and all combinations of one or more of the associated listed items. Furthermore, technical features involved in the different embodiments of this application described below may be combined with each other as long as they do not conflict with each other.

[0024] To achieve anti-runaway vehicle protection, see the relevant technologies, see [link / reference]. Figure 1 The anti-runaway circuit includes a voltage divider module 1, an isolation voltage module 2, a control switch module 3, a voltage regulator module 4, and an electrolytic capacitor EC1. The first voltage divider terminal of the voltage divider module 1 is connected to the positive terminal of the electrolytic capacitor EC1. The second voltage divider terminal of the voltage divider module 1 is connected to the input terminal of the isolation voltage module 2. The output terminal of the isolation voltage module 2 is connected to the start switch 5. The third voltage divider terminal of the voltage divider module 1 is connected to the control terminal of the control switch module 3. The output terminal of the control switch module 3 is connected to the input terminal of the voltage regulator module 4. The input terminal of the control switch module 3 is connected to the first voltage divider terminal of the voltage divider module 1. In this anti-runaway circuit, turning on the start switch 5 will turn on the control switch module 3. Thus, when the power tool is powered on again, the voltage of the electrolytic capacitor EC1 can be detected using the analog-to-digital (ADI) port of the microcontroller 6 to determine the state of the start switch. However, this method cannot be used when the microcontroller's ADI interface is insufficient.

[0025] To address the issue of insufficient analog sampling ports in microcontrollers preventing the implementation of runaway protection, this application provides a runaway protection circuit and power tool that eliminates the need for AD ports for detection, reducing reliance on controller AD ports while still achieving runaway protection and improving the safety of power tool use.

[0026] In a first aspect, embodiments of this application provide an anti-runaway circuit, see [reference]. Figure 2 The anti-flying vehicle circuit 100 includes: an energy storage module 10, a voltage divider module 20, a first switch module 30, a second switch module 40, and a control module 50.

[0027] The first end of the energy storage module 10 is connected to the first end of the voltage divider module 20, the first end of the second switch module 40, and the battery 200, respectively. The second end of the energy storage module 10 is connected to the second end of the voltage divider module 20 and the first end of the first switch module 30, respectively. The second end of the first switch module 30 is connected to the first end of the control module 50, the second end of the second switch module 40 is connected to the second end of the control module 50, and the third end of the control module 50 is connected to the motor 300.

[0028] The second switch module 40 is configured to be turned on or off. The energy storage module 10 is configured to output a first voltage of the battery 200 to the first switch module 30 at the initial moment of connection between the battery 200 and the energy storage module 10 after the second switch module 40 is turned on, thereby turning on the first switch module 30. The voltage divider module 20 is configured to output a voltage divider signal to the first switch module 30 based on the first voltage after the duration of connection between the battery 200 and the energy storage module 10 exceeds a first preset duration, thereby turning off the first switch module 30. The first switch module 30 is configured to output a first level signal when turned on and a second level signal when turned off. The control module 50 is configured to acquire the level signal output by the first switch module 30 after the second switch module 40 is turned on, and control the motor 300 to stop working when the level signal changes.

[0029] When the energy storage module 10 is connected to the battery 200, it can charge and store energy based on the first voltage of the battery 200. When it is disconnected from the battery 200, it can discharge to ensure normal operation next time.

[0030] Motor 300 is a DC motor 300, which may be a sensorless brushless DC (BLDC) motor.

[0031] The control module 50 includes a microcontroller unit (MCU), a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), a microcontroller, an acorn RISC machine (ARM), or other programmable logic devices, discrete gate or transistor logic, discrete hardware components, or any combination of these components.

[0032] The first switching module 30 refers to a device that turns on or off based on the voltage at its first terminal. Specifically, when the voltage at the first terminal of the first switching module 30 is greater than a conduction threshold, it turns on and outputs a first-level signal; when the voltage at the first terminal of the first switching module 30 is less than the conduction threshold, it turns off and outputs a second-level signal. For example, when the first voltage output by the energy storage module 10 is received, if this first voltage is greater than the conduction threshold, the first switching module 30 turns on and outputs the first-level signal. When the voltage divider module 20 receives a voltage divider signal based on the first voltage, if this voltage divider signal is less than the conduction threshold, the first switching module 30 turns off and outputs the second-level signal.

[0033] The second switch module 40 is the start switch for the motor 300. The second switch module 40 can turn on or off the device according to the external trigger signal. The control module 50 determines whether to start the motor 300 to work according to the second switch module 40.

[0034] Battery 200 includes multiple cells connected in parallel, series, or mixed configurations for storing and providing electrical energy; mixed configurations include both series and parallel connections. The first voltage should be greater than the conduction threshold of the first switching module 30.

[0035] The anti-runaway circuit 100 can be applied to power tools. When the second switch module 40 is in the on state, if the battery 200 is connected to the power tool and connected to the energy storage module 10, at the beginning of the connection between the battery 200 and the energy storage module 10 (i.e., the moment the battery 200 is just connected to the power tool), the energy storage module 10 will output the first voltage of the battery 200 to the first switch module 30 to turn on the first switch module 30. The first switch module 30 will output a first level signal to the control module 50. Then, when the duration of the connection between the battery 200 and the energy storage module 10 reaches a first preset duration, the voltage divider module 20 will output a voltage divider signal to the first switch module 30 based on the first voltage to turn off the first switch module 30. The first switch module 30 will output a second level signal to the control module 50. In this situation, the control module 50 can receive the level signal output by the first switch module 30 and detect the situation where the first level signal jumps to the second level signal. Thus, the control module 50 determines that the current situation is that the second switch module 40 is turned on first and the battery 200 is connected later, which may cause the vehicle to run away. Therefore, the control module 50 controls the motor 300 to keep it stopped to prevent the vehicle from running away.

[0036] Before the second switch module 40 is in the on state, that is, when the second switch module 40 is in the off state, the battery 200 has already been connected to the power tool. That is, the second switch module 40 is only turned on after the battery 200 has been connected to the energy storage module 10 for a period of time longer than the first preset time. In this case, after the second switch module 40 is turned on, since the battery 200 has been connected to the energy storage module 10 for a period of time longer than the first preset time, the first switch module 30 is in the off state. The first switch module 30 always outputs a second level signal to the control module 50. The control module 50 cannot detect the situation of the first level signal jumping to the second level signal. The control module 50 can determine that the current situation is that the battery 200 is connected first and the second switch module 40 is turned on later, which will not cause the runaway phenomenon. The control module 50 can control the motor 300 to operate normally.

[0037] In summary, when the second switch module 40 is turned on first and the battery 200 is connected later, the control module 50 stops the motor 300 to prevent runaway. When the battery 200 is connected first and the second switch module 40 is turned on later, the motor 300 can maintain normal operation. Therefore, the anti-runaway circuit 100 provided in this application can prevent the power tool from running away, ensuring that the motor 300 will not start when the battery 200 is inserted after the start switch (second switch module 40) of the motor 300 is closed, thus achieving anti-runaway protection (i.e., power-off protection), while also maintaining the normal operation of the motor 300 in the power tool. Furthermore, in this application, compared to embodiments that omit the first switch module 30, i.e., compared to embodiments that directly connect the second terminal of the voltage divider module 20 and the second terminal of the energy storage module 10 to the control module 50, the method of using the control module 50 to detect whether the battery 200 is inserted only after the start switch is closed eliminates the need to occupy the analog sampling port of the control module 50.

[0038] In some of these embodiments, see Figure 3 The energy storage module 10 includes an energy storage capacitor C2. The first end of the energy storage module 10 is the first end of the energy storage capacitor C2, and the second end of the energy storage module 10 is the second end of the energy storage capacitor C2.

[0039] During the charging or discharging process of the energy storage module 10, the voltage across the energy storage capacitor C2 cannot change suddenly; instead, it requires a certain amount of time to complete the accumulation or release of charge. This is because the accumulation and release of charge inside the energy storage capacitor C2 takes time, preventing the voltage from changing instantaneously. Figure 4 As shown, at the instant the battery 200 is connected to the energy storage capacitor C2 (the initial moment), the voltage across the energy storage capacitor C2 cannot change abruptly. The voltage across the energy storage capacitor C2 is always the first voltage output by the battery 200, which is then output to the first terminal of the first switching module 30. Afterwards, the charging process of the energy storage capacitor C2 ends. At this point, after the duration of connection between the battery 200 and the energy storage capacitor C2 exceeds a first preset duration, the voltage output to the first terminal of the first switching module 30 is determined by the voltage divider signal output by the voltage divider module 20.

[0040] In some of these embodiments, see Figure 3 The voltage divider module 20 includes a first voltage divider resistor Rf1 and a second voltage divider resistor Rf2. The first end of the first voltage divider resistor Rf1 is connected to the first end of the energy storage module 10, the first end of the second switch module 40, and the battery 200, respectively. The second end of the first voltage divider resistor Rf1 is connected to the first end of the second voltage divider resistor Rf2, the second end of the energy storage module 10, and the first end of the first switch module 30, respectively. The second end of the second voltage divider resistor Rf2 is grounded.

[0041] When the battery 200 is connected to the first terminal of the first voltage divider resistor Rf1, the first voltage divider resistor Rf1 and the second voltage divider resistor Rf2 divide the first voltage and output a voltage divider signal. By setting the resistance values ​​of the first voltage divider resistor Rf1 and the second voltage divider resistor Rf2, the voltage divider signal can be made less than the conduction threshold of the first switch module 30.

[0042] In some of these embodiments, see Figure 3 The first switching module 30 includes a first switching transistor Q1 and a first resistor R1. The first terminal of the first switching transistor Q1 is connected to the second terminal of the energy storage module 10 and the second terminal of the voltage divider module 20, respectively. The second terminal of the first switching transistor Q1 is connected to the first terminal of the control module 50 and the first terminal of the first resistor R1, respectively. The second terminal of the first resistor R1 is connected to the first power supply VCC, and the third terminal of the first switching transistor Q1 is grounded.

[0043] The first switching transistor Q1 can be any controllable switch, such as an insulated-gate bipolar transistor (IGBT), an integrated gate-commutated thyristor (MCC), a gate-turn-off thyristor (GRT), a silicon controlled rectifier (SCR), a junction-gate field-effect transistor (JFET), or a transistor. Figure 3 In the illustrated embodiment, the first switch Q1 is an NMOS transistor, the low-level signal is the first level signal, and the high-level signal is the second level signal. The first terminal of the first switch Q1 is the gate of the NMOS transistor, the second terminal of the first switch Q1 is the drain of the NMOS transistor, and the third terminal of the first switch Q1 is the source of the NMOS transistor.

[0044] The first power supply VCC is an independent power supply, or the voltage of the 200 battery packs can be converted by a voltage conversion circuit to obtain the voltage of the first power supply VCC. The voltage of the first power supply VCC can be set as needed.

[0045] In this circuit, at the initial moment when the battery 200 is connected to the energy storage module 10 (i.e., when the battery 200 is just connected to the power tool), the energy storage module 10 will output the first voltage of the battery 200 to the first switch Q1. The first switch Q1 is turned on, and the second terminal of the first switch Q1 is at a low level signal (first level signal). When the battery 200 is connected to the energy storage module 10 for a first preset time, the voltage divider signal will turn off the first switch Q1, and the second terminal of the first switch Q1 will be pulled up to a high level signal (second level signal) by the first resistor R1.

[0046] In some of these embodiments, see Figure 3The first switching module 30 also includes a second resistor R2, a Zener diode ZD1, a third resistor R3, and a first capacitor C1. The first end of the second resistor R2 is connected to the second end of both the energy storage module 10 and the voltage divider module 20, and the second end of the second resistor R2 is connected to the first end of the first switching transistor Q1. The cathode of the Zener diode ZD1 is connected to the first end of the first switching transistor Q1, and the anode of the Zener diode ZD1 is grounded. The first end of the third resistor R3 is connected to the second end of both the first switching transistor Q1 and the first end of the first resistor R1, and the second end of the third resistor R3 is connected to the first end of the control module 50. The first end of the first capacitor C1 is connected to the first end of the control module 50, and the second end of the first capacitor C1 is grounded.

[0047] When the energy storage module 10 outputs the first voltage to the first switch Q1 or the voltage divider module 20 outputs the voltage divider signal to the first switch Q1, the second resistor R2 can limit the current input to the first switch Q1 to protect the first switch Q1.

[0048] Zener diode ZD1 clamps the voltage at the first terminal of the first switching transistor Q1 to a preset voltage value, preventing the first switching transistor Q1 from being damaged by the high voltage during the charging of the energy storage module 10, thus protecting the first switching transistor Q1. The preset voltage value is related to the selection of Zener diode ZD1, and is not limited here.

[0049] When the first switch Q1 outputs a level signal to the control module 50, the third resistor R3 can limit the current input to the control module 50 to protect the control module 50.

[0050] The first capacitor C1 can filter the signal input to the control module 50, thereby filtering out high-frequency noise and interference signals, and improving the accuracy and reliability of the circuit operation.

[0051] In some of these embodiments, see Figure 3 The second switching module 40 includes a first switching unit 41 and a second switching unit 42. The first terminal of the second switching unit 42 is connected to the first terminal of the energy storage module 10, the first terminal of the voltage divider module 20, and the battery 200, respectively. The second terminal of the second switching unit 42 is connected to the power supply terminal of the control module 50. The third terminal of the second switching unit 42 is connected to the first terminal of the first switching unit 41 and the second terminal of the control module 50, respectively. The second terminal of the first switching unit 41 is grounded. The first switching unit 41 is configured to turn on or off in response to a trigger signal. The second switching unit 42 is configured to turn on when the first switching unit 41 is on and supply power to the control unit based on a first voltage, and to turn off when the first switching unit 41 is off.

[0052] The trigger signal can be a press signal. The first switch unit 41 is turned on when it receives a press signal and turned off when it does not receive a press signal. The first switch unit 41 can also be a touch switch, and the trigger signal can also be a touch signal. It can also be a remote control switch device, and its corresponding trigger signal is a remote control signal. In practical applications, the type of the first switch unit 41 and the corresponding trigger signal can be set according to actual needs.

[0053] The second switching unit 42 is turned on when the first switching unit 41 is turned on, establishing a connection between the battery 200 and the power supply terminal of the control module 50, enabling the control module 50 to power on and operate. The second switching unit 42 is turned off when the first switching unit 41 is turned off, disconnecting the connection between the battery 200 and the power supply terminal of the control module 50, thus de-energizing the control module 50. In this way, when the first switching unit 41 is turned off, the control module 50 is in a sleep state, which can reduce the power consumption of the overall circuit.

[0054] In some of these embodiments, see Figure 3 The first switch unit 41 includes a button K1. The first end of the button K1 is connected to the third end of the second switch unit 42 and the second end of the control module 50, respectively, and the second end of the button K1 is grounded to GND.

[0055] Button K1 is a push-button switch. When button K1 is pressed, the connection between the first end and the second end of button K1 is established. When button K1 is not pressed, the connection between the first end and the second end of button K1 is broken.

[0056] In some of these embodiments, see Figure 3 The first switching unit 41 also includes a first diode D1 and a fourth resistor R4. The cathode of the first diode D1 is connected to the first terminal of the button K1 and the third terminal of the second switching unit 42, respectively. The anode of the first diode D1 is connected to the first power supply VCC and the first terminal of the fourth resistor R4, respectively. The second terminal of the fourth resistor R4 is connected to the second terminal of the control module 50.

[0057] The first diode D1 is used to prevent current from flowing back from the cathode of the first diode D1 to the second terminal of the control module 50, thereby protecting the control module 50. The fourth resistor R4 limits the current input to the second terminal of the control module 50 and pulls the second terminal of the control module 50 high when the button K1 is open.

[0058] In some of these embodiments, see Figure 3The second switching unit 42 includes a second switching transistor Q2, a fifth resistor R5, and a sixth resistor R6. The first terminal of the second switching transistor Q2 is connected to the first terminal of the fifth resistor R5, the first terminal of the energy storage module 10, the first terminal of the voltage divider module 20, and the battery 200, respectively. The second terminal of the second switching transistor Q2 is connected to the power supply terminal of the control module 50. The third terminal of the second switching transistor Q2 is connected to the second terminal of the fifth resistor R5 and the first terminal of the sixth resistor R6, respectively. The second terminal of the sixth resistor R6 is connected to the first terminal of the first switching unit 41 and the second terminal of the control module 50, respectively.

[0059] The second switch Q2 can be any controllable switch, such as an insulated-gate bipolar transistor (IGBT), an integrated gate commutated thyristor (IGCT), a gate turn-off thyristor (GTO), a silicon controlled rectifier (SCR), a junction-gate field-effect transistor (JFET), a MOS-controlled thyristor (MCT), a transistor, etc. Figure 3 In the illustrated embodiment, the second switch Q2 is a PNP transistor. The first terminal of the second switch Q2 is the emitter of the PNP transistor, the second terminal of the second switch Q2 is the collector of the PNP transistor, and the third terminal of the second switch Q2 is the base of the PNP transistor.

[0060] When the voltage signal at the third terminal of the second switch Q2 is unstable, the fifth resistor R5 pulls the third terminal of the second switch Q2 up to the level of the first voltage, ensuring the reliable turn-off of the second switch Q2, reducing the chance of the second switch Q2 being falsely triggered and turned on, and improving the reliability of the circuit operation.

[0061] When the first switching unit 41 is turned on, the sixth resistor R6 limits the current flowing through the first switching unit 41 by the first voltage, reducing the possibility of device damage and improving the reliability of circuit operation.

[0062] In some of these embodiments, see Figure 3 The second switching unit 42 also includes a second diode D2. The anode of the second diode D2 is connected to the second terminal of the sixth resistor R6, and the cathode of the second diode D2 is connected to the first terminal of the first switching unit 41 and the second terminal of the control module 50, respectively.

[0063] The second diode D2 can be used to prevent current from flowing back into the battery 200.

[0064] The following is Figure 3 The working process of the embodiments of this application is illustrated by taking the illustrated example.

[0065] When button K1 is triggered and closed, battery 200 is connected to the first terminal of energy storage capacitor C2. Since button K1 is closed, the connection of battery 200 will turn on the second switch Q2, allowing battery 200 to provide power to control module 50 through the second switch Q2. Thus, control module 50 powers on and begins operation. At the initial moment of connection between battery 200 and energy storage capacitor C2 (e.g., at...) Figure 5 At time t1, the energy storage capacitor C2 will output the first voltage to the first switching transistor Q1, causing Q1 to turn on. At this time, the first terminal of the control module 50 receives a low-level signal. After the battery 200 is connected to the energy storage capacitor C2 for a first preset time (e.g., at time t1), the energy storage capacitor C2 will output the first voltage to the first switching transistor Q1, causing Q1 to turn on. At this time, the first terminal of the control module 50 receives a low-level signal. Figure 5 At time t2, the first switch Q1 turns off after receiving the voltage divider signal. At this time, the first terminal of the control module 50 is pulled up to a high level by the first resistor R1. That is, the first terminal of the control module 50 will first receive a low-level signal and then a high-level signal. The level jump indicates that the current situation is that button K1 is pressed first and battery 200 is connected later, which may cause a runaway phenomenon. Therefore, the control module 50 controls the motor to keep it stopped to prevent the runaway phenomenon. Figure 5 In the diagram, line S1 represents the waveform of node B, and line S2 represents the waveform of node A.

[0066] When button K1 is disconnected and battery 200 is connected, button K1 will only close after the battery 200 has been connected to the anti-runaway circuit 100 for a duration longer than the first preset duration. At this time, since the first switch Q1 is already in the off state, only a high-level signal is present after node B. Thus, when button K1 is subsequently closed, the control module 50 is powered on and operates. After the first preset duration is reached, the first terminal (node ​​B) of the control module 50 is always a high-level signal, and the second terminal (the second terminal of the fourth resistor) of the control module 50 is a low-level signal. The control module 50 can determine that the current situation is that battery 200 is connected first and button K1 is pressed later, which will not cause the runaway phenomenon and can control the motor 300 to operate normally.

[0067] In summary, the anti-runaway circuit provided in this application can both prevent the power tool from running away and maintain the normal operation of the motor in the power tool. Moreover, it solves the problem of using the control module 50 to detect whether the battery 200 is inserted only after the start switch is closed during the design of the anti-runaway circuit for power tools, without occupying the analog sampling port of the control module 50.

[0068] Secondly, this application provides an electric tool, which includes a motor and an anti-runaway circuit as described in any of the above claims; the control module in the anti-runaway circuit is connected to the motor.

[0069] In this embodiment, the anti-flying vehicle circuit has the same structure and function as the anti-flying vehicle circuit described in any of the first aspects, and will not be repeated here.

[0070] It should be noted that the device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs.

[0071] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and not to limit them; under the concept of this application, the technical features of the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations of different aspects of this application as described above, which are not provided in detail for the sake of brevity; although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or make equivalent substitutions for some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A circuit for preventing runaway vehicles, characterized in that, include: Energy storage module, voltage divider module, first switch module, second switch module, and control module; The first end of the energy storage module is connected to the first end of the voltage divider module, the first end of the second switch module, and the battery, respectively. The second end of the energy storage module is connected to the second end of the voltage divider module and the first end of the first switch module, respectively. The second end of the first switch module is connected to the first end of the control module, the second end of the second switch module is connected to the second end of the control module, and the third end of the control module is connected to the motor. The second switch module is configured to be on or off; The energy storage module is configured to output the first voltage of the battery to the first switching module at the beginning of the connection between the battery and the energy storage module after the second switching module is turned on, so as to turn on the first switching module. The voltage divider module is configured to output a voltage divider signal to the first switch module based on the first voltage after the battery is connected to the energy storage module for a period of time longer than a first preset period of time, so that the first switch module is turned off. The first switch module is configured to output a first level signal when it is turned on and a second level signal when it is turned off; The control module is configured to acquire the level signal output by the first switch module after the second switch module is turned on, and control the motor to stop working when the level signal changes.

2. The anti-runaway circuit according to claim 1, characterized in that, The first switching module includes a first switching transistor and a first resistor; The first terminal of the first switching transistor is connected to the second terminal of the energy storage module and the second terminal of the voltage divider module, respectively. The second terminal of the first switching transistor is connected to the first terminal of the control module and the first terminal of the first resistor, respectively. The second terminal of the first resistor is connected to the first power supply, and the third terminal of the first switching transistor is grounded.

3. The anti-runaway circuit according to claim 2, characterized in that, The first switching module also includes a second resistor, a Zener diode, a third resistor, and a first capacitor; The first end of the second resistor is connected to the second end of the energy storage module and the second end of the voltage divider module, respectively, and the second end of the second resistor is connected to the first end of the first switching transistor. The cathode of the Zener diode is connected to the first terminal of the first switching transistor, and the anode of the Zener diode is grounded. The first end of the third resistor is connected to the second end of the first switching transistor and the first end of the first resistor, respectively, and the second end of the third resistor is connected to the first end of the control module. The first terminal of the first capacitor is connected to the first terminal of the control module, and the second terminal of the first capacitor is grounded.

4. The anti-runaway circuit according to any one of claims 1-3, characterized in that, The second switch module includes a first switch unit and a second switch unit; The first terminal of the second switching unit is connected to the first terminal of the energy storage module, the first terminal of the voltage divider module, and the battery, respectively. The second terminal of the second switching unit is connected to the power supply terminal of the control module. The third terminal of the second switching unit is connected to the first terminal of the first switching unit and the second terminal of the control module, respectively. The second terminal of the first switching unit is grounded. The first switching unit is configured to turn on or off in response to a trigger signal; The second switching unit is configured to turn on when the first switching unit is turned on, and to supply power to the control module based on the first voltage, and to turn off when the first switching unit is turned off.

5. The anti-runaway circuit according to claim 4, characterized in that, The first switching unit includes a button; The first end of the button is connected to the third end of the second switch unit and the second end of the control module, respectively, and the second end of the button is grounded.

6. The anti-runaway circuit according to claim 5, characterized in that, The first switching unit further includes a first diode and a fourth resistor; The cathode of the first diode is connected to the first end of the button and the third end of the second switch unit, respectively. The anode of the first diode is connected to the first power supply and the first end of the fourth resistor, respectively. The second end of the fourth resistor is connected to the second end of the control module.

7. The anti-runaway circuit according to claim 4, characterized in that, The second switching unit includes a second switching transistor, a fifth resistor, and a sixth resistor; The first end of the second switch is connected to the first end of the fifth resistor, the first end of the energy storage module, the first end of the voltage divider module, and the battery, respectively. The second end of the second switch is connected to the power supply end of the control module. The third end of the second switch is connected to the second end of the fifth resistor and the first end of the sixth resistor, respectively. The second end of the sixth resistor is connected to the first end of the first switch unit and the second end of the control module, respectively.

8. The anti-runaway circuit according to claim 7, characterized in that, The second switching unit also includes a second diode; The anode of the second diode is connected to the second terminal of the sixth resistor, and the cathode of the second diode is connected to the first terminal of the first switching unit and the second terminal of the control module, respectively.

9. The anti-runaway circuit according to any one of claims 1-3, characterized in that, The voltage divider module includes a first voltage divider resistor and a second voltage divider resistor; The first end of the first voltage divider resistor is connected to the first end of the energy storage module, the first end of the second switch module, and the battery, respectively. The second end of the first voltage divider resistor is connected to the first end of the second voltage divider resistor, the second end of the energy storage module, and the first end of the first switch module, respectively. The second end of the second voltage divider resistor is grounded.

10. A power tool, characterized in that, Includes a motor and an anti-runaway circuit as described in any one of claims 1-9; The control module in the anti-runaway circuit is connected to the motor.

Images