Protection circuit and electrical equipment

Abstract

The invention discloses a protection circuit and electrical equipment. The protection circuit comprises a protection module, a driving module, a software detection module and a hardware detection module. The protection module comprises a protection resistor and a transistor switch which are connected in series, the driving output end of the driving module is connected to the control end of the transistor switch, and the driving module drives the transistor switch to enter a conducting state under the condition that the first driving end receives a first trigger signal or the second driving end receives a second trigger signal. The software detection module comprises a control unit, a control program is stored in the control unit, and the hardware detection module is an integrated circuit formed by a plurality of electronic components. According to the protection circuit provided by the invention, the monitoring work of the bus voltage is realized by adopting a mode of combining software and hardware. And if the software detection module fails, the existence of the hardware detection module can ensure that the protection resistor can be smoothly activated under the condition that the bus voltage is too high, so that the working safety of the electrical equipment is ensured.

Description

Technical Field

[0001] The present application relates to the technical field of electrical equipment, and more specifically, to a protection circuit and an electrical equipment. Background Art

[0002] In electrical equipment, the regenerative energy generated by motor deceleration feeds back into the device's DC bus, causing the bus voltage to increase. To protect electronic components at the bus (e.g., bus capacitors) from damage caused by excessive bus voltage exceeding their withstand voltage limits, electrical equipment often incorporates a regenerative resistor. This resistor activates when the bus voltage exceeds a safety threshold to absorb excess regenerative energy and ensure stable operation of the electrical equipment.

[0003] Existing technical solutions use software logic to control the activation of regenerative resistors. Specifically, a controller (Microcontroller Unit, MCU) monitors the digitally sampled bus voltage. When the bus voltage exceeds a safety threshold, the control program within the MCU turns on the branch where the regenerative resistor is located to absorb excess energy.

[0004] However, once the MCU hardware fails or the control program has an operating error, the regeneration resistor cannot be activated smoothly, increasing the risk of bus capacitor overvoltage and reducing the operating safety of the electrical equipment. Summary of the Invention

[0005] Embodiments of the present application provide a protection circuit and an electrical device.

[0006] According to a first aspect of the present application, an embodiment of the present application provides a protection circuit, comprising a bus voltage input terminal and a bus voltage ground terminal, wherein the bus voltage input terminal is used to input a bus voltage, and the protection circuit includes a protection module, a drive module, a software detection module, and a hardware detection module. The protection module includes a protection resistor and a transistor switch, wherein the protection resistor and the transistor switch are connected in series between the bus voltage input terminal and the bus voltage ground terminal. The drive module includes a first drive terminal, a second drive terminal, and a drive output terminal, wherein the drive output terminal is connected to a control terminal of the transistor switch. The drive module drives the transistor switch to an on state when the first drive terminal receives a first trigger signal or the second drive terminal receives a second trigger signal. The software detection module includes a control unit connected between the bus voltage input terminal and the first drive terminal, wherein a control program is stored in the control unit, and wherein the control program is used to instruct the control unit to send a first trigger signal to the first drive terminal when the bus voltage is greater than or equal to a first specified voltage. The hardware detection module is connected between the bus voltage input terminal and the second driving terminal, and is used to send a second trigger signal to the second driving terminal when the bus voltage is greater than or equal to the second specified voltage; the hardware detection module refers to an integrated circuit implemented by multiple electronic components.

[0007] According to a second aspect of the present application, an embodiment of the present application further provides an electrical device comprising a power supply circuit, a workload, and the aforementioned protection circuit. The power supply circuit is configured to provide a bus voltage, and the workload is connected to the power supply circuit. The protection circuit is provided with a bus voltage input terminal, which is connected to the power supply circuit.

[0008] The present application provides a protection circuit and electrical equipment, wherein the protection circuit includes a protection module, a drive module, a software detection module and a hardware detection module. Among them, the drive module is provided with a first drive end, a second drive end and a drive output end, the first drive end is connected to the software detection module, the second drive end is connected to the hardware detection module, and the drive output end is connected to the transistor switch of the protection module. Specifically, when the first drive end receives a first trigger signal sent by the software detection module or the second drive end receives a second trigger signal sent by the hardware detection module, the transistor switch will be driven to enter the on state. At this time, the protection resistor connected in series with the transistor switch enters an activated state, thereby consuming part of the electrical energy in the bus voltage to avoid the occurrence of excessive bus voltage.

[0009] Specifically, the software detection module may include a control unit storing a control program, which can instruct the control unit to send a first trigger signal when the bus voltage is greater than or equal to a first specified voltage. Therefore, the software detection module controls the drive module through software program logic. The hardware detection module refers to an integrated circuit implemented by multiple electronic components, which can send a second trigger signal when the bus voltage is greater than or equal to a second specified voltage. Therefore, the hardware detection module controls the drive module through hardware circuit logic.

[0010] The protection circuit in this application uses a combination of software and hardware to monitor the bus voltage. Therefore, if the software detection module fails (for example, a hardware failure in the control unit, an error in the control program, etc.), the presence of the hardware detection module can ensure that the protection resistor can be successfully activated when the bus voltage is too high, avoiding overvoltage on the bus capacitor and ensuring the safety of the electrical equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0012] Figure 1 This is a structural block diagram of an electrical device provided in an embodiment of the present application.

[0013] Figure 2 yes Figure 1 A structural diagram of the protection circuit in the electrical equipment shown.

[0014] Figure 3 yes Figure 1 Another structural schematic diagram of the protection circuit in the electrical equipment shown.

[0015] Figure 4 yes Figure 2 A structural diagram of the driving module in the protection circuit shown.

[0016] Figure 5 yes Figure 2 Another structural schematic diagram of the driving module in the protection circuit shown.

[0017] Figure 6 yes Figure 2 A structural diagram of the hardware detection module in the protection circuit shown.

[0018] Figure 7 yes Figure 2 Another structural diagram of the hardware detection module in the protection circuit shown.

[0019] Figure 8 yes Figure 2 Another structural diagram of the hardware detection module in the protection circuit shown.

[0020] Figure 9 yes Figure 1 Another structural schematic diagram of the protection circuit in the electrical equipment shown. DETAILED DESCRIPTION

[0021] In order to enable those skilled in the art to better understand the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0022] See also Figure 1 and Figure 2 , an embodiment of the present application provides a protection circuit 100 and an electrical device 200 equipped with the protection circuit 100. The electrical device 200 refers to a device that uses electricity to work, which can be a household appliance or an industrial device. Among them, the electrical device 200 may include a power supply circuit 210, a workload 230 and a protection circuit 100. The power supply circuit 210 is used to provide a bus voltage BUS, where the "bus voltage BUS" refers to the DC voltage after the mains voltage is rectified. When the amplitude of the mains voltage is 220V, the amplitude of the bus voltage BUS is 310V. Specifically, the power supply circuit may include a rectifier circuit (for example, a bridge rectifier circuit), a filter subcircuit, and the like. For example, the filter subcircuit may include a bus capacitor, which can smooth the bus voltage BUS so that the bus voltage BUS is more stable when output. This embodiment does not specifically limit the implementation method of the power supply circuit 210.

[0023] Workload 230 is connected to power supply circuit 210 and is configured to operate under the power of bus voltage BUS. For example, if electrical device 200 is a robot, workload 230 may be a motor within the robot. If electrical device 200 is an air fryer, workload 230 may be the heating element and fan within the air fryer.

[0024] In some possible scenarios, when the electrical device 200 is working, the bus voltage BUS may suddenly increase. For example, when the motor inside the robot is decelerating, the regenerative energy it generates will be fed back to the DC bus of the electrical device 200 (that is, the transmission cable corresponding to the bus voltage BUS), thereby causing the bus voltage BUS to increase. At this time, it is possible that the bus capacitor is damaged due to the excessively high bus voltage BUS exceeding its withstand voltage limit. For another example, when the mains voltage fluctuates greatly, the bus voltage BUS will also increase. At this time, it is also possible that the bus capacitor is damaged, thereby reducing the working safety of the electrical device 200.

[0025] Therefore, in order to solve the problem of the bus voltage BUS being too large and thus damaging the bus capacitor, the present application further provides a protection circuit 100 in the electrical device 200, wherein the protection circuit 100 is provided with a bus voltage input terminal 101, which is connected to the power supply circuit 210 and is used to input the bus voltage BUS. The protection circuit 100 is used to monitor the bus voltage BUS and, when the bus voltage BUS is too large, consumes part of the electrical energy in the bus voltage BUS so that the bus voltage BUS can be maintained within a normal range (for example, between 305V and 315V). In addition, the protection circuit 100 is also provided with a bus voltage grounding terminal 103, which is used to connect the ground terminal corresponding to the bus voltage BUS (that is, the 0V reference point corresponding to the bus voltage BUS). For ease of distinction, in the accompanying drawings of the specification, the bus voltage BUS is marked as "BUS+" and the ground terminal corresponding to the bus voltage BUS is marked as "BUS-".

[0026] See also Figure 2 The protection circuit 100 may include a protection module 10, a driving module 30, a software detection module 50, and a hardware detection module 70. The protection module 10 may include a protection resistor 120 and a transistor switch 140, which are connected in series between the bus voltage input terminal 101 and the bus voltage ground terminal 103. The driving module 30 includes a first driving terminal 301, a second driving terminal 303, and a driving output terminal 305. The driving output terminal 305 is connected to the control terminal 1401 of the transistor switch 140. When the first driving terminal 301 receives a first trigger signal or the second driving terminal 303 receives a second trigger signal, the driving module 30 drives the transistor switch 140 to enter the on state.

[0027] The software detection module 50 may include a control unit 520, which is connected between the bus voltage input terminal 101 and the first drive terminal 301. A control program is stored in the control unit 520, and the control program is used to instruct the control unit 520 to send a first trigger signal to the first drive terminal 301 when the bus voltage BUS is greater than or equal to the first specified voltage. The "first specified voltage" here can be the maximum bus voltage value that the electrical device 200 can withstand. For example, the first specified voltage is 350V, 380V, etc. Specifically, the first specified voltage can be a default value, or it can be determined by the R&D personnel based on the actual working conditions of the electrical device 200. The first specified voltage can be directly written into the control program, and the control unit 520 determines whether the bus voltage BUS is too large through the control program. Therefore, the software detection module 50 in this embodiment controls the drive module 30 through software program logic. It should be noted that in the actual operation of the software detection module 50, the control unit 520 inputs the bus voltage BUS after voltage division and reduction. Therefore, the "first specified voltage" here also needs to be scaled in the same proportion as the bus voltage BUS. For example, if the bus voltage BUS is reduced to 1 / 5 by the voltage divider circuit and then input to the control unit 520, the first specified voltage also needs to be reduced to 1 / 5.

[0028] The hardware detection module 70 is connected between the bus voltage input terminal 101 and the second driver terminal 303, and is used to send a second trigger signal to the second driver terminal 303 when the bus voltage BUS is greater than or equal to the second specified voltage. Among them, the hardware detection module 70 refers to an integrated circuit implemented by multiple electronic components. In other words, the hardware detection module 70 controls the driver module 30 through hardware circuit logic. The hardware detection module 70 does not include a controller storing a software program, but rather uses multiple electronic components (for example, resistors, capacitors, integrated operational amplifiers, etc.) to determine whether the bus voltage BUS is too large. The "second specified voltage" here can be the maximum bus voltage value that the electrical device 200 can withstand, for example, the second specified voltage is 350V, 380V, etc. Specifically, the second specified voltage and the first specified voltage can be the same or different. The second specified voltage can be a default value, or it can be determined by R&D personnel based on the actual working conditions of the electrical device 200. Similarly, in actual operation of the hardware detection module 70 , the bus voltage BUS is first divided and reduced. Therefore, the “second specified voltage” here also needs to be scaled in the same proportion as the bus voltage BUS, which is not specifically limited in this embodiment.

[0029] Therefore, the protection circuit 100 in the present application adopts the mode of combining software and hardware to realize the monitoring work to bus voltage BUS.On the one hand, if the software detection module 50 breaks down (for example, hardware failure occurs in the control unit 520, and operation error occurs in the control program, etc.), the existence of the hardware detection module 70 can ensure that when the bus voltage BUS is too large, the protection resistor 120 can also be smoothly activated, thereby avoiding the occurrence of the situation that the bus capacitor is over-voltage, and ensuring the working safety of the electrical equipment 200.On the other hand, compared to the detection mode of the software detection module 50, the hardware detection module 70 can promptly detect the bus voltage BUS that is too fast to boost, thereby avoiding the occurrence of the situation that the software detection module 50 responds to delays when the bus voltage BUS changes rapidly, and reducing the risk of bus capacitor overvoltage.

[0030] The specific circuit structure of the protection circuit 100 is introduced below.

[0031] In this embodiment, the protection module 10 is used to consume part of the electrical energy in the bus voltage BUS when the bus voltage BUS is too large, so as to restore the bus voltage BUS to a normal value. Among them, the transistor switch 140 enters the on state when receiving the drive signal sent by the drive module 30. At this time, the protection resistor 120 connected in series with the transistor switch 140 is connected between the bus voltage input terminal 101 and the bus voltage ground terminal 103 (that is, the protection resistor 120 is activated), and then part of the electrical energy in the bus voltage BUS is consumed by the protection resistor 120. Specifically, the protection resistor 120 can be a regenerative resistor, which is an electronic component that can absorb energy by converting current and voltage. The resistance of the regenerative resistor can be greater than or equal to 5 ohms, for example, 5 ohms, 10 ohms, etc. In some other possible embodiments, the protection resistor 120 can also be a resistor network formed by one or more resistors. This embodiment does not limit the specific implementation of the protection resistor 120.

[0032] See also Figure 3 The transistor switch 140 is used to control whether the protection resistor 120 is activated, wherein the transistor switch 140 can also be provided with a first connection terminal 1403 and a second connection terminal 1405, wherein the first connection terminal 1403 is connected to the bus voltage input terminal 101 through the protection resistor 120, and the second connection terminal 1405 is connected to the bus voltage ground terminal 103.

[0033] Specifically, in Figure 3In the illustrated embodiment, transistor switch 140 is an insulated-gate bipolar transistor (IGBT), wherein first connection terminal 1403 is the collector of the IGBT, second connection terminal 1405 is the emitter of the IGBT, and control terminal 1401 is the gate of the IGBT. When the IGBT receives a drive signal (i.e., a high-level signal) from driver module 30, the IGBT enters an on-state, and protection resistor 120 is activated. Conversely, when the IGBT does not receive a drive signal from driver module 30, the IGBT enters an off-state, the branch where protection resistor 120 is located is disconnected, and protection resistor 120 is inactivated. In other possible embodiments, transistor switch 140 may also be a bipolar junction transistor (BJT), a metal-oxide-semiconductor field-effect transistor (MOSFET), etc. This embodiment does not limit the specific implementation of transistor switch 140.

[0034] In some possible embodiments, the protection module 10 may further include a diode 160, with the anode of the diode 160 connected to the first connection terminal 1403, and the cathode of the diode 160 connected to the bus voltage input terminal 101. Therefore, the diode 160 is connected in parallel with the protection resistor 120 and can play a role in freewheeling the current in the protection resistor 120 when the transistor switch 140 is disconnected, thereby preventing the current in the protection resistor 120 from suddenly changing, thereby ensuring the normal operation of the protection resistor 120.

[0035] In this embodiment, the driving module 30 is used to send a driving signal to the transistor switch 140 via the driving output terminal 305 when the first driving terminal 301 receives a first trigger signal or the second driving terminal 303 receives a second trigger signal. Figure 4 The driving module 30 may include an OR gate logic unit 320 and a driving unit 340, wherein the OR gate logic unit 320 is provided with a first driving terminal 301, a second driving terminal 303, and an OR gate output terminal 321. The driving unit 340 is provided with a driving input terminal 341 and a driving output terminal 305, wherein the driving input terminal 341 is connected to the OR gate output terminal 321. The driving unit 340 is used to drive the transistor switch 140 into the conductive state based on the signal sent by the OR gate logic unit 320.

[0036] Specifically, the OR gate logic unit 320 can be an OR gate chip. That is, the aforementioned "first trigger signal" and "second trigger signal" are high-level signals. When the OR gate chip receives at least one high-level signal, the OR gate output terminal 321 will also output a high-level signal to the driving unit 340. The driving unit 340 can be a driver adapted for the transistor switch 140. For example, when the transistor switch 140 is an IGBT, the driving unit 340 can be a gate driver corresponding to the IGBT. Specifically, when the driving unit 340 receives the high-level signal output by the OR gate logic unit 320, it will output a driving signal to the transistor switch 140 to turn on the branch where the transistor switch 140 is located.

[0037] It should be noted here that when the OR gate logic unit 320 is working, it needs to be connected to the first power supply voltage VDD. Here, the first power supply voltage VDD and the bus voltage BUS belong to different electrical networks. Specifically, the bus voltage BUS belongs to a strong power network, and the first power supply voltage VDD belongs to a weak power network. For example, the first power supply voltage VDD can be provided by a power supply (for example, a battery) arranged inside the electrical device 200. Exemplarily, the first power supply voltage VDD can be 5V, 8V, etc. Therefore, in order to isolate different electrical networks and avoid interference between electrical networks, the drive unit 340 in this embodiment is an isolation driver (ISO Driver). An isolation subunit (not shown in the figure) is provided at the signal input end of the isolation driver. The isolation subunit is used to prevent the bus voltage BUS on the transistor switch 140 from flowing to the OR gate logic unit 320 through the isolation driver, thereby ensuring the working safety of the OR gate logic unit 320.

[0038] See also Figure 5 In this embodiment, the driving unit 340 may further include a status terminal 343 for outputting a status signal. The status signal indicates whether the driving unit 340 is in a normal working state. Specifically, when the driving unit 340 is in a normal working state, the status signal is a high level; when the driving unit 340 is in an abnormal working state, the status signal is a low level.

[0039] The driver module 30 may further include an AND gate logic unit 360, which is provided with a third driver terminal 361, a fourth driver terminal 363, and an AND gate output terminal 365. The third driver terminal 361 is connected to the hardware detection module 70, the fourth driver terminal 363 is connected to the status terminal 343 of the driver unit 340, and the AND gate output terminal 365 is connected to the second driver terminal 303 of the OR gate logic unit 320. In other words, the AND gate logic unit 360 is connected between the hardware detection module 70 and the OR gate logic unit 320. It is not difficult to understand here that the phrase "the hardware detection module 70 sends the second trigger signal to the second driver terminal 303" should be understood as: the hardware detection module 70 sends the second trigger signal to the second driver terminal 303 via the AND gate logic unit 360.

[0040] Specifically, the AND gate logic unit 360 can be an AND gate chip. When the AND gate chip receives a high-level signal from the hardware detection module 70 and the status signal is also high, the AND gate output terminal 365 will output a high-level signal (i.e., the second trigger signal) to the second driving terminal 303 of the OR gate logic unit 320. Conversely, when the status signal is low, the AND gate output terminal 365 will not send the second trigger signal. Therefore, when the driving unit 340 is in an abnormal operating state, the OR gate logic unit 320 cannot receive the second trigger signal, thereby preventing the driving unit 340 from responding incorrectly and thus causing the transistor switch 140 to be malfunctioning.

[0041] In some possible embodiments, the driving module 30 may further include a current-limiting resistor Rc, one end of which is used to input the first supply voltage VDD, and the other end of which is connected to the fourth driving terminal 363. The current-limiting resistor Rc can be used to limit the amplitude of the state signal input to the fourth driving terminal 363 to ensure safe operation of the AND gate logic unit 360.

[0042] In some possible embodiments, the status terminal 343 may also be connected to the control unit 520 (not shown in the figure). The control program in the control unit 520 is further configured to, when determining that the status signal is at a low level, instruct the control unit 520 to stop sending the first trigger signal to the first driving terminal 301. Therefore, when the driving unit 340 is in an abnormal working state, the OR gate logic unit 320 cannot receive the first trigger signal, thereby preventing the driving unit 340 from making an erroneous response and thus causing the transistor switch 140 to be erroneously driven.

[0043] See also Figure 6In this embodiment, the hardware detection module 70 may include a voltage divider unit 720 and a hysteresis comparison unit 740. The voltage divider unit 720 is connected between the bus voltage input terminal 101 and the bus voltage ground terminal 103, and is used to divide the bus voltage BUS and output the divided bus voltage BUS through the voltage divider output terminal 721 of the voltage divider unit 720. Figure 6 In the illustrated embodiment, the voltage divider unit 720 may include N first voltage divider resistors Rf1 and second voltage divider resistors Rf2, wherein the N first voltage divider resistors Rf1 and second voltage divider resistors Rf2 are sequentially connected in series, one of the first voltage divider resistors Rf1 is connected to the bus voltage input terminal 101, the second voltage divider resistor Rf2 is connected to the bus voltage ground terminal 103, and the second voltage divider resistor Rf2 and the connection terminal of one of the first voltage divider resistors Rf1 form a voltage divider output terminal 721. Specifically, the number and resistance value of the first voltage divider resistors Rf1 and the resistance value of the second voltage divider resistor Rf2 can be determined by researchers based on the bus voltage value after voltage division, and this embodiment does not limit this.

[0044] In some possible embodiments, the voltage divider unit 720 may further include a filter capacitor C, one end of the filter capacitor C being connected to the voltage divider output terminal 721, and the other end being connected to the bus voltage ground terminal 103. The filter capacitor C may be used to filter out noise signals in the divided bus voltage BUS, so that the divided bus voltage BUS may be more stable during output.

[0045] In this embodiment, the hysteresis comparator 740 is connected between the voltage divider output terminal 721 and the second driving terminal 303 of the driver module 30. It is configured to cause the second driving terminal 303 to receive a second trigger signal when the divided bus voltage BUS is greater than or equal to a first reference voltage. The "first reference voltage" herein can be determined by the resistance value of a resistor in the hysteresis comparator 740. Specifically, when the divided bus voltage BUS is greater than or equal to the first reference voltage, it indicates that the bus voltage BUS is greater than or equal to the second specified voltage.

[0046] exist Figure 6 In the illustrated embodiment, the protection circuit 100 further includes a first power supply terminal 105 for inputting a second power supply voltage VCC. The second power supply voltage VCC may be a voltage that is stepped down from the bus voltage BUS. That is, the second power supply voltage VCC and the bus voltage BUS belong to the same electrical network. Specifically, the second power supply voltage VCC may be 5V, 3.3V, or the like.

[0047] The hysteresis comparator 740 may include a hysteresis comparator 741, a first resistor R1, a second resistor R2, and a third resistor R3. The hysteresis comparator 741 includes a first non-inverting input terminal 7412, a first inverting input terminal 7414, and a comparison output terminal 7416. The first inverting input terminal 7414 is used to input a first reference voltage. The first non-inverting input terminal 7412 is connected to the voltage divider output terminal 721 of the voltage divider unit 720 via the first resistor R1. The comparison output terminal 7416 is connected to the second driving terminal 303 of the driving module 30. The second resistor R2 is connected between the first power supply terminal 105 and the comparison output terminal 7416. The third resistor R3 is connected between the comparison output terminal 7416 and the first non-inverting input terminal 7412.

[0048] Therefore, the divided bus voltage BUS output from the voltage divider output terminal 721 is again divided by the first resistor R1, the second resistor R2, and the third resistor R3 before being input to the first non-inverting input terminal 7412 for comparison with the first reference voltage. Specifically, the hysteresis comparator 741 can be a hysteresis comparator chip, and the resistance values ​​of the first resistor R1, the second resistor R2, and the third resistor R3 can be adjusted by researchers based on the actual operating conditions of the hysteresis comparator unit 740.

[0049] In some possible embodiments, the hysteresis comparison unit 740 may further include a third voltage-dividing resistor Rf3 and a fourth voltage-dividing resistor Rf4, wherein the third voltage-dividing resistor Rf3 and the fourth voltage-dividing resistor Rf4 are connected in series between the first power supply terminal 105 and the bus voltage ground terminal 103, and a common terminal of the third voltage-dividing resistor Rf3 and the fourth voltage-dividing resistor Rf4 is connected to the first inverting input terminal 7414. Therefore, the "first reference voltage" in this embodiment is the voltage of the second power supply voltage VCC after voltage division. Specifically, the resistance values ​​of the third voltage-dividing resistor Rf3 and the fourth voltage-dividing resistor Rf4 can be determined by researchers based on the first reference voltage, and this embodiment does not limit this.

[0050] Because the hardware detection module 70 in this embodiment uses a hysteresis comparator 741 with a hysteresis function when performing voltage comparison, it can avoid the situation where the signal output by the hysteresis comparator 741 frequently fluctuates between high and low levels when noise appears in the voltage signal input by the first non-inverting input terminal 7412, thereby outputting a more stable second trigger signal to the driving module 30. Specifically, because the hysteresis comparator 741 can set a precise hysteresis voltage window, the driving module 30 will only activate the protection resistor 120 when the bus voltage BUS actually exceeds the safety threshold. The design of the hysteresis comparator 741 takes into account the voltage fluctuations and noise interference that may exist in the protection circuit 100, ensuring that the protection mechanism is activated only when necessary, avoiding unnecessary switching, and thus enhancing the operating reliability and efficiency of the protection circuit 100.

[0051] See also Figure 7 The hardware detection module 70 may further include a voltage follower 760, which is provided with a second positive-phase input terminal 761, a second negative-phase input terminal 763, and a follower output terminal 765. The second positive-phase input terminal 761 is connected to the voltage-dividing output terminal 721 of the voltage-dividing unit 720, the second negative-phase input terminal 763 is connected to the follower output terminal 765, and the follower output terminal 765 is connected to the hysteresis comparison unit 740. Specifically, the first resistor R1 in the hysteresis comparison unit 740 is connected to the voltage-dividing output terminal 721 via the voltage follower 760. That is, the divided bus voltage BUS outputted from the voltage-dividing output terminal 721 first passes through the voltage follower 760 and is then inputted into the hysteresis comparison unit 740. Specifically, the voltage follower 760 may be a voltage follower chip, which may be integrated with one or more operational amplifiers.

[0052] This embodiment provides a voltage follower 760 between the voltage divider unit 720 and the hysteresis comparator unit 740. This ensures signal stability of the divided bus voltage BUS. Furthermore, because the voltage follower 760 has high input impedance and low output impedance, the magnitude of the divided bus voltage BUS is not affected by loads in the back-end circuit (e.g., the resistor in the hysteresis comparator unit 740), thereby improving the stability and reliability of the entire protection circuit 100.

[0053] See also Figure 8 The hardware detection module 70 may further include an isolation unit 780. The isolation unit 780 may include an optocoupler 7810. The optocoupler 7810 is connected between the hysteresis comparison unit 740 and the second driving terminal 303 of the driving module 30. The optocoupler 7810 is configured to enable the second driving terminal 303 to receive the second trigger signal based on the signal sent by the hysteresis comparison unit 740. Specifically, when the hysteresis comparison unit 740 determines that the divided bus voltage BUS is greater than or equal to the first reference voltage, it outputs a specified signal (e.g., a high-level signal). The specified signal is configured to drive the optocoupler 7810 to conduct, so that the optocoupler 7810 sends the second trigger signal to the second driving terminal 303. Of course, when the driving module 30 includes an AND gate logic unit 360, the optocoupler 7810 may send a high-level signal to the AND gate logic unit 360, so that the AND gate logic unit 360 sends the second trigger signal to the second driving terminal 303.

[0054] Specifically, the protection circuit 100 is also provided with a first power supply terminal 105, a second power supply terminal 107 and a designated ground terminal 109. The first power supply terminal 105 is used to input the second power supply voltage VCC, and the second power supply terminal 107 is used to input the first power supply voltage VDD, that is, the power supply voltages corresponding to the first power supply terminal 105 and the second power supply terminal 107 belong to different electrical networks. Specifically, the second power supply voltage VCC belongs to the strong power network, and the first power supply voltage VDD belongs to the weak power network. The designated ground terminal 109 is used to connect the ground terminal corresponding to the first power supply voltage VDD (that is, the 0V reference point corresponding to the first power supply voltage VDD), that is, the power supply voltage corresponding to the second power supply terminal 107 and the ground terminal corresponding to the designated ground terminal 109 belong to the same electrical network. For ease of distinction, the ground terminal corresponding to the first power supply voltage VDD is marked as "GND" in the accompanying drawings of the specification.

[0055] exist Figure 8 In the illustrated embodiment, the optocoupler 7810 includes a first input terminal 7812, a second input terminal 7814, a first output terminal 7816, and a second output terminal 7818. The second output terminal 7818 is connected to the second driving terminal 303. The isolation unit 780 may further include an inverting Schmitt trigger 7830, a fourth resistor R4, a fifth resistor R5, and a sixth resistor R6. The fourth resistor R4 is connected between the first power supply terminal 105 and the first input terminal 7812, the fifth resistor R5 is connected between the second power supply terminal 107 and the first output terminal 7816, and the sixth resistor R6 is connected between the second output terminal 7818 and the designated ground terminal 109. The input terminal 7832 of the inverting Schmitt trigger 7830 is connected to the hysteresis comparator 740, and the output terminal 7834 of the inverting Schmitt trigger 7830 is connected to the second input terminal 7814. Specifically, the input terminal 7832 of the inverting Schmitt trigger 7830 is connected to the comparison output terminal 7416 of the hysteresis comparator 741 .

[0056] In this embodiment, the inverting Schmitt trigger 7830 can be a dedicated trigger chip that is used to invert the level of the signal output by the hysteresis comparator 741. Specifically, when the hysteresis comparator unit 740 determines that the divided bus voltage BUS is greater than or equal to the first reference voltage, it will output a high-level signal. The inverting Schmitt trigger 7830 converts the high-level signal into a low-level signal and outputs it to the second input terminal 7814 of the optocoupler 7810. At this time, the light-emitting diode within the optocoupler 7810 enters the on state, thereby causing the branch between the first output terminal 7816 and the second output terminal 7818 to be conductive. After the first supply voltage VDD is divided by the fifth resistor R5 and the sixth resistor R6, a high-level signal is transmitted through the second output terminal 7818. Therefore, the inverting Schmitt trigger 7830 in this embodiment can play a signal matching role, so that the optocoupler 7810 can operate smoothly. In addition, the inverting Schmitt trigger 7830 also has a hysteresis characteristic, which can eliminate the noise in the output signal of the hysteresis comparison unit 740 to a certain extent, making the optocoupler 7810 more stable during operation.

[0057] Specifically, the fourth resistor R4 is a current limiting resistor, which is used to limit the magnitude of the input current of the light-emitting diode inside the optocoupler 7810. The resistance values ​​of the fourth resistor R4, the fifth resistor R5 and the sixth resistor R6 can be adjusted by R&D personnel based on the actual working conditions of the isolation unit 780.

[0058] It is not difficult to find here that the circuit elements on the input side of the optocoupler 7810 (for example, the voltage follower 760, the hysteresis comparator 741, the inverting Schmitt trigger 7830, etc.) are all connected to the second power supply voltage VCC or the bus voltage BUS, which is powered by a strong power network; the circuit elements on the output side of the optocoupler 7810 (for example, the OR gate logic unit 320, the AND gate logic unit 360, etc.) are all connected to the first power supply voltage VDD, which is powered by a weak power network. Therefore, the optocoupler 7810 in this embodiment can isolate different electrical networks, avoid interference between electrical networks, and thus ensure the normal operation of the protection circuit 100.

[0059] Therefore, the hardware detection module 70 in this embodiment implements overvoltage detection of the bus voltage through multiple electronic components. This allows the hardware detection module 70 to operate independently even if the software detection module 50 fails, providing overvoltage protection for the electrical device 200. Furthermore, the introduction of the voltage follower 760 and the hysteresis comparator 741 in the hardware detection module 70 improves the monitoring accuracy and response speed of the bus voltage BUS, thereby enhancing the operational safety of the electrical device 200.

[0060] In this example, see Figure 9The software detection module 50 may further include a digital sampling unit 540, which is connected between the follower output terminal 765 of the voltage follower 760 and the control unit 520, and is used to discretely sample the bus voltage BUS after voltage division and input it into the control unit 520. Specifically, the digital sampling unit 540 may be an analog-to-digital converter (ADC), and the control unit 520 may be a controller, such as a microcontroller unit (MCU). It is not difficult to find that when the software detection module 50 is connected to the bus voltage input terminal 101, the voltage divider unit 720 and the voltage follower 760 in the hardware detection module 70 are reused, which can save the hardware cost of the protection circuit 100 and make the overall circuit of the protection circuit 100 more compact. Of course, the software detection module 50 can also be provided with an independent voltage divider circuit and voltage follower, so that the software detection module 50 and the hardware detection module 70 can be completely independent when working, thereby ensuring the monitoring reliability of the protection circuit 100.

[0061] In addition, due to the lack of precision in the digital sampling unit 540 during digital sampling, the control unit 520 may have certain errors when performing voltage monitoring. However, the hysteresis comparison unit 740 in the hardware detection module 70 can directly monitor the bus voltage BUS after voltage division, eliminating the error caused by insufficient ADC precision, and thus improving the monitoring accuracy of the protection circuit 100 for the bus voltage BUS. Specifically, Figure 9 In the illustrated embodiment, the hardware detection module 70 includes a voltage divider unit 720, a voltage follower 760, a hysteresis comparator unit 740, and an isolation unit 780. The driving module 30 includes an OR gate logic unit 320, a driving unit 340, and an AND gate logic unit 360. For the specific implementation of the driving module 30 and the hardware detection module 70, reference can be made to the relevant description in the above specification and will not be repeated here.

[0062] The embodiment of the present application provides a protection circuit 100 and an electrical device 200 equipped with the protection circuit 100. The protection circuit 100 may include a protection module 10, a drive module 30, a software detection module 50, and a hardware detection module 70. The protection module 10 may include a protection resistor 120 and a transistor switch 140, and the protection resistor 120 and the transistor switch 140 are connected in series between the bus voltage input terminal 101 and the bus voltage ground terminal 103. The drive module 30 is provided with a first drive terminal 301, a second drive terminal 303, and a drive output terminal 305. The drive output terminal 305 is connected to the control terminal 1401 of the transistor switch 140. When the first drive terminal 301 receives a first trigger signal or the second drive terminal 303 receives a second trigger signal, the drive module 30 drives the transistor switch 140 to enter the on state.

[0063] The software detection module 50 may include a control unit 520 connected between the bus voltage input terminal 101 and the first driver terminal 301. The control unit 520 stores a control program configured to instruct the control unit 520 to send a first trigger signal to the first driver terminal 301 when the bus voltage BUS is greater than or equal to a first specified voltage. The hardware detection module 70 is connected between the bus voltage input terminal 101 and the second driver terminal 303 and configured to send a second trigger signal to the second driver terminal 303 when the bus voltage BUS is greater than or equal to a second specified voltage. The hardware detection module 70 is an integrated circuit implemented by multiple electronic components.

[0064] Therefore, the protection circuit 100 in the present application adopts the mode of combining software and hardware to realize the monitoring work to bus voltage BUS.On the one hand, if the software detection module 50 breaks down (for example, hardware failure occurs in the control unit 520, and operation error occurs in the control program, etc.), the existence of the hardware detection module 70 can ensure that when the bus voltage BUS is too large, the protection resistor 120 can also be smoothly activated, thereby avoiding the occurrence of the situation that the bus capacitor is over-voltage, and ensuring the working safety of the electrical equipment 200.On the other hand, compared to the detection mode of the software detection module 50, the hardware detection module 70 can promptly detect the bus voltage BUS that is too fast to boost, thereby avoiding the occurrence of the situation that the software detection module 50 responds to delays when the bus voltage BUS changes rapidly, and reducing the risk of bus capacitor overvoltage.

[0065] In the specification of this application, certain words are used to refer to specific components in the specification and claims. Those skilled in the art should understand that hardware manufacturers may use different terms to refer to the same component. The specification and claims do not use the difference in name as a way to distinguish components, but use the difference in function of the components as the criterion for distinction. For example, "including" mentioned throughout the specification and claims is an open term and should be interpreted as "including but not limited to"; "substantially" means that those skilled in the art can solve the technical problem within a certain error range and basically achieve the technical effect.

[0066] In the description of this application, it should be understood that the terms "upper", "lower", "front", "back", "left", "right", "inside", etc. indicating directions or positional relationships are based on the directions or positional relationships shown in the accompanying drawings. They are only used to simplify the description for the convenience of describing this application, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, they should not be understood as limitations on this application.

[0067] In this application, unless otherwise expressly specified or limited, terms such as "mounted," "connected," "connect," and "fixed" should be interpreted broadly. For example, these terms may refer to fixed, removable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediary; internal communication between two components; or mere surface contact. Those skilled in the art will understand the specific meanings of these terms in this application based on the specific circumstances.

[0068] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and features of different embodiments or examples without contradiction.

[0069] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of such features. Throughout the description of this application, "plurality" means at least two, for example, two, three, etc., unless otherwise specifically defined.

[0070] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A protection circuit, characterized in that: A bus voltage input terminal and a bus voltage grounding terminal are provided, wherein the bus voltage input terminal is used to input the bus voltage; the protection circuit includes: A protection module, comprising a protection resistor and a transistor switch, wherein the protection resistor and the transistor switch are connected in series between the bus voltage input terminal and the bus voltage ground terminal; a driving module having a first driving end, a second driving end, and a driving output end, wherein the driving output end is connected to the control end of the transistor switch, and the driving module drives the transistor switch to enter a conducting state when the first driving end receives a first trigger signal or the second driving end receives a second trigger signal; a software detection module, comprising a control unit connected between the bus voltage input terminal and the first driving terminal, wherein the control unit stores a control program, wherein the control program is configured to instruct the control unit to send the first trigger signal to the first driving terminal when the bus voltage is greater than or equal to a first specified voltage; and A hardware detection module is connected between the bus voltage input terminal and the second driving terminal, and is used to send the second trigger signal to the second driving terminal when the bus voltage is greater than or equal to the second specified voltage; the hardware detection module refers to an integrated circuit implemented by multiple electronic components.

2. The protection circuit according to claim 1, wherein: The driving module includes an OR gate logic unit and a driving unit, wherein the OR gate logic unit is provided with the first driving end, the second driving end and an OR gate output end; The driving unit is provided with a driving input terminal and a driving output terminal, wherein the driving input terminal is connected to the OR gate output terminal; the driving unit is used for driving the transistor switch to enter the on state based on the signal sent by the OR gate logic unit.

3. The protection circuit according to claim 2, wherein: The driving unit is further provided with a status terminal, which is used to output a status signal, wherein the status signal indicates whether the driving unit is in a normal working state; The driving module also includes an AND gate logic unit, which is provided with a third driving end, a fourth driving end and an AND gate output end; the third driving end is connected to the hardware detection module, the fourth driving end is connected to the status end of the driving unit, and the AND gate output end is connected to the second driving end of the OR gate logic unit.

4. The protection circuit according to claim 1, wherein: The transistor switch is provided with a first connection terminal and a second connection terminal, the first connection terminal is connected to the bus voltage input terminal through the protection resistor, and the second connection terminal is connected to the bus voltage ground terminal; The protection module further includes a diode, wherein the anode of the diode is connected to the first connection end, and the cathode of the diode is connected to the bus voltage input end.

5. The protection circuit according to any one of claims 1 to 4, characterized in that: The hardware detection module includes a voltage divider unit and a hysteresis comparison unit; The voltage dividing unit is connected between the bus voltage input terminal and the bus voltage ground terminal, and is used to divide the bus voltage and output the divided bus voltage through the voltage dividing output terminal of the voltage dividing unit; The hysteresis comparison unit is connected between the voltage divider output terminal and the second driving terminal of the driving module, and is used to enable the second driving terminal to receive the second trigger signal when the bus voltage after voltage division is greater than or equal to the first reference voltage.

6. The protection circuit according to claim 5, characterized in that: The protection circuit is further provided with a first power supply terminal, and the hysteresis comparison unit includes a hysteresis comparator, a first resistor, a second resistor and a third resistor; The hysteresis comparator is provided with a first non-inverting input terminal, a first inverting input terminal and a comparison output terminal, wherein the first inverting input terminal is used to input the first reference voltage, the first non-inverting input terminal is connected to the voltage divider output terminal of the voltage divider unit through the first resistor, and the comparison output terminal is connected to the second driving terminal of the driving module; The second resistor is connected between the first power supply terminal and the comparison output terminal; The third resistor is connected between the comparison output terminal and the first non-inverting input terminal.

7. The protection circuit according to claim 5, characterized in that: The hardware detection module also includes a voltage follower, which has a second positive input terminal, a second negative input terminal and a follower output terminal. The second positive input terminal is connected to the voltage divider output terminal of the voltage divider unit, the second negative input terminal is connected to the follower output terminal, and the follower output terminal is connected to the hysteresis comparison unit.

8. The protection circuit according to claim 5, wherein: The hardware detection module also includes an isolation unit, which includes an optocoupler. The optocoupler is connected between the hysteresis comparison unit and the second driving end of the driving module, and is used to enable the second driving end to receive the second trigger signal based on the signal sent by the hysteresis comparison unit.

9. The protection circuit according to claim 8, characterized in that: The protection circuit further includes a first power supply terminal, a second power supply terminal, and a designated ground terminal. The power supply voltages corresponding to the first power supply terminal and the second power supply terminal belong to different electrical networks, and the power supply voltage corresponding to the second power supply terminal and the ground terminal corresponding to the designated ground terminal belong to the same electrical network. The optocoupler includes a first input terminal, a second input terminal, a first output terminal, and a second output terminal. The second output terminal is connected to the second driving terminal. The isolation unit further includes an inverting Schmitt trigger, a fourth resistor, a fifth resistor, and a sixth resistor; the fourth resistor is connected between the first power supply terminal and the first input terminal, the fifth resistor is connected between the second power supply terminal and the first output terminal, and the sixth resistor is connected between the second output terminal and the designated ground terminal; The input terminal of the inverting Schmitt trigger is connected to the hysteresis comparison unit, and the output terminal of the inverting Schmitt trigger is connected to the second input terminal.

10. The protection circuit according to claim 7, wherein: The software detection module also includes a digital sampling unit, which is connected between the follower output end of the voltage follower and the control unit, and is used to discretely sample the divided bus voltage and input it into the control unit.

11. An electrical device, characterized in that: include: A power supply circuit for providing bus voltage; a workload connected to the power supply circuit; as well as The protection circuit according to any one of claims 1 to 10, wherein the protection circuit is provided with a bus voltage input terminal, and the bus voltage input terminal is connected to the power supply circuit.

Images