Lightning protection bus isolator

Abstract

This application discloses a surge-protected bus isolator, belonging to the field of bus isolator protection technology. It includes a switching step-down module that achieves efficient voltage reduction through high-frequency switching, inductor energy storage, and capacitor filtering; a linear voltage regulator module that reduces voltage in the linear operating region of the regulating transistor to output low-ripple, low-noise voltage; an input protection module that breaks down and conducts when surges or transient high voltages occur, clamping the voltage within a safe range to protect downstream circuits; a power processing and bus protection module that provides a stable internal power supply to the system; a current detection and signal conditioning module that detects the bus current and converts the current signal into a voltage signal; a power drive module that receives control signals from the MCU chip, amplifies them, and drives the main power transistor to switch on and off, achieving power control or switching of the bus load; and a control and communication module that collects signal data and executes corresponding control logic. This design adds surge protection to the bus isolator, avoiding the risk of the bus isolator itself being struck by lightning.

Description

Technical Field

[0001] This application belongs to the field of bus isolator protection technology, specifically, it relates to a lightning protection bus isolator. Background Technology

[0002] Bus-based automatic fire alarm systems all share a common problem: a short circuit in one section of the bus will paralyze the entire bus. Therefore, necessary protective measures should be taken in the engineering design. The current protective measure is to use bus isolation modules, which connect bus isolators to each segment of the bus or the nodes between the trunk and branches. Once a short circuit occurs on the bus, the bus isolator will automatically disconnect the section with the short circuit from the bus, ensuring normal communication of the remaining parts of the bus. After the short circuit is cleared, normal communication of the entire bus can be automatically restored.

[0003] Bus isolators, also known as isolation modules, are connected to the front end of the system bus. When a short circuit or other fault occurs in the loop, they isolate the back-end connected part from the system, ensuring that other systems can also work normally after isolation. Once the faulty part of the line is repaired, the isolator can automatically resume normal operation. However, existing isolation modules require the isolation group to be connected to the back end of the ring network to sense whether there is a short circuit before entering the line for isolation. Utility Model Content

[0004] To address the aforementioned problems and technical deficiencies, this application adopts the following technical solution: a surge protection bus isolator, characterized in that it comprises:

[0005] Switching step-down modules are used to achieve efficient voltage reduction through high-frequency switching, inductor energy storage, and capacitor filtering.

[0006] Linear voltage regulator modules are used to step down voltage by adjusting the linear operating range of the regulator tube, outputting low-ripple and low-noise voltage.

[0007] The input protection module is used to break down and conduct when a surge or transient high voltage occurs, clamping the voltage within a safe range to protect the downstream circuitry.

[0008] The power handling and bus protection module is used to provide a stable internal power supply for the system.

[0009] The current detection and signal conditioning module is used to convert the current signal into a voltage signal by detecting the bus current;

[0010] The power drive module receives control signals from the MCU chip, amplifies them, and drives the main power transistor to switch on and off, thereby controlling or switching the power of the bus load.

[0011] The control and communication module is used to acquire signal data and execute corresponding control logic.

[0012] Preferably, the switching buck module includes:

[0013] The switching buck regulator U1 is used to integrate internal switching transistors and control circuits, and stabilizes the output voltage by adjusting the switching duty cycle.

[0014] The energy storage inductor L1 is used to store energy when the switching transistor is turned on and release energy to the load when it is turned off, thereby realizing voltage conversion.

[0015] Output filter capacitors C5, C6, C7, C8, and C9 are used to reduce switching ripple.

[0016] Ferrite beads FB1 and FB2 are used to suppress high-frequency noise and improve electromagnetic compatibility.

[0017] Voltage divider resistors R9 and R11 are used to connect to the FB pin of the switching buck regulator U1 to output voltage through voltage divider feedback.

[0018] The bootstrap capacitor C10 is used to connect to the BST pin of the switching buck regulator U1 to provide voltage for the internal high-side MOSFET drive and ensure that the switching transistor is turned on normally.

[0019] The compensation filter circuit is used to stabilize the input voltage of the switching buck regulator U1, ensuring circuit stability and preventing oscillation.

[0020] Furthermore, the compensation filter circuit includes a resistor R10, a capacitor C12, and a capacitor C11;

[0021] Resistor R10 and capacitor C12 form a feedback loop compensation network to prevent oscillation;

[0022] C11 is the input filter capacitor, which stabilizes the input voltage of the switching buck regulator U1.

[0023] The resistor R10 has a value of 100kΩ, the capacitor C12 has a value of 0.1μF, and the capacitor C11 has a value of 47μF.

[0024] Preferably, the linear voltage regulator module includes:

[0025] The low dropout linear regulator U2 integrates an internal regulating transistor and error amplifier to linearly step down the input voltage to a stable value.

[0026] The reverse protection diode D5 is used to reverse cut off the reverse current and protect the subsequent circuit when the input power polarity is reversed.

[0027] Output filter capacitor C13 is used to reduce LDO output ripple;

[0028] The load resistor R12 is used to provide minimum load or current limiting under light load conditions.

[0029] Preferably, the input protection module includes: TVS diodes Q21, Q22, and Q23, current-limiting resistors R1 and R3, and a filter capacitor C7;

[0030] Current-limiting resistors are used to limit current and prevent damage to devices from transient high currents, while filter capacitors are used to smooth input voltage ripple.

[0031] Preferably, the power processing and bus protection module includes: a power module U1-BUS, a reverse polarity protection diode D8, and TVS diodes D1, D2, and D3;

[0032] Reverse connection protection diodes are used in reverse series connection to prevent damage to the circuit when the power supply is reversed.

[0033] TVS diodes are used to provide overvoltage protection for the bus. When the bus voltage is abnormal, the TVS diode breaks down, clamping the voltage to the rated value and protecting the bus devices.

[0034] Preferably, the current detection and signal conditioning module includes: a current sensing amplifier U6 and a filter circuit;

[0035] The filtering circuit filters the output voltage to obtain the BUS_I_ADC signal, which is then output to the ADC pin of the MCU chip to realize bus current monitoring.

[0036] Preferably, the power drive module includes: power transistors Q1 and Q2, drive transistors Q3 and Q4, freewheeling diode D10, and gate resistors R18 and R19;

[0037] A freewheeling diode is used to provide a discharge path for the reverse induced current of an inductive load when the power transistor is turned off, preventing overvoltage damage to the device.

[0038] Gate resistors are used to limit gate current and stabilize the switching process.

[0039] Preferably, the control and communication module includes: an MCU chip, a status indicator LED, and a serial communication pin;

[0040] The serial communication pin is used to communicate with external devices, upload status information, or receive commands.

[0041] Status indicator LEDs are used to indicate the system's operating status.

[0042] Compared to existing technologies, the beneficial effects of this application are as follows:

[0043] (1) This application uses a switching step-down module and a linear voltage regulator module to form a power supply circuit, and an input protection module, a power processing and bus protection module, a current detection and signal conditioning module, a power drive module and a control and communication module to form a bus lightning protection circuit. By adding lightning protection function to the bus isolator, the lightning protector is saved, and the cost can be saved more, avoiding the risk of the bus isolator itself being struck by lightning.

[0044] (2) The power supply circuit of this application uses a switch to step down the voltage to handle high current or wide input scenarios, uses inductor energy storage to achieve efficient energy conversion, uses linear voltage regulation to handle loads sensitive to ripple or noise, uses linear adjustment to achieve low noise output, and uses auxiliary circuits such as reverse connection protection diodes, magnetic bead filters, and capacitor voltage regulation to improve the system's anti-interference capability and stability.

[0045] (3) The bus surge protection circuit of this application realizes surge / overvoltage protection through TVS tube and resistor to ensure hardware safety. It provides stable power supply by connecting filter and reverse connection protection diode through power module. It realizes accurate current detection by connecting current sensing amplifier and filter circuit to provide a basis for control. It realizes power switching or regulation by connecting drive tube and drive circuit. It integrates signal processing, logic control and communication interaction through MCU chip to ensure intelligent and reliable operation of system. Attached Figure Description

[0046] In the attached diagram:

[0047] Figure 1 This is a schematic diagram of the structure of an embodiment of this application;

[0048] Figure 2 A circuit diagram of the power supply circuit for this application;

[0049] Figure 3 This is the circuit diagram of the bus surge protection circuit of this application. Detailed Implementation

[0050] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are some embodiments of this application, but not all embodiments. Generally, the components of the embodiments of this application described and shown in the accompanying drawings can be arranged and designed in various different configurations.

[0051] Example

[0052] like Figure 1 , Figure 2 and Figure 3 As shown, a surge protection bus isolator includes:

[0053] Switching step-down modules are used to achieve efficient voltage reduction through high-frequency switching, inductor energy storage, and capacitor filtering.

[0054] The switching step-down module includes:

[0055] The switching buck regulator U1 is used to integrate internal switching transistors and control circuits, and stabilizes the output voltage by adjusting the switching duty cycle.

[0056] The energy storage inductor L1 is used to store energy when the switching transistor is turned on and release energy to the load when it is turned off, thereby realizing voltage conversion.

[0057] The energy storage inductor L1 has a capacity of 15μH.

[0058] Output filter capacitors C5, C6, C7, C8, and C9 are used to reduce switching ripple.

[0059] Ferrite beads FB1 and FB2 are used to suppress high-frequency noise and improve electromagnetic compatibility (EMC).

[0060] Voltage divider resistors R9 and R11 are used to connect to the FB pin of the switching buck regulator U1 to output voltage through voltage divider feedback.

[0061] The formula for calculating the output voltage of the voltage divider resistor is as follows:

[0062] V OUT =V REF ×(1+R9 / R11)

[0063] Among them, V OUT V is the output voltage. REF R9 and R11 are the internal reference voltage of the chip, and R9 and R11 are the resistance values ​​of the voltage divider resistors R9 and R11.

[0064] The bootstrap capacitor C10 is used to connect to the BST pin of the switching buck regulator U1 to provide voltage for the internal high-side MOSFET drive and ensure that the switching transistor is turned on normally.

[0065] The bootstrap capacitor C10 has a capacitance of 0.1μF.

[0066] The compensation filter circuit is used to stabilize the input voltage of the switching buck regulator U1, ensuring circuit stability and preventing oscillation.

[0067] The compensation filter circuit includes resistor R10, capacitor C12, and capacitor C11;

[0068] Resistor R10 and capacitor C12 form a feedback loop compensation network to prevent oscillation;

[0069] C11 is the input filter capacitor, which stabilizes the input voltage of the switching buck regulator U1.

[0070] The resistor R10 has a value of 100kΩ, the capacitor C12 has a value of 0.1μF, and the capacitor C11 has a value of 47μF.

[0071] Linear voltage regulator modules are used to step down voltage by adjusting the linear operating range of the regulator tube, outputting low-ripple and low-noise voltage.

[0072] The linear regulator module includes:

[0073] The low dropout linear regulator U2 integrates an internal regulating transistor and error amplifier to linearly step down the input voltage to a stable value.

[0074] The reverse protection diode D5 is used to reverse cut off the reverse current and protect the subsequent circuit when the input power polarity is reversed.

[0075] Output filter capacitor C13 is used to reduce LDO output ripple;

[0076] The output filter capacitor C13 has a value of 10μF.

[0077] The load resistor R12 is used to provide minimum load or current limiting under light load conditions.

[0078] The load resistor R12 has a value of 1kΩ.

[0079] The input protection module is used to break down and conduct when a surge or transient high voltage occurs, clamping the voltage within a safe range to protect the downstream circuitry.

[0080] The input protection module includes: TVS diodes Q21, Q22, and Q23, current-limiting resistors R1 and R3, and filter capacitor C7;

[0081] Current-limiting resistors are used to limit current and prevent damage to devices from transient high currents, while filter capacitors are used to smooth input voltage ripple.

[0082] The power handling and bus protection module is used to provide a stable internal power supply for the system.

[0083] The power handling and bus protection module includes: power module U1-BUS, reverse polarity protection diode D8, TVS diodes D1, D2, and D3;

[0084] Reverse connection protection diodes are used in reverse series connection to prevent damage to the circuit when the power supply is reversed.

[0085] TVS diodes are used to provide overvoltage protection for the bus. When the bus voltage is abnormal, the TVS diode breaks down, clamping the voltage to the rated value and protecting the bus devices.

[0086] The current detection and signal conditioning module is used to convert the current signal into a voltage signal by detecting the bus current;

[0087] The current detection and signal conditioning module includes: current sensing amplifier U6 and filter circuit;

[0088] The filtering circuit filters the output voltage to obtain the BUS_I_ADC signal, which is then output to the ADC pin of the MCU chip to realize bus current monitoring.

[0089] The power drive module receives control signals from the MCU chip, amplifies them, and drives the main power transistor to switch on and off, thereby controlling or switching the power of the bus load.

[0090] The power drive module includes: power transistors Q1 and Q2, drive transistors Q3 and Q4, freewheeling diode D10, and gate resistors R18 and R19;

[0091] A freewheeling diode is used to provide a discharge path for the reverse induced current of an inductive load when the power transistor is turned off, preventing overvoltage damage to the device.

[0092] Gate resistors are used to limit gate current and stabilize the switching process.

[0093] The control and communication module is used to acquire signal data and execute corresponding control logic.

[0094] The control and communication module includes: an MCU chip, status indicator LEDs, and serial communication pins;

[0095] The serial communication pin is used to communicate with external devices, upload status information, or receive commands.

[0096] Status indicator LEDs are used to indicate the system's operating status.

[0097] The embodiments described above are merely preferred embodiments of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of this application. It should be noted that those skilled in the art can make various modifications, improvements, and substitutions without departing from the concept of this application, and these all fall within the protection scope of this application.

Claims

1. A surge protection bus isolator, characterized in that, include: Switching step-down modules are used to achieve efficient voltage reduction through high-frequency switching, inductor energy storage, and capacitor filtering. Linear voltage regulator modules are used to step down voltage by adjusting the linear operating range of the regulator tube, outputting low-ripple and low-noise voltage; The input protection module is used to break down and conduct when a surge or transient high voltage occurs, clamping the voltage within a safe range to protect the downstream circuitry. The power handling and bus protection module is used to provide a stable internal power supply for the system. The current detection and signal conditioning module is used to convert the current signal into a voltage signal by detecting the bus current; The power drive module receives control signals from the MCU chip, amplifies them, and drives the main power transistor to switch on and off, thereby controlling or switching the power of the bus load. The control and communication module is used to acquire signal data and execute corresponding control logic.

2. The surge protection bus isolator according to claim 1, characterized in that, The switching step-down module includes: The switching buck regulator U1 is used to integrate internal switching transistors and control circuits, and stabilizes the output voltage by adjusting the switching duty cycle. The energy storage inductor L1 is used to store energy when the switching transistor is turned on and release energy to the load when it is turned off, thereby realizing voltage conversion. Output filter capacitors C5, C6, C7, C8, and C9 are used to reduce switching ripple. Ferrite beads FB1 and FB2 are used to suppress high-frequency noise and improve electromagnetic compatibility. Voltage divider resistors R9 and R11 are used to connect to the FB pin of the switching buck regulator U1 to output voltage through voltage divider feedback. The bootstrap capacitor C10 is used to connect to the BST pin of the switching buck regulator U1 to provide voltage for the internal high-side MOSFET drive and ensure that the switching transistor is turned on normally. The compensation filter circuit is used to stabilize the input voltage of the switching buck regulator U1, ensuring circuit stability and preventing oscillation.

3. A surge protection bus isolator according to claim 2, characterized in that, The compensation filter circuit includes a resistor R10, a capacitor C12, and a capacitor C11; Resistor R10 and capacitor C12 form a feedback loop compensation network to prevent oscillation; C11 is the input filter capacitor, which stabilizes the input voltage of the switching buck regulator U1; The resistor R10 has a value of 100kΩ, the capacitor C12 has a value of 0.1μF, and the capacitor C11 has a value of 47μF.

4. A surge protection bus isolator according to claim 1, characterized in that, The linear voltage regulator module includes: The low dropout linear regulator U2 integrates an internal regulating transistor and error amplifier to linearly step down the input voltage to a stable value. The reverse protection diode D5 is used to reverse cut off the reverse current and protect the subsequent circuit when the input power polarity is reversed. Output filter capacitor C13 is used to reduce LDO output ripple; The load resistor R12 is used to provide minimum load or current limiting under light load conditions.

5. A surge protection bus isolator according to claim 1, characterized in that, The input protection module includes: TVS diodes Q21, Q22, and Q23, current-limiting resistors R1 and R3, and filter capacitor C7; Current-limiting resistors are used to limit current and prevent damage to devices from transient high currents, while filter capacitors are used to smooth input voltage ripple.

6. A surge protection bus isolator according to claim 1, characterized in that, The power processing and bus protection module includes: power module U1-BUS, reverse connection protection diode D8, TVS diodes D1, D2, and D3; Reverse connection protection diodes are used in reverse series connection to prevent damage to the circuit when the power supply is reversed. TVS diodes are used to provide overvoltage protection for the bus. When the bus voltage is abnormal, the TVS diode breaks down, clamping the voltage to the rated value and protecting the bus devices.

7. A surge protection bus isolator according to claim 1, characterized in that, The current detection and signal conditioning module includes: a current sensing amplifier U6 and a filter circuit; The filtering circuit filters the output voltage to obtain the BUS_I_ADC signal, which is then output to the ADC pin of the MCU chip to realize bus current monitoring.

8. A surge protection bus isolator according to claim 1, characterized in that, The power drive module includes: power transistors Q1 and Q2, drive transistors Q3 and Q4, freewheeling diode D10, and gate resistors R18 and R19. A freewheeling diode is used to provide a discharge path for the reverse induced current of an inductive load when the power transistor is turned off, preventing overvoltage damage to the device. Gate resistors are used to limit gate current and stabilize the switching process.

9. A surge protection bus isolator according to claim 1, characterized in that, The control and communication module includes: an MCU chip, status indicator LEDs, and serial communication pins; The serial communication pin is used to communicate with external devices, upload status information, or receive commands. Status indicator LEDs are used to indicate the system's operating status.

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