Hardware front-end protection circuit

Abstract

The utility model discloses a hardware front-end protection circuit which is arranged between a positive voltage input end and a voltage acquisition point and comprises a diode D3 and a thermistor PTC which are connected in series, the thermistor PTC is connected to the negative electrode of the diode D3, the positive electrode of the diode D3 is connected to the positive voltage input end, a relay JDQ1 is connected to the diode D3 and the thermistor PTC in parallel, and the relay JDQ1 is connected to the positive voltage input end in parallel. The relay JDQ1 is connected to a voltage acquisition point through a protection module, and the protection module is connected with a signal of a micro control unit (MCU). Through reverse turn-off of a diode D3 and overcurrent protection of a thermistor PTC, a main loop is limited, an input front-end component is protected, and a relay JDQ1 and a protection module thereof can cut off connection between a voltage acquisition point and an input end in an abnormal state, so that effective protection of the whole system is realized.

Description

Technical Field

[0001] The utility model belongs to the field of voltage detection, and in particular relates to a hardware front-end protection circuit. Background Art

[0002] In modern electronic devices, power management is a crucial component in ensuring system stability and reliability. The increasing popularity of electronic products and technological advancements are placing higher demands on power system protection. This is particularly true in areas such as industrial control systems, automotive electronics, and communications equipment. These complex and ever-changing application environments can expose users to abnormalities such as overvoltage, reverse voltage, overload, and short circuits, necessitating the design of effective protection circuits to ensure safe system operation.

[0003] Traditional protection circuits typically employ simple fuses, relays, or coordinated control via a microcontroller (MCU). However, these methods often suffer from slow response times and non-recoverable circuits. The MCUs commonly used in existing technologies experience significant delays in processing. Especially when the input power is high, the MCU's delay and the potential for relay sticking under high current conditions can prevent the main circuit from being disconnected in a timely manner, potentially permanently damaging input circuit components. Furthermore, simple protection measures often fail to effectively address reverse voltage at the power input, potentially damaging the device's internal circuitry.

[0004] In view of this, this application is hereby filed. Utility Model Content

[0005] The technical problem to be solved by the utility model is to overcome the deficiencies of the prior art and provide a hardware front-end protection circuit.

[0006] In order to achieve the above purpose, the technical solution of the utility model is:

[0007] A hardware front-end protection circuit is provided between a positive voltage input terminal and a voltage collection point, and includes a diode D3 and a thermistor PTC connected in series. The thermistor PTC is connected to the cathode of the diode D3, and the anode of the diode D3 is connected to the positive voltage input terminal. A relay JDQ1 is connected in parallel to the diode D3 and the thermistor PTC. The relay JDQ1 is connected to the voltage collection point via a protection module, and the protection module is connected to the signal of a microcontroller unit MCU.

[0008] Preferably, a relay freewheeling diode D2 is connected in parallel to the relay JDQ1 , the positive electrode of the relay freewheeling diode D2 is connected between the relay JDQ1 and the protection module, and the negative electrode of the relay freewheeling diode D2 is connected to the current limiting resistor R7 .

[0009] Preferably, one end of the current limiting resistor R7 is connected to the cathode of the relay JDQ1 and the relay freewheeling diode D2, and the other end is connected to the positive electrode of the power supply voltage.

[0010] Preferably, one end of the current-limiting resistor R7 connected to the positive electrode of the power supply voltage is also grounded through the relay filter capacitor C2.

[0011] Preferably, the protection module includes a relay filter capacitor C1, a transistor Q2, a transistor Q1 and an optocoupler PQ1, the signal of the microcontroller MCU is connected between the transistor Q2 and the transistor Q1, and the A pole and K pole of the optocoupler PQ1 are respectively connected to the positive pole and negative pole of the voltage collection point.

[0012] Preferably, one end of the relay filter capacitor C1 is connected to the collector of the transistor Q2, and the other end is grounded.

[0013] Preferably, the signal of the micro control unit MCU is connected to the base of the transistor Q2, the base of the transistor Q2 is also connected to the collector of the transistor Q1, and the base of the transistor Q1 is connected to the C pole of the optical coupler PQ1.

[0014] Preferably, the base of the transistor Q2 is connected to a signal of the microcontroller unit MCU through a pull-up resistor R5 and is grounded through a pull-down resistor R6.

[0015] Preferably, the base of the transistor Q1 is connected to the power supply through a pull-up resistor R3 and is grounded through a pull-down resistor R4.

[0016] Preferably, the A pole and K pole of the optocoupler are connected to a parallel optocoupler clamping resistor R2 and an optocoupler clamping diode D1, the A pole of the optocoupler PQ1 is connected to the positive pole of the voltage collection point through the current limiting resistor R1, the positive pole of the optocoupler clamping diode D1 is connected to the K pole of the optocoupler, and the negative pole is connected to the A pole of the optocoupler.

[0017] After adopting the above technical solution, the hardware front-end protection circuit provided by the present invention has the following beneficial effects compared with the prior art.

[0018] 1. Through the reverse shutdown of diode D3 and the overcurrent protection of thermistor PTC, the main circuit is limited and the input front-end components are protected. Relay JDQ1 and its protection module can cut off the connection between the voltage collection point and the input end under abnormal conditions, thereby achieving effective protection for the entire system.

[0019] 2. By setting the relay freewheeling diode D2, the reverse electromotive force generated when the relay JDQ1 is disconnected can be absorbed, avoiding damage to the relay contacts or other electronic components that may be caused by this, and improving the stability and reliability of the system.

[0020] 3. By setting the current limiting resistor R7, it is ensured that the current in the circuit will not exceed the safety threshold, and the current can be limited as much as possible under fault conditions, further enhancing the safety of the circuit.

[0021] 4. By setting the current limiting resistor R1 and the optocoupler clamping resistor R2, the protection voltage value of the detection point can be set according to the optocoupler's on-current and other specifications, which broadens the universality of the circuit application.

[0022] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The accompanying drawings are part of the present invention and are used to provide a further understanding of the present invention. The illustrative embodiments of the present invention and their descriptions are used to explain the present invention but do not constitute an improper limitation of the present invention. Obviously, the drawings described below are only some embodiments. For those skilled in the art, other drawings can be obtained based on these drawings without inventive work. In the drawings:

[0024] Figure 1 It is a schematic diagram of the circuit structure of the utility model.

[0025] It should be noted that these drawings and textual descriptions are not intended to limit the conceptual scope of the present invention in any way, but rather to illustrate the concept of the present invention for those skilled in the art by referring to specific embodiments. DETAILED DESCRIPTION

[0026] like Figure 1 As shown, the utility model provides a hardware front-end protection circuit, which is arranged between the positive voltage input terminal and the voltage collection point, including a diode D3 and a thermistor PTC connected in series, the thermistor PTC is connected to the cathode of the diode D3, the anode of the diode D3 is connected to the positive voltage input terminal, and a relay JDQ1 is connected in parallel to the diode D3 and the thermistor PTC. The relay JDQ1 is connected to the voltage collection point through a protection module, and the protection module is connected to the signal of the microcontroller unit MCU.

[0027] Through the reverse shutdown of diode D3 and the overcurrent protection of thermistor PTC, the main circuit is limited and the input front-end components are protected. Relay JDQ1 and its protection module can cut off the connection between the voltage collection point and the input end under abnormal conditions, thereby achieving effective protection for the entire system.

[0028] Compared with ordinary relay protection circuits, this protection circuit still retains the logic protection function of the microcontroller unit MCU of ordinary relay protection circuits. In addition, hardware protection is added to directly collect input circuit voltage changes without the need for microcontroller unit MCU to process. The hardware can promptly shut down the main input circuit to achieve dual protection of software and hardware.

[0029] A relay freewheeling diode D2 is connected in parallel to the relay JDQ1 , the positive electrode of the relay freewheeling diode D2 is connected between the relay JDQ1 and the protection module, and the negative electrode of the relay freewheeling diode D2 is connected to the current limiting resistor R7 .

[0030] By setting the relay freewheeling diode D2, the reverse electromotive force generated when the relay JDQ1 is disconnected can be absorbed, thereby avoiding damage to the relay contacts or other electronic components that may be caused by this, and improving the stability and reliability of the system.

[0031] Preferably, one end of the current-limiting resistor R7 is connected to the cathode of relay JDQ1 and relay freewheeling diode D2, and the other end is connected to the positive supply voltage. By providing the current-limiting resistor R7, the current in the circuit is ensured not to exceed the safety threshold, and the current is limited as much as possible even under fault conditions, further enhancing the safety of the circuit.

[0032] One end of the current limiting resistor R7 connected to the positive pole of the power supply voltage is also grounded through the relay filter capacitor C2.

[0033] The relay filter capacitor C2 can filter out the voltage fluctuation on the current limiting resistor R7, ensuring the stability of the power supply voltage, reducing noise interference, and improving the working performance of the circuit.

[0034] Furthermore, the protection module includes a relay filter capacitor C1, a transistor Q2, a transistor Q1 and an optocoupler PQ1. The signal of the microcontroller MCU is connected between the transistor Q2 and the transistor Q1. The A pole and K pole of the optocoupler PQ1 are respectively connected to the positive pole and negative pole of the voltage collection point.

[0035] Preferably, one end of the relay filter capacitor C1 is connected to the collector of the transistor Q2, and the other end is grounded. The relay filter capacitor C1 can filter out the noise output by the transistor Q2, ensuring that the subsequent circuit receives a clean and stable signal, which helps improve the overall performance of the system.

[0036] Preferably, the signal of the micro control unit MCU is connected to the base of the transistor Q2, the base of the transistor Q2 is also connected to the collector of the transistor Q1, and the base of the transistor Q1 is connected to the C pole of the optical coupler PQ1.

[0037] Preferably, the base of transistor Q2 is connected to a signal from the microcontroller unit (MCU) via a pull-up resistor R5 and to ground via a pull-down resistor R6. Pull-up resistors R5 and R6 ensure a stable base state for transistor Q2, enabling a rapid response to changes in the MCU signal, thereby improving the circuit's response speed and stability.

[0038] Preferably, the base of transistor Q1 is connected to the power supply via a pull-up resistor R3 and to ground via a pull-down resistor R4. Pull-up resistor R3 and pull-down resistor R4 provide a stable bias voltage for the base of transistor Q1, enabling transistor Q1 to operate stably and ensuring normal operation of the circuit.

[0039] Further preferably, the A pole and K pole of the optocoupler are connected to the optocoupler clamping resistor R2 and the optocoupler clamping diode D1 in parallel, the A pole of the optocoupler PQ1 is connected to the positive pole of the voltage collection point through the current limiting resistor R1, the positive pole of the optocoupler clamping diode D1 is connected to the K pole of the optocoupler, and the negative pole is connected to the A pole of the optocoupler.

[0040] The optocoupler clamp resistor R2 and the optocoupler clamp diode D1 can effectively limit the voltage across the optocoupler PQ1, avoiding overvoltage and reverse breakdown. At the same time, they protect the optocoupler PQ1 from voltage spikes, thereby improving the reliability and durability of the circuit.

[0041] By setting the current limiting resistor R1 and the optocoupler clamping resistor R2, the protection voltage value of the detection point can be set according to the specifications of the optocoupler such as the on-current, which broadens the universality of the circuit application.

[0042] Under normal circumstances, when Vi+ at the voltage collection point is greater than Vi-, the optocoupler's light-emitting side conducts, the output transistor conducts, and the base of transistor Q1 is limited to a low level. At this time, transistor Q1 is turned off, and the base potential of transistor Q2 is determined by the signal from the microcontroller unit MCU. When the microcontroller unit MCU outputs a high level, transistor Q2 conducts, the auxiliary coil of relay JDQ1 conducts, relay JDQ1 is attracted, and the main power circuit conducts. The high and low levels of the microcontroller unit MCU are controlled by the output circuit protection logic.

[0043] When Vi+ minus Vi- is detected to be close to 0 or a negative value, the light-emitting side of the optocoupler PQ1 is turned off, and the optocoupler clamping diode D1 clamps the protective optocoupler to prevent the reverse breakdown voltage from exceeding the required value. At this time, transistor Q1 can be set to conduct based on the values ​​of the voltage divider resistors, namely the pull-up resistor R3 and the pull-down resistor R4. The base potential of transistor Q2 is forced to be pulled low. At this time, regardless of the input voltage level of the microcontroller unit MCU, the base of transistor Q2 always remains low, transistor Q2 is disconnected, and the relay does not attract.

[0044] The above description is merely a preferred embodiment of the present invention and does not constitute any form of limitation to the present invention. Although the present invention has been disclosed as above with preferred embodiments, it is not intended to limit the present invention. Any technician familiar with this patent can make some changes or modifications to equivalent embodiments with equivalent changes using the above-mentioned technical contents without departing from the scope of the technical solution of the present invention. The implementation schemes in the above embodiments can also be further combined or replaced. However, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the solution of the present invention.

Claims

1. A hardware front-end protection circuit, arranged between the positive voltage input terminal and the voltage collection point, characterized in that: It includes a diode D3 and a thermistor PTC connected in series, the thermistor PTC is connected to the cathode of the diode D3, the anode of the diode D3 is connected to the positive voltage input terminal, a relay JDQ1 is connected in parallel to the diode D3 and the thermistor PTC, the relay JDQ1 is connected to a voltage collection point through a protection module, and the protection module is connected to a signal from a microcontroller unit MCU.

2. The hardware front-end protection circuit according to claim 1, characterized in that: A relay freewheeling diode D2 is connected in parallel to the relay JDQ1 , the positive electrode of the relay freewheeling diode D2 is connected between the relay JDQ1 and the protection module, and the negative electrode of the relay freewheeling diode D2 is connected to the current limiting resistor R7 .

3. The hardware front-end protection circuit according to claim 2, characterized in that: One end of the current limiting resistor R7 is connected to the cathode of the relay JDQ1 and the relay freewheeling diode D2, and the other end is connected to the positive electrode of the power supply voltage.

4. The hardware front-end protection circuit according to claim 3, characterized in that: One end of the current limiting resistor R7 is connected to the positive electrode of the power supply voltage and is also grounded through the relay filter capacitor C2.

5. The hardware front-end protection circuit according to claim 1, characterized in that: The protection module includes a relay filter capacitor C1, a transistor Q2, a transistor Q1 and an optocoupler PQ1. The signal of the microcontroller MCU is connected between the transistor Q2 and the transistor Q1. The A pole and K pole of the optocoupler PQ1 are respectively connected to the positive pole and negative pole of the voltage collection point.

6. The hardware front-end protection circuit according to claim 5, characterized in that: One end of the relay filter capacitor C1 is connected to the collector of the transistor Q2, and the other end is grounded.

7. The hardware front-end protection circuit according to claim 5, characterized in that: The signal of the microcontroller unit MCU is connected to the base of the transistor Q2 , the base of the transistor Q2 is also connected to the collector of the transistor Q1 , and the base of the transistor Q1 is connected to the C pole of the optical coupler PQ1 .

8. The hardware front-end protection circuit according to claim 7, characterized in that: The base of the transistor Q2 is connected to a signal of the microcontroller unit MCU via a pull-up resistor R5 and is grounded via a pull-down resistor R6.

9. The hardware front-end protection circuit according to claim 7, characterized in that: The base of the transistor Q1 is connected to the power supply through a pull-up resistor R3 and is grounded through a pull-down resistor R4.

10. The hardware front-end protection circuit according to claim 7, characterized in that: The A pole and K pole of the optocoupler are connected to the optocoupler clamping resistor R2 and the optocoupler clamping diode D1 in parallel. The A pole of the optocoupler PQ1 is connected to the positive pole of the voltage collection point through the current limiting resistor R1. The positive pole of the optocoupler clamping diode D1 is connected to the K pole of the optocoupler, and the negative pole is connected to the A pole of the optocoupler.

Images