A fast response power overvoltage protection circuit

Abstract

The application relates to the technical field of circuit protection, and provides a fast-response power overvoltage protection circuit.The circuit comprises a power input end, a power output end, a voltage reference module, a voltage comparison module and a switch control module.A reference voltage value is provided by the voltage reference module, the voltage comparison module is used for comparing a sampling voltage value with the reference voltage value in real time, when the sampling voltage value is greater than or equal to the reference voltage value, the switch control module can quickly respond to a second level signal output by the voltage comparison module, and the main passage is cut off, so that the fast detection and response to the power overvoltage are realized, and the power passage is completely cut off to protect the subsequent circuit.

Description

Technical Field

[0001] This application relates to the field of circuit protection technology, and in particular to a fast-response power supply overvoltage protection circuit. Background Technology

[0002] In the development of modern electronic devices, a stable power supply plays a crucial role. With continuous technological advancements, electronic devices have become increasingly powerful and efficient, finding widespread application in all aspects of life and work. Portable electronic devices make life more convenient, industrial control systems ensure efficient industrial production, data center servers support the storage and processing of massive amounts of information, and medical equipment safeguards people's health. However, the reliable operation of these electronic devices is highly dependent on a stable power supply. Power supply problems can lead to equipment malfunctions, and even economic losses and safety hazards. Therefore, ensuring the stability and reliability of power supplies has become a key issue in the field of electronic circuit technology.

[0003] In existing technologies, various solutions are commonly used to address power supply overvoltage protection. One common solution is to use fuses or resettable fuses. When an overvoltage occurs in the circuit, the fuse melts, thus cutting off the circuit and providing protection; a resettable fuse automatically resumes conduction after the overvoltage condition disappears. Another solution is to use dedicated protection chips, which have specific functions and performance characteristics, enabling more precise protection of the power supply. There are also some simple clamping protection circuits that protect downstream circuits by limiting the voltage within a certain range. These solutions can address power supply overvoltage problems to a certain extent and are widely used in the field of electronic circuits.

[0004] However, existing technical solutions have significant drawbacks. Fuses or resettable fuses have slow response times and cannot respond promptly to instantaneous high-voltage pulses, potentially causing damage to core components within a short period. While dedicated protection chips offer better performance, they are expensive, have fixed protection thresholds, lack flexibility, and are difficult to meet the needs of different application scenarios. Simple clamping protection circuits may themselves be damaged when absorbing large energy surges and cannot completely cut off the power supply path, posing a risk of continuous overvoltage and failing to effectively protect subsequent circuits. Utility Model Content

[0005] In order to at least partially solve the above-mentioned technical problems in the prior art, this application provides a fast-response power supply overvoltage protection circuit.

[0006] The fast-response power supply overvoltage protection circuit provided in this application adopts the following technical solution: A fast-response power supply overvoltage protection circuit includes: Power input terminal and power output terminal; A voltage reference module, connected to the power input terminal, includes a voltage reference source and a sampling circuit. The voltage reference source is used to provide a reference voltage value, and the sampling circuit is used to provide a sampled voltage value. A voltage comparison module is provided, wherein a first input terminal of the voltage comparison module is connected to the voltage reference source, and a second input terminal of the voltage comparison module is connected to the sampling circuit; the voltage comparison module is used to compare the reference voltage value and the sampled voltage value; if the sampled voltage value is less than the reference voltage value, a first level signal is output; if the sampled voltage value is greater than or equal to the reference voltage value, a second level signal is output. A switch control module is provided, wherein the main path of the switch control module is connected between the power input terminal and the power output terminal, and the controlled terminal of the switch control module is connected to the output terminal of the voltage comparison module; wherein, when the controlled terminal receives the first level signal, the main path is turned on; when the controlled terminal receives the second level signal, the main path is turned off.

[0007] Using the above technical solution, a reference voltage value is provided by a voltage reference module, and a voltage comparison module is used to compare the sampled voltage value with the reference voltage value in real time. When the sampled voltage value is greater than or equal to the reference voltage value (i.e., overvoltage occurs), the switch control module can quickly respond to the second level signal output by the voltage comparison module and cut off its main path, thereby realizing rapid detection and response to power overvoltage and completely cutting off the power path to protect subsequent circuits.

[0008] Optionally, the power input terminal includes a high-potential input terminal and a low-potential input terminal, the high-potential input terminal being connected to the voltage reference module, and the low-potential input terminal being connected to ground.

[0009] The above technical solution clarifies the specific connection method of the high-potential input terminal and the low-potential input terminal. The high-potential input terminal is connected to the voltage reference module, and the low-potential input terminal is connected to ground, providing a stable input source and reference ground for the voltage reference module, which is the basis for realizing accurate reference and sampling.

[0010] Optionally, the input terminal of the voltage reference source is connected to the high-potential input terminal via a fifth resistor.

[0011] By adopting the above technical solution, the input terminal of the voltage reference source is connected to the high potential input terminal through the fifth resistor, which can serve as a bias resistor to provide a suitable operating current for the voltage reference source, enabling it to work stably and output an accurate reference voltage value.

[0012] Optionally, the sampling circuit includes a sixth resistor and a seventh resistor. The sixth resistor is connected to the high-potential input terminal, the first end of the seventh resistor is connected to the sixth resistor, and the second end of the seventh resistor is connected to ground. The connection node between the sixth resistor and the seventh resistor serves as a sampling point connected to the second input terminal of the voltage comparison module.

[0013] By adopting the above technical solution, a voltage divider sampling circuit is formed by the sixth and seventh resistors to divide the high potential at the power input terminal proportionally to obtain a sampled voltage value. This sampling point is then connected to the second input terminal of the voltage comparison module, thereby realizing real-time sampling of the input voltage.

[0014] Optionally, the voltage reference module further includes a filter capacitor connected between the high-potential input terminal and the ground terminal.

[0015] By adopting the above technical solution, and by setting a filter capacitor connected between the high-potential input terminal and the ground terminal, high-frequency noise and ripple of the input voltage can be effectively filtered out, the stability of the input power supply can be improved, the voltage reference module and the voltage comparison module can be ensured to obtain a purer voltage signal, and the reliability of the circuit operation can be enhanced.

[0016] Optionally, the voltage comparison module includes a comparator, the flip time of the comparator's output signal being less than 1 microsecond; wherein, the first input terminal of the comparator is connected to the output terminal of the voltage reference module to obtain a reference voltage value, the second input terminal of the comparator is connected to the power input terminal through the sampling circuit to obtain a sampled voltage value, and the output terminal of the comparator is connected to the switch control module.

[0017] By employing the above technical solution and utilizing a high-speed comparator with an output signal switching time of less than 1 microsecond, the voltage comparison module ensures an extremely fast response speed. When the sampled voltage value reaches or exceeds the reference voltage value, the comparator can quickly switch the output state, thereby shortening the response time of the entire protection circuit and achieving the technical effect of "fast response".

[0018] Optionally, the voltage comparison module further includes a fourth resistor connected between the output terminal of the comparator and the power input terminal.

[0019] By adopting the above technical solution, a fourth resistor connected between the comparator output and the power input can be used as a pull-up resistor to ensure that the comparator can provide a definite high-level signal, providing a clear and stable drive signal for the subsequent switch control module.

[0020] Optionally, the switch control module includes a P-type field-effect transistor, the gate of which forms the controlled terminal, and the drain and source of which form the main path.

[0021] The above technical solution utilizes a P-type field-effect transistor (FET) as the switching control module. Its gate forms the controlled terminal, and the drain and source form the main path. When the comparator module outputs a second-level signal (e.g., a high level), the gate-source voltage of the P-type FET causes it to quickly turn off, thus cutting off the main path. When the first-level signal (e.g., a low level) is output, the P-type FET turns on. This FET-based approach achieves rapid switching.

[0022] Optionally, a primary protection module is also included, which is connected in parallel between the power input terminal and the ground terminal to absorb instantaneous pulse energy.

[0023] By adopting the above technical solution, and by adding a primary protection module connected in parallel between the power input terminal and the ground terminal, it can respond first when there is a transient high voltage pulse or electrostatic shock to the input terminal, absorb the transient pulse energy, and play a pre-protection role for the subsequent comparison and switching modules, thereby improving the overall surge and electrostatic resistance of the circuit.

[0024] Optionally, the primary protection module includes a transient voltage suppression diode.

[0025] The above technical solution uses transient voltage suppression diodes as the primary protection module. By utilizing their ability to withstand high-energy surges instantaneously, the voltage is clamped to a safe level within a very short time after an instantaneous overvoltage occurs, effectively absorbing surges and electrostatic shocks, and protecting the subsequent precision comparator circuits and switching modules.

[0026] In summary, this application includes at least one of the following beneficial technical effects: 1. A reference voltage value is provided by a voltage reference module. The voltage comparison module is used to compare the sampled voltage value with the reference voltage value in real time. When the sampled voltage value is greater than or equal to the reference voltage value (i.e., overvoltage occurs), the switch control module can quickly respond to the second level signal output by the voltage comparison module and cut off its main path, thereby realizing rapid detection and response to power overvoltage and completely cutting off the power path to protect the subsequent circuits.

[0027] 2. By employing a high-speed comparator with an output signal switching time of less than 1 microsecond, the voltage comparison module ensures an extremely fast response speed. When the sampled voltage value reaches or exceeds the reference voltage value, the comparator can quickly switch the output state, thereby shortening the response time of the entire protection circuit and achieving the technical effect of "fast response".

[0028] 3. By adding a primary protection module connected in parallel between the power input terminal and the ground terminal, it can respond first when there is a transient high voltage pulse or electrostatic shock to the input terminal, absorb the transient pulse energy, and play a pre-protection role for the subsequent comparison and switching modules, thereby improving the overall surge and electrostatic resistance of the circuit. Attached Figure Description

[0029] Figure 1 A schematic diagram of the circuit structure of a fast-response power overvoltage protection circuit according to an embodiment of this application is shown.

[0030] Explanation of reference numerals in the attached diagram: 10, power input terminal; 20, voltage reference module; 30, voltage comparison module; 40, switch control module; 50, primary protection module; 60, power output terminal. Detailed Implementation

[0031] The following combination Figure 1 This application will be described in further detail.

[0032] This application discloses a fast-response power supply overvoltage protection circuit.

[0033] Figure 1 A schematic diagram of the circuit structure of a fast-response power supply overvoltage protection circuit according to an embodiment of this application is shown. Figure 1 As shown, the circuit includes a power input terminal 10, a voltage reference module 20, a voltage comparison module 30, a switch control module 40, a primary protection module 50, and a power output terminal 60. The output terminal of the voltage reference module 20 is connected to the first input terminal of the voltage comparison module 30, providing a reference voltage for the voltage comparison module 30. The second input terminal of the voltage comparison module 30 is connected to the power input terminal 10 via a sampling circuit to obtain a sampled value of the input voltage. The main path of the switch control module 40 is connected in series between the power input terminal 10 and the power output terminal 60, and its controlled terminal is connected to the output terminal of the voltage comparison module 30, controlling the on / off state of the power path according to the output signal of the voltage comparison module 30. The primary protection module 50 is connected in parallel between the power input terminal 10 and ground to absorb high-energy transient pulses and static electricity, achieving rapid detection and response to overvoltage conditions of the external input power supply, realizing electrostatic discharge protection, surge protection, and instantaneous overvoltage protection. When the input voltage exceeds a set threshold, it can completely cut off the power path, protecting subsequent circuits. This is because through the coordinated work of each module, the input voltage can be monitored in real time, and a rapid response can be made in case of abnormalities.

[0034] In some embodiments, the power input terminal 10 includes a high-potential input terminal CN3 and a low-potential input terminal CN4. The high-potential input terminal CN3 is the positive terminal of the input voltage and is connected to the voltage reference module 20. The low-potential input terminal CN4 is the negative terminal of the input voltage and is connected to ground.

[0035] In some embodiments, the voltage reference module 20 includes a voltage reference source U2, a fifth resistor R5, a sixth resistor R6, a seventh resistor R7, and a filter capacitor C1. The voltage reference source U2 can be a CJ431 voltage reference chip, which can output a precise nominal voltage, such as a feedback input voltage of 2.5V. The input terminal of the voltage reference source U2 is connected to the high-potential input terminal CN3 via the fifth resistor R5. The fifth resistor R5 acts as a bias resistor for the voltage reference source U2, providing a suitable operating current to ensure a stable output reference voltage. The reference terminal of the voltage reference source U2 is connected to ground, and the output terminal of the voltage reference source U2 is connected to the first input terminal of the voltage comparison module 30.

[0036] The sixth resistor R6 and the seventh resistor R7 constitute a sampling circuit. The sixth resistor R6 is connected to the high-potential input terminal CN3, the first end of the seventh resistor R7 is connected to the sixth resistor R6, and the second end of the seventh resistor R7 is connected to ground. The connection point between the sixth resistor R6 and the seventh resistor R7 serves as a sampling point connected to the second input terminal of the voltage comparison module 30.

[0037] The filter capacitor C1 is connected between the high-potential input terminal CN3 and the ground terminal to filter out high-frequency noise and ripple in the input voltage.

[0038] In some embodiments, the voltage comparison module 30 includes a comparator U1 and a fourth resistor R4. The output signal of comparator U1 has a switching time of less than 1 microsecond, such as an AP331AWG-7 high-speed comparator. Comparator U1 has a fast response characteristic, enabling it to quickly change its output state when the input voltage changes. The first input terminal of comparator U1 is connected to the output terminal of voltage reference module 20 to obtain a reference voltage value; the second input terminal of comparator U1 is connected to power input terminal 10 through a sampling circuit to obtain a sampled voltage value; the reference terminal of comparator U1 is connected to ground; and the output terminal of comparator U1 is connected to switch control module 40. Comparator U1 compares the sampled voltage value with the reference voltage value. If the sampled voltage value is less than the reference voltage value, voltage comparison module 30 outputs a first level signal (e.g., low level); if the sampled voltage value is greater than or equal to the reference voltage value, the output state of voltage comparison module 30 quickly flips, outputting a second level signal (e.g., high level). The fourth resistor R4 is connected between the output terminal of comparator U1 and the high-potential input terminal CN3 as a pull-up resistor.

[0039] In some embodiments, the switch control module 40 can employ a P-type field-effect transistor (FET), with its gate serving as the controlled terminal and its drain and source forming the main path. A P-type FET, such as the AO3401A, operates as follows: when the voltage comparator module 30 outputs a low level, the voltage applied to the gate of the P-type FET makes its gate-source voltage Vgs negative, causing the P-type FET to conduct. The voltage at the power input terminal 10 can then be transmitted to the power output terminal 60 through the main path of the P-type FET, supplying power to subsequent circuits. When the voltage comparator module 30 outputs a high level, the gate-source voltage Vgs of the P-type FET approaches zero or becomes positive, causing the P-type FET to quickly turn off, thereby cutting off the power input-to-output path and achieving overvoltage protection. Furthermore, the drain of the P-type FET is electrically isolated from the current path of the primary protection module 50, preventing the current from the primary protection module 50 from affecting the FET and improving the stability and reliability of the circuit.

[0040] In some embodiments, the primary protection module 50 includes a transient voltage suppression diode, the breakdown voltage of which is lower than the trigger threshold of the voltage comparator module 30. The transient voltage suppression diode, such as an SMF6.0A, can withstand high-energy surges instantaneously, clamping abnormally high voltages within a safe range. When a transient high-voltage pulse occurs at the input voltage, the transient voltage suppression diode conducts first, absorbing the high-energy transient pulse and static electricity, protecting subsequent circuits from damage. Optionally, the transient voltage suppression diode can also be connected in parallel with a gas discharge tube or a varistor to form a composite protection structure. A gas discharge tube has a large current-carrying capacity and can quickly conduct at higher voltages, releasing a large amount of energy; a varistor has a non-linear volt-ampere characteristic and can rapidly reduce resistance when the voltage exceeds a certain value, limiting the voltage within a safe range. This composite protection structure can further improve the protection capability of the primary protection module 50 and enhance the circuit's anti-interference capability.

[0041] In some embodiments, the voltage reference source U2 has a feedback input voltage of, for example, 2.5V, and the protection threshold of the power input terminal 10 is, for example, 5.25V. When the input power supply is greater than 5.25V, the voltage is divided by the sixth resistor R6 and the seventh resistor R7, the voltage at the second input terminal of comparator U1 is greater than 2.5V, and the output terminal of comparator U1 outputs a high level, causing the switch control module 40 to turn off, and power supplies above 5.25V cannot supply power to the circuit through the switch control module 40; when the input power supply is less than 5.25V, the voltage is divided by the sixth resistor R6 and the seventh resistor R7, the voltage at the second input terminal of comparator U1 is less than 2.5V, and the output terminal of comparator U1 outputs a low level, causing the switch control module 40 to turn on, and power supplies less than 5.25V supply power to the circuit through the switch control module 40.

[0042] The implementation principle of a fast-response power overvoltage protection circuit according to an embodiment of this application is as follows: This fast-response power overvoltage protection circuit achieves real-time monitoring and rapid response of the power input voltage through the coordinated operation of its various modules. The voltage reference module 20 provides a high-precision reference voltage, and the voltage comparison module 30 compares the sampled value of the input voltage with the reference voltage, controlling the on / off state of the switch control module 40 based on the comparison result. The primary protection module 50 is the first to function when a transient high-voltage pulse occurs in the input voltage, absorbing the high-energy impact and protecting subsequent circuits. Compared with existing technologies, this circuit has the advantages of low cost, fast response speed, adjustable protection threshold, and the ability to completely cut off faulty power supplies, improving the stability and reliability of the power supply to electronic equipment.

[0043] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A fast-response power supply overvoltage protection circuit, characterized in that, include: Power input terminal (10) and power output terminal (60). A voltage reference module (20) is connected to the power input terminal (10) and includes a voltage reference source U2 and a sampling circuit. The voltage reference source is used to provide a reference voltage value, and the sampling circuit is used to provide a sampled voltage value. A voltage comparison module (30) is provided, wherein the first input terminal of the voltage comparison module (30) is connected to the voltage reference source, and the second input terminal of the voltage comparison module (30) is connected to the sampling circuit; the voltage comparison module (30) is used to compare the reference voltage value and the sampled voltage value; if the sampled voltage value is less than the reference voltage value, a first level signal is output; if the sampled voltage value is greater than or equal to the reference voltage value, a second level signal is output. A switch control module (40) is provided, wherein the main path of the switch control module (40) is connected between the power input terminal (10) and the power output terminal (60), and the controlled terminal of the switch control module (40) is connected to the output terminal of the voltage comparison module (30); wherein, when the controlled terminal receives the first level signal, the main path is turned on; when the controlled terminal receives the second level signal, the main path is turned off.

2. The fast-response power supply overvoltage protection circuit according to claim 1, characterized in that, The power input terminal (10) includes a high potential input terminal CN3 and a low potential input terminal CN4. The high potential input terminal CN3 is connected to the voltage reference module (20), and the low potential input terminal CN4 is connected to ground.

3. The fast-response power supply overvoltage protection circuit according to claim 2, characterized in that, The input terminal of the voltage reference source U2 is connected to the high-potential input terminal CN3 through the fifth resistor R5.

4. The fast-response power supply overvoltage protection circuit according to claim 2, characterized in that, The sampling circuit includes a sixth resistor R6 and a seventh resistor R7. The sixth resistor R6 is connected to the high-potential input terminal CN3. The first end of the seventh resistor R7 is connected to the sixth resistor R6, and the second end of the seventh resistor R7 is connected to ground. The connection node between the sixth resistor R6 and the seventh resistor R7 serves as a sampling point and is connected to the second input terminal of the voltage comparison module (30).

5. The fast-response power supply overvoltage protection circuit according to claim 2, characterized in that, The voltage reference module (20) also includes a filter capacitor C1, which is connected between the high potential input terminal CN3 and the ground terminal.

6. The fast-response power supply overvoltage protection circuit according to claim 1, characterized in that, The voltage comparison module (30) includes a comparator U1, the flip time of the output signal of the comparator U1 is less than 1 microsecond; wherein, the first input terminal of the comparator U1 is connected to the output terminal of the voltage reference module (20) to obtain the reference voltage value, the second input terminal of the comparator U1 is connected to the power input terminal (10) through the sampling circuit to obtain the sampled voltage value, and the output terminal of the comparator U1 is connected to the switch control module (40).

7. The fast-response power supply overvoltage protection circuit according to claim 6, characterized in that, The voltage comparison module (30) also includes a fourth resistor R4, which is connected between the output terminal of the comparator U1 and the power input terminal (10).

8. The fast-response power supply overvoltage protection circuit according to claim 1, characterized in that, The switch control module (40) includes a P-type field-effect transistor, the gate of which forms the controlled terminal, and the drain and source of which form the main path.

9. The fast-response power supply overvoltage protection circuit according to claim 1, characterized in that, It also includes a primary protection module (50), which is connected in parallel between the power input terminal (10) and the ground terminal to absorb instantaneous pulse energy.

10. The fast-response power supply overvoltage protection circuit according to claim 9, characterized in that, The primary protection module (50) includes a transient voltage suppression diode.

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