Hysteresis overvoltage protection circuit for high-power emergency power supply
By introducing pre-filters and post-filters into the hysteresis overvoltage protection circuit, and combining them with a complex filter circuit composed of operational amplifiers and transistors, the problem of insufficient interference signal suppression capability of traditional hysteresis overvoltage protection circuits is solved, achieving higher output accuracy and lower false trigger probability.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-08-25
- Publication Date
- 2026-04-03
AI Technical Summary
Traditional hysteresis overvoltage protection circuits have limited ability to suppress interference signals in voltage sampling signals, resulting in a high probability of false triggering.
The design employs a pre-filter and a post-filter, combined with a complex filter circuit composed of operational amplifiers and transistors. The pre-filter eliminates large-amplitude occasional disturbances, while the post-filter suppresses high-frequency interference, thereby improving the output accuracy of the hysteresis comparator.
It effectively eliminates interference in the voltage sampling signal, reduces the probability of false triggering of overvoltage protection, and improves the output accuracy of the hysteresis comparator.
Smart Images
Figure CN224083180U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to an overvoltage protection circuit, and more particularly to a hysteresis overvoltage protection circuit for high-power emergency power supplies. Background Technology
[0002] High-power emergency power supplies can cause brief voltage fluctuations during startup or sudden load changes. Using ordinary overvoltage protection circuits may lead to false triggering of the overvoltage protection. Therefore, hysteresis overvoltage protection circuits are generally used. However, traditional hysteresis overvoltage protection circuits have limited ability to suppress interference signals in the voltage sampling signal, and there is still a certain probability of false triggering. Utility Model Content
[0003] The technical problem to be solved by this utility model is to provide a hysteresis overvoltage protection circuit for high-power emergency power supplies, which can overcome the shortcomings of the prior art and further reduce the probability of false triggering of overvoltage protection.
[0004] To solve the above-mentioned technical problems, the technical solution adopted by this utility model is as follows.
[0005] A hysteresis overvoltage protection circuit for a high-power emergency power supply is disclosed. The voltage signal input terminal of the hysteresis overvoltage protection circuit is connected to the positive input terminal of a first operational amplifier (op-amp) via a series connection of a first resistor, a first inductor, and a second inductor. The inverting input terminal of the first op-amp is grounded via a second resistor. A first capacitor connects the first inductor and the second inductor to ground. The inverting input terminal of the first op-amp is connected to its output terminal via a third resistor. The output terminal of the first op-amp is connected to the positive input terminal of a second op-amp via a series connection of a fourth resistor and a fifth resistor. The inverting input terminal of the second op-amp is grounded via a sixth resistor. The inverting input terminal of the second op-amp is connected to its output terminal via a seventh resistor. A second capacitor connects the fourth and fifth resistors to the output terminal of the second op-amp. The positive input terminal of the second op-amp is grounded via the third capacitor. The output terminal of the second op-amp is connected to the input terminal of a hysteresis comparator. The reference terminal of the hysteresis comparator is connected to a reference voltage. The output terminal of the hysteresis comparator serves as the control signal output terminal of the hysteresis overvoltage protection circuit.
[0006] Preferably, the output terminal of the second operational amplifier is connected to the collector of the first transistor, the base of the first transistor is connected to the output terminal of the first operational amplifier through an eighth resistor, and the emitter of the first transistor is grounded through a fourth capacitor.
[0007] Preferably, the emitter of the first transistor is connected to the base and collector of the second transistor via a ninth resistor, and the emitter of the second transistor is grounded via a fifth capacitor.
[0008] The beneficial effects of adopting the above technical solution are as follows: Based on the traditional hysteresis comparator, this utility model effectively eliminates interference in the voltage sampling signal and improves the output accuracy of the hysteresis comparator by designing a pre-filter and a post-filter. Attached Figure Description
[0009] Figure 1 This is a circuit diagram of one specific embodiment of the present invention. Detailed Implementation
[0010] Reference Figure 1 In one specific embodiment of this utility model, the voltage signal input terminal IN of the hysteresis overvoltage protection circuit is connected to the positive input terminal of the first operational amplifier A1 through a series connection of a first resistor R1, a first inductor L1, and a second inductor L2. The inverting input terminal of the first operational amplifier A1 is grounded through a second resistor R2. The first inductor L1 and the second inductor L2 are grounded through a first capacitor C1. The inverting input terminal of the first operational amplifier A2 is connected to the output terminal of the first operational amplifier A1 through a third resistor R3. The output terminal of the first operational amplifier A1 is connected to the positive input terminal of the second operational amplifier A2 through a series connection of a fourth resistor R4 and a fifth resistor R5. The inverting input of the second operational amplifier A2 is grounded through the sixth resistor R6. The inverting input of the second operational amplifier A2 is connected to its output through the seventh resistor R7. The fourth resistor R4 and the fifth resistor R5 are connected to the output of the second operational amplifier A2 through the second capacitor C2. The non-inverting input of the second operational amplifier A2 is grounded through the third capacitor C3. The output of the second operational amplifier A2 is connected to the input of the hysteresis comparator HC. The reference terminal of the hysteresis comparator HC is connected to a reference voltage. The output of the hysteresis comparator HC serves as the control signal output (OUT) of the hysteresis overvoltage protection circuit. The first resistor R1, the first inductor L1, the second inductor L2, and the first capacitor C1 form a pre-filter circuit to filter out large-amplitude occasional disturbances in the sampled signal. The first operational amplifier A1 forms an amplification circuit to amplify the sampled signal, and the second operational amplifier A2 forms a post-filter circuit to filter out high-frequency interference in the sampled signal. Through the processing of the sampled signal by these two filtering circuits, interference signals can be effectively suppressed.
[0011] The output of the second operational amplifier A2 is connected to the collector of the first transistor Q1. The base of the first transistor Q1 is connected to the output of the first operational amplifier A1 through the eighth resistor R8. The emitter of the first transistor Q1 is grounded through the fourth capacitor C4. The emitter of the first transistor Q1 is connected to the base and collector of the second transistor Q2 through the ninth resistor R9. The emitter of the second transistor Q2 is grounded through the fifth capacitor C5. The two transistors form a two-stage compound filter circuit. When the output voltage of the amplifier circuit exceeds a preset value, the compound filter circuit is turned on, and together with the post-filter circuit, it filters the output of the amplifier circuit.
[0012] In this embodiment, the first resistor R1 is 2.3kΩ, the second resistor R2 is 0.5kΩ, the third resistor R3 is 1kΩ, the fourth resistor R4 is 0.3kΩ, the fifth resistor R5 is 1.2kΩ, the sixth resistor R6 is 3kΩ, the seventh resistor R7 is 2.5kΩ, the eighth resistor R8 is 1.5kΩ, and the ninth resistor R9 is 1.7kΩ. The first capacitor C1 is 300μF, the second resistor C2 is 80μF, the third capacitor C3 is 50μF, the fourth capacitor C4 is 100μF, the fifth capacitor is 200μF, the first inductor L1 is 0.1mH, and the second inductor L2 is 0.25mH.
[0013] In the description of this utility model, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.
[0014] The foregoing has shown and described the basic principles, main features, and advantages of this utility model. Those skilled in the art should understand that this utility model is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of this utility model. Various changes and modifications can be made to this utility model without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claims. The scope of protection of this utility model is defined by the appended claims and their equivalents.
Claims
1. A hysteresis overvoltage protection circuit for high power emergency power supplies, characterized by: The voltage signal input end (IN) of the hysteresis overvoltage protection circuit is connected to the positive input end of the first operational amplifier (A1) through the series connection of the first resistor (R1), the first inductor (L1) and the second inductor (L2), the inverting input end of the first operational amplifier (A1) is connected to the ground through the second resistor (R2), the first inductor (L1) and the second inductor (L2) are connected to the ground through the first capacitor (C1), the inverting input end of the first operational amplifier (A1) is connected to the output end of the first operational amplifier (A1) through the third resistor (R3), the output end of the first operational amplifier (A1) is connected to the positive input end of the second operational amplifier (A2) through the series connection of the fourth resistor (R4) and the fifth resistor (R5), the inverting input end of the second operational amplifier (A2) is connected to the ground through the sixth resistor (R6), the inverting input end of the second operational amplifier (A2) is connected to the output end of the second operational amplifier (A2) through the seventh resistor (R7), the second capacitor (C2) is connected to the output end of the second operational amplifier (A2) between the fourth resistor (R4) and the fifth resistor (R5), the positive input end of the second operational amplifier (A2) is connected to the ground through the third capacitor (C3), the output end of the second operational amplifier (A2) is connected to the input end of the hysteresis comparator (HC), the reference end of the hysteresis comparator (HC) is connected to the reference voltage, and the output end of the hysteresis comparator (HC) is used as the control signal output end (OUT) of the hysteresis overvoltage protection circuit.
2. The hysteresis overvoltage protection circuit for high power emergency power supplies according to claim 1, characterized in that: The output end of the second operational amplifier (A2) is connected to the collector of the first transistor (Q1), the base of the first transistor (Q1) is connected to the output end of the first operational amplifier (A1) through the eighth resistor (R8), and the emitter of the first transistor (Q1) is connected to the ground through the fourth capacitor (C4).
3. The hysteresis overvoltage protection circuit for high power emergency power supplies according to claim 2, characterized in that: The emitter of the first transistor (Q1) is connected to the base and the collector of the second transistor (Q2) through the ninth resistor (R9) respectively, and the emitter of the second transistor (Q2) is connected to the ground through the fifth capacitor (C5).