Multifunctional protection filter circuit
By designing a multi-function protective filter circuit, lightning protection, reverse connection and filtering functions are integrated, solving the problems of single functions and high complexity of traditional filter circuits, and miniaturization and efficient protection of the equipment are achieved.
Patent Information
- Application Number
- CN202510910027.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-02
- Publication Date
- 2025-08-26
AI Technical Summary
The existing traditional filter circuit has single functions and complex cascades, which increases the complexity and volume of the system, which is not conducive to the miniaturization of equipment.
A multi-functional protective filter circuit is designed to integrate lightning protection, anti-reverse connection and filtering functions into an integrated composite filter circuit. Through inter-stage optimization design, it includes lightning protection unit, anti-reverse connection unit and filter unit. It uses components such as varistors, discharge tubes, MOS tubes, differential mode capacitors and common mode inductors to achieve multiple protection functions.
It realizes the integration and miniaturization of multiple protection functions, enhances the protection and filtering effects of the circuit, simplifies the system structure, and reduces volume and weight.
Smart Images
Figure CN120546447A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of circuits, and in particular to a multifunctional protective filter circuit. Background Art
[0002] Currently, power supply filters are widely used to address conducted interference in power supply systems, as the most effective way to resolve electromagnetic compatibility issues. However, existing traditional filter circuits have a single topology and typically only provide circuit filtering, with relatively limited functionality. To meet multiple functional requirements of a power supply system, such as lightning protection and reverse polarity protection, multiple functional modules are typically cascaded. This increases overall system complexity and makes it difficult to achieve good matching between stages. Furthermore, it increases system weight and size, hindering the development of miniaturized equipment.
[0003] Therefore, there is an urgent need for a composite filter circuit that integrates a lightning protection circuit, an anti-reverse connection circuit, and a filter circuit into an integrated circuit through inter-stage optimization design. Summary of the Invention
[0004] The purpose of the present invention is to overcome the shortcomings of the prior art that the cascade connection of multiple functional modules increases the complexity of the entire system and makes it difficult to achieve good matching between stages; on the other hand, it also increases the weight and size of the system, which is not conducive to the miniaturization of the equipment, and provides a multifunctional protective filter circuit.
[0005] In order to solve the above technical problems, the present invention provides the following technical solutions: A multifunctional protection filter circuit comprises: a lightning protection unit, an anti-reverse connection unit and a filter unit electrically connected in sequence; The lightning protection unit is used to protect the entire circuit when a lightning impulse voltage enters; The anti-reverse connection unit is used to prevent the circuit from outputting when a reverse power supply is connected to the circuit input terminal; The filtering unit is used to suppress common-mode interference and differential-mode interference in the circuit, and is combined with the lightning protection unit to suppress peak interference.
[0006] As a preferred solution of the present invention, the lightning protection unit includes: a varistor MOV1, a varistor MOV2, a varistor MOV3, a discharge tube GDT1 and a discharge tube GDT2; The first end of the varistor MOV1 is electrically connected to the first end of the varistor MOV2; The second end of the varistor MOV1 is electrically connected to the first end of the varistor MOV3; The second end of the varistor MOV2 is electrically connected to the first end of the discharge tube GDT1; The second end of the varistor MOV3 is electrically connected to the first end of the discharge tube GDT2; The second end of the discharge tube GDT1 and the second end of the discharge tube GDT2 are both grounded.
[0007] As a preferred solution of the present invention, the single-stage discharge unit includes: a voltage-dividing resistor R1, a voltage-dividing resistor R2, a MOS tube Q1 and a voltage-stabilizing diode D1; The first end of the voltage-dividing resistor R1 is electrically connected to the first end of the varistor MOV1; The gate of the MOS transistor, the first end of the voltage-dividing resistor R2 and the cathode of the voltage-stabilizing diode D1 are all electrically connected to the second end of the voltage-dividing resistor R1; The drain of the MOS tube is electrically connected to the first end of the varistor MOV3; The second end of the voltage-dividing resistor R2 and the anode of the voltage-stabilizing diode D1 are both electrically connected to the source of the MOS transistor.
[0008] As a preferred solution of the present invention, the filtering unit includes a differential mode module, a common mode inductor L3, a differential mode capacitor module and a common mode capacitor unit which are electrically connected in sequence.
[0009] As a preferred solution of the present invention, the differential mode module includes a differential mode capacitor CX1, a differential mode capacitor CX2, a differential mode inductor L1 and a differential mode inductor L2; The first end of the differential mode capacitor CX1 and the first end of the differential mode inductor L1 are both electrically connected to the first end of the voltage divider resistor R1; The second end of the differential mode capacitor CX1 and the first end of the differential mode inductor L1 are both electrically connected to the anode of the voltage stabilizing diode D1; The second end of the differential mode inductor L1 and the first end of the differential mode capacitor CX2 are both electrically connected to the first end of the common mode inductor L3; The second end of the differential mode inductor L2 and the second end of the differential mode capacitor CX2 are both electrically connected to the second end of the common mode inductor L3.
[0010] As a preferred solution of the present invention, the differential mode capacitor module includes a differential mode capacitor CX3, a surge protection circuit and a differential mode capacitor CX4 which are sequentially connected in parallel to the third end and the fourth end of the common mode inductor L3.
[0011] As a preferred solution of the present invention, the surge protection circuit includes a transient voltage suppression diode D2, and the transient voltage suppression diode D2 is connected in parallel between the differential mode capacitor CX3 and the differential mode capacitor CX4.
[0012] As a preferred solution of the present invention, the common-mode capacitor module includes a common-mode capacitor CY1 and a common-mode capacitor CY2, wherein the common-mode capacitor CY1 and the common-mode capacitor CY2 are connected in series and then in parallel with the differential-mode capacitor CX4; The common end of the common-mode capacitor CY1 and the common-mode capacitor CY2 connected in series is grounded.
[0013] Compared with the prior art, the advantages of the present invention are: It solves the problem of single protection function and complex cascade of current filtering circuits. Through inter-stage optimization design, the lightning protection unit, anti-reverse connection unit and filtering unit are integrated into an integrated composite filtering circuit, which can provide multiple protection functions. Through the coordinated design of various functional circuits, the overall protection and filtering effect of the circuit is enhanced, and the effect of 1+1>2 is achieved. Through the comprehensive design of various functional modules, the multifunctional protection circuit has the advantages of miniaturization and integration, and solves the technical problems of large size and poor coordination of traditional cascade modules. BRIEF DESCRIPTION OF THE DRAWINGS
[0014] Various other advantages and benefits will become apparent to those skilled in the art upon reading the detailed description of the preferred embodiment below. The accompanying drawings are for illustration purposes only and are not to be considered as limiting the present invention. Throughout the drawings, the same reference numerals are used to denote the same components. In the drawings: Figure 1 This is a structural block diagram of a multifunctional protective filter circuit according to Example 1 of the present invention; Figure 2 This is a schematic diagram of a multifunctional protective filter circuit according to Embodiment 2 and Embodiment 3 of the present invention; Reference numerals: 1-lightning protection unit, 2-reverse connection protection unit, 3-filtering unit, 4-surge protection circuit. DETAILED DESCRIPTION
[0015] 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 a part of the embodiments of the present invention, not all of the embodiments. The components of the embodiments of the present invention generally described and shown in the drawings herein can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making creative work are within the scope of protection of the present invention.
[0016] It should be noted that similar numbers and letters represent similar items in the following figures. Therefore, once an item is defined in one figure, it does not need to be further defined or explained in subsequent figures. At the same time, in the description of the present invention, the terms "first" and "second" are used only to distinguish the description and should not be understood as indicating or implying relative importance, or implying any actual relationship or order between these entities or operations. In addition, the terms "connected" and "connected" can refer to direct connection between components or indirect connection through other components. Example
[0017] A multifunctional protection filter circuit, such as Figure 1 As shown, it includes: a lightning protection unit 1, an anti-reverse connection unit 2 and a filter unit 3 which are electrically connected in sequence; Lightning protection unit 1 is mainly used for lightning protection of the entire circuit to prevent lightning energy from damaging the subsequent circuits; The anti-reverse connection unit 2 is mainly used to prevent the circuit from outputting when the circuit input terminal is connected to a reverse power supply, thereby preventing the subsequent circuit from being damaged by the reverse voltage. The filter unit 3 is mainly used to suppress common-mode interference and differential-mode interference in the circuit, and cooperates with the whole machine to meet the electromagnetic compatibility requirements of the system.
[0018] Example 1
[0019] This embodiment is a preferred embodiment of the multifunctional protection filter circuit described in Example 1; like Figure 2 As shown, the lightning protection unit 1 includes: a varistor MOV1, a varistor MOV2, a varistor MOV3, a discharge tube GDT1 and a discharge tube GDT2; The first end of the varistor MOV1 is electrically connected to the first end of the varistor MOV2; The second end of the varistor MOV1 is electrically connected to the first end of the varistor MOV3; The second end of the varistor MOV2 is electrically connected to the first end of the discharge tube GDT1; The second end of the varistor MOV3 is electrically connected to the first end of the discharge tube GDT2; The second end of the discharge tube GDT1 and the second end of the discharge tube GDT2 are both grounded.
[0020] The single-stage unit includes: a voltage dividing resistor R1, a voltage dividing resistor R2, a MOS tube Q1 and a voltage stabilizing diode D1; The first end of the voltage-dividing resistor R1 is electrically connected to the first end of the varistor MOV1; The gate of the MOS transistor, the first end of the voltage-dividing resistor R2 and the cathode of the voltage-stabilizing diode D1 are all electrically connected to the second end of the voltage-dividing resistor R1; The drain of the MOS tube is electrically connected to the first end of the varistor MOV3; The second end of the voltage-dividing resistor R2 and the anode of the voltage-stabilizing diode D1 are both electrically connected to the source of the MOS transistor.
[0021] The filtering unit 3 includes a differential mode module, a common mode inductor L3, a differential mode capacitor module and a common mode capacitor unit which are electrically connected in sequence.
[0022] As a preferred solution of the present invention, the differential mode module includes a differential mode capacitor CX1, a differential mode capacitor CX2, a differential mode inductor L1 and a differential mode inductor L2; The first end of the differential mode capacitor CX1 and the first end of the differential mode inductor L1 are both electrically connected to the first end of the voltage divider resistor R1; The second end of the differential mode capacitor CX1 and the first end of the differential mode inductor L1 are both electrically connected to the anode of the voltage stabilizing diode D1; The second end of the differential mode inductor L1 and the first end of the differential mode capacitor CX2 are both electrically connected to the first end of the common mode inductor L3; The second end of the differential mode inductor L2 and the second end of the differential mode capacitor CX2 are both electrically connected to the second end of the common mode inductor L3.
[0023] The differential mode capacitor module includes a differential mode capacitor CX3, an anti-surge circuit 4 and a differential mode capacitor CX4 which are sequentially connected in parallel to the third end and the fourth end of the common mode inductor L3.
[0024] The surge protection circuit 4 is mainly used for overvoltage protection in the circuit, limiting the overvoltage to below the tolerance value of the subsequent circuit to protect the subsequent circuit from damage caused by overvoltage surge.
[0025] The surge protection circuit 4 includes a transient voltage suppressor diode D2 , which is connected in parallel between the differential mode capacitor CX3 and the differential mode capacitor CX4 .
[0026] The common-mode capacitor module includes a common-mode capacitor CY1 and a common-mode capacitor CY2, wherein the common-mode capacitor CY1 and the common-mode capacitor CY2 are connected in series and then in parallel with the differential-mode capacitor CX4; The common end of the common-mode capacitor CY1 and the common-mode capacitor CY2 connected in series is grounded.
[0027] Example 2
[0028] This embodiment is a multifunctional protective filter circuit as described in Embodiment 1 or 2. The specific working principle is as follows: Working principle of lightning protection unit 1: When the lightning impulse voltage enters Figure 2 In the circuit shown, the lightning current first passes through lightning protection unit 1. Under the influence of overvoltage, the varistor's resistance decreases, becoming low-resistance. The lightning voltage then acts on both ends of the gas discharge tube, breaking it down. This creates a low-resistance flow path from line to varistor, then to ground. The lightning current is discharged to the ground through the varistor and gas discharge tube, thus protecting subsequent circuits from lightning current surges. Simultaneously, the post-stage filter unit 3 and surge protection circuit 4 limit the residual voltage after lightning protection unit 1's protection to below a safe value, enhancing the overall circuit's lightning protection capabilities.
[0029] Working principle of anti-reverse polarity unit 2: When the circuit is connected in the forward direction, the Vin+ voltage acts on both ends of the voltage-dividing resistors R1 and R2, providing a voltage bias for the MOS transistor Q1, so that the gate voltage VGS of the MOS transistor Q1 is greater than its turn-on threshold voltage VGS(th), the MOS transistor is turned on, and a complete power supply circuit is formed; when the circuit is connected in the reverse direction, the Vin+ voltage acts on the drain of the N-channel MOS, the VGS voltage is low, which is lower than the turn-on threshold voltage of the MOS transistor, the MOS transistor Q1 is in the cut-off state, and the power supply circuit is disconnected, thereby preventing the reverse power supply from damaging the load.
[0030] Working Principle of Filter Unit 3: Filter Unit 3 primarily consists of differential-mode capacitors (CX1, CX2, CX3), differential-mode inductors (L1, L2), common-mode capacitors (CY1, CY2), and common-mode inductor (L3). When common-mode interference enters, the π-shaped circuit formed by the common-mode capacitors (CY1, CY2) and common-mode inductor (L3) filters out the common-mode interference. When differential-mode interference enters, the differential-mode capacitors (CX1, CX2, CX3) and differential-mode inductors (L1, L2) filter out the differential-mode interference. Combined with the front-end lightning protection unit 1 to suppress spike interference, this enhances the overall circuit's high-frequency interference suppression capabilities.
[0031] Surge protection circuit 4: This circuit primarily consists of a transient voltage suppressor (TVS) diode (D2). When an overvoltage surge flows across D2, the diode reverses and breaks down, limiting the surge to a safe, stable value. Combined with the front-end lightning protection unit 1 and filter unit 3, this circuit forms a three-stage surge voltage suppression circuit, enhancing the overall voltage suppression capability of the circuit.
[0032] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any appropriate manner without contradiction. In order to avoid unnecessary repetition, the present disclosure will not further describe various possible combinations.
[0033] In addition, the various embodiments of the present disclosure may be arbitrarily combined, and as long as they do not violate the concept of the present disclosure, they should also be regarded as the contents disclosed by the present disclosure.
Claims
1. A multifunctional protective filter circuit, characterized in that: include: A lightning protection unit, an anti-reverse connection unit, and a filter unit electrically connected in sequence; The lightning protection unit is used to protect the entire circuit when a lightning impulse voltage enters; The anti-reverse connection unit is used to prevent the circuit from outputting when a reverse power supply is connected to the circuit input terminal; The filtering unit is used to suppress common-mode interference and differential-mode interference in the circuit, and is combined with the lightning protection unit to suppress peak interference.
2. A multifunctional protective filter circuit according to claim 1, characterized in that: The lightning protection unit includes: a varistor MOV1, a varistor MOV2, a varistor MOV3, a discharge tube GDT1 and a discharge tube GDT2; The first end of the varistor MOV1 is electrically connected to the first end of the varistor MOV2; The second end of the varistor MOV1 is electrically connected to the first end of the varistor MOV3; The second end of the varistor MOV2 is electrically connected to the first end of the discharge tube GDT1; The second end of the varistor MOV3 is electrically connected to the first end of the discharge tube GDT2; The second end of the discharge tube GDT1 and the second end of the discharge tube GDT2 are both grounded.
3. A multifunctional protective filter circuit according to claim 2, characterized in that: The single-stage unit includes: a voltage dividing resistor R1, a voltage dividing resistor R2, a MOS tube Q1 and a voltage stabilizing diode D1; The first end of the voltage-dividing resistor R1 is electrically connected to the first end of the varistor MOV1; The gate of the MOS transistor, the first end of the voltage-dividing resistor R2 and the cathode of the voltage-stabilizing diode D1 are all electrically connected to the second end of the voltage-dividing resistor R1; The drain of the MOS tube is electrically connected to the first end of the varistor MOV3; The second end of the voltage-dividing resistor R2 and the anode of the voltage-stabilizing diode D1 are both electrically connected to the source of the MOS transistor.
4. A multifunctional protective filter circuit according to claim 3, characterized in that: The filtering unit includes a differential mode module, a common mode inductor L3, a differential mode capacitor module and a common mode capacitor unit which are electrically connected in sequence.
5. A multifunctional protective filter circuit according to claim 4, characterized in that: The differential mode module includes a differential mode capacitor CX1, a differential mode capacitor CX2, a differential mode inductor L1 and a differential mode inductor L2; The first end of the differential mode capacitor CX1 and the first end of the differential mode inductor L1 are both electrically connected to the first end of the voltage divider resistor R1; The second end of the differential mode capacitor CX1 and the first end of the differential mode inductor L1 are both electrically connected to the anode of the voltage stabilizing diode D1; The second end of the differential mode inductor L1 and the first end of the differential mode capacitor CX2 are both electrically connected to the first end of the common mode inductor L3; The second end of the differential mode inductor L2 and the second end of the differential mode capacitor CX2 are both electrically connected to the second end of the common mode inductor L3.
6. A multifunctional protective filter circuit according to claim 4, characterized in that: The differential mode capacitor module includes a differential mode capacitor CX3, a surge protection circuit, and a differential mode capacitor CX4, which are sequentially connected in parallel to the third end and the fourth end of the common mode inductor L3.
7. A multifunctional protective filter circuit according to claim 6, characterized in that: The surge protection circuit includes a transient voltage suppression diode D2 , which is connected in parallel between the differential mode capacitor CX3 and the differential mode capacitor CX4 .
8. The multifunctional protective filter circuit according to claim 6, characterized in that: The common-mode capacitor module includes a common-mode capacitor CY1 and a common-mode capacitor CY2, wherein the common-mode capacitor CY1 and the common-mode capacitor CY2 are connected in series and then in parallel with the differential-mode capacitor CX4; The common end of the common-mode capacitor CY1 and the common-mode capacitor CY2 connected in series is grounded.