EMI filter circuit, electronic equipment and vehicle

Abstract

The present application provides an EMI filter circuit, an electronic device and a vehicle, wherein the EMI filter circuit includes an initial filter subcircuit and an active filter subcircuit; the active filter subcircuit includes an active element; the initial filter subcircuit is used to filter out the low-frequency component of the EMI signal on the power line to obtain an EMI signal with a high-frequency component retained; the active filter subcircuit is used to generate an anti-phase interference signal according to the detected noise signal on the power line to filter out the noise signal. The EMI filter circuit in the present application can more effectively suppress electromagnetic interference caused by rapid load changes on the power line or signal line. Therefore, the present application can adapt to dynamic electromagnetic environments. Furthermore, since the present application can more effectively utilize the active elements in the active filter subcircuit to enhance the filtering performance, other parts of the EMI filter circuit in the present application can use capacitors and inductors of smaller sizes, so the circuit in the present application occupies less space as a whole and can be miniaturized.

Description

Technical Field

[0001] The present application relates to the technical field of circuit structures, and in particular to an EMI filter circuit, an electronic device and a vehicle. Background Art

[0002] With the development of the automotive industry, complex electronic devices such as advanced driver assistance systems, electric vehicle control systems, and infotainment systems inside vehicles act as electromagnetic radiation sources, generating a large amount of electromagnetic radiation, making the electromagnetic interference (EMI) problem in vehicles more prominent. The EMI of vehicles not only comes from electromagnetic sources inside the vehicle, but also from electromagnetic sources outside the vehicle. If EMI is not effectively managed, various systems or devices inside the vehicle may not function properly, and in serious cases, it may endanger driving safety.

[0003] Currently, passive EMI filters are used to block or absorb EMI noise signals through passive components such as inductors, capacitors and resistors, but they have obvious limitations in dealing with high-frequency interference, achieving miniaturization and adapting to dynamic electromagnetic environments. Utility Model Content

[0004] Based on this, the present application provides an EMI filtering circuit, an electronic device and a vehicle, which are used to provide an EMI filtering technical solution that can handle high-frequency interference, achieve miniaturization and adapt to dynamic electromagnetic environments.

[0005] In a first aspect, the present application provides an EMI filter circuit, which includes an initial filter subcircuit and an active filter subcircuit; the initial filter subcircuit and the active filter subcircuit are connected, the input end of the initial filter subcircuit is used to connect to an external switching power supply, and the output end of the active filter subcircuit is used to connect to an external DC power supply system; wherein the external switching power supply is connected to the external DC power supply system via a power line, and the active filter subcircuit includes active elements.

[0006] The initial filtering subcircuit is used to filter out the low-frequency component of the EMI signal on the power line to obtain the EMI signal with the high-frequency component retained.

[0007] The active filtering subcircuit is used to generate an anti-phase interference signal according to the detected noise signal to filter out the noise signal; wherein the noise signal includes a high-frequency component of the EMI signal.

[0008] In an optional implementation, the initial filtering subcircuit includes an oscillation unit and a damping unit.

[0009] The first end of the oscillation unit is used to be connected to the external switching power supply, and the second end is grounded through the damping unit.

[0010] In an optional implementation, the oscillation unit includes a first inductor and a first capacitor;

[0011] The first inductor is connected between the external switching power supply and the active filtering sub-circuit, the first end of the first capacitor is connected between the first inductor and the active filtering sub-circuit, and the second end is grounded through the damping unit.

[0012] And / or, the damping unit includes a first resistor.

[0013] The first resistor is connected between the oscillation unit and a ground terminal.

[0014] In an optional implementation, the EMI filtering circuit further includes a feedback isolation subcircuit, and the feedback isolation subcircuit is connected between the initial filtering subcircuit and the active filtering subcircuit.

[0015] The feedback isolation subcircuit is used to feed back the high-frequency component in the EMI signal to the active filtering subcircuit.

[0016] In an optional implementation, the feedback isolation subcircuit includes a first feedback isolation unit and a second feedback isolation unit.

[0017] The first feedback isolation unit is connected between the output end of the initial filtering subcircuit and the input end of the active filtering subcircuit, and the second feedback isolation unit is connected between the output end of the active filtering subcircuit and the output end of the initial filtering subcircuit.

[0018] In an optional implementation manner, the first feedback isolation unit includes a second capacitor, and the second feedback isolation unit includes a third capacitor and a second resistor connected to each other.

[0019] The second capacitor is connected between the output end of the initial filtering subcircuit and the input end of the active filtering subcircuit.

[0020] The first end of the third capacitor is connected to the output end of the active filtering subcircuit through the second resistor, and the second end of the third capacitor is connected to the output end of the initial filtering subcircuit.

[0021] In an optional implementation, the feedback isolation sub-circuit further includes a compensation unit, a first end of the compensation unit is connected between the first feedback isolation unit and the input end of the active filtering sub-circuit, and a second end of the compensation unit is connected between the output end of the active filtering sub-circuit and the second feedback isolation unit.

[0022] In an optional implementation, the compensation unit includes a fourth capacitor, a third resistor and a fourth resistor.

[0023] The first end of the fourth capacitor is connected between the first feedback isolation unit and the input end of the active filtering sub-circuit, and the second end is connected between the output end of the active filtering sub-circuit and the second feedback isolation unit through the third resistor.

[0024] The first end of the fourth resistor is connected between the first feedback isolation unit and the input end of the active filtering sub-circuit, and the second end of the fourth resistor is connected between the output end of the active filtering sub-circuit and the second feedback isolation unit.

[0025] In a second aspect, the present application provides an electronic device, comprising the EMI filtering circuit of the first aspect.

[0026] In a third aspect, the present application provides a vehicle, comprising the electronic device of the second aspect.

[0027] The initial filtering subcircuit in the EMI filtering circuit provided by the present application can filter out the low-frequency components of the EMI signal on the power line, and the active filtering subcircuit can filter out the noise signal including the high-frequency components of the EMI signal. Therefore, the EMI filtering circuit provided by the present application can effectively prevent the EMI signal from interfering with the external DC power supply system. Since the active filtering subcircuit includes active components, and the active components can quickly adjust their outputs to cope with the rapid changes of the input signal. This enables the EMI filtering circuit in the present application to more effectively suppress the electromagnetic interference caused by rapid load changes on the power line. Therefore, the present application can dynamically adjust the electromagnetic interference and adapt to the dynamic electromagnetic environment.

[0028] Furthermore, since the present application can utilize active components in the active filtering subcircuit to enhance filtering performance, other parts of the EMI filtering circuit in the present application can use smaller capacitors and inductors. Therefore, the circuit in the present application occupies less space as a whole, which is conducive to miniaturization, and is not easy to fall off during vibration and drop tests, and has the advantages of low cost and high reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0030] Figure 1 It is a structural diagram of a passive filtering circuit applied to an automotive domain controller in the prior art;

[0031] Figure 2 The active EMI filter circuit control topology diagram provided in the embodiment of the present application;

[0032] Figure 3 Schematic diagram of the structure of the EMI filter circuit provided in the embodiment of the present application Figure 1 ;

[0033] Figure 4 Schematic diagram of the structure of the EMI filter circuit provided in the embodiment of the present application Figure 2 .

[0034] The above drawings have shown clear embodiments of the present application, which will be described in more detail later. These drawings and text descriptions are not intended to limit the scope of the present application in any way, but to illustrate the concept of the present application to those skilled in the art by referring to specific embodiments. DETAILED DESCRIPTION

[0035] Exemplary embodiments will be described in detail herein, examples of which are shown in the accompanying drawings. When the following description refers to the drawings, the same numbers in different drawings represent the same or similar elements unless otherwise indicated. The implementations described in the following exemplary embodiments do not represent all implementations consistent with the present application. Instead, they are merely examples of devices and methods consistent with some aspects of the present application as detailed in the appended claims.

[0036] It should be noted that, in this article, the terms "include", "comprises" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "includes a ..." does not exclude the existence of other identical elements in the process, method, article or device including the element. In addition, components, features, and elements with the same name in different embodiments of the present application may have the same meaning or different meanings, and their specific meanings need to be determined by their explanation in the specific embodiment or further combined with the context of the specific embodiment.

[0037] It should be understood that, although the terms first, second, third, etc. may be used to describe various information in this article, these information should not be limited to these terms. These terms are only used to distinguish the same type of information from each other. For example, without departing from the scope of this article, the first information may also be referred to as the second information, and similarly, the second information may also be referred to as the first information. Depending on the context, the word "if" as used herein can be interpreted as "at the time of" or "when" or "in response to determination". Furthermore, as used in this article, the singular forms "one", "one" and "the" are intended to also include plural forms, unless there is an opposite indication in the context. It should be further understood that the terms "comprising", "including" indicate the existence of features, steps, operations, elements, components, projects, kinds, and / or groups, but do not exclude the existence, occurrence or addition of one or more other features, steps, operations, elements, components, projects, kinds, and / or groups. The terms "or", "and / or", "including at least one of the following" etc. used in this application can be interpreted as inclusive, or mean any one or any combination. For example, “comprising at least one of the following: A, B, C” means “any of the following: A; B; C; A and B; A and C; B and C; A and B and C”, and for another example, “A, B or C” or “A, B and / or C” means “any of the following: A; B; C; A and B; A and C; B and C; A and B and C”. An exception to this definition will only occur when a combination of elements, functions, steps or operations are inherently mutually exclusive in some manner.

[0038] It should be understood that, although the various steps in the flowchart in the embodiment of the present application are displayed in sequence according to the indication of the arrows, these steps are not necessarily performed in sequence according to the order indicated by the arrows. Unless there is a clear explanation in this article, the execution of these steps does not have a strict order restriction, and it can be performed in other orders. Moreover, at least a portion of the steps in the figure may include a plurality of sub-steps or a plurality of stages, and these sub-steps or stages are not necessarily performed at the same time, but can be performed at different times, and their execution order is not necessarily performed in sequence, but can be performed in turn or alternately with other steps or at least a portion of the sub-steps or stages of other steps.

[0039] As used herein, the words "if" and "if" may be interpreted as "at the time of" or "when" or "in response to determining" or "in response to detecting", depending on the context. Similarly, the phrases "if it is determined" or "if (stated condition or event) is detected" may be interpreted as "when it is determined" or "in response to determining" or "when detecting (stated condition or event)" or "in response to detecting (stated condition or event)", depending on the context.

[0040] It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0041] With the development of the automotive industry, complex electronic devices such as advanced driver assistance systems, electric vehicle control systems, and infotainment systems inside vehicles act as electromagnetic radiation sources, generating a large amount of electromagnetic radiation, making the electromagnetic interference (EMI) problem in vehicles more prominent. The EMI of vehicles not only comes from electromagnetic sources inside the vehicle, but also from electromagnetic sources outside the vehicle. If EMI is not effectively managed, various systems or devices inside the vehicle may not function properly, and in serious cases, it may endanger driving safety.

[0042] Traditional passive EMI filters block or absorb noise signals through passive components such as inductors, capacitors and resistors. Figure 1 A structure diagram of a passive filtering circuit applied to a car domain controller is shown, Figure 1 As shown, the passive filter circuit includes a capacitor C located between the switching power supply and the battery. FB , C F , C IN1 , C BULK , C IN2 , C HF , inductance L L , common mode inductance L M , magnetic beads R C , where the common mode inductor L M , capacitor C FB , C F , C IN1 , C BULK , C IN2 , C HF Connected in parallel between the battery and the switching power supply, the inductor L L Series in C F and C IN1 Between the beads R C Series in C FB , C F Although these components are relatively simple to implement, they have the following limitations when applied to the automotive industry, especially in the field of smart vehicles:

[0043] In the application scenario of smart vehicles, the operating current of the domain controller is large, and an inductor with a high current resistance value is required. In addition, considering reliability, the port capacitor needs to use a soft terminal capacitor or two capacitors in series. Therefore, it will bring high material costs.

[0044] In the automotive industry, there is often high-power interference. In order to effectively suppress high-power interference, the inductor and capacitor components required by passive filters are often large in size, which is not conducive to the automotive industry's demand for miniaturization and lightweight equipment. In addition, as the density of electronic devices increases, space becomes a major limiting factor. And passive filters lack active adjustment mechanisms to respond instantly to changes in interference in the environment. They cannot adjust the filtering characteristics according to real-time interference signals, which is particularly insufficient in dynamic and unpredictable electromagnetic environments.

[0045] In order to solve the above problems, on the first hand, the present application provides an EMI filter circuit, which introduces active components, such as operational amplifiers or control circuits, and requires a large number of capacitors, inductors and other devices compared to passive filters. It is not only less expensive, but also can offset the interference signals transmitted by the circuit, and dynamically adjust the filtering characteristics according to the specific characteristics of the interference signals. Based on this, the filtering effect is significantly improved, especially the performance in the high-frequency range, which is more in line with the needs of modern vehicle electronic systems.

[0046] like Figure 2 As shown, a control topology diagram of the active EMI filter circuit proposed in the present application is shown. The principle is that the active EMI filter circuit detects the noise interference between the switching power supply and the DC power supply system, and outputs an inverted signal to offset the noise. The active EMI filter circuit can dynamically adjust the filtering characteristics of the filter circuit according to the actual noise.

[0047] Figure 3 Schematic diagram of the structure of the EMI filter circuit provided in this application Figure 1 ,like Figure 3 As shown, the EMI filter circuit includes an initial filter subcircuit 10 and an active filter subcircuit 20, and the initial filter subcircuit 10 is connected to the active filter subcircuit 20. In the application process, the input end of the initial filter subcircuit 10 can be connected to an external switching power supply, and the output end of the active filter subcircuit 20 can be connected to an external DC power supply system, and the external switching power supply is connected to the external DC power supply system through a power line. Among them, the switching power supply (Switch Mode Power Supply, referred to as SMPS), also known as a switching power supply, a switching converter, is a high-frequency power conversion device and a type of power supply. Its function is to convert a voltage of a level into a voltage or current required by the user end through different forms of architecture. The input of the switching power supply is mostly an AC power supply (such as a mains power supply) or a DC power supply, and the output is mostly a device or system that requires a DC power supply, such as a battery of a new energy vehicle, or a generator, and the switching power supply is used to convert the voltage and current between the two. The above-mentioned external DC power supply system can be the above-mentioned car battery, generator, etc.

[0048] The above-mentioned initial filtering subcircuit 10 is used to filter out the low-frequency component of the EMI signal between the switching power supply and the external DC power supply system, and obtain an EMI signal that retains the high-frequency component. Among them, the initial filtering subcircuit can be composed of passive components to simplify the implementation method. The above-mentioned active filtering subcircuit 20 is used to generate an anti-phase interference signal based on the detected noise signal on the power line to filter out the noise signal; wherein the noise signal includes the high-frequency component of the EMI signal. Based on the above-mentioned initial filtering subcircuit 10 and active filtering subcircuit 20, this embodiment can filter out the EMI signal on the power line to prevent the EMI signal from interfering with the back-end DC power supply system.

[0049] The active filtering subcircuit 20 in this embodiment includes active components. It should be understood that the active components can quickly adjust their outputs to cope with rapid changes in input signals. This enables this embodiment to more effectively suppress electromagnetic interference caused by rapid load changes on power lines or signal lines. It is especially suitable for application scenarios that need to deal with high-speed signals or frequently changing loads. Therefore, the present application can dynamically adjust electromagnetic interference and adapt to dynamic electromagnetic environments. And because the active components have adjustment flexibility, it can be shown that through simple circuit adjustment or programming, its own adjustment characteristics can be modified to optimize its suppression effect on specific frequency interference. Therefore, the circuit of this embodiment can be adapted to a variety of different application scenarios.

[0050] Based on the filtering performance of active components, other structures in the circuit of this embodiment can use smaller sizes and fewer passive components (such as capacitors and inductors), which means that when achieving the same filtering effect, the physical size of the circuit in this embodiment and the number of components used can be smaller, thereby reducing material costs. Furthermore, based on the smaller size and fewer number of passive components, the circuit in this embodiment is more easily integrated into a circuit board and easier to integrate with other electronic systems, which helps to reduce additional assembly and processing steps, thereby reducing production costs, and is not easy to fall off during vibration and drop tests, and has the advantages of low cost and high reliability.

[0051] Furthermore, based on the smaller size and fewer number of passive components, the circuit in this embodiment can be applied to space-constrained devices, such as electronic devices for automotive applications or portable devices. In addition, this embodiment can optimize the overall performance of the circuit by adjusting the parameters of the active components without adding additional physical space, which is conducive to applying the circuit in this application to other scenarios.

[0052] Optional, see Figure 3 The initial filtering subcircuit may include an oscillating unit 101 and a damping unit 102. A first end of the oscillating unit 101 is used to be connected to an external switching power supply, and a second end thereof is grounded through the damping unit 102.

[0053] The oscillation unit 101 is used to filter out the low-frequency components of the EMI signal on the power line and allow the high-frequency components of the EMI signal to pass through. The damping unit 102 is used to eliminate the resonance generated by the oscillation unit 101 to reduce the addition of other noises and avoid the influence of other noises on the circuit itself.

[0054] The above-mentioned oscillation unit can adopt any structure that can filter out the low-frequency components in the EMI signal, and the above-mentioned damping unit can adopt any structure that can eliminate the resonance generated by the oscillation unit, and the embodiments of the present application do not make specific limitations on this.

[0055] For example, refer to Figure 3 The oscillating unit 101 includes a first inductor L1 and a first capacitor C1. The damping unit 102 includes a first resistor R1.

[0056] The first inductor L1 is connected between the external switching power supply and the active filtering sub-circuit 20 . The first end of the first capacitor C1 is connected between the first inductor L1 and the active filtering sub-circuit 20 , and the second end is grounded through the first resistor R1 .

[0057] The first inductor L1 and the first capacitor C1 form an LC filter, which is used to filter out the low-frequency components of the EMI signal on the power line and allow the high-frequency components of the EMI signal to pass. However, during the filtering process, the LC filter will produce resonance, which will affect the circuit itself. This embodiment uses the first resistor R1 as a damping resistor to eliminate the resonance generated by the LC filter. Among them, the resistance value of the first resistor R1 needs to satisfy the following formula:

[0058] When the active element is an operational amplifier, the resistance of the first resistor satisfies Among them, G op represents the gain of the amplifier, L1 represents the inductance value of the first inductor, and C1 represents the capacitance value of the first capacitor.

[0059] Figure 4 The structure of the EMI filter circuit provided by the present application is shown in FIG. Figure 2 ,like Figure 4 As shown, the EMI filtering circuit further includes a feedback isolation subcircuit 30, which is connected between the initial filtering subcircuit 10 and the active filtering subcircuit 20, and is used to feed back at least the high-frequency component in the EMI signal to the active filtering subcircuit 20, so as to utilize the active filtering subcircuit to filter out the high-frequency component in the EMI signal.

[0060] Optional, such as Figure 4As shown, the feedback isolation subcircuit 30 comprises a first feedback isolation unit 301 and a second feedback isolation unit 302. The first feedback isolation unit 301 is connected between the output end of the initial filtering subcircuit 10 and the input end of the active filtering subcircuit 20. The second feedback isolation unit 302 is connected between the output end of the active filtering subcircuit 20 and the output end of the initial filtering subcircuit 10.

[0061] In this embodiment, if Figure 4 As shown, the first feedback isolation unit 301 and the second feedback isolation unit 302 can isolate the active filter sub-circuit from an external power supply network formed by an external switching power supply and an external DC power supply system.

[0062] In practical applications, such as Figure 4 As shown, the first feedback isolation sub-unit 301 is used to isolate the DC signal in the high-frequency component of the EMI signal, and pass the AC signal in the high-frequency component of the EMI signal to the active filter sub-circuit. The anti-phase interference signal output by the active filter sub-circuit 20 is output to the power line through the second feedback isolation unit 302, and is offset by the EMI signal existing in the power supply itself. The second feedback isolation unit 302 is combined with the first feedback isolation sub-unit 301 to isolate the active filter sub-circuit 20 from the power supply network, and the second feedback isolation unit 302 is also used to further filter the low-frequency component of the EMI signal between the switching power supply and the external DC power supply system.

[0063] The first feedback isolation unit 301 and the second feedback isolation unit 302 may adopt any structure capable of isolating the DC signal in the high-frequency component of the EMI signal, which is not specifically limited in the embodiment of the present application.

[0064] For example, Figure 4 As shown, the first feedback isolation unit 301 includes a second capacitor C2. The second feedback isolation unit 302 includes a third capacitor C3 and a second resistor R2 connected to each other.

[0065] like Figure 4 As shown, the second capacitor C2 is connected between the output end of the initial filtering subcircuit 10 and the input end of the active filtering subcircuit 20. It should be understood that the second capacitor C2 can isolate the DC signal in the high-frequency component of the EMI signal and pass the AC signal in the high-frequency component of the EMI signal to the active filtering subcircuit.

[0066] like Figure 4As shown, the first end of the third capacitor C3 is connected to the output end of the active filter subcircuit 20 through the second resistor R2, and the second end is connected to the output end of the initial filter subcircuit 10. The anti-phase interference signal output by the active filter subcircuit 20 is output to the power line after passing through the second resistor R2 and the third capacitor C3. The third capacitor C3 can form an LC filter with the first inductor L1 to further filter the low-frequency component of the EMI signal on the power line. The second resistor R2 is used to limit the open-loop gain of the operational amplifier. Based on this, the second resistor Among them, G op represents the open-loop gain of the amplifier, L1 represents the inductance value of the first inductor in the initial filtering circuit, and C3 represents the capacitance value of the third capacitor.

[0067] In some examples, such as Figure 4 As shown, the feedback isolation subcircuit 30 further includes a compensation unit 303, a first end of the compensation unit 303 is connected between the first feedback isolation unit 301 and the input end of the active filtering subcircuit 10, and a second end of the compensation unit 303 is connected between the output end of the active filtering subcircuit 20 and the second feedback isolation unit 302. The compensation unit is used to improve the stability of the closed-loop network composed of the active filtering subcircuit and the feedback isolation subcircuit.

[0068] The compensation unit 303 may adopt any structure that can improve the stability of the closed-loop network composed of the active filtering sub-circuit and the feedback isolation sub-circuit, and the embodiment of the present application does not specifically limit this.

[0069] For example, Figure 4 As shown, the compensation unit 303 includes a fourth capacitor C4, a third resistor R3 and a fourth resistor R4; a first end of the fourth capacitor C4 is connected between the first feedback isolation unit 301 and the input end of the active filtering sub-circuit 20, and a second end is connected between the output end of the active filtering sub-circuit 20 and the second feedback isolation unit 302 through the third resistor R3. A first end of the fourth resistor R4 is connected between the first feedback isolation unit 301 and the input end of the active filtering sub-circuit 20, and a second end is connected between the output end of the active filtering sub-circuit 20 and the second feedback isolation unit 302.

[0070] The fourth resistor R4 is used to limit the open-loop gain of the operational amplifier; the third resistor R3 is used to fine-tune the open-loop gain of the operational amplifier. The compensation unit 303 formed by the third resistor R3, the fourth resistor R4 and the fourth capacitor C4 is used to improve the stability of the closed-loop network composed of the active filter subcircuit and the feedback isolation subcircuit.

[0071] Optionally, when the active element is an operational amplifier, G op ≈C2 / C4; where G oprepresents the gain of the operational amplifier, C2 represents the capacitance value of the second capacitor, and C4 represents the capacitance value of the fourth capacitor.

[0072] This embodiment supports the operational amplifier to filter out high-frequency noise by configuring inductors and capacitors, and controls the amplitude and phase of the signal input to the active filter subcircuit through the above circuit structure, thereby ensuring the stable operation of the entire circuit.

[0073] It is worth noting that the active element in the present application can be any noise signal between the switching power supply and the external DC power supply system that can be detected, generating an anti-phase interference signal to filter out the structure of the noise signal, and the embodiments of the present application do not make specific limitations on this.

[0074] Exemplarily, the active element is an operational amplifier, the noise on the power line enters the operational amplifier through the second capacitor C2, and then the operational amplifier outputs an inverted signal through the second resistor R2 and the third capacitor C3 to offset the noise on the power line. The second capacitor C2, the second resistor R2 and the third capacitor C3 can isolate the operational amplifier from the power network. The fourth capacitor C4, the third resistor R3 and the fourth resistor R4 in the compensation unit are compensation units for improving the stability of the circuit.

[0075] In this embodiment, the active filtering subcircuit and the feedback isolation subcircuit can be equivalent to a capacitor with a variable capacitance, and the equivalent impedance reference formula is:

[0076]

[0077] Among them, Z AEF is the equivalent impedance, Z OP is the output impedance of the operational amplifier, Z damp is the impedance of the second resistor R2, Z INJ is the impedance of the third capacitor C3, G OP is the gain of the operational amplifier.

[0078] Based on the above, since the circuit of this embodiment can more effectively utilize active components to enhance the filtering performance of the circuit, smaller capacitors and inductors can be used in both the initial filtering subcircuit and the feedback isolation subcircuit in the circuit. This means that when achieving the same filtering effect, the physical size of the circuit in this embodiment and the number of components used can be smaller, thereby reducing material costs and enabling the circuit to be applied to space-constrained applications such as automotive electronics or portable devices.

[0079] Furthermore, based on the use of smaller size and fewer passive components in the circuit of this embodiment, the circuit in this embodiment is more easily integrated onto a circuit board and is easier to integrate with other electronic systems, which helps to reduce additional assembly and processing steps, thereby reducing production costs.

[0080] Furthermore, based on the smaller size and fewer number of passive components, the circuit in this embodiment can be applied to space-constrained devices, such as electronic devices for automotive applications or portable devices. In addition, this embodiment can optimize the overall performance of the circuit by adjusting the parameters of the active components without adding additional physical space, which is conducive to applying the circuit in this application to other scenarios.

[0081] In a second aspect, an embodiment of the present application further provides an electronic device, which includes the EMI filter circuit in the first aspect. The electronic device may also include a control unit for adjusting parameters of active components (such as operational amplifiers) to adapt to circuit application scenarios.

[0082] In the embodiment of the present application, the above-mentioned electronic device may be, for example, a complex electronic device equipped with an advanced driver assistance system (ADAS), an electric vehicle control system, and an infotainment system widely used inside a vehicle, such as a vehicle domain controller.

[0083] In a third aspect, an embodiment of the present application further provides a vehicle, which includes the electronic device in the first aspect.

[0084] Those skilled in the art will readily appreciate other embodiments of the present application after considering the specification and practicing the utility model disclosed herein. The present application is intended to cover any variations, uses or adaptations of the present application, which follow the general principles of the present application and include common knowledge or customary techniques in the art that are not disclosed in the present application. The specification and examples are intended to be exemplary only, and the true scope and spirit of the present application are indicated by the following claims.

[0085] It should be understood that the present application is not limited to the precise structures that have been described above and shown in the drawings, and that various modifications and changes may be made without departing from the scope thereof. The scope of the present application is limited only by the appended claims.

Claims

1. An EMI filter circuit, characterized in that: The EMI filter circuit includes an initial filter subcircuit and an active filter subcircuit; the initial filter subcircuit and the active filter subcircuit are connected, the input end of the initial filter subcircuit is used to connect to an external switching power supply, and the output end of the active filter subcircuit is used to connect to an external DC power supply system; wherein the external switching power supply is connected to the external DC power supply system via a power line, and the active filter subcircuit includes active components; The initial filtering subcircuit is used to filter out the low-frequency component of the EMI signal on the power line to obtain an EMI signal with high-frequency components retained; The active filtering subcircuit is used to generate an anti-phase interference signal according to the detected noise signal on the power line to filter out the noise signal; wherein the noise signal includes a high-frequency component of the EMI signal.

2. The EMI filter circuit according to claim 1, characterized in that: The initial filtering subcircuit includes an oscillation unit and a damping unit; The first end of the oscillation unit is used to be connected to the external switching power supply, and the second end is grounded through the damping unit.

3. The EMI filter circuit according to claim 2, characterized in that: The oscillation unit includes a first inductor and a first capacitor; The first inductor is connected between the external switching power supply and the active filtering subcircuit, the first end of the first capacitor is connected between the first inductor and the active filtering subcircuit, and the second end is grounded through the damping unit; And / or, the damping unit includes a first resistor; The first resistor is connected between the oscillation unit and a ground terminal.

4. The EMI filter circuit according to claim 1, characterized in that: The EMI filter circuit further includes a feedback isolation subcircuit, wherein the feedback isolation subcircuit is connected between the initial filter subcircuit and the active filter subcircuit; The feedback isolation subcircuit is used to feed back the high-frequency component in the EMI signal to the active filtering subcircuit.

5. The EMI filter circuit according to claim 4, characterized in that: The feedback isolation subcircuit comprises a first feedback isolation unit and a second feedback isolation unit; The first feedback isolation unit is connected between the output end of the initial filtering subcircuit and the input end of the active filtering subcircuit, and the second feedback isolation unit is connected between the output end of the active filtering subcircuit and the output end of the initial filtering subcircuit.

6. The EMI filter circuit according to claim 5, characterized in that: The first feedback isolation unit includes a second capacitor, and the second feedback isolation unit includes a third capacitor and a second resistor connected to each other; The second capacitor is connected between the output end of the initial filtering subcircuit and the input end of the active filtering subcircuit; The first end of the third capacitor is connected to the output end of the active filtering subcircuit through the second resistor, and the second end of the third capacitor is connected to the output end of the initial filtering subcircuit.

7. The EMI filter circuit according to claim 5, characterized in that: The feedback isolation subcircuit also includes a compensation unit, a first end of the compensation unit is connected between the first feedback isolation unit and the input end of the active filtering subcircuit, and a second end of the compensation unit is connected between the output end of the active filtering subcircuit and the second feedback isolation unit.

8. The EMI filter circuit according to claim 7, characterized in that: The compensation unit includes a fourth capacitor, a third resistor and a fourth resistor; The first end of the fourth capacitor is connected between the first feedback isolation unit and the input end of the active filtering sub-circuit, and the second end is connected between the output end of the active filtering sub-circuit and the second feedback isolation unit through the third resistor; The first end of the fourth resistor is connected between the first feedback isolation unit and the input end of the active filtering sub-circuit, and the second end of the fourth resistor is connected between the output end of the active filtering sub-circuit and the second feedback isolation unit.

9. An electronic device, characterized in that: The EMI filter circuit comprises the EMI filter circuit described in any one of claims 1 to 8.

10. A vehicle, characterized in that: An electronic device comprising the electronic device described in claim 9.

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