Protection circuit for reducing power input disturbances

Abstract

The application relates to a power input interference reduction protection circuit. The power input interference reduction protection circuit comprises an input module, a suppression module and a noise reduction module, the suppression module comprises a capacitor CX1 and an inductor L1, a first end of the capacitor CX1 is electrically connected with the input module, a second end of the capacitor CX1 is electrically connected with a first end of the inductor L1; and the noise reduction module is electrically connected with a second end of the inductor L1. The scheme provided by the application can suppress EMI interference noise in a power input circuit.

Description

Technical Field

[0001] This utility model relates to the field of circuit technology, and in particular to a protection circuit for reducing power input interference. Background Technology

[0002] Power modules supply power to electronic products, and the power input circuit plays a crucial role in these modules. However, current power input circuits are prone to EMI interference noise that crosstalks between the power grid and the circuitry. Utility Model Content

[0003] The purpose of this invention is to overcome the shortcomings of the prior art and provide a protection circuit that reduces power input interference and can suppress EMI interference noise in the power input circuit.

[0004] The objective of this utility model is achieved through the following technical solution: The first aspect of this application provides a protection circuit for reducing power input interference, comprising: an input module; a suppression module, including a capacitor CX1 and an inductor L1, wherein a first terminal of the capacitor CX1 is electrically connected to the input module, and a second terminal of the capacitor CX1 is electrically connected to the first terminal of the inductor L1; and a noise reduction module, electrically connected to the second terminal of the inductor L1.

[0005] The input module includes a varistor TVR1, which is used for electrical connection to an external power supply.

[0006] The input module also includes a thermistor NTC1, the first end of which is electrically connected to the varistor TVR1, and the second end of which is electrically connected to the first end of the capacitor CX1.

[0007] The noise reduction module includes a high-frequency filtering unit, which includes capacitor C1 and capacitor C3. The first end of capacitor C1 is electrically connected to the second end of inductor L1, and the second end of capacitor C1 is grounded. The first end of capacitor C3 is electrically connected to the second end of inductor L1, and the second end of capacitor C3 is grounded.

[0008] The noise reduction module also includes an inductor L2, the first end of which is electrically connected to the first end of the capacitor C1 and the first end of the capacitor C3.

[0009] The noise reduction module further includes an intermediate frequency filtering unit, which includes capacitor C2 and capacitor C5. The first end of capacitor C2 is electrically connected to the first end of capacitor C1, the second end of capacitor C2 is electrically connected to the first end of capacitor C3, and the first and second ends of capacitor C5 are respectively electrically connected to the second end of inductor L2.

[0010] The noise reduction module includes a low-frequency filtering unit, which includes capacitor C4 and capacitor C6. The first terminal of capacitor C4 is electrically connected to the first terminal of capacitor C5, and the second terminal of capacitor C4 is grounded. The first terminal of capacitor C6 is electrically connected to the second terminal of capacitor C5, and the second terminal of capacitor C6 is grounded.

[0011] Compared with the prior art, the present invention has at least the following advantages: Capacitor CX1 is connected between the live and neutral wires to suppress common-mode interference from the input power supply and eliminate EMI noise from the AC power grid. Simultaneously, it bypasses high-frequency interference signals from the power grid and transmits them back to the grid, reducing interference noise signals entering subsequent circuits and ensuring voltage stability in those circuits. Inductor L1 has one end connected to both the live and neutral wires of the input terminal, presenting high impedance to the common-mode interference current of the input voltage, thus suppressing EMI interference noise from the power grid. Attached Figure Description

[0012] To more clearly illustrate the technical solutions of the embodiments of this utility model, the accompanying drawings used in the embodiments will be briefly described below.

[0013] Figure 1 This is a functional block diagram of a protection circuit for reducing power input interference in one embodiment of the present invention; Figure 2 This is a circuit diagram of a protection circuit for reducing power input interference in one embodiment of the present invention. Detailed Implementation

[0014] Embodiments of this application will now be described in more detail with reference to the accompanying drawings. While embodiments of this application are shown in the drawings, it should be understood that this application may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided to make this application more thorough and complete, and to fully convey the scope of this application to those skilled in the art.

[0015] It should be understood that although the terms "first," "second," "third," etc., may be used in this application to describe various information, this information should not be limited to these terms. These terms are only used to distinguish information of the same type from one another. For example, without departing from the scope of this application, first information may also be referred to as second information, and similarly, second information may also be referred to as first information. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0016] Unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0017] Power modules supply power to electronic products, and the power input circuit plays a crucial role in these modules. Current power input circuits are prone to EMI interference noise that cross-talks between the power grid and the circuitry.

[0018] To address the aforementioned issues, embodiments of this application provide a protection circuit for reducing power input interference, which can suppress EMI interference noise in the power input circuit.

[0019] The technical solutions of the embodiments of this application are described in detail below with reference to the accompanying drawings.

[0020] See Figure 1 and Figure 2 A protection circuit for reducing power input interference includes: an input module 100, a suppression module 200, and a noise reduction module 300. The suppression module 200 includes a capacitor CX1 and an inductor L1. The first end of the capacitor CX1 is electrically connected to the input module 100, and the second end of the capacitor CX1 is electrically connected to the first end of the inductor L1. The noise reduction module 300 is electrically connected to the second end of the inductor L1.

[0021] It should be noted that the input module 100 is connected to an external power grid, which is 220V AC. The noise reduction module 300 is used for filtering, and the suppression module 200 is used to suppress EMI noise. Furthermore, capacitor CX1 is connected between the live wire and the neutral wire to suppress common-mode interference from the input power supply and eliminate EMI noise from the AC power grid. Simultaneously, it bypasses high-frequency interference signals from the power grid and transmits them back to the grid, reducing the amount of interference noise signals entering subsequent circuits and ensuring voltage stability in those circuits. One end of inductor L1 is connected to both the live wire and the neutral wire, presenting a high impedance to the common-mode interference current of the input voltage, thus suppressing EMI interference noise from the power grid.

[0022] See Figure 2 In one embodiment, the input module 100 includes a varistor TVR1, which is used for electrical connection to an external power supply.

[0023] It is understandable that the varistor TVR1 is used to prevent the circuit board from being damaged by high voltage surges during thunderstorms, and to absorb large currents to protect the downstream circuits from high voltage damage.

[0024] See Figure 2 In one embodiment, the input module 100 further includes a thermistor NTC1, the first end of which is electrically connected to a varistor TVR1, and the second end of which is electrically connected to the first end of a capacitor CX1.

[0025] It is understandable that the thermistor NTC1 plays a role in reducing power consumption.

[0026] See Figure 2 In one embodiment, the noise reduction module 300 includes a high-frequency filtering unit, which includes capacitor C1 and capacitor C3. The first end of capacitor C1 is electrically connected to the second end of inductor L1, and the second end of capacitor C1 is grounded. The first end of capacitor C3 is electrically connected to the second end of inductor L1, and the second end of capacitor C3 is grounded.

[0027] It should be noted that capacitors C1 and C3 can be NPO ceramic capacitors.

[0028] See Figure 2 In one embodiment, the noise reduction module 300 further includes an inductor L2, the first end of which is electrically connected to the first end of capacitor C1 and the first end of capacitor C3, respectively.

[0029] It should be noted that inductor L2 is a common-mode inductor, forming a symmetrical winding with inductor L1. It presents high impedance to common-mode interference and cancels out the magnetic flux of differential-mode signals, thereby improving the electrical compatibility of the circuit.

[0030] See Figure 2 In one embodiment, the noise reduction module 300 further includes an intermediate frequency filtering unit, which includes capacitor C2 and capacitor C5. The first end of capacitor C2 is electrically connected to the first end of capacitor C1, the second end of capacitor C2 is electrically connected to the first end of capacitor C3, and the first and second ends of capacitor C5 are respectively electrically connected to the second end of inductor L2.

[0031] It should be noted that capacitors C2 and C5 can be X7R ceramic capacitors with a capacitance range of 1nF-100μF.

[0032] See Figure 2 In one embodiment, the noise reduction module 300 includes a low-frequency filtering unit, which includes capacitor C4 and capacitor C6. The first end of capacitor C4 is electrically connected to the first end of capacitor C5, and the second end of capacitor C4 is grounded. The first end of capacitor C6 is electrically connected to the second end of capacitor C5, and the second end of capacitor C6 is grounded.

[0033] It should be noted that capacitors C4 and C6 can be aluminum electrolytic capacitors, with capacitance ranging from 1μF to 10000μF.

[0034] The circuit principle of this application is explained below: First, the 220V AC power supply at the input terminal provides the input voltage to the entire circuit. A varistor TVR1 is connected between the live and neutral wires at the input terminal. Under normal operation, the resistance of TVR1 is extremely high and does not affect the power supply voltage input. When a surge voltage occurs in the power grid, the resistance of TVR1 rapidly decreases, short-circuiting the overvoltage to ground, preventing damage from high-voltage surges during thunderstorms. It also absorbs large currents, thus protecting downstream circuits from high-voltage damage. A negative temperature thermistor NTC1 is connected in series with the input terminal circuit and also connected to one end of the TVR1. At room temperature, its resistance is at its maximum, limiting the peak current surge at power-on and preventing excessive backflow at the input terminal from damaging components, thus providing current limiting protection. As the circuit operates, the NTC1 begins to heat up, and its resistance gradually decreases, reducing power consumption during normal operation. Capacitor CX1 connects the live and neutral wires at the input, suppressing common-mode interference from the input power supply and eliminating EMI noise from the AC mains. Simultaneously, it bypasses high-frequency interference signals from the mains and transmits them back to the mains, reducing interference noise signals entering subsequent circuits and ensuring voltage stability. One end of common-mode inductor L1 connects to both the live and neutral wires at the input, presenting high impedance to the common-mode interference current of the input voltage, thus suppressing EMI noise from the mains. The other end of common-mode inductor L1 is then connected to capacitors C1 and C3 for filtering to ground, removing high-frequency interference signals from the input voltage. Capacitor C2 connects between capacitors C1 and C3, eliminating magnetic field interference signals from common-mode inductor L1 itself, acting as a first-stage common-mode filter. The voltage filtered by capacitors C1 and C3 is transmitted to common-mode inductor L2, forming a symmetrical winding with the preceding common-mode inductor L1. This winding presents high impedance to common-mode interference and cancels out differential-mode signal flux, thereby improving the circuit's electrical compatibility. The other end of the common-mode inductor L2 is connected to capacitors C4 and C6 for filtering and grounding, removing low-frequency interference signals from the input voltage and attenuating low-frequency ripple to achieve a stable output voltage. Capacitor C5 is connected between capacitors C4 and C6, eliminating the magnetic field interference signal generated by the common-mode inductor L2 itself. Working in conjunction with capacitor C2, it eliminates interference signals in specific frequency bands generated by the input voltage passing through the circuit, improving the anti-interference capability of the power input circuit, thus acting as a secondary common-mode filter circuit. Subsequently, through the filtering and grounding of all capacitors, interference signals in the input voltage are filtered out, ultimately providing a stable, low-noise voltage to the subsequent circuit at the OUT output. In summary, the circuit of this invention suppresses peak voltage and surge current through protective components, suppresses symmetrical interference through a common-mode filter circuit, and filters out asymmetrical interference and ripple through a differential-mode filter circuit, ultimately outputting a stable power signal, achieving protection and interference suppression for the subsequent circuit.

[0035] The solution of this application has been described in detail above with reference to the accompanying drawings. In the above embodiments, the descriptions of each embodiment have different focuses; for parts not described in detail in a certain embodiment, please refer to the relevant descriptions of other embodiments. Those skilled in the art should also understand that the actions and modules involved in the specification are not necessarily essential to this application. Furthermore, it is understood that the steps in the method of this application embodiment can be adjusted, combined, and deleted according to actual needs, and the modules in the device of this application embodiment can be combined, divided, and deleted according to actual needs. The various embodiments of this application have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen to best explain the principles, practical application, or improvement of the technology in the market, or to enable others skilled in the art to understand the embodiments disclosed herein.

Claims

1. A protection circuit for reducing power input interference, characterized in that, include: Input module; The suppression module includes a capacitor CX1 and an inductor L1. The first end of the capacitor CX1 is electrically connected to the input module, and the second end of the capacitor CX1 is electrically connected to the first end of the inductor L1. The noise reduction module is electrically connected to the second terminal of the inductor L1.

2. The protection circuit for reducing power input interference according to claim 1, characterized in that, The input module includes a varistor TVR1, which is used for electrical connection to an external power supply.

3. The protection circuit for reducing power input interference according to claim 2, characterized in that, The input module also includes a thermistor NTC1, the first end of which is electrically connected to the varistor TVR1, and the second end of which is electrically connected to the first end of the capacitor CX1.

4. The protection circuit for reducing power input interference according to claim 1, characterized in that, The noise reduction module includes a high-frequency filtering unit, which includes capacitor C1 and capacitor C3. The first end of capacitor C1 is electrically connected to the second end of inductor L1, and the second end of capacitor C1 is grounded. The first end of capacitor C3 is electrically connected to the second end of inductor L1, and the second end of capacitor C3 is grounded.

5. The protection circuit for reducing power input interference according to claim 4, characterized in that, The noise reduction module also includes an inductor L2, the first end of which is electrically connected to the first end of the capacitor C1 and the first end of the capacitor C3.

6. The protection circuit for reducing power input interference according to claim 5, characterized in that, The noise reduction module further includes an intermediate frequency filtering unit, which includes capacitor C2 and capacitor C5. The first end of capacitor C2 is electrically connected to the first end of capacitor C1, the second end of capacitor C2 is electrically connected to the first end of capacitor C3, and the first and second ends of capacitor C5 are respectively electrically connected to the second end of inductor L2.

7. The protection circuit for reducing power input interference according to claim 1, characterized in that, The noise reduction module includes a low-frequency filtering unit, which includes capacitor C4 and capacitor C6. The first terminal of capacitor C4 is electrically connected to the first terminal of capacitor C5, and the second terminal of capacitor C4 is grounded. The first terminal of capacitor C6 is electrically connected to the second terminal of capacitor C5, and the second terminal of capacitor C6 is grounded.

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