Communication signal detection circuit adopting magnetic bead filtering

Abstract

The utility model discloses a communication signal detection circuit adopting magnetic bead filtering. The communication signal detection circuit comprises a signal output module, a rectification module, a magnetic bead filtering module, an optocoupler, a level output module and an MCU detection module. The signal output module, the rectification module and the magnetic bead filtering module are electrically connected with the input end of the optocoupler in sequence. When the signal output module outputs a signal, the signal output by the signal output module is rectified by the rectifier module to form a pulsating direct current, the pulsating direct current is filtered by the magnetic bead filter module composed of the magnetic beads, and compared with a common mode inductor for filtering, the magnetic beads can attenuate a high-frequency signal and allow a low-frequency signal to pass at the same time. The magnetic beads are adopted to absorb high-frequency interference signals including high-frequency differential-mode noise on the circuit, so that the electromagnetic compatibility of the product is improved, the size is reduced, and the cost is reduced.

Description

Technical Field

[0001] This utility model belongs to the technical field of electronic circuits, specifically a communication signal detection circuit using magnetic bead filtering. Background Technology

[0002] In circuit design, electromagnetic compatibility has become a hot and difficult issue in electronic design and manufacturing, especially in communication signal circuits. The circuit's anti-interference capability has always been an important standard for evaluating the quality of circuit design. Currently, π-type filters composed of common-mode inductors are often used in circuit design to improve the electromagnetic compatibility of products.

[0003] For example, the patent document "CN107911035A" discloses "a power supply system with multi-section π-type RC filter output". Its technical solution uses a double π-type filter network composed of capacitor C1, common mode inductor L1, capacitor C2, and capacitor C3 to suppress electromagnetic noise and noise signals of the input power supply and prevent interference to the power supply.

[0004] In this patent, the use of a common-mode inductor to suppress noise results in a larger circuit size, and the common-mode inductor has a poor ability to handle high-frequency differential-mode noise. Utility Model Content

[0005] The purpose of this invention is to provide a communication signal detection circuit using magnetic bead filtering to solve the problems mentioned in the background art.

[0006] To achieve the above objectives, this utility model provides the following technical solution:

[0007] A communication signal detection circuit employing ferrite bead filtering includes a signal output module, a rectification module, a ferrite bead filtering module, an optocoupler, a level output module, and an MCU detection module.

[0008] The signal output module, the rectifier module, the ferrite bead filter module and the input terminal of the optocoupler are electrically connected in sequence. The first output terminal of the level output module is electrically connected to the output terminal of the optocoupler, and the second output terminal of the level output module is electrically connected to the MCU detection module.

[0009] The signal output module is used to output communication signals to the optocoupler after passing through the rectification module and the ferrite bead filter module. The level output module is used to output different result levels to the MCU detection module according to the conduction state of the optocoupler. The MCU detection module is used to detect the switching of the signal output module according to the different result levels received.

[0010] In a further technical solution, the magnetic bead filter module includes a magnetic bead FB1, a capacitor C1, and a capacitor C2. The capacitor C1 and the capacitor C2 are connected in series, and one end of the capacitor C1 is electrically connected to the input terminal of the magnetic bead FB1, and one end of the capacitor C2 is electrically connected to the output terminal of the magnetic bead FB1.

[0011] The second terminal of the rectifier module is electrically connected to the capacitor C1 and the ferrite bead FB1. The other terminal of the capacitor C1 is electrically connected to the fourth terminal of the rectifier module, and the other terminal of the capacitor C2 is electrically connected to the fourth terminal of the rectifier module.

[0012] In a further technical solution, the size range of the magnetic bead FB1 is 0402-1206.

[0013] In a further technical solution, a voltage regulator circuit is connected in parallel across the two ends of the light-emitting diode inside the optocoupler. The voltage regulator circuit is used to limit and protect the voltage across the light-emitting diode inside the optocoupler.

[0014] In a further technical solution, the voltage regulator circuit includes a Zener diode, which is connected in antiparallel with the light-emitting diode inside the optocoupler.

[0015] In a further technical solution, the level output module includes an external power supply and a resistor R1, the external power supply and the resistor R1 are electrically connected, the other end of the resistor R1 is electrically connected to the third terminal of the optocoupler, and the fourth terminal of the optocoupler is grounded.

[0016] In a further technical solution, the MCU detection module includes an MCU microprocessor, and the MCU microprocessor is electrically connected to the resistor R1 and the third terminal of the optocoupler via a resistor R2.

[0017] The beneficial effects of this utility model are:

[0018] When a signal is transmitted from the input terminal of the optocoupler to the signal output module, the optocoupler is turned on, allowing the level output module to form a path with the optocoupler. This results in the level transmitted from the level output module to the MCU detection module being low, causing the MCU detection module to display that a signal output from the signal output module has been detected. When no signal is transmitted from the input terminal of the optocoupler to the signal output module, the optocoupler is turned off, preventing the level output module from forming a path with the optocoupler. This results in the level transmitted from the level output module to the MCU detection module being high, causing the MCU detection module to display that no signal output from the signal output module has been detected.

[0019] In addition, when the signal output module outputs a signal, the signal output by the signal output module is first rectified by the rectifier module to form a pulsating DC current. The pulsating DC current is filtered by a ferrite bead filter module composed of ferrite beads. Compared with filtering by common mode inductors, ferrite beads can attenuate higher frequency signals while allowing lower frequency signals to pass. By using ferrite beads to absorb high-frequency interference signals, including high-frequency differential mode noise, on the line, the electromagnetic compatibility of the product is improved, and the size and cost are reduced.

[0020] Other features and advantages of this invention will be described in detail in the following detailed description section. Attached Figure Description

[0021] Figure 1 : Circuit diagram of this utility model.

[0022] Reference numerals: 1. Ferrite bead filter module; 2. Optocoupler; 3. Level output module Detailed Implementation

[0023] The technical solutions in the embodiments of the present invention will be described clearly and completely below with reference to the accompanying drawings in the embodiments of the present invention.

[0024] Please refer to Figure 1 ;

[0025] A communication signal detection circuit using ferrite bead filtering includes a signal output module, a rectifier module, a ferrite bead filtering module 1, an optocoupler 2, a level output module 3, and an MCU detection module; the input terminals of the signal output module, the rectifier module, the ferrite bead filtering module 1, and the optocoupler 2 are electrically connected in sequence; the first output terminal of the level output module 3 is electrically connected to the output terminal of the optocoupler 2; and the second output terminal of the level output module 3 is electrically connected to the MCU detection module.

[0026] In this embodiment, the signal output module is used to output communication signals. The output communication signals are rectified by the rectifier module and converted into pulsating DC signals, which are then transmitted to the ferrite bead filter module 1 for filtering before being output to the optocoupler 2. The level output module 3 is used to output high and low levels to the MCU detection module according to the conduction state of the optocoupler 2. The MCU detection module is used to detect the switching of the signal output module according to the different levels received. In this embodiment, the rectifier module can use a rectifier bridge for rectification. The input terminal of the rectifier bridge is electrically connected to the signal output module, and the output module of the rectifier bridge is electrically connected to the ferrite bead filter module 1. The ferrite bead filter module 1 in this embodiment includes a ferrite bead FB1, a capacitor C1, and a capacitor C2. The capacitors C1 and C2 are connected in series, and one end of the capacitor C1 is electrically connected to the input terminal of the ferrite bead FB1, and one end of the capacitor C2 is electrically connected to the output terminal of the ferrite bead FB1. The second terminal of the rectifier bridge is electrically connected to the capacitor C1 and the ferrite bead FB1, the other end of the capacitor C1 is electrically connected to the fourth terminal of the rectifier bridge, and the other end of the capacitor C2 is electrically connected to the fourth terminal of the rectifier module.

[0027] Specifically, when a signal is transmitted from the input terminal of optocoupler 2 to the signal output module, optocoupler 2 is turned on, allowing the level output module 3 to form a path with optocoupler 2. This results in the level transmitted from the level output module 3 to the MCU detection module being low, causing the MCU detection module to display that a signal output from the signal output module has been detected. Conversely, when no signal is transmitted from the input terminal of optocoupler 2 to the signal output module, optocoupler 2 is turned off, preventing the level output module 3 from forming a path with optocoupler 2. This results in the level transmitted from the level output module 3 to the MCU detection module being high, causing the MCU detection module to display that no signal output has been detected. The signal output by the module; In this embodiment, it is worth noting that when the signal output module has a signal output, the signal output by the signal output module is first rectified by the rectifier bridge to form a pulsating DC current. The pulsating DC current is filtered by a π-type filter composed of a ferrite bead FB1, capacitor C1, and capacitor C2. Compared with the common-mode inductor for filtering, since the ferrite bead FB1 can attenuate higher frequency signals while allowing lower frequency signals to pass, the EMC in the circuit of this embodiment is controlled. The use of the ferrite bead FB1 to absorb high-frequency interference signals, including high-frequency differential-mode noise, on the line improves the electromagnetic compatibility of the product and reduces the size and cost.

[0028] It is worth noting that in this embodiment, the size range of the ferrite bead FB1 is 0402-1206 to better meet the needs of the communication signal detection circuit in this embodiment. In this embodiment, the size of the ferrite bead FB1 is preferably 0603 to better suppress high-frequency noise.

[0029] More specifically, in this embodiment, a voltage regulator circuit is connected in parallel across the two ends of the light-emitting diode inside the optocoupler 2. The voltage regulator circuit is used to limit and protect the voltage across the light-emitting diode inside the optocoupler 2. Preferably, the voltage regulator circuit includes a Zener diode, which is connected in anti-parallel with the light-emitting diode inside the optocoupler 2. The level output module 3 includes an external power supply and a resistor R1, which are electrically connected. The other end of the resistor R1 is electrically connected to the third terminal of the optocoupler 2, and the fourth terminal of the optocoupler 2 is grounded. The MCU detection module includes an MCU microprocessor, and a resistor R2 is electrically connected between the MCU microprocessor, the resistor R1, and the third terminal of the optocoupler 2.

[0030] The working principle of the circuit in this embodiment is as follows: When the signal output module has a signal output, the signal output by the signal output module is first rectified by the rectifier bridge to form a pulsating DC current. The pulsating DC current is filtered by a π-type filter composed of a magnetic bead FB1, capacitor C1 and capacitor C2. The filtered DC current signal passes through the light-emitting diode of optocoupler 2, causing the light-emitting diode to light up, thereby turning on the sensing diode. Then, the external power supply, resistor R1 and sensing diode form a path. Since the sensing diode is grounded, the level of the external power supply transmitted to the MCU microprocessor is low, thereby causing the MCU microprocessor to display that the signal output by the signal output module has been detected.

[0031] When the signal output module has no signal output, no DC signal passes through the LED of optocoupler 2, causing optocoupler 2 to turn off. Consequently, the external power supply, resistor R1, and sensing diode cannot form a circuit, resulting in the signal transmitted by the external power supply to the MCU microprocessor after passing through resistors R1 and R2 being at a high level. This causes the MCU microprocessor to display that no signal output from the signal output module has been detected.

[0032] It will be apparent to those skilled in the art that this invention is not limited to the details of the exemplary embodiments described above, and that it can be implemented in other specific forms without departing from the spirit or essential characteristics of this invention. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of this invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within this invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0033] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style of the specification is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other implementations that can be understood by those skilled in the art.

Claims

1. A communication signal detection circuit employing ferrite bead filtering, characterized in that, It includes a signal output module, a rectification module, a ferrite bead filter module (1), an optocoupler (2), a level output module (3), and an MCU detection module; The signal output module, the rectifier module, the ferrite bead filter module (1) and the input terminal of the optocoupler (2) are electrically connected in sequence. The first output terminal of the level output module (3) is electrically connected to the output terminal of the optocoupler (2). The second output terminal of the level output module (3) is electrically connected to the MCU detection module. The signal output module is used to output communication signals to the optocoupler (2) after passing through the rectification module and the magnetic bead filter module (1). The level output module (3) is used to output different result levels to the MCU detection module according to the conduction state of the optocoupler (2). The MCU detection module is used to detect the switching of the signal output module according to the different result levels received.

2. The communication signal detection circuit using ferrite bead filtering according to claim 1, characterized in that, The magnetic bead filter module (1) includes a magnetic bead FB1, a capacitor C1 and a capacitor C2. The capacitor C1 and the capacitor C2 are connected in series, and one end of the capacitor C1 is electrically connected to the input terminal of the magnetic bead FB1, and one end of the capacitor C2 is electrically connected to the output terminal of the magnetic bead FB1. The second terminal of the rectifier module is electrically connected to the capacitor C1 and the ferrite bead FB1. The other terminal of the capacitor C1 is electrically connected to the fourth terminal of the rectifier module, and the other terminal of the capacitor C2 is electrically connected to the fourth terminal of the rectifier module.

3. The communication signal detection circuit using ferrite bead filtering according to claim 2, characterized in that, The package size range for FB1 magnetic beads is 0402-1206.

4. The communication signal detection circuit using ferrite bead filtering according to claim 1, characterized in that, A voltage regulator circuit is connected in parallel across the two ends of the light-emitting diode inside the optocoupler (2). The voltage regulator circuit is used to limit and protect the voltage across the light-emitting diode inside the optocoupler (2).

5. A communication signal detection circuit using ferrite bead filtering according to claim 4, characterized in that, The voltage regulator circuit includes a Zener diode, which is connected in antiparallel with the light-emitting diode inside the optocoupler (2).

6. A communication signal detection circuit using ferrite bead filtering according to claim 1, characterized in that, The level output module (3) includes an external power supply and a resistor R1. The external power supply and the resistor R1 are electrically connected. The other end of the resistor R1 is electrically connected to the third end of the optocoupler (2). The fourth end of the optocoupler (2) is grounded.

7. A communication signal detection circuit using ferrite bead filtering according to claim 6, characterized in that, The MCU detection module includes an MCU microprocessor, and the MCU microprocessor is electrically connected to the resistor R1 and the third terminal of the optocoupler (2) by a resistor R2.

Images