Adapter filter circuit for high frequency signal transmission interference and adapter

Abstract

The utility model relates to power adapter technical field discloses an adapter filters high frequency signal transmission interference circuit and adapter including rectifier bridge BD1, capacitor CX1, capacitor C1, capacitor C2, capacitor C3, capacitor C4, capacitor C5, capacitor C6, capacitor C7, capacitor C8, capacitor C9, resistance R1, resistance R2, resistance R3, resistance R4, resistance R5, resistance R6, resistance R8, resistance R9, resistance R10, resistance R11, resistance R12, resistance R13, resistance R14, resistance R15, common mode inductance LF1, inductance L1, PWM control chip U1, diode D1, diode D2, diode D3, diode D4, diode D5, diode D6, diode D43, diode D44, transformer T1, Y1 capacitor CY1, Y1 capacitor CY2, fuse F1, piezoresistance MOV. The utility model can effectively reduce the interference of high frequency signal to ac circuit, improve the electromagnetic compatibility of power, and circuit structure is simple, and the small shell space is occupied, and the cost is low.

Description

Technical Field

[0001] This utility model relates to the field of power adapter technology, and in particular to an adapter circuit and adapter for filtering high-frequency signal conduction interference. Background Technology

[0002] A power adapter is a power conversion device for small portable electronic devices and appliances. Also called an external power supply, it is a voltage conversion device for small portable electronic devices and appliances. It is commonly found in small electronic products such as mobile phones, LCD monitors, and laptops. With the progress of society, there are more and more types of electronic products, and therefore more and more power adapters.

[0003] The main function of the interference filtering circuit in an adapter is to prevent interference signals generated inside the adapter from being conducted to the power grid, or to prevent interference signals from the power grid from being conducted to the adapter. Existing interference filtering circuits in adapters generally fall into two categories: one involves adding a common-mode inductor before the bridge rectifier (BD1) to filter conducted interference; the other involves placing a ferrite core on the output DC line. Both of these circuits occupy a significant amount of space in the casing and are costly. Utility Model Content

[0004] Based on the above, the purpose of this utility model is to provide an adapter circuit and adapter for filtering high-frequency signal conduction interference, which can effectively filter high-frequency signal conduction interference, improve the electromagnetic compatibility of the power adapter, and has a simple circuit structure, small footprint, and low cost.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] On the one hand, this utility model provides an adapter circuit for filtering high-frequency signal conduction interference, comprising:

[0007] The rectifier bridge BD1, the inductor L1 connected to the output terminal of the rectifier bridge BD1, the capacitor C1 connected in parallel with the inductor L1, and the diodes D1 and D2 connected in series with the capacitor C1.

[0008] The cathode of diode D1 is connected to one end of inductor L1, and the anode of diode D2 is connected to the other end of inductor L1.

[0009] A capacitor C2 is connected in parallel with the capacitor C1, and a diode D3 is connected in series with the capacitor C2. The anode of the diode D3 is connected to one end of the inductor L1.

[0010] The input terminal of the rectifier bridge BD1 is also connected to a fuse F1 and a varistor MOV, which are connected in parallel with the input terminal of the rectifier bridge BD1.

[0011] Resistors R1 and R2 are connected in series and then in parallel with capacitor CX1. The fuse F1, varistor MOV, and the series resistors R1, R2 and capacitor CX1 are all connected in parallel with the input terminal of the rectifier bridge BD1.

[0012] A PWM control chip U1 is connected to the output terminal of the rectifier bridge BD1. Pins 5 and 6 of the PWM control chip U1 are connected to the primary coil HV of the transformer T1. The secondary coil of the transformer T1 is connected to the anode of the diode D6. The cathode of the diode D6 is connected to the positive terminal of the capacitors C5 and C6. The negative terminals of the capacitors C5 and C6 are connected to the secondary ground of the circuit.

[0013] Resistors R10, R11, and R12 are connected to the primary coil HV of the transformer T1. Resistors R10 and R11 are connected in series and then in parallel with resistor R12. The other end of resistor R12 is connected to the cathode of diode D4, and the anode of diode D4 is connected to the other end of the primary coil HV of the transformer T1.

[0014] A resistor R3 is connected to pin 1 of the PWM control chip U1. The other end of the resistor R3 is connected to the anode of the diode D5. The cathode of the diode D5 is connected to pin 1 of the PWM control chip U1. Pin 1 of the PWM control chip U1 is also connected to the positive terminal of the capacitor C4. The negative terminal of the capacitor C4 is connected to the primary ground of the circuit.

[0015] Resistors R8 and R9 are connected to pin 4 of the PWM control chip U1, and the other end of resistors R8 and R9 is connected to the primary ground of the circuit.

[0016] A capacitor C7 is connected to pins 5 and 6 of the PWM control chip U1, and the other end of the capacitor C7 is connected to the primary ground of the circuit.

[0017] A Y1 capacitor CY1 is connected to the primary circuit HV, and the other end of the Y1 capacitor CY1 is connected to the secondary ground of the circuit.

[0018] A diode D43 is connected to the primary circuit L-1. The anode of the diode D43 is connected to the primary circuit L-1. The cathode of the diode D43 is connected to the Y1 capacitor CY2. The other end of the Y1 capacitor CY2 is connected to the anode of the diode D44. The cathode of the diode D44 is connected to the secondary ground of the circuit.

[0019] A resistor R14 is connected in parallel with capacitors C5 and C6, and a capacitor C9 is connected in series with resistor R14. The series combination of resistor R14 and capacitor C9 is connected in parallel with diode D6.

[0020] A common-mode inductor LF1 is connected to the positive terminals of capacitors C5 and C6. Two pins of the common-mode inductor LF1 are connected to the positive and negative terminals of capacitor C6, respectively, and the other two pins are connected to D+ and D-, respectively.

[0021] Furthermore, the PWM control chip is model DP2701F.

[0022] Furthermore, the primary coil HV of the transformer T1 is connected to pins 5 and 6 of the PWM control chip U1 to convert the pulse width modulation signal generated by the PWM control chip U1 into high-frequency AC power.

[0023] Furthermore, the Y1 capacitor CY1 and the filter branch composed of the diode D43, Y1 capacitor CY2, and diode D44 are used to filter out electromagnetic interference signals. The Y1 capacitor CY1 is used to filter out conventional EMI interference, and the diodes D43 and D44 utilize their unidirectional conduction characteristics to enable the Y1 capacitor CY2 to absorb EMI interference while blocking high-frequency signal interference to the AC line L-1 of the circuit.

[0024] Furthermore, the common-mode inductor LF1 is used to suppress differential-mode interference and prevent high-frequency signals from being conducted at the power output terminal.

[0025] Furthermore, the fuse F1 is used to blow when the circuit is overloaded or short-circuited, cutting off the input power of the circuit and protecting the circuit and power supply.

[0026] Furthermore, the varistor MOV is used to absorb surge voltages and transient overvoltages in the circuit, protecting subsequent circuits from damage caused by voltage spikes.

[0027] Furthermore, the resistors R1 and R2 are connected in series and then in parallel with the capacitor CX1 to filter out high-frequency interference signals at the input.

[0028] Furthermore, capacitors C5 and C6 are connected in parallel and then connected to the cathode of diode D6 to filter the pulse voltage output from the secondary winding of transformer T1, thereby obtaining a stable DC output voltage.

[0029] On the other hand, an adapter is provided, including the adapter filtering high-frequency signal conduction interference circuit described above.

[0030] The beneficial effects of this utility model are as follows:

[0031] When AC power is input to the circuit, it first undergoes overcurrent protection via F1, and then high-frequency interference signals at the input are filtered out by a filter network composed of CX1, R1, and R2. Next, the AC power is rectified into DC power by rectifier bridge BD1. This DC power is further filtered and rectified by an input filter circuit composed of components L1, C1, D1, and D2 to obtain a smoother DC voltage, providing a stable input power supply for the subsequent PWM control circuit. Under the action of the PWM control chip U1, the input DC voltage is converted into a high-frequency pulse signal, which is applied to the primary coil HV of transformer T1. Transformer T1 converts and transmits this high-frequency pulse signal, generating a corresponding pulse voltage in the secondary coil. The secondary pulse voltage is rectified by D6 and filtered by C5 and C6 to obtain a stable DC output voltage, providing power to the load. Simultaneously, capacitor Y1 (CY1) and the filter branch composed of D43, CY2, and D44 work together to filter out EMI interference signals generated during circuit operation. Among them, CY1 mainly filters out conventional EMI interference, while the combination structure of D43, CY2, and D44 utilizes the unidirectional conduction characteristics of diodes to enable capacitor CY2 to absorb EMI interference while blocking the conduction of high-frequency signals to the AC input terminal L-1, thereby effectively reducing the interference of high-frequency signals on the AC line, improving the electromagnetic compatibility of the power supply, and the circuit structure is simple, occupies little space in the casing, and has low cost. Attached Figure Description

[0032] To more clearly illustrate the technical solutions in the embodiments of this utility model, the drawings used in the description of the embodiments of this utility model will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on the content of the embodiments of this utility model and these drawings without creative effort.

[0033] Figure 1 This invention provides a circuit diagram of an adapter circuit for filtering high-frequency signal conduction interference. Detailed Implementation

[0034] To make the technical problems solved by this utility model, the technical solutions adopted, and the technical effects achieved clearer, the technical solutions of the embodiments of this utility model will be further described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0035] In the description of this utility model, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" 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 utility model based on the specific circumstances.

[0036] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0037] In the description of this embodiment, the terms "upper," "lower," "left," "right," etc., refer to the orientation or positional relationship shown in the accompanying drawings. They are used only for ease of description and simplification of operation, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model. In addition, the terms "first" and "second" are only used for distinction in description and have no special meaning.

[0038] Example 1

[0039] like Figure 1As shown, this utility model embodiment provides an adapter circuit for filtering high-frequency signal conduction interference, including a rectifier bridge BD1, capacitors CX1, C1, C2, C3, C4, C5, C6, C7, C8, and C9, resistors R1, R2, R3, R4, R5, R6, R8, R9, R10, R11, R12, R13, R14, and R15, a common-mode inductor LF1, an inductor L1, a PWM control chip U1, diodes D1, D2, D3, D4, D5, D6, D43, and D44, a transformer T1, Y1 capacitors CY1 and CY2, a fuse F1, and a varistor MOV.

[0040] Specifically, the output terminal of the rectifier bridge BD1 is connected to the inductor L1, the inductor L1 is connected in parallel with the capacitor C1, and the capacitor C1 is connected in series with the diodes D1 and D2; the cathode of the diode D1 is connected to one end of the inductor L1, and the anode of the diode D2 is connected to the other end of the inductor L1; the capacitor C1 is connected in parallel with the capacitor C2, the capacitor C2 is connected in series with the diode D3, and the anode of the diode D3 is connected to one end of the inductor L1; the input terminal of the rectifier bridge BD1 is also connected to the fuse F1 and the varistor MOV, and the fuse F1 and the varistor MOV are connected in parallel with the input terminal of the rectifier bridge BD1; resistors R1 and R2 are connected in series and then in parallel with the capacitor CX1; the fuse F1, the varistor MOV, and the series resistors R1, R2, and capacitor CX1 are all connected in parallel with the input terminal of the rectifier bridge BD1; the rectifier bridge BD1... The output terminal is connected to the PWM control chip U1. Pins 5 and 6 of the PWM control chip U1 are connected to the primary coil HV of transformer T1. The secondary coil of transformer T1 is connected to the anode of diode D6. The cathode of diode D6 is connected to the positive terminals of capacitors C5 and C6. The negative terminals of capacitors C5 and C6 are connected to the secondary ground of the circuit. The primary coil HV of transformer T1 is connected to resistors R10, R11, and R12. Resistors R10 and R11 are connected in series and then in parallel with resistor R12. The other end of resistor R12 is connected to the cathode of diode D4. The anode of diode D4 is connected to the other end of the primary coil HV of transformer T1. Pin 1 of the PWM control chip U1 is connected to resistor R3. The other end of resistor R3 is connected to the anode of diode D5. The cathode of diode D5 is connected to pin 1 of the PWM control chip U1. Pin 1 of the control chip U1 is also connected to the positive terminal of capacitor C4, and the negative terminal of capacitor C4 is connected to the primary ground of the circuit; pin 4 of the PWM control chip U1 is connected to resistors R8 and R9, and the other end of resistors R8 and R9 is connected to the primary ground of the circuit; pins 5 and 6 of the PWM control chip U1 are connected to capacitor C7, and the other end of capacitor C7 is connected to the primary ground of the circuit; the primary HV of the circuit is connected to capacitor Y1 CY1, and the other end of capacitor Y1 CY1 is connected to the secondary ground of the circuit;The primary circuit L-1 is connected to diode D43. The anode of diode D43 is connected to the primary circuit L-1. The cathode of diode D43 is connected to capacitor CY2 (Y1). The other end of capacitor CY2 is connected to the anode of diode D44. The cathode of diode D44 is connected to the secondary ground of the circuit. Capacitors C5 and C6 are connected in parallel with resistor R14. Resistor R14 is connected in series with capacitor C9. The series combination of resistor R14 and capacitor C9 is connected in parallel with diode D6. The positive terminals of capacitors C5 and C6 are connected to common-mode inductor LF1. Two pins of common-mode inductor LF1 are connected to the positive and negative terminals of capacitor C6, respectively. The other two pins are connected to D+ and D-, respectively.

[0041] In this embodiment, when the circuit is working, after the AC power is input, it first passes through fuse F1 for overcurrent protection, and then passes through a filter network composed of capacitor CX1, resistors R1 and R2 to filter out high-frequency interference signals at the input end. The AC power is rectified into DC power by rectifier bridge BD1. This DC power is further filtered and rectified by an input filter circuit composed of inductor L1, capacitor C1, diodes D1 and D2, etc., to obtain a relatively smooth DC voltage, providing a stable input power supply for the subsequent PWM control circuit. The PWM control chip U1 generates a pulse width modulation signal based on the input voltage, current and other signals, controls the switching transistor to turn on and off, and adjusts the output voltage magnitude and stability. This pulse width modulation signal is transmitted through the primary coil HV of transformer T1. The secondary coil of transformer T1 outputs a pulse voltage, which is rectified by diode D6 and filtered by capacitors C5 and C6 to obtain a stable DC output voltage, providing power to the load. In the circuit, capacitor Y1 CY1 is connected between the primary HV and the secondary ground to filter out conventional EMI interference signals and reduce electromagnetic radiation and interference. In the filter branch composed of diode D43, capacitor CY2, and diode D44, the anode of diode D43 is connected to the primary circuit L-1, and the cathode is connected to capacitor CY2. The other end of capacitor CY2 is connected to the anode of diode D44, and the cathode of diode D44 is connected to the secondary ground of the circuit. This structure utilizes the unidirectional conduction characteristic of diodes, allowing capacitor CY2 to absorb EMI interference while blocking high-frequency signals from being conducted to AC line L-1. This effectively reduces high-frequency signal interference to the AC line, improves power supply electromagnetic compatibility, and features a simple circuit structure, small footprint, and low cost.

[0042] In some embodiments, the PWM control chip is model DP2701F.

[0043] In some embodiments, the primary coil HV of the transformer T1 is connected to pins 5 and 6 of the PWM control chip U1 to convert the pulse width modulation signal generated by the PWM control chip U1 into high-frequency alternating current.

[0044] In some embodiments, the Y1 capacitor CY1 and the filter branch composed of the diode D43, Y1 capacitor CY2, and diode D44 are used to filter out electromagnetic interference signals. The Y1 capacitor CY1 is used to filter out conventional EMI interference, and the diodes D43 and D44 utilize their unidirectional conduction characteristics to enable the Y1 capacitor CY2 to absorb EMI interference while blocking high-frequency signal interference to the AC line L-1 of the circuit.

[0045] In some embodiments, the common-mode inductor LF1 is used to suppress differential-mode interference and prevent high-frequency signals from being conducted at the power output terminal.

[0046] In some embodiments, the fuse F1 is used to blow when an overload or short circuit occurs in the circuit, cutting off the input power supply to the circuit and protecting the circuit and power supply.

[0047] In some embodiments, the varistor MOV is used to absorb surge voltages and transient overvoltages in the circuit, protecting subsequent circuits from damage caused by voltage spikes.

[0048] In some embodiments, the resistors R1 and R2 are connected in series and then in parallel with the capacitor CX1 to filter out high-frequency interference signals at the input.

[0049] In some embodiments, capacitors C5 and C6 are connected in parallel and then connected to the cathode of diode D6 to filter the pulse voltage output from the secondary winding of transformer T1, thereby obtaining a stable DC output voltage.

[0050] Example 2

[0051] This utility model embodiment provides an adapter based on embodiment one, including the adapter filtering high-frequency signal conduction interference circuit described above.

[0052] Note that the above description is merely a preferred embodiment of the present invention and the technical principles employed. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and various obvious changes, readjustments, and substitutions can be made without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments, and may include many other equivalent embodiments without departing from the concept of the present invention. The scope of the present invention is determined by the scope of the appended claims.

Claims

1. An adapter circuit for filtering high-frequency signal conduction interference, characterized in that, include: The rectifier bridge BD1, the inductor L1 connected to the output terminal of the rectifier bridge BD1, the capacitor C1 connected in parallel with the inductor L1, and the diodes D1 and D2 connected in series with the capacitor C1. The cathode of diode D1 is connected to one end of inductor L1, and the anode of diode D2 is connected to the other end of inductor L1. A capacitor C2 is connected in parallel with the capacitor C1, and a diode D3 is connected in series with the capacitor C2. The anode of the diode D3 is connected to one end of the inductor L1. The input terminal of the rectifier bridge BD1 is also connected to a fuse F1 and a varistor MOV, which are connected in parallel with the input terminal of the rectifier bridge BD1. Resistors R1 and R2 are connected in series and then in parallel with capacitor CX1. The fuse F1, varistor MOV, and the series resistors R1, R2 and capacitor CX1 are all connected in parallel with the input terminal of the rectifier bridge BD1. A PWM control chip U1 is connected to the output terminal of the rectifier bridge BD1. Pins 5 and 6 of the PWM control chip U1 are connected to the primary coil HV of the transformer T1. The secondary coil of the transformer T1 is connected to the anode of the diode D6. The cathode of the diode D6 is connected to the positive terminal of the capacitors C5 and C6. The negative terminals of the capacitors C5 and C6 are connected to the secondary ground of the circuit. Resistors R10, R11, and R12 are connected to the primary coil HV of the transformer T1. Resistors R10 and R11 are connected in series and then in parallel with resistor R12. The other end of resistor R12 is connected to the cathode of diode D4, and the anode of diode D4 is connected to the other end of the primary coil HV of the transformer T1. A resistor R3 is connected to pin 1 of the PWM control chip U1. The other end of the resistor R3 is connected to the anode of the diode D5. The cathode of the diode D5 is connected to pin 1 of the PWM control chip U1. Pin 1 of the PWM control chip U1 is also connected to the positive terminal of the capacitor C4. The negative terminal of the capacitor C4 is connected to the primary ground of the circuit. Resistors R8 and R9 are connected to pin 4 of the PWM control chip U1, and the other end of resistors R8 and R9 is connected to the primary ground of the circuit. A capacitor C7 is connected to pins 5 and 6 of the PWM control chip U1, and the other end of the capacitor C7 is connected to the primary ground of the circuit. A Y1 capacitor CY1 is connected to the primary circuit HV, and the other end of the Y1 capacitor CY1 is connected to the secondary ground of the circuit. A diode D43 is connected to the primary circuit L-1. The anode of the diode D43 is connected to the primary circuit L-1. The cathode of the diode D43 is connected to the Y1 capacitor CY2. The other end of the Y1 capacitor CY2 is connected to the anode of the diode D44. The cathode of the diode D44 is connected to the secondary ground of the circuit. A resistor R14 is connected in parallel with capacitors C5 and C6, and a capacitor C9 is connected in series with resistor R14. The series combination of resistor R14 and capacitor C9 is connected in parallel with diode D6. A common-mode inductor LF1 is connected to the positive terminals of capacitors C5 and C6. Two pins of the common-mode inductor LF1 are connected to the positive and negative terminals of capacitor C6, respectively, and the other two pins are connected to D+ and D-, respectively.

2. The adapter circuit for filtering high-frequency signal conduction interference according to claim 1, characterized in that, The PWM control chip is model DP2701F.

3. The adapter circuit for filtering high-frequency signal conduction interference according to claim 1, characterized in that, The primary coil HV of the transformer T1 is connected to pins 5 and 6 of the PWM control chip U1, and is used to convert the pulse width modulation signal generated by the PWM control chip U1 into high-frequency AC power.

4. The adapter circuit for filtering high-frequency signal conduction interference according to claim 1, characterized in that, The Y1 capacitor CY1 and the filter branch composed of the diode D43, Y1 capacitor CY2, and diode D44 are used to filter out electromagnetic interference signals. The Y1 capacitor CY1 is used to filter out EMI interference. The diodes D43 and D44 use their unidirectional conduction characteristics to enable the Y1 capacitor CY2 to absorb EMI interference while blocking high-frequency signal interference to the AC line L-1 of the circuit.

5. The adapter circuit for filtering high-frequency signal conduction interference according to claim 1, characterized in that, The common-mode inductor LF1 is used to suppress differential-mode interference and prevent high-frequency signals from being conducted at the power output terminal.

6. The adapter circuit for filtering high-frequency signal conduction interference according to claim 1, characterized in that, The fuse F1 is used to blow when an overload or short circuit occurs in the circuit, cutting off the input power to the circuit and protecting the circuit and power supply.

7. The adapter circuit for filtering high-frequency signal conduction interference according to claim 1, characterized in that, The varistor MOV is used to absorb surge voltages and transient overvoltages in the circuit, protecting subsequent circuits from damage caused by voltage spikes.

8. The adapter circuit for filtering high-frequency signal conduction interference according to claim 1, characterized in that, The resistors R1 and R2 are connected in series and then in parallel with the capacitor CX1 to filter out high-frequency interference signals at the input.

9. The adapter circuit for filtering high-frequency signal conduction interference according to claim 1, characterized in that, The capacitors C5 and C6 are connected in parallel and then connected to the cathode of the diode D6 to filter the pulse voltage output from the secondary winding of the transformer T1, thereby obtaining a stable DC output voltage.

10. An adapter, characterized in that, The adapter includes the high-frequency signal conduction interference filtering circuit as described in any one of claims 1 to 9.

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