Anti-electromagnetic interference USB converter

Abstract

The utility model provides an anti-electromagnetic interference USB converter, which relates to the technical field of power supply anti-interference, and comprises a rectification filter circuit, a transformer circuit and a power supply output circuit, and a spike pulse absorption circuit is arranged between the output end of the rectification filter circuit and the primary side of the transformer circuit. The spike pulse absorption circuit comprises a resistor R1, a resistor R3, a capacitor C1, a diode D1 and an inductor L2; the output end of the rectification filter circuit is electrically connected with the primary side positive electrode of the transformer circuit, the primary side negative electrode of the transformer circuit is electrically connected with the positive electrode of the D1 through the L2, the negative electrode of the D1 is connected with the R3 and the R1 in series and then electrically connected with the output end of the rectification filter circuit, and the C1 is connected to the two ends of the R1 in parallel. According to the USB converter, the L2 is used for actively inhibiting high-frequency interference to absorb peak current in a loop, so that radiation in electromagnetic interference can be solved, the stability of the whole circuit is ensured, and stable voltage is output.

Description

Technical Field

[0001] The utility model relates to the technical field of power supply anti-interference, and in particular to a USB converter that is anti-electromagnetic interference. Background Art

[0002] A power adapter is a power supply conversion device for small portable electronic devices and electronic appliances. It is generally composed of a housing, a transformer, an inductor, a capacitor, a control IC, a PCB board and other components. Its working principle is to convert AC input into DC output. Among them, the most widely used is the USB converter, such as mobile phone chargers, household low-current power adapters, etc., which convert AC input into DC output of the USB interface.

[0003] In the prior art, when this type of USB converter is just turned on, its power supply works in a high-frequency oscillation circuit, which results in extremely high spike pulse voltage. Due to this electromagnetic interference, the USB converter does not have a stable voltage output when it is just turned on, and there is a risk of the load being damaged by high voltage. Utility Model Content

[0004] The technical problem to be solved by the utility model is that a USB converter will have an extremely high peak pulse voltage when it just works. In order to overcome the defects of the above prior art, the utility model provides a USB converter that is resistant to electromagnetic interference.

[0005] The utility model provides an anti-electromagnetic interference USB converter, comprising a rectifier filter circuit, a transformer circuit and a power output circuit, wherein two AC input ends of the rectifier filter circuit are electrically connected to a live wire and a neutral wire respectively, the output end of the rectifier filter circuit is electrically connected to a primary side of the transformer circuit, and the secondary side of the transformer circuit is electrically connected to the input end of the power output circuit; a peak pulse absorption circuit is arranged between the output end of the rectifier filter circuit and the primary side of the transformer circuit, and the peak pulse absorption circuit comprises a resistor R1, a resistor R3, a capacitor C1, a diode D1 and an inductor L2; the output end of the rectifier filter circuit is electrically connected to the primary positive pole of the transformer circuit, the primary negative pole of the transformer circuit is electrically connected to the positive pole of the diode D1 through the inductor L2, the negative pole of the diode D1 is electrically connected to the output end of the rectifier filter circuit after being connected in series with a resistor R3 and a resistor R1, and the capacitor C1 is connected in parallel to both ends of the resistor R1.

[0006] Compared with the prior art, the present invention discloses an anti-electromagnetic interference USB converter, which has the following advantages: a tip pulse absorption circuit composed of a resistor R1, a resistor R3, a capacitor C1, a diode D1 and an inductor L2 is used, and the inductor L2 is used to actively suppress high-frequency interference to absorb the peak current in the loop and reduce the rise rate of the peak current, so that the radiation in the electromagnetic interference can be resolved, ensuring the stability of the entire circuit and outputting a stable voltage.

[0007] In a possible implementation manner, the nominal impedance of the inductor L2 is 100-300Ω.

[0008] Compared with the prior art, the above technical solution can achieve better impedance and current, and can better actively suppress high-frequency interference.

[0009] In a possible implementation manner, the nominal impedance of the inductor L2 is 100Ω.

[0010] In a possible implementation, the rectifier and filter circuit includes a rectifier bridge DB1, an inductor L1, an inductor L3, a load resistor RL, a capacitor EC1, and a capacitor EC2; the two AC ends of the rectifier bridge DB1 are electrically connected to the live wire and the neutral wire respectively, the DC positive pole of the rectifier bridge DB1 is electrically connected to the input end of the transformer circuit through the inductor L1, the DC positive pole of the rectifier bridge DB1 is electrically connected to the positive pole of the capacitor EC2 through the inductor L1, and the negative pole of the capacitor EC2 is grounded; the load resistor RL is connected in parallel to the two ends of the inductor L1, the DC positive pole of the rectifier bridge DB1 is electrically connected to the positive pole of the capacitor EC1, the negative pole of the capacitor EC1 is electrically connected to the DC negative pole of the rectifier bridge DB1, and the DC negative pole of the rectifier bridge DB1 is grounded through the inductor L3.

[0011] Compared with the prior art, the above technical solution can ensure that the voltage input to the transformer circuit is periodic and stable.

[0012] In a possible implementation, the transformer circuit includes a transformer, a capacitor EC4, a capacitor EC5 and a resistor R10; the primary positive pole of the transformer is electrically connected to the resistor R1, the primary negative pole of the transformer is electrically connected to the inductor L2, the secondary positive pole of the transformer is electrically connected to the input end of the power supply output circuit, the secondary positive pole of the transformer is electrically connected to the positive pole of the capacitor EC4, the secondary negative pole of the transformer and the negative pole of the capacitor EC4 are both grounded, the capacitor EC5 is connected in parallel across the capacitor EC4, and the resistor R10 is connected in parallel across the capacitor EC5.

[0013] Compared with the prior art, the above technical solution can ensure that the voltage after transformation by the transformer circuit is also stable, and thus the voltage output by the power output circuit is also stable.

[0014] In a possible implementation manner, the input end of the transformer circuit is also electrically connected to a feedback loop for detecting the voltage at the input end of the transformer circuit.

[0015] Compared with the prior art, the above technical solution can identify whether the voltage on the primary side of the transformer circuit reaches a preset voltage through a feedback loop, and then adjust it.

[0016] In a possible implementation, the power output circuit includes a control chip U3, a Type-C interface, and a USB interface. The output end of the transformer circuit is electrically connected to the control chip U3, the Type-C interface, and the USB interface, respectively. The control chip U3 is communicatively connected to the Type-C interface and the USB interface.

[0017] Compared with the prior art, the above technical solution can output voltage through two different interfaces, the Type-C interface and the USB interface, making it convenient to adapt to more electrical appliances.

[0018] In a possible implementation, a plurality of protection resistors are electrically connected between the first AC input terminal and the second AC input terminal of the rectifier and filter circuit, and a safety capacitor CX1 is electrically connected between the first AC input terminal and the second AC input terminal of the rectifier and filter circuit.

[0019] Compared with the prior art, the above technical solution can achieve that the first AC input terminal and the second AC input terminal can filter out common-mode and differential-mode interference in the AC power line through the protection resistor and the safety capacitor.

[0020] In a possible implementation manner, the first AC input terminal of the rectifier and filter circuit is electrically connected to the live wire through a fuse F1.

[0021] Compared with the prior art, the above technical solution can effectively limit the current through the fuse F1 to prevent the current from being burned due to excessive current.

[0022] In a possible implementation manner, the second AC input terminal of the rectifier and filter circuit is electrically connected to the neutral line through a thermistor.

[0023] Compared with the prior art, the above technical solution can prevent the internal temperature of the USB converter from being too high through the thermistor. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 The utility model is a circuit diagram of a USB converter with anti-electromagnetic interference. DETAILED DESCRIPTION

[0025] First, those skilled in the art should understand that these implementations are only used to explain the technical principles of the embodiments of the present application, and are not intended to limit the protection scope of the embodiments of the present application. Those skilled in the art can make adjustments to them as needed to adapt to specific application scenarios.

[0026] In the description of the embodiments of the present application, it should be noted that, unless otherwise clearly specified and limited, the terms "connected" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the embodiments of the present application can be understood according to specific circumstances.

[0027] The present application is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0028] See also Figure 1 As shown, an embodiment of the present application discloses an electromagnetic interference resistant USB converter, including a rectifier and filter circuit, a transformer circuit and a power output circuit, wherein two AC input terminals of the rectifier and filter circuit are electrically connected to a live wire and a neutral wire respectively, an output terminal of the rectifier and filter circuit is electrically connected to a primary side of the transformer circuit, and a secondary side of the transformer circuit is electrically connected to an input terminal of the power output circuit.

[0029] A peak pulse absorption circuit is provided between the output end of the rectifier filter circuit and the primary side of the transformer circuit. The peak pulse absorption circuit includes a resistor R1, a resistor R3, a capacitor C1, a diode D1 and an inductor L2.

[0030] The output end of the rectifier and filter circuit is electrically connected to the primary positive electrode of the transformer circuit, the primary negative electrode of the transformer circuit is electrically connected to the positive electrode of the diode D1 through the inductor L2, the negative electrode of the diode D1 is electrically connected to the output end of the rectifier and filter circuit after being connected in series with the resistor R3 and the resistor R1, and the capacitor C1 is connected in parallel to both ends of the resistor R1.

[0031] In this embodiment, a tip pulse absorption circuit is formed by resistor R1, resistor R3, capacitor C1, diode D1 and inductor L2, and inductor L2 is used to actively suppress high-frequency interference to absorb the peak current in the loop and reduce the rising rate of the peak current, so that the radiation in the electromagnetic interference can be resolved, ensuring the stability of the entire circuit and outputting a stable voltage.

[0032] The nominal impedance of the inductor L2 is 100-300Ω.

[0033] Limiting the nominal impedance of inductor L2 within this range can provide better impedance and current control, and can better actively suppress high-frequency interference.

[0034] In this embodiment, the nominal impedance of the inductor L2 is 100Ω.

[0035] The rectifying and filtering circuit includes a rectifying bridge DB1, an inductor L1, an inductor L3, a load resistor RL, a capacitor EC1, and a capacitor EC2.

[0036] The AC ends of the rectifier bridge DB1 are electrically connected to the live wire and the neutral wire respectively, the DC positive pole of the rectifier bridge DB1 is electrically connected to the input end of the transformer circuit through the inductor L1, the DC positive pole of the rectifier bridge DB1 is electrically connected to the positive pole of the capacitor EC2 through the inductor L1, and the negative pole of the capacitor EC2 is grounded; the load resistor RL is connected in parallel to the two ends of the inductor L1, the DC positive pole of the rectifier bridge DB1 is electrically connected to the positive pole of the capacitor EC1, the negative pole of the capacitor EC1 is electrically connected to the DC negative pole of the rectifier bridge DB1, and the DC negative pole of the rectifier bridge DB1 is grounded through the inductor L3.

[0037] The rectifier and filter circuit can ensure that the voltage input to the transformer circuit is periodic and stable. The rectifier and filter circuit is a conventional circuit and can also be implemented by other methods in the prior art.

[0038] The transformer circuit includes a transformer, a capacitor EC4, a capacitor EC5 and a resistor R10.

[0039] The primary positive pole of the transformer is electrically connected to the resistor R1, the primary negative pole of the transformer is electrically connected to the inductor L2, the secondary positive pole of the transformer is electrically connected to the input end of the power supply output circuit, the secondary positive pole of the transformer is electrically connected to the positive pole of the capacitor EC4, the secondary negative pole of the transformer and the negative pole of the capacitor EC4 are both grounded, the capacitor EC5 is connected in parallel across the capacitor EC4, and the resistor R10 is connected in parallel across the capacitor EC5.

[0040] It can ensure that the voltage after transformation by the transformer circuit is also stable, and thus the voltage output by the power output circuit is also stable.

[0041] In this embodiment, the input end of the transformer circuit is also electrically connected to a feedback loop for detecting the voltage at the input end of the transformer circuit.

[0042] The feedback loop can be used to identify whether the voltage on the primary side of the transformer circuit has reached a preset voltage, and then adjust it. The feedback loop is a prior art and will not be described in detail here.

[0043] Among them, the power output circuit includes a control chip U3, a Type-C interface and a USB interface, the output end of the transformer circuit is electrically connected to the control chip U3, the Type-C interface and the USB interface respectively, and the control chip U3 is communicatively connected to the Type-C interface and the USB interface.

[0044] It can output voltage through two different interfaces, Type-C interface and USB interface, making it convenient to adapt to more electrical appliances.

[0045] In actual use, the control chip U3 can be used to adjust the two interfaces, for example, the two interfaces cannot work at the same time; or the two interfaces can work at the same time; or under the continuous output of the Type-C interface, the USB interface can still output a small current stably for a long time to power small current home appliances such as night lights.

[0046] In this embodiment, a plurality of protection resistors are electrically connected between the first AC input terminal and the second AC input terminal of the rectifier and filter circuit, and a safety capacitor CX1 is electrically connected between the first AC input terminal and the second AC input terminal of the rectifier and filter circuit.

[0047] The first AC input terminal and the second AC input terminal can filter out common-mode and differential-mode interference in the AC power line through the protective resistor and the safety capacitor.

[0048] The first AC input terminal of the rectifier filter circuit is electrically connected to the live wire through the fuse F1. The fuse F1 effectively limits the current to prevent the current from burning out. In this embodiment, the fuse F1 is of the model 250V / 2A.

[0049] The second AC input terminal of the rectifier and filter circuit is electrically connected to the neutral line through a thermistor. The thermistor is used to prevent the internal temperature of the USB converter from being too high. In this embodiment, the thermistor is NTC 5D-7.

[0050] The USB converter of this embodiment has a shorter electromagnetic interference debugging cycle, is easier to pass, and is easier to certify the product, thereby increasing the product qualification rate.

[0051] In the description of the present application, the description with reference to the terms "one embodiment", "some embodiments", "in the present embodiment", "specific example", or "some examples" etc. means that the specific features, mechanisms, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, mechanisms, materials or characteristics described may be combined in a suitable manner in any one or more embodiments or examples. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0052] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application shall be based on the protection scope of the claims.

Claims

1. An anti-electromagnetic interference USB converter, comprising a rectifier filter circuit, a transformer circuit and a power output circuit, wherein the two AC input terminals of the rectifier filter circuit are electrically connected to the live wire and the neutral wire respectively, the output terminal of the rectifier filter circuit is electrically connected to the primary side of the transformer circuit, and the secondary side of the transformer circuit is electrically connected to the input terminal of the power output circuit; characterized in that: A peak pulse absorption circuit is provided between the output end of the rectifier filter circuit and the primary side of the transformer circuit, and the peak pulse absorption circuit includes a resistor R1, a resistor R3, a capacitor C1, a diode D1 and an inductor L2; The output end of the rectifier and filter circuit is electrically connected to the primary positive electrode of the transformer circuit, the primary negative electrode of the transformer circuit is electrically connected to the positive electrode of the diode D1 through the inductor L2, the negative electrode of the diode D1 is electrically connected to the output end of the rectifier and filter circuit after being connected in series with the resistor R3 and the resistor R1, and the capacitor C1 is connected in parallel to both ends of the resistor R1.

2. The anti-electromagnetic interference USB converter according to claim 1, characterized in that: The nominal impedance of the inductor L2 is 100-300Ω.

3. The anti-electromagnetic interference USB converter according to claim 2, characterized in that: The nominal impedance of the inductor L2 is 100Ω.

4. The anti-electromagnetic interference USB converter according to claim 1, characterized in that: The rectifier and filter circuit includes a rectifier bridge DB1, an inductor L1, an inductor L3, a load resistor RL, a capacitor EC1, and a capacitor EC2; The AC ends of the rectifier bridge DB1 are electrically connected to the live wire and the neutral wire respectively, the DC positive pole of the rectifier bridge DB1 is electrically connected to the input end of the transformer circuit through the inductor L1, the DC positive pole of the rectifier bridge DB1 is electrically connected to the positive pole of the capacitor EC2 through the inductor L1, and the negative pole of the capacitor EC2 is grounded; the load resistor RL is connected in parallel to the two ends of the inductor L1, the DC positive pole of the rectifier bridge DB1 is electrically connected to the positive pole of the capacitor EC1, the negative pole of the capacitor EC1 is electrically connected to the DC negative pole of the rectifier bridge DB1, and the DC negative pole of the rectifier bridge DB1 is grounded through the inductor L3.

5. The anti-electromagnetic interference USB converter according to claim 1, characterized in that: The transformer circuit includes a transformer, a capacitor EC4, a capacitor EC5 and a resistor R10; The primary positive pole of the transformer is electrically connected to the resistor R1, the primary negative pole of the transformer is electrically connected to the inductor L2, the secondary positive pole of the transformer is electrically connected to the input end of the power output circuit, the secondary positive pole of the transformer is electrically connected to the positive pole of the capacitor EC4, the secondary negative pole of the transformer and the negative pole of the capacitor EC4 are both grounded, the capacitor EC5 is connected in parallel across the capacitor EC4, and the resistor R10 is connected in parallel across the capacitor EC5.

6. The anti-electromagnetic interference USB converter according to claim 1, characterized in that: The input end of the transformer circuit is also electrically connected to a feedback loop for detecting the voltage at the input end of the transformer circuit.

7. The anti-electromagnetic interference USB converter according to claim 1, characterized in that: The power output circuit includes a control chip U3, a Type-C interface and a USB interface. The output end of the transformer circuit is electrically connected to the control chip U3, the Type-C interface and the USB interface respectively. The control chip U3 is communicatively connected to the Type-C interface and the USB interface.

8. The anti-electromagnetic interference USB converter according to claim 1, characterized in that: A plurality of protection resistors are electrically connected between the first AC input terminal and the second AC input terminal of the rectifier and filter circuit, and a safety capacitor CX1 is electrically connected between the first AC input terminal and the second AC input terminal of the rectifier and filter circuit.

9. The anti-electromagnetic interference USB converter according to claim 1, characterized in that: The first AC input terminal of the rectifier and filter circuit is electrically connected to the live wire through the fuse F1.

10. The anti-electromagnetic interference USB converter according to claim 1, characterized in that: The second AC input terminal of the rectifier and filter circuit is electrically connected to the neutral line through a thermistor.

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