CN214175837U - Transformer structure and power adapter - Google Patents

Abstract

The utility model discloses a transformer structure, which comprises a main winding, a secondary winding and a feedback winding, wherein the main winding is coupled with the secondary winding, the negative pole of the feedback winding is connected with the ground of the main winding through a rectifier diode, the negative pole of the feedback winding is connected with the cathode of the rectifier diode, and the anode of the rectifier diode is grounded; the positive pole of the feedback winding is connected with the positive pole of a capacitor, and the positive pole of the feedback winding is the starting point of the feedback winding. Compared with the prior art, the utility model discloses the feedback winding negative pole passes through rectifier diode ground connection, and rectifier diode is anodal at primary winding's earthing terminal, and the feedback winding plays to connect electric capacity's positive pole around the point for rectifier diode's positive pole and play the voltage ratio of winding the point are more stable, make this feedback winding use as shielding winding when as the electric capacity feed end, keep apart the common mode voltage that main winding and secondary produced. Make this transformer structure need not to set up solitary shielding layer, simple structure, and is with low costs, need not to adjust the shielding layer repeatedly.

Description

Transformer structure and power adapter

Technical Field

The utility model relates to a transformer structure especially relates to a transformer structure.

Background

With the development of smart phones in recent years, a mobile phone capacitive screen increasingly occupies the mainstream position, and a power adapter is a high-frequency switching power supply, so that in the switching process, common-mode interference generated by a transformer is transmitted to a mobile phone through a data line, so that when the mobile phone is used and a person touches the screen, phenomena such as false triggering, dialing failure and the like can be caused, and the following methods are generally adopted for solving the problems of common-mode interference and EMC of the power adapter; 1; the structure of the transformer needs to be adjusted, in the existing low-power supply, a flyback framework is mostly adopted, and shielding layers are added on a primary winding and a secondary winding to isolate common-mode interference of the primary winding and the secondary winding. The EMI amplitude is reduced. 2; and the Y capacitor is adopted, so that the primary interference is coupled to the output ground through the Y capacitor, and the interference is filtered. Both of these methods, however, cause the following problems. 1; the cost is increased, the transformer needs to repeatedly adjust the shielding layer, the structure is complex, and the cost is increased. 2; the increase in Y capacitance presents a problem of leakage current.

Referring to chinese patent CN201220061317.2, a transformer structure is disclosed, which includes a primary winding NP, a shield winding NM, a power supply winding MAUX (feedback winding) and a secondary winding. The anode of the power supply winding MAUX is connected in series with a rectifier diode and a capacitor, the anode of the rectifier diode is connected with the anode of the power supply winding MAUX, the anode of the capacitor is connected with the cathode of the rectifier diode, and the cathode of the capacitor is grounded. The positive pole of the power supply winding MAUX is a node of the transformer voltage change, and when the voltage is changed, because the reverse recovery characteristic of the rectifier diode is difficult to avoid, certain interference can be generated, so that the power supply winding MAUX has large fluctuation and can only be used as the power supply winding, and a shielding winding NM must be added between a primary winding NP and a secondary winding to solve the problems of common mode interference and EMC of a power adapter, so that the transformer has a complex structure and increased cost, and the transformer needs to repeatedly adjust a shielding layer.

Therefore, a transformer structure capable of solving the above problems is urgently needed.

SUMMERY OF THE UTILITY MODEL

The utility model aims at providing a transformer structure, its feedback winding can regard as shielding winding to use when as the electric capacity feeder ear for this transformer structure need not to set up solitary shielding winding, simple structure, and is with low costs, need not to adjust the shielding layer repeatedly.

In order to achieve the above object, the present invention discloses a transformer structure, which comprises a main winding, a secondary winding and a feedback winding, wherein the main winding is coupled with the secondary winding, the negative pole of the feedback winding is connected to the ground of the main winding through a rectifier diode, the negative pole of the feedback winding is connected to the cathode of the rectifier diode, and the anode of the rectifier diode is grounded; the positive pole of the feedback winding is connected with the positive pole of a capacitor, and the positive pole of the feedback winding is the starting point of the feedback winding.

Compared with the prior art, the utility model discloses the feedback winding negative pole passes through rectifier diode ground connection, and rectifier diode's positive pole is at primary winding's earthing terminal, and the feedback winding plays to connect the positive pole of electric capacity around the point for rectifier diode's anodal voltage and play to wind the voltage of point for more stable voltage, can not produce bigger interference, thereby make this feedback winding use as shielding winding when as the electric capacity feed end, keep apart the common mode voltage that main winding and secondary produced. Make this transformer structure need not to set up solitary shielding layer, simple structure, and is with low costs, need not to adjust the shielding layer repeatedly.

Preferably, the capacitor is an electrolytic capacitor.

Preferably, the negative pole of the capacitor is connected with the ground of the main winding.

Preferably, the winding start point of the feedback winding is far away from the winding start point of the main winding, and the tail end of the feedback winding is far away from the winding start point of the secondary winding.

Preferably, the negative pole of the main winding is a winding start point, and the positive pole of the secondary winding is a winding start point. Of course, the winding starting points of the main winding and the secondary winding are set according to the requirement and are not limited to the scheme.

Preferably, both ends of the main winding are connected with direct current signals, and the transformer is matched with direct current for use.

The invention also discloses a power adapter, which comprises a rectifying circuit and a transformer, wherein the rectifying circuit converts the input alternating current into a first direct current, the transformer reduces the voltage of the first direct current and converts the first direct current into a second direct current, the output filter circuit filters and outputs the second direct current, the transformer is as above, the main winding is connected with the first direct current, and the secondary winding is connected with the input end of the rectifying circuit and outputs the second direct current.

Compared with the prior art, the utility model discloses a rectifier diode's positive pole is at primary winding's earthing terminal, and feedback winding plays to connect the positive pole of electric capacity around the point for rectifier diode's anodal voltage and play to wind the voltage of point are more stable voltage, can not produce bigger interference, thereby make this feedback winding regard as electric capacity power supply winding to use as shielding winding simultaneously, keep apart the common mode voltage that main winding and secondary produced. The transformer structure is free from arranging an independent shielding winding, simple in structure and low in cost, and a shielding layer is not required to be adjusted repeatedly.

Preferably, the power adapter further includes an output filter circuit, and the output filter circuit filters and outputs the second direct current.

Preferably, the rectification circuit is a rectification filter circuit.

Preferably, the power adapter further comprises an input protection circuit, the input protection circuit acts to disconnect the input of the alternating current when the alternating current is abnormal, and the capacitor supplies power to the input protection circuit.

Preferably, the power adapter is a power adapter of a charger.

Specifically, the charger is a mobile phone charger.

Drawings

Fig. 1 is a schematic winding diagram of the transformer of the present invention.

Fig. 2 is a circuit diagram of the transformer of the present invention.

Fig. 3 is a circuit diagram of the mobile phone charger of the present invention.

Detailed Description

In order to explain technical contents, structural features, and objects and effects of the present invention in detail, the following description is given in conjunction with the embodiments and the accompanying drawings.

Referring to fig. 3, the present invention discloses a mobile phone charger, which includes a power adapter 100, where the power adapter 100 includes a rectifying circuit 12 and a transformer T1, the rectifying circuit 12 converts an input ac power into a first dc power, the transformer T1 down-converts the first dc power into a second dc power, a main winding L1 of a transformer T1 is connected to the first dc power, and a secondary winding L2 is connected to an input end of the rectifying circuit and outputs the second dc power.

Referring to fig. 1 and 2, the transformer T1 includes a main winding L1, a secondary winding L2 and a feedback winding L3, the main winding L1 is coupled to the secondary winding L2, a cathode of the feedback winding L3 is connected to the ground of the main winding L1 through a rectifier diode D1, a cathode of the feedback winding L3 is connected to a cathode of the rectifier diode D1, and an anode of the rectifier diode D1 is connected to the ground; the positive electrode of the feedback winding L3 is connected with the positive electrode of a capacitor C1, and the positive electrode of the feedback winding L3 is the starting point of the feedback winding L3. The utility model discloses rectifier diode D1 ground connection is passed through to feedback winding L3 negative pole, and rectifier diode D1's positive pole is at primary winding's earthing terminal, feedback winding L3 plays around the positive pole of some grafting electric capacity C1, make rectifier diode D1's anodal voltage and play the voltage of winding some be more stable voltage, can not produce great interference, thereby make this feedback winding L3 use as shielding winding when as electric capacity C1 feeder terminal, keep apart the common mode voltage that main winding L1 and secondary winding L2 produced. The transformer structure is free from arranging an independent shielding winding, simple in structure and low in cost, and a shielding layer is not required to be adjusted repeatedly.

In this embodiment, both ends of the main winding L1 are connected to a dc signal, and in this embodiment, both ends of the main winding L1 are connected to a first dc signal.

Wherein the capacitor C1 is an electrolytic capacitor. The negative electrode of the capacitor C1 is connected with the ground of the main winding L1.

Preferably, the winding start point of the feedback winding L3 is far away from the winding start point of the main winding L1, and the tail end of the feedback winding L3 is far away from the winding start point of the secondary winding L2.

Referring to fig. 2, pin 1 of the transformer T1 is the positive electrode of the main winding L1, pin 2 is the negative electrode of the transformer, pin 3 is the positive electrode of the feedback winding L3, and is connected to the positive electrode of the capacitor C1, pin 4 of the transformer T1 is the negative electrode of the feedback winding L3, and is connected to the ground of the main winding L1 through the rectifier diode D1. The pin 5 is the negative pole of the secondary winding L2, the pin 6 is the negative pole of the secondary winding L2, and the pins 1, 3 and 5 are terminals with the same name.

Referring to fig. 1, pin 2 of the transformer T1 is the start winding point of the main winding L1, pin 1 is the end of the main winding L1, pin 6 is the start winding point of the secondary winding L2, pin 5 is the end of the secondary winding L2, pin 3 is the start winding point of the feedback winding L3, and pin 4 is the end of the feedback winding L3.

The rectifying circuit is a rectifying and filtering circuit.

The power adapter 100 further includes an output filter circuit 13, and the output filter circuit 13 filters and outputs the second direct current.

The power adapter 100 further includes an input protection circuit 11, the input protection circuit 11 operates to disconnect the input of the alternating current when the alternating current is abnormal, and the capacitor C1 supplies power to the input protection circuit. Of course, the power adapter 100 may also include other control chips, and the capacitor C1 supplies power to the control chips.

Of course, the present invention is not limited to a mobile phone charger, but can also be used for chargers of other electronic devices or power adapters for other purposes. The utility model discloses can be used to 5W-65W's vary voltage converting circuit.

The above disclosure is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the scope of the invention, therefore, the invention is not limited thereto.

Claims (10)

1. A transformer structure comprising a primary winding, a secondary winding and a feedback winding, the primary winding coupled to the secondary winding, characterized in that: the negative pole of the feedback winding is connected with the ground of the main winding through a rectifier diode, the negative pole of the feedback winding is connected with the cathode of the rectifier diode, and the anode of the rectifier diode is grounded; the positive pole of the feedback winding is connected with the positive pole of a capacitor, and the positive pole of the feedback winding is the starting point of the feedback winding.

2. The transformer structure of claim 1, wherein: the capacitor is an electrolytic capacitor.

3. The transformer structure of claim 1, wherein: the negative pole of the capacitor is connected with the ground of the main winding.

4. The transformer structure of claim 1, wherein: the starting winding point of the feedback winding is far away from the starting winding point of the main winding, and the ending end of the feedback winding is far away from the starting winding point of the secondary winding.

5. The transformer structure of claim 1, wherein: the negative pole of the main winding is a starting winding point, and the positive pole of the secondary winding is a starting winding point.

6. The transformer structure of claim 1, wherein: and two ends of the main winding are connected with direct current signals.

7. The utility model provides a power adapter, includes rectifier circuit and transformer, rectifier circuit converts the alternating current of input into first direct current, the transformer will first direct current carries out step-down and converts into second direct current, its characterized in that: the transformer according to any of claims 1-6, wherein the primary winding is connected to the first direct current, and the secondary winding is connected to the input of the rectifier circuit and outputs the second direct current.

8. The power adapter as recited in claim 7 wherein: the second direct current is filtered and output by the output filter circuit, and the rectifying circuit is a rectifying filter circuit.

9. The power adapter as recited in claim 7 wherein: the alternating current protection circuit is characterized by further comprising an input protection circuit, the input protection circuit acts to disconnect the input of the alternating current when the alternating current is abnormal, and the capacitor supplies power to the input protection circuit.

10. The power adapter as recited in claim 7 wherein: the power adapter is a power adapter of a mobile phone charger.

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