CN112233888A - A transformer device, switching power supply and power adapter - Google Patents
A transformer device, switching power supply and power adapter Download PDFInfo
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- CN112233888A CN112233888A CN202011010778.2A CN202011010778A CN112233888A CN 112233888 A CN112233888 A CN 112233888A CN 202011010778 A CN202011010778 A CN 202011010778A CN 112233888 A CN112233888 A CN 112233888A
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F27/00—Details of transformers or inductances, in general
- H01F27/28—Coils; Windings; Conductive connections
- H01F27/288—Shielding
- H01F27/2885—Shielding with shields or electrodes
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F19/00—Fixed transformers or mutual inductances of the signal type
- H01F19/04—Transformers or mutual inductances suitable for handling frequencies considerably beyond the audio range
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F27/00—Details of transformers or inductances, in general
- H01F27/28—Coils; Windings; Conductive connections
- H01F27/30—Fastening or clamping coils, windings, or parts thereof together; Fastening or mounting coils or windings on core, casing, or other support
- H01F27/306—Fastening or mounting coils or windings on core, casing or other support
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F27/00—Details of transformers or inductances, in general
- H01F27/28—Coils; Windings; Conductive connections
- H01F27/32—Insulating of coils, windings, or parts thereof
- H01F27/324—Insulation between coil and core, between different winding sections, around the coil; Other insulation structures
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M1/00—Details of apparatus for conversion
- H02M1/12—Arrangements for reducing harmonics from AC input or output
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M7/00—Conversion of AC power input into DC power output; Conversion of DC power input into AC power output
- H02M7/02—Conversion of AC power input into DC power output without possibility of reversal
- H02M7/04—Conversion of AC power input into DC power output without possibility of reversal by static converters
- H02M7/06—Conversion of AC power input into DC power output without possibility of reversal by static converters using discharge tubes without control electrode or semiconductor devices without control electrode
- H02M7/068—Conversion of AC power input into DC power output without possibility of reversal by static converters using discharge tubes without control electrode or semiconductor devices without control electrode mounted on a transformer
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Abstract
The invention discloses a transformer device, a switching power supply and a power adapter, wherein the device comprises: the primary winding module, the secondary winding and the shielding layer; the primary winding module includes: a primary winding first portion and a primary winding second portion; the primary winding first part, the secondary winding, the shielding layer and the primary winding second part are sequentially arranged in a set direction; the primary winding first part is configured to be connected with a direct current bus; the primary winding second part is configured to be connected with a main power device of a switching power supply. The scheme of the invention can solve the problem that the high-frequency transformer is provided with the auxiliary winding to increase the circuit complexity, and achieves the effect of simplifying the circuit structure of the high-frequency transformer.
Description
Technical Field
The invention belongs to the technical field of electronic circuits, and particularly relates to a transformer device, a switching power supply and a power adapter, in particular to a high-frequency transformer, a switching power supply circuit and a power adapter applying the same.
Background
Some high frequency transformers for switching power supplies and power adapters have auxiliary windings, and the auxiliary windings and their loops add to the circuit complexity.
The above is only for the purpose of assisting understanding of the technical aspects of the present invention, and does not represent an admission that the above is prior art.
Disclosure of Invention
The invention aims to provide a transformer device, a switching power supply and a power adapter, which are used for solving the problem that the high-frequency transformer is provided with an auxiliary winding to increase the circuit complexity and achieving the effect of simplifying the circuit structure of the high-frequency transformer.
The present invention provides a transformer apparatus, comprising: the primary winding module, the secondary winding and the shielding layer; the primary winding module includes: a primary winding first portion and a primary winding second portion; the primary winding first part, the secondary winding, the shielding layer and the primary winding second part are sequentially arranged in a set direction; the primary winding first part is configured to be connected with a direct current bus; the primary winding second part is configured to be connected with a main power device of a switching power supply.
In some embodiments, further comprising: a transformer bobbin; the primary winding first part, the secondary winding, the shielding layer and the primary winding second part are wound on the transformer framework; and adjacent parts of the primary winding first part, the secondary winding, the shielding layer and the primary winding second part are insulated by adopting an insulating tape.
In some embodiments, the first portion of the primary winding is wound around only one layer and is densely or sparsely wound over the entire layer; a first end of the primary winding first portion configured to connect to a direct current bus positive; a second end of the first portion of the primary winding configured to be connected to an intermediate node of the transformer arrangement.
In some embodiments, the secondary winding is capable of determining at least one of a number of winding strands, a wire diameter, and a number of turns based on at least one of a target number of output paths, a target output current, and a target output voltage.
In some embodiments, the shielding layer comprises a shielding winding; the shielding winding is wound by any one of metal foils, metal strips and metal wires, is fully wound by one layer and can be wound by a multi-strand parallel winding mode; the shielding winding is configured to be connected with the positive electrode of the direct current bus, and the head end and the tail end of the shielding winding are arranged in a short circuit prevention mode.
In some embodiments, the second portion of the primary winding is wound in two layers, with the same wire as the first portion of the primary winding, around the entire layer; a first end of the second portion of the primary winding configured to be connected to an intermediate node of the transformer arrangement; and the second end of the second part of the primary winding is configured to be connected with the drain electrode of a main power device of the switching power supply.
In accordance with another aspect of the present invention, there is provided a switching power supply, including: the device comprises a rectification filter circuit, a high-frequency transformer, a main control unit, an alternating current low-impedance bypass circuit, a follow current and absorption circuit thereof and an output filter circuit; the main control unit comprises: a main switching device and a control system; the high-frequency transformer adopts the transformer device; the rectification filter circuit is connected to a primary winding of the transformer device and the main control unit; the secondary winding of the transformer device is connected to an output filter circuit after passing through the follow current and the absorption circuit thereof; the control system obtains electricity from the secondary side of the transformer device under a first output voltage; taking electricity from the primary side of the transformer device under a second output voltage; the output precision of the first output voltage is greater than that of the second voltage.
In some embodiments, the rectifying and filtering circuit includes: a rectifier bridge and a filter circuit; the rectifier bridge is matched with the filter circuit; the filter circuit includes: two differential mode inductors and two capacitors; the two differential mode inductors are arranged in parallel, and the two capacitors are arranged at the end parts of the two differential mode inductors in parallel.
In some embodiments, the rectifier bridge is disposed between the two capacitors and located on either side of the two differential mode inductors, or the rectifier bridge is disposed on the same side of the two capacitors; of the two capacitors, the capacitor on the AC side is a thin film capacitor, and the capacitor on the DC side is an electrolytic capacitor.
In accordance with the above switching power supply, a further aspect of the present invention provides a power adapter, including: the switching power supply described above.
Therefore, according to the scheme provided by the invention, the control circuit of the main power device is used for getting power from the direct current bus or the drain electrode, and the high-frequency transformer without the auxiliary winding is arranged, so that the problem that the circuit complexity is increased due to the auxiliary winding of the high-frequency transformer is solved, and the effect of simplifying the circuit structure of the high-frequency transformer is achieved.
Additional features and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention.
The technical solution of the present invention is further described in detail by the accompanying drawings and embodiments.
Drawings
FIG. 1 is a schematic diagram of an embodiment of a rectifying-filtering circuit;
FIG. 2 is a schematic structural diagram of a transformer apparatus according to an embodiment of the present invention;
FIG. 3 is a schematic diagram of an embodiment of a switching power supply circuit;
FIG. 4 is a schematic diagram of an embodiment of a transformer winding;
FIG. 5 is a graph illustrating first test results for conducted EMI.
The reference numbers in the embodiments of the present invention are as follows, in combination with the accompanying drawings:
1-a transformer skeleton; 2-insulating adhesive tape.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the technical solutions of the present invention will be clearly and completely described below with reference to the specific embodiments of the present invention and the accompanying drawings. It is to be understood that the described embodiments are merely exemplary of the invention, and not restrictive of the full scope of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
According to an embodiment of the present invention, there is provided a transformer apparatus. Referring to fig. 1, a schematic diagram of an embodiment of the apparatus of the present invention is shown. The transformer device includes a primary winding module, a secondary winding (i.e., an output winding), and a shielding layer. The primary winding module includes: a primary winding first portion and a primary winding second portion.
The primary winding first portion, the secondary winding, the shielding layer, and the primary winding second portion are sequentially disposed in a predetermined direction, for example, may be sequentially disposed from the outside to the inside. The primary winding first part is configured to be connected with the positive pole of a direct current bus, namely a dead point of a circuit; the second portion of the primary winding is configured to be connected to a main power device of the switching power supply, such as to a drain of the main power device of the switching power supply.
For example: the high-frequency transformer has no auxiliary winding, only a primary winding and an output winding. The outmost layer of the transformer is the first part of the primary winding, only one layer of the outmost layer of the transformer is wound, and the outmost layer of the transformer is connected with a dead point of a direct current bus. The primary winding first part, the output winding, the shielding layer and the primary winding second part are sequentially arranged from outside to inside. The second part of the primary winding is connected with the main power device.
Therefore, the transformer structure is simplified by making the transformer structure have no auxiliary winding, the production is more convenient and the cost is lower.
In some embodiments, further comprising: transformer bobbin 1. The primary winding first part, the secondary winding, the shielding layer and the primary winding second part are wound on the transformer framework 1. And an insulating layer is arranged between the adjacent parts of the primary winding first part, the secondary winding, the shielding layer and the primary winding second part, such as an insulating tape 2.
For example: the primary winding is the primary winding, and the secondary winding is the secondary winding. In the transformer winding structure, a primary winding first part, a secondary winding, a shielding winding and a primary winding second part are sequentially arranged from outside to inside, the windings are wound on a transformer framework 1, insulating tapes 2 are adopted for insulation among the windings, and the number of turns of the tapes is usually 1-3. The primary winding is divided into two parts, and the structure can reduce the leakage inductance of the transformer to a certain extent.
In some embodiments, the first portion of the primary winding is wound around only one layer and is densely or loosely wound over the entire layer. The first end of the first part of the primary winding is configured to be connected with the positive pole of the direct current bus. A second end of the first portion of the primary winding configured to be connected to an intermediate node of the transformer arrangement.
That is to say, the first part of the primary winding is wound by only one layer and is paved on the whole layer in a close winding or sparse winding mode, one end of the first part of the primary winding is connected with the positive electrode of the direct current bus, and the other end of the first part of the primary winding is connected with the middle node of the transformer. The first part of the primary winding is arranged at the outermost layer of the transformer, the number of layers is less than that of the second part of the primary winding, and the fact that most of interference of the primary winding is shielded to a certain extent through the secondary winding in the middle is equivalent. The first part of the primary winding is connected with the circuit 'dead point' because the interference of the 'dead point' is small and does not need to be placed in the inner layer for shielding.
In some embodiments, the secondary winding is capable of determining at least one of a number of winding strands, a wire diameter, and a number of turns based on at least one of a target number of output paths, a target output current, and a target output voltage.
For example: and the secondary winding determines the number of strands, the wire diameter and the number of turns of the winding according to the number of output circuits, current and voltage. The secondary winding needs to be determined according to the actual circuit. The number of winding strands of the secondary winding, namely the number of winding strands of the secondary winding, is equal to the number of winding strands of the secondary winding.
In some embodiments, the shielding layer comprises a shielding winding. The shielding winding is wound by any one of metal foils, metal strips and metal wires, is fully wound by one layer and can be wound in a multi-strand parallel winding mode. The shielding winding is configured to be connected with the positive electrode of the direct current bus, and the head end and the tail end of the shielding winding are arranged in a short circuit prevention mode.
For example: the shielding winding is wound by metal foil, metal strip or metal wire, is fully wound by one layer, and can adopt a multi-strand parallel winding mode. The shielding winding is connected with the positive end of the direct current bus, and the head end and the tail end of the shielding winding cannot be short-circuited. The shielding winding is connected with a circuit 'dead point', coupling interference is released, and head-tail short circuit cannot form effective shielding.
In some embodiments, the second portion of the primary winding is wound in two layers and the entire layer is wound with the same wire as the first portion of the primary winding. A first end of the second portion of the primary winding configured to be connected to an intermediate node of the transformer arrangement. And the second end of the second part of the primary winding is configured to be connected with the drain electrode of a main power device of the switching power supply. Specifically, the primary winding is wound in two parts, and the inner second part is wound in two layers.
For example: the second part of the primary winding is made of the same wire as the first part and is usually wound by an integer number of layers, and the number of layers and the number of turns of the second part are not required to be close to or equal to those of the first part. One end of the second part of the primary winding is connected with the middle node of the transformer, and the other end of the second part of the primary winding is connected with the main power device. The second part of the primary winding is arranged at the innermost side of the transformer and is connected with a point with larger du/dt on a circuit, and the winding at the outer layer can effectively shield the interference.
Through a large number of tests, the technical scheme of the invention is adopted, the control circuit of the main power device is used for getting power from the direct current bus or the drain electrode, and the high-frequency transformer without the auxiliary winding is arranged, so that the electromagnetic compatibility related test can be met by adopting the differential mode inductor, the differential mode inductor is convenient for automatic production, and the production efficiency is improved.
According to an embodiment of the present invention, there is also provided a switching power supply corresponding to the transformer apparatus. The switching power supply may include: the device comprises a rectification filter circuit, a high-frequency transformer, a main control unit, an alternating current low-impedance bypass circuit, a follow current and absorption circuit thereof and an output filter circuit. The main control unit comprises: a main switching device and a control system. The high-frequency transformer adopts the transformer device.
Wherein the rectifying and filtering circuit is connected to the primary winding of the transformer device and the main control unit. And the secondary winding of the transformer device is connected to an output filter circuit after passing through the follow current and the absorption circuit thereof.
For example: the switching power supply circuit includes: the device comprises a rectification filter circuit, follow current and absorption circuits thereof, a high-frequency transformer, an alternating current low-impedance bypass circuit, a main switching device and a control circuit thereof, and an output filter circuit. The input of the alternating current power supply is connected to the rectification filter circuit, the rectification filter circuit is connected with a circuit formed by connecting a primary winding of the high-frequency transformer and the main switching device in series, a secondary winding of the high-frequency transformer is connected with follow current and an absorption circuit thereof, the follow current and the absorption circuit thereof are connected with the output filter circuit, and the output filter circuit is connected with a load. The ac low impedance bypass circuit functions to provide a bypass path for common mode interference, and is generally formed by one or more series capacitors.
And the control system obtains electricity from the secondary side of the transformer device under the first output voltage. At a second output voltage, power is taken from the primary side of the transformer device. The output precision of the first output voltage is greater than that of the second voltage. The first output voltage is an output voltage that has a high requirement for output accuracy. The second output voltage is an output voltage with a low requirement for output accuracy.
For example: the transformer has no auxiliary winding. The control circuit may be powered by a dc bus or drain voltage. There are two types of electricity-taking methods, namely direct current bus electricity-taking and drain electrode electricity-taking. The feedback mode has two kinds, namely the requirement on the precision of the output voltage is high, secondary side feedback is adopted, and isolation is realized through a transformer or an optical coupler. If the requirement on the precision of the output voltage is not high, primary side feedback is adopted.
Therefore, the control circuit of the main power device gets power from the direct current bus or the drain electrode, the transformer has no auxiliary winding, the problems of complex circuit, multiple loop components and high cost caused by the fact that the transformer is provided with the auxiliary winding can be solved, and the circuit structure is simplified.
In some embodiments, the rectifying and filtering circuit includes: a rectifier bridge and a filter circuit; the rectifier bridge is matched with the filter circuit. The filter circuit includes: two differential mode inductances and two capacitances. The two differential mode inductors are arranged in parallel, and the two capacitors are arranged at the end parts of the two differential mode inductors in parallel.
For example: the rectification filter circuit consists of a rectification bridge and a filter circuit, the filter circuit consists of two differential mode inductors and two capacitors, the inductance values of the two differential mode inductors can be the same or different, and the capacitance values of the two capacitors can be the same or different. The common mode inductor is adopted, but the common mode inductor can not be inserted, and the scheme of the invention adopts the differential mode inductor to replace the common mode inductor, thereby realizing automatic production. The capacitor on the AC side is a thin film capacitor, and the capacitor on the DC side is an electrolytic capacitor. The whole structure plays a role in rectifying and filtering, and the rectifier bridge plays a role in converting alternating current into direct current. At each position, the first capacitor C1, the second capacitor C2, the first inductor L1 and the second inductor L2 can play a role in suppressing electromagnetic interference of a power grid.
In some embodiments, the rectifier bridge is disposed between the two capacitors and located on either side of the two differential-mode inductors, or the rectifier bridge is disposed on the same side of the two capacitors. Of the two capacitors, the capacitor on the AC side is a thin film capacitor, and the capacitor on the DC side is an electrolytic capacitor.
For example: the rectification filter circuit can be divided into 4 structures according to the fact that the filter component is located on the alternating current side or the direct current side, wherein a capacitor located on the alternating current side is a thin film capacitor, and a capacitor located on the direct current side is an electrolytic capacitor. The alternating current side capacitor has the function of filtering differential mode interference, and the direct current side capacitor has the function of stabilizing direct current voltage through charging and discharging. The functions are different and are selected according to the characteristics of the capacitor.
Since the processing and functions implemented by the switching power supply of this embodiment substantially correspond to the embodiments, principles, and examples of the foregoing devices, reference may be made to the related descriptions in the foregoing embodiments without being detailed in the description of this embodiment.
Through a large number of tests, the technical scheme of the invention is adopted, the driving and control circuit gets power from the direct current bus or the drain electrode, and the transformer has no auxiliary winding, so that the transformer has smaller volume, lower leakage inductance and simpler circuit structure.
According to the embodiment of the invention, a power adapter corresponding to the switching power supply is also provided. The power adapter may include: the switching power supply described above.
The switching power supply and the power adapter convert the strong power of a power grid into the weak power used by electronic equipment, and are key core parts of a plurality of electronic equipment. In order to meet the requirement of electromagnetic compatibility testing, common-mode inductors are adopted as filters by most of switching power supplies and power adapters in some schemes, but the common-mode inductors cannot be inserted by machines, so that the common-mode inductors are not beneficial to automatic production, and the labor cost and the working time are increased. In some schemes, most high-frequency transformers of the switching power supply and the power adapter are provided with auxiliary windings for control of a main power device and output voltage feedback, the auxiliary windings and loops thereof increase circuit complexity, product cost is improved, the size and leakage inductance of the transformer are increased, voltage stress of the main power device is increased, and reliability of the switching power supply and the power adapter is reduced.
In some embodiments, the present invention provides a switching power supply circuit that can use two differential mode inductors instead of a common mode inductor and has no auxiliary winding of a high frequency transformer, and the switching power supply circuit can be applied to a power adapter.
In the scheme of the invention, the main circuit adopts differential mode inductance filtering and has no common mode inductance;
according to the scheme provided by the invention, through the special design of the transformer winding, the electromagnetic compatibility test can be satisfied by adopting the differential mode inductor to replace the common mode inductor, and the problem that the common mode inductor is not beneficial to automatic production because the common mode inductor can not be inserted by a machine can be solved, so that the automatic production is facilitated and the production efficiency is improved. In other words, the scheme of the invention solves the problem that the traditional filter circuit cannot be mechanically plugged by adopting a common mode inductor through the special design of the transformer winding, can meet the relevant test of electromagnetic compatibility by adopting a differential mode inductor, is convenient for automatic production and improves the production efficiency.
In the scheme of the invention, the driving and control circuit gets power from a direct current bus or a drain electrode, and the transformer has no auxiliary winding. Specifically, in the scheme of the invention, the high-frequency transformer only has a primary winding and an output winding; the outermost layer of the transformer is a first part of a primary winding, only one layer of the primary winding is wound, and the outermost layer of the transformer is connected with a dead point of a direct-current bus; the primary winding first part, the output winding, the shielding layer and the primary winding second part are sequentially arranged from outside to inside; the second part of the primary winding is connected with the main power device.
According to the scheme, the control circuit of the main power device obtains power from the direct current bus or the drain electrode, the transformer is provided with no auxiliary winding, the problems of complex circuit, multiple loop components and high cost caused by the fact that the transformer is provided with the auxiliary winding can be solved, and the circuit structure is simplified. In other words, in the scheme of the invention, the control circuit of the main power device adopts direct current bus electricity taking or drain electrode electricity taking, so that the problems that the traditional transformer needs an auxiliary winding and the circuit structure is complex are solved, and the transformer has smaller volume, lower leakage inductance and simpler circuit structure.
In some embodiments, a specific implementation process of the scheme of the present invention may be exemplarily described in conjunction with the examples shown in fig. 1 to 5.
Fig. 2 is a schematic structural diagram of an embodiment of a switching power supply circuit. As shown in fig. 2, the switching power supply circuit includes: the device comprises a rectification filter circuit, follow current and absorption circuits thereof, a high-frequency transformer, an alternating current low-impedance bypass circuit, a main switching device and a control circuit thereof, and an output filter circuit. The input of the alternating current power supply is connected to the rectification filter circuit, the rectification filter circuit is connected with a circuit formed by connecting a primary winding of the high-frequency transformer and the main switching device in series, a secondary winding of the high-frequency transformer is connected with follow current and an absorption circuit thereof, the follow current and the absorption circuit thereof are connected with the output filter circuit, and the output filter circuit is connected with a load.
In the example shown in fig. 2, the transformer has no auxiliary winding. There are two types of electricity-taking methods, namely direct current bus electricity-taking and drain electrode electricity-taking. Two feedback modes are provided, namely, the requirement on the precision of output voltage is high, secondary side feedback is adopted, and isolation is realized through a transformer or an optical coupler; if the requirement on the precision of the output voltage is not high, primary side feedback is adopted.
In the example of fig. 2, the ac low impedance bypass circuit functions to provide a bypass path for common mode interference, typically using one or more series capacitors. In particular, 2nF ceramic capacitors are used in series in this embodiment.
In the example shown in fig. 2, the main power device and its control circuit may be integrated in a chip, or may be discrete devices. As shown in fig. 2, the control circuit may be powered by a dc bus or drain voltage. The output voltage has two feedback modes, usually secondary side feedback, and is isolated by a transformer or an optical coupler; if the requirement on the precision of the output voltage is not high, primary side feedback can also be adopted.
Fig. 3 is a schematic structural diagram of an embodiment of a rectifying and filtering circuit. As shown in fig. 3, the rectifying and filtering circuit is composed of a rectifying bridge and a filtering circuit, the filtering circuit is composed of two differential mode inductors and two capacitors, the inductance values of the two differential mode inductors may be the same or different, and the capacitance values of the two capacitors may be the same or different.
In the example shown in fig. 3, a common mode inductor is used, but the common mode inductor cannot be mechanically inserted, and the scheme of the invention adopts a differential mode inductor instead of the common mode inductor, so that automatic production can be realized. The capacitor on the ac side is a thin film capacitor, the capacitor on the dc side is an electrolytic capacitor, and the rectifier bridge can be placed at any position as shown in fig. 3. The whole structure plays a role in rectifying and filtering, and the rectifier bridge plays a role in converting alternating current into direct current; at each position, the first capacitor C1, the second capacitor C2, the first inductor L1 and the second inductor L2 can play a role in suppressing electromagnetic interference of a power grid.
Generally, in the scheme of the present invention, the rectifying and filtering circuit may be divided into 4 structures as shown in fig. 3 according to whether the filtering component is located on the ac or dc side, where the capacitor located on the ac side is a thin film capacitor, and the capacitor located on the dc side is an electrolytic capacitor.
The structure 4 in fig. 3 is adopted, wherein 2 differential mode inductors are all h-shaped inductors of 220uH, and the first capacitor C1 and the second inductor C2 are aluminum electrolytic capacitors of 10F/400V and 33F/400V respectively.
In some embodiments, the transformer winding structure is as shown in fig. 1. The primary winding is the primary winding, and the secondary winding is the secondary winding. In the transformer winding structure, a primary winding first part, a secondary winding, a shielding winding and a primary winding second part are sequentially arranged from outside to inside, the windings are wound on a transformer framework 1, insulating tapes 2 are adopted for insulation among the windings, and the number of turns of the tapes is usually 1-3.
The first part of the primary winding is only wound on one layer, the whole layer is paved in a close winding or sparse winding mode, one end of the first part of the primary winding is connected with the positive electrode of the direct-current bus, and the other end of the first part of the primary winding is connected with the middle node of the transformer.
And the secondary winding determines the number of strands, the wire diameter and the number of turns of the winding according to the number of output circuits, current and voltage.
The shielding winding is wound by adopting metal foil, metal strip or metal wire, is fully wound by one layer and can adopt a multi-strand parallel winding mode; the shielding winding is connected with the positive end of the direct current bus, and the head end and the tail end of the shielding winding cannot be short-circuited.
The second part of the primary winding is made of the same wire as the first part and is usually wound by an integer number of layers, and the number of layers and the number of turns of the second part are not required to be close to or equal to those of the first part; one end of the second part of the primary winding is connected with the middle node of the transformer, and the other end of the second part of the primary winding is connected with the main power device.
In particular, in one embodiment, the number of output paths is 1, the wire diameter of the secondary winding is 0.4mm, and 2 strands are wound in parallel and fully wound by 2 layers; the wire diameter of the first part of the primary winding is 0.3mm, and the single strand is wound all over one layer; the diameter of the second part of the primary winding is 0.3mm, and the single strand is wound fully in 2 layers; the diameter of the shielding winding wire is 0.18mm, and 4 strands are wound in parallel and are fully wound.
In the scheme of the invention, the whole circuit is simple, the later-stage PCB layout is convenient, the device type selection is favorable for automatic assembly, and the excellent EMC performance can be ensured while the control circuit is low in cost. Fig. 4 shows the actual measurement result of conducted EMI of the switching power supply circuit according to the embodiment, where the margin is higher than 7.54dB in the frequency band of 150kHz to 30MHz, which completely meets the national standard requirements.
FIGS. 4 and 5 illustrate the technical effects and advantages of the present invention in a typical circuit, i.e., good EMI performance; the transformer structure has no auxiliary winding, the transformer structure is simplified, the production is more convenient, and the cost is lower.
Since the processing and functions implemented by the method of this embodiment substantially correspond to the embodiments, principles, and examples of the switching power supply, reference may be made to the related descriptions in the foregoing embodiments without being detailed in the description of this embodiment.
Through a large number of tests, the technical scheme of the embodiment is adopted, and the two differential mode inductors are adopted to replace a common mode inductor and a switching power supply circuit without an auxiliary winding of a high-frequency transformer, so that the switching power supply circuit is applied to a power adapter, the circuit structure can be simplified, and the production efficiency can be improved.
In summary, it is readily understood by those skilled in the art that the advantageous modes described above can be freely combined and superimposed without conflict.
The above description is only an example of the present invention, and is not intended to limit the present invention, and it is obvious to those skilled in the art that various modifications and variations can be made in the present invention. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the scope of the claims of the present invention.
Claims (10)
1. A transformer apparatus, comprising: the primary winding module, the secondary winding and the shielding layer; the primary winding module includes: a primary winding first portion and a primary winding second portion; wherein,
the primary winding first part, the secondary winding, the shielding layer and the primary winding second part are sequentially arranged according to a set direction;
the primary winding first part is configured to be connected with a direct current bus; the primary winding second part is configured to be connected with a main power device of a switching power supply.
2. The transformer apparatus of claim 1, further comprising: a transformer bobbin (1);
the primary winding first part, the secondary winding, the shielding layer and the primary winding second part are wound on the transformer framework (1); and an insulating layer is arranged between adjacent parts of the primary winding first part, the secondary winding, the shielding layer and the primary winding second part.
3. The transformer arrangement according to claim 1 or 2, wherein the first part of the primary winding is wound only one layer and is laid over the entire layer in a close-wound or open-wound manner; a first end of the primary winding first portion configured to connect to a direct current bus positive; a second end of the first portion of the primary winding configured to be connected to an intermediate node of the transformer arrangement.
4. The transformer arrangement according to claim 1 or 2, wherein the secondary winding is capable of determining at least one of a number of winding strands, a wire diameter and a number of turns based on at least one of a target output number, a target output current and a target output voltage.
5. The transformer arrangement according to claim 1 or 2, characterized in that the shielding layer comprises a shielding winding; the shielding winding is wound by any one of metal foils, metal strips and metal wires, is fully wound by one layer and can be wound by a multi-strand parallel winding mode; the shielding winding is configured to be connected with the positive electrode of the direct current bus, and the head end and the tail end of the shielding winding are arranged in a short circuit prevention mode.
6. The transformer arrangement according to claim 1 or 2, wherein the second part of the primary winding is wound in two layers and in the entire layer using the same wire as the first part of the primary winding; a first end of the second portion of the primary winding configured to be connected to an intermediate node of the transformer arrangement; and the second end of the second part of the primary winding is configured to be connected with the drain electrode of a main power device of the switching power supply.
7. A switching power supply, comprising: the device comprises a rectification filter circuit, a high-frequency transformer, a main control unit, an alternating current low-impedance bypass circuit, a follow current and absorption circuit thereof and an output filter circuit; the main control unit comprises: a main switching device and a control system; the high-frequency transformer, which adopts the transformer device of any one of claims 1 to 6; wherein,
the rectification filter circuit is connected to the primary winding of the transformer device and the main control unit; the secondary winding of the transformer device is connected to the output filter circuit after passing through the follow current and the absorption circuit thereof;
the control system obtains electricity from the secondary side of the transformer device under a first output voltage; taking electricity from the primary side of the transformer device under a second output voltage; the output precision of the first output voltage is greater than that of the second voltage; the output precision of the first output voltage is greater than that of the second voltage.
8. The switching power supply according to claim 7, wherein the rectifying-filtering circuit comprises: a rectifier bridge and a filter circuit; the rectifier bridge is matched with the filter circuit; the filter circuit includes: two differential mode inductors and two capacitors; the two differential mode inductors are arranged in parallel, and the two capacitors are arranged at the end parts of the two differential mode inductors in parallel.
9. The switching power supply according to claim 8, wherein the rectifier bridge is disposed between the two capacitors and on either side of the two differential mode inductors, or the rectifier bridge is disposed on the same side of the two capacitors; of the two capacitors, the capacitor on the AC side is a thin film capacitor, and the capacitor on the DC side is an electrolytic capacitor.
10. A power adapter, comprising: the switching power supply according to any one of claims 7 to 9.
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| CN202011010778.2A CN112233888A (en) | 2020-09-23 | 2020-09-23 | A transformer device, switching power supply and power adapter |
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| CN202011010778.2A CN112233888A (en) | 2020-09-23 | 2020-09-23 | A transformer device, switching power supply and power adapter |
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| CN112821787A (en) * | 2021-01-04 | 2021-05-18 | 格力电器（武汉）有限公司 | Switching power supply transformer, switching power supply circuit and switching power supply |
| CN113436865A (en) * | 2021-06-24 | 2021-09-24 | 珠海格力电器股份有限公司 | Transformer and switching power supply circuit |
| CN113470948A (en) * | 2021-07-05 | 2021-10-01 | 珠海格力电器股份有限公司 | High-frequency transformer, flyback switching power supply and power adapter |
| CN113726183A (en) * | 2021-09-14 | 2021-11-30 | 珠海格力电器股份有限公司 | Switching power supply circuit and power adapter |
| US20220174798A1 (en) * | 2020-12-01 | 2022-06-02 | Eti Solid State Lighting (Zhuhai) Ltd. | Lamp control system |
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