CN112994440A - Electromagnetic interference suppression device and method of power adapter and power adapter - Google Patents
Electromagnetic interference suppression device and method of power adapter and power adapter Download PDFInfo
- Publication number
- CN112994440A CN112994440A CN202110156488.7A CN202110156488A CN112994440A CN 112994440 A CN112994440 A CN 112994440A CN 202110156488 A CN202110156488 A CN 202110156488A CN 112994440 A CN112994440 A CN 112994440A
- Authority
- CN
- China
- Prior art keywords
- electromagnetic interference
- differential mode
- unit
- electrolytic capacitor
- bus
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 230000001629 suppression Effects 0.000 title claims abstract description 48
- 238000000034 method Methods 0.000 title claims abstract description 18
- 239000003990 capacitor Substances 0.000 claims abstract description 128
- 238000001914 filtration Methods 0.000 claims abstract description 38
- 230000006641 stabilisation Effects 0.000 claims description 9
- 238000011105 stabilization Methods 0.000 claims description 9
- 230000001681 protective effect Effects 0.000 claims description 5
- 238000012545 processing Methods 0.000 claims description 3
- 230000010349 pulsation Effects 0.000 claims description 2
- 239000000126 substance Substances 0.000 claims 4
- 230000000694 effects Effects 0.000 abstract description 22
- 238000012360 testing method Methods 0.000 description 12
- 238000010586 diagram Methods 0.000 description 11
- 230000035699 permeability Effects 0.000 description 11
- 239000011888 foil Substances 0.000 description 9
- 239000000463 material Substances 0.000 description 7
- 230000004907 flux Effects 0.000 description 6
- 229910001053 Nickel-zinc ferrite Inorganic materials 0.000 description 4
- 238000011161 development Methods 0.000 description 4
- 230000002829 reductive effect Effects 0.000 description 4
- 238000004804 winding Methods 0.000 description 4
- 229910052782 aluminium Inorganic materials 0.000 description 3
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 3
- 239000004020 conductor Substances 0.000 description 3
- 239000003989 dielectric material Substances 0.000 description 3
- 238000007599 discharging Methods 0.000 description 3
- 239000003792 electrolyte Substances 0.000 description 3
- 238000004146 energy storage Methods 0.000 description 3
- 229910052751 metal Inorganic materials 0.000 description 3
- 239000002184 metal Substances 0.000 description 3
- 229910044991 metal oxide Inorganic materials 0.000 description 3
- 150000004706 metal oxides Chemical class 0.000 description 3
- TWNQGVIAIRXVLR-UHFFFAOYSA-N oxo(oxoalumanyloxy)alumane Chemical compound O=[Al]O[Al]=O TWNQGVIAIRXVLR-UHFFFAOYSA-N 0.000 description 3
- BPUBBGLMJRNUCC-UHFFFAOYSA-N oxygen(2-);tantalum(5+) Chemical compound [O-2].[O-2].[O-2].[O-2].[O-2].[Ta+5].[Ta+5] BPUBBGLMJRNUCC-UHFFFAOYSA-N 0.000 description 3
- 229910052715 tantalum Inorganic materials 0.000 description 3
- GUVRBAGPIYLISA-UHFFFAOYSA-N tantalum atom Chemical compound [Ta] GUVRBAGPIYLISA-UHFFFAOYSA-N 0.000 description 3
- PBCFLUZVCVVTBY-UHFFFAOYSA-N tantalum pentoxide Inorganic materials O=[Ta](=O)O[Ta](=O)=O PBCFLUZVCVVTBY-UHFFFAOYSA-N 0.000 description 3
- 230000002146 bilateral effect Effects 0.000 description 2
- 230000005540 biological transmission Effects 0.000 description 2
- 238000001514 detection method Methods 0.000 description 2
- 230000005764 inhibitory process Effects 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000007935 neutral effect Effects 0.000 description 2
- 230000008569 process Effects 0.000 description 2
- 229910001018 Cast iron Inorganic materials 0.000 description 1
- 229910000976 Electrical steel Inorganic materials 0.000 description 1
- JIYIUPFAJUGHNL-UHFFFAOYSA-N [O--].[O--].[O--].[O--].[O--].[O--].[O--].[O--].[O--].[O--].[O--].[O--].[O--].[O--].[O--].[O--].[O--].[O--].[O--].[O--].[Mn++].[Mn++].[Mn++].[Fe+3].[Fe+3].[Fe+3].[Fe+3].[Fe+3].[Fe+3].[Fe+3].[Fe+3].[Fe+3].[Fe+3].[Zn++].[Zn++] Chemical group [O--].[O--].[O--].[O--].[O--].[O--].[O--].[O--].[O--].[O--].[O--].[O--].[O--].[O--].[O--].[O--].[O--].[O--].[O--].[O--].[Mn++].[Mn++].[Mn++].[Fe+3].[Fe+3].[Fe+3].[Fe+3].[Fe+3].[Fe+3].[Fe+3].[Fe+3].[Fe+3].[Fe+3].[Zn++].[Zn++] JIYIUPFAJUGHNL-UHFFFAOYSA-N 0.000 description 1
- 230000002238 attenuated effect Effects 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 238000013016 damping Methods 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 230000005670 electromagnetic radiation Effects 0.000 description 1
- 230000036039 immunity Effects 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 230000001939 inductive effect Effects 0.000 description 1
- 230000002401 inhibitory effect Effects 0.000 description 1
- 239000000696 magnetic material Substances 0.000 description 1
- 230000003071 parasitic effect Effects 0.000 description 1
- 229910000859 α-Fe Inorganic materials 0.000 description 1
Images
Classifications
-
- 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
- H02M1/44—Circuits or arrangements for compensating for electromagnetic interference in converters or inverters
-
- 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
- H02M1/126—Arrangements for reducing harmonics from ac input or output using passive filters
-
- 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
- H02M1/14—Arrangements for reducing ripples from dc input or output
-
- 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
- H02M1/32—Means for protecting converters other than automatic disconnection
Landscapes
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Physics & Mathematics (AREA)
- Electromagnetism (AREA)
- Filters And Equalizers (AREA)
Abstract
The invention discloses an electromagnetic interference suppression device and method of a power adapter and the power adapter, the device includes: the input ends of a live wire and a zero line of an alternating current power supply of the power adapter are provided with a protection unit, a rectification unit and an electromagnetic interference suppression unit; the electromagnetic interference suppression unit is arranged on the positive bus and the negative bus of the output end of the rectification unit; the protection unit is configured to perform overvoltage protection on input ends of a live wire and a zero wire of an alternating-current power supply; the rectifying unit is configured to rectify alternating currents input from a live line and a zero line of an alternating current power supply and output unidirectional pulsating direct current voltage to the positive bus and the negative bus; and the electromagnetic interference suppression unit is configured to suppress electromagnetic interference carried in the unidirectional pulsating direct current voltage so as to suppress the electromagnetic interference of the power supply of the electrical equipment. According to the scheme, the differential mode inductor and the electrolytic capacitor are adopted to suppress the common mode noise, and the filtering effect can be improved.
Description
Technical Field
The invention belongs to the technical field of power supplies, particularly relates to an electromagnetic interference suppression device and method of a power adapter and the power adapter, and particularly relates to an electromagnetic interference suppression device and method of a conduction power adapter and the power adapter.
Background
Electromagnetic Interference (EMI), which is electronic noise that interferes with the cable signal and reduces the integrity of the signal, is typically generated by sources of Electromagnetic radiation, such as motors and machinery. Conducted electromagnetic interference is mainly classified into common mode noise and differential mode noise. Common mode noise refers to noise of the power supply lines to ground, and differential mode noise mainly refers to noise between the power supply lines. The common mode noise is mainly transmitted back to the power supply inlet end through a power supply to ground distribution parameter, particularly a return flow path formed by a parasitic capacitance of the device to the ground.
In the related scheme, a common mode choke coil is adopted, and differential mode filtering is performed by utilizing magnetic flux leakage generated by the non-dense winding of the common mode choke coil, so that the common mode choke coil is used for inhibiting common mode noise and has a poor filtering effect.
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 an electromagnetic interference suppression device and method of a power adapter and the power adapter, so as to solve the problems that the common mode noise is suppressed and the filtering effect is poor by using magnetic flux leakage generated by the winding of a common mode choke coil, and the common mode noise is suppressed by using a differential mode inductor and an electrolytic capacitor, and the effect of improving the filtering effect can be achieved.
The invention provides an electromagnetic interference suppression device of a power adapter, comprising: the input ends of a live wire and a zero line of an alternating current power supply of the power adapter are provided with a protection unit, a rectification unit and an electromagnetic interference suppression unit; the electromagnetic interference suppression unit is arranged on the positive bus and the negative bus of the output end of the rectification unit; the protection unit is configured to perform overvoltage protection on input ends of a live wire and a zero wire of the alternating-current power supply; the rectifying unit is configured to rectify alternating currents input from a live line and a zero line of the alternating current power supply and output unidirectional pulsating direct current voltage to a positive bus and a negative bus; the electromagnetic interference suppression unit is configured to suppress electromagnetic interference carried in the unidirectional pulsating direct current voltage so as to suppress electromagnetic interference of a power supply of electrical equipment.
In some embodiments, the protection unit includes: a piezoresistor and a fuse tube; the piezoresistor and the protective tube are arranged at the input ends of the live wire and the zero line of the alternating current power supply.
In some embodiments, the rectifying unit includes: a rectifier module or a rectifier bridge; the rectification module includes: and the diode rectifying module.
In some embodiments, the electromagnetic interference suppressing unit includes: a differential mode inductance module and an electrolytic capacitor module; the differential mode inductance module is configured to perform common mode rejection on the unidirectional pulsating direct current voltage; the electrolytic capacitor module is configured to perform voltage stabilization and filtering processing on the unidirectional pulsating direct current voltage.
In some embodiments, the differential mode inductance module comprises: a first differential mode inductance and a second differential mode inductance; the first differential mode inductor is arranged on a positive bus in positive and negative buses at the output end of the rectifying unit; and the second differential mode inductor is symmetrical to the first differential mode inductor and is arranged on a negative bus in the positive and negative buses at the output end of the rectifying unit.
In some embodiments, the electrolytic capacitor module comprises: a first electrolytic capacitor and a second electrolytic capacitor; the first electrolytic capacitor is positioned on one side of the differential mode inductance module, which is close to the rectifying unit, and is arranged between a positive bus and a negative bus in a positive bus and a negative bus at the output end of the rectifying unit; the first electrolytic capacitor is positioned on one side, far away from the rectifying unit, of the differential mode inductance module and is arranged between a positive bus and a negative bus in the positive bus and the negative bus at the output end of the rectifying unit.
In accordance with the above apparatus, a further aspect of the present invention provides a power adapter, comprising: the electromagnetic interference suppression device of the power adapter is described above.
In another aspect, the present invention provides a method for suppressing electromagnetic interference of a power adapter, including: performing overvoltage protection on input ends of a live wire and a zero line of the alternating current power supply through a protection unit; rectifying alternating current input from a live wire and a zero line of the alternating current power supply through a rectifying unit, and outputting unidirectional pulsating direct current voltage to a positive bus and a negative bus; through an electromagnetic interference suppression unit, suppressing electromagnetic interference carried in the unidirectional pulsating direct current voltage so as to suppress the electromagnetic interference of a power supply of electrical equipment; the protection unit, the rectification unit and the electromagnetic interference suppression unit are arranged at the input ends of a live wire and a zero wire of an alternating current power supply of the power adapter; the electromagnetic interference suppression unit is arranged on the positive bus and the negative bus of the output end of the rectification unit.
In some embodiments, the electromagnetic interference suppressing unit includes: a differential mode inductance module and an electrolytic capacitor module; through electromagnetic interference suppression unit, restrain the electromagnetic interference who carries in the one-way pulsation direct current voltage, include: common mode suppression is carried out on the unidirectional pulsating direct current voltage through a differential mode inductance module; and carrying out voltage stabilization and filtering treatment on the unidirectional pulsating direct current voltage through an electrolytic capacitor module.
In some embodiments, wherein the differential mode inductance module comprises: a first differential mode inductance and a second differential mode inductance; the first differential mode inductor is arranged on a positive bus in positive and negative buses at the output end of the rectifying unit; the second differential mode inductor is symmetrical to the first differential mode inductor and is arranged on a negative bus in the positive and negative buses at the output end of the rectifying unit; the electrolytic capacitor module comprises: a first electrolytic capacitor and a second electrolytic capacitor; the first electrolytic capacitor is positioned on one side, close to the rectifying unit, of the differential mode inductance module and is arranged between a positive bus and a negative bus in the positive bus and the negative bus at the output end of the rectifying unit; the first electrolytic capacitor is positioned on one side, far away from the rectifying unit, of the differential mode inductance module and is arranged between a positive bus and a negative bus in the positive bus and the negative bus at the output end of the rectifying unit.
Therefore, according to the scheme of the invention, a pair of differential mode inductors capable of symmetrically filtering are connected in series on the positive bus and the negative bus of the power adapter, and a pair of electrolytic capacitors are arranged on the front side and the rear side of the pair of differential mode inductors, so that common mode noise of the power adapter is suppressed; therefore, the filtering effect can be improved by adopting the differential mode inductor and the electrolytic capacitor to suppress the common mode noise; in addition, an X capacitor is not needed for filtering, and cost can be saved.
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 structural diagram of an EMI suppression apparatus for a power adapter according to an embodiment of the present invention;
FIG. 2 is a schematic diagram of an embodiment of a filter circuit of a power adapter according to the related art;
FIG. 3 is a graph illustrating a filtering effect test result of the filter circuit shown in FIG. 2, wherein a terminal disturbance voltage at 2.22 megahertz (MHz) actually exceeds 1.93 decibels (dB);
fig. 4 is a schematic structural diagram of an embodiment of a filter circuit of a power adapter of the present invention, and in particular, is a schematic structural diagram of an embodiment of a positive-negative bus differential mode inductance symmetric common mode filter circuit;
FIG. 5 is a schematic diagram of a curve of a filtering effect test result using the filter circuit shown in FIG. 4, specifically measuring a margin 8.95dB at a position of 2.48MHz of a terminal disturbance voltage;
fig. 6 is a flowchart illustrating an electromagnetic interference suppressing method for a power adapter according to an embodiment of the present invention.
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 an electromagnetic interference suppressing apparatus for a power adapter. Referring to fig. 1, a schematic diagram of an embodiment of the apparatus of the present invention is shown. The electromagnetic interference suppression device of the power adapter may include: the input ends of the live wire and the zero line of the alternating current power supply of the power adapter are provided with a protection unit (such as a protection circuit), a rectification unit (such as a rectification circuit) and an electromagnetic interference suppression unit. The electromagnetic interference suppression unit is arranged on the positive bus and the negative bus of the output end of the rectification unit.
The protection unit is configured to perform overvoltage protection on input ends of a live wire and a zero wire of the alternating current power supply.
In some embodiments, the protection unit includes: a piezoresistor and a fuse tube. The voltage dependent resistor and the protective tube are arranged at the input ends of the live wire and the zero line of the alternating current power supply so as to carry out overvoltage protection on the input ends of the live wire and the zero line of the alternating current power supply.
Specifically, the protection circuit consists of a piezoresistor and a protective tube and is used for overvoltage protection at the alternating current input end of electrical equipment.
The rectifying unit is configured to rectify alternating currents input from a live line and a zero line of the alternating current power supply and output unidirectional pulsating direct current voltage to the positive and negative buses.
In some embodiments, the rectifying unit includes: and the rectifier module or the rectifier bridge is used for rectifying alternating current input from a live wire and a zero line of the alternating current power supply and outputting unidirectional pulsating direct current voltage to the positive bus and the negative bus. The rectification module includes: and the diode rectifying module.
Specifically, the rectifying circuit is internally composed of 4 rectifying diodes or a single rectifying bridge, and unidirectional pulsating direct-current voltage is output by controlling the on-off of different diodes by utilizing the unidirectional conduction characteristic of the diodes.
The electromagnetic interference suppression unit is configured to suppress electromagnetic interference carried in the unidirectional pulsating direct current voltage so as to suppress electromagnetic interference of a power supply of electrical equipment.
Therefore, by adopting the protection unit (such as a protection circuit), the rectification unit (such as a rectification circuit) and the electromagnetic interference suppression unit, the EMI of the high-frequency switch circuit in the power adapter can be suppressed starting from the interference noise propagation path, and the electromagnetic interference of the power adapter and the electromagnetic interference propagation path can be effectively suppressed.
In some embodiments, the electromagnetic interference suppressing unit includes: the device comprises a differential mode inductance module and an electrolytic capacitor module. The differential mode inductance module and the electrolytic capacitor module are both arranged on a positive bus and a negative bus of the output end of the rectifying unit.
Wherein the differential mode inductance module is configured to perform common mode rejection on the unidirectional pulsating direct current voltage.
In some embodiments, the differential mode inductance module comprises: a first differential mode inductance and a second differential mode inductance. The first differential mode inductor is arranged on a positive bus in the positive and negative buses at the output end of the rectifying unit. And the second differential mode inductor is symmetrical to the first differential mode inductor and is arranged on a negative bus in the positive and negative buses at the output end of the rectifying unit.
Specifically, symmetrical differential mode inductors are connected in series on the positive bus and the negative bus of the power adapter, so that the positive bus and the negative bus are balanced, and a common mode rejection effect is generated. The filter inductor behind the rectifying circuit consists of two differential mode inductors with the same size, and the nominal inductance value is between 110 microhenries (mu H) and 680 mu H. Generally, a nickel-zinc ferrite magnetic core is adopted, and the initial magnetic conductivity is 100-1000. By optimizing the filter inductance, the unilateral inductance (such as common mode inductance) in the related scheme is changed into bilateral inductance (such as a pair of differential mode inductances), namely, a pair of symmetric differential mode inductances are connected in series on a positive bus and a negative bus at the output side of the rectifying circuit, and the differential mode inductance has lower initial permeability and stronger inhibition capability on high-frequency noise due to the material of a magnetic core.
Here, the initial permeability refers to relative permeability, which is defined as a ratio of permeability μ to vacuum permeability μ 0. Commonly used vacuum permeability μ 0 ═ 4 π × 10-7H/m. If the relative permeability of air (i.e., the nonmagnetic material) is 1, the relative permeability of ferrite is 10000, i.e., when compared, the density of magnetic flux passing through the magnetic material is 10000 times. The cast iron is 200-400; the silicon steel sheet is 7000-10000; the nickel-zinc ferrite is 10-1000. No additional units are required.
The electrolytic capacitor module is configured to perform voltage stabilization and filtering processing on the unidirectional pulsating direct current voltage.
Specifically, the problem of poor differential mode filtering effect of the common mode choke coil is solved by adopting a combination of an electrolytic capacitor (such as a first electrolytic capacitor and a second electrolytic capacitor) and a symmetrical filtering differential mode inductor connected in series on a positive bus and a negative bus (namely, a differential mode inductor is distributed and connected in series on the positive bus and the negative bus), and adjusting device parameters, namely adjusting the device parameters of the electrolytic capacitor (such as the first electrolytic capacitor and the second electrolytic capacitor) and the differential mode inductor, so that an X capacitor can be omitted, the development cost is saved, the conducted electromagnetic interference is effectively reduced, and the reliability of the product is improved.
In some embodiments, the electrolytic capacitor module comprises: a first electrolytic capacitor and a second electrolytic capacitor. The first electrolytic capacitor is positioned on one side of the differential mode inductance module, which is close to the rectifying unit, and is arranged between a positive bus and a negative bus in the positive bus and the negative bus at the output end of the rectifying unit. The first electrolytic capacitor is positioned on one side, far away from the rectifying unit, of the differential mode inductance module and is arranged between a positive bus and a negative bus in the positive bus and the negative bus at the output end of the rectifying unit.
Specifically, electrolytic capacitors (e.g., a first electrolytic capacitor and a second electrolytic capacitor) are employed as differential mode filter capacitors. In the first electrolytic capacitor and the second electrolytic capacitor, the positive electrodes of the first electrolytic capacitor and the second electrolytic capacitor are metal foils (such as aluminum foils or tantalum foils), metal oxide films (such as aluminum oxide or tantalum pentoxide) attached to the positive electrodes are dielectrics, and the negative electrodes are made of conductive materials, electrolytes and other materials, so that the cost is relatively low. By utilizing the charging and discharging characteristics of the rectifier circuit, the pulsating direct current voltage rectified by the rectifier circuit is changed into relatively stable direct current voltage, and the rectifier circuit has the functions of energy storage, voltage stabilization and filtering.
The capacitance value of the first electrolytic capacitor and the second electrolytic capacitor ranges from 5 to 30 muF, and an appropriate capacitance value is selected according to the output voltage. Generally, the sum of the capacitance values of the first electrolytic capacitor and the second electrolytic capacitor is greater than twice the value of the output voltage. The capacitance values of the two capacitors are distributed through the EMI test result.
Through a large number of tests, the technical scheme of the invention is adopted, a pair of differential mode inductors capable of symmetrically filtering are connected in series on the positive bus and the negative bus of the power adapter, and a pair of electrolytic capacitors are arranged on the front side and the rear side of the pair of differential mode inductors, so that the common mode noise of the power adapter is inhibited. Therefore, the filtering effect can be improved by adopting the differential mode inductor and the electrolytic capacitor to suppress the common mode noise.
According to the embodiment of the invention, the power adapter corresponding to the electromagnetic interference suppression device of the power adapter is also provided. The power adapter may include: the electromagnetic interference suppression device of the power adapter is described above.
The Power adapter (Power adapter) is a Power supply conversion device for small portable electronic equipment and electronic appliances, generally comprises components such as a shell, a transformer, an inductor, a capacitor, a control chip (namely a control IC), a printed circuit board (namely a PCB) and the like, and the working principle of the Power adapter is that alternating current input is converted into direct current output; according to the connection mode, the device can be divided into a wall-inserting type and a desktop type. The intelligent anti-theft device is widely matched with security cameras, set top boxes, routers, light bars, massage instruments and other equipment.
In the related scheme, the power adapter adopts the common mode choking coil, and utilizes the magnetic flux leakage generated by the non-dense winding of the common mode choking coil to perform differential mode filtering, and the filtering effect is poor because the magnetic flux leakage amount (namely the leakage magnetic flux) generated by the non-dense winding of the common mode choking coil is not large. Therefore, an X capacitor needs to be added to the ac side of the power adapter for differential mode filtering, but the cost of the X capacitor is high.
Wherein, the X capacitor is a capacitor for suppressing power supply electromagnetic interference. The main roles in the circuit are: and the power supply overline circuit, the EMI filtering circuit, the spark eliminating circuit and the like ensure that the finished product of the electronic product meets the EMC requirement.
Fig. 2 is a schematic structural diagram of an embodiment of a filter circuit of a power adapter in a related scheme. As shown in fig. 2, the filter circuit of the power adapter includes: the protection circuit, the first X capacitor, the filter inductor, the second X capacitor, the rectifying circuit and the electrolytic capacitor are sequentially connected with a live wire (L) and a zero line (N) of an alternating current power supply.
In the example shown in fig. 2, the value of the X capacitance is generally in the range of 0.01 microfarad (uF) -1uF, and is mainly used for suppressing the differential mode noise interference. Generally, a safety resistor is connected in parallel to two ends of the X capacitor. In the related scheme, a common mode choke (such as a common mode inductor) is used as a filter inductor of the filter circuit, the common mode choke generally adopts a manganese-zinc ferrite core, and the initial permeability of the common mode choke is 8000-10000. When a common mode current flows through the coil of the common mode choke coil, due to the common mode current isotropy, an equidirectional magnetic field is generated in the coil of the common mode choke coil to increase the inductive reactance of the coil, so that the coil of the common mode choke coil presents high impedance, a strong damping effect is generated, the common mode current is attenuated, and the purpose of filtering is achieved. However, in such a filter circuit, the cost of the device is high, for example, the cost of the common mode choke coil and the cost of the X capacitor are high.
Fig. 3 is a schematic diagram of a curve of a filtering effect test result of the filter circuit shown in fig. 2, specifically, a terminal disturbance voltage 2.22 megahertz (MHz) exceeds 1.93 decibels (dB).
In some embodiments, according to an aspect of the present invention, an electromagnetic interference suppression method for a conduction power adapter and a power adapter are provided, where an X-capacitor-free filter circuit is used to suppress EMI of a high-frequency switch circuit in the power adapter from an interference noise propagation path, so as to effectively suppress electromagnetic interference of the power adapter and the propagation path thereof.
Specifically, according to the scheme of the invention, symmetrical differential mode inductors are connected in series on the positive bus and the negative bus of the power adapter, so that the positive bus and the negative bus are balanced in circuit, and a common mode rejection effect is generated.
The scheme of the invention adopts electrolytic capacitors (such as a first electrolytic capacitor and a second electrolytic capacitor) as differential mode filter capacitors.
Thus, according to the scheme of the invention, a combination of an electrolytic capacitor (such as a first electrolytic capacitor and a second electrolytic capacitor) and a symmetrical filtering differential mode inductor connected in series on a positive bus and a negative bus (namely, a differential mode inductor is distributed and connected in series on the positive bus and the negative bus) is adopted, and device parameters are adjusted, namely, the device parameters of the electrolytic capacitor (such as the first electrolytic capacitor and the second electrolytic capacitor) and the differential mode inductor are adjusted, so that the problem of poor differential mode filtering effect of the common mode choke coil is solved, an X capacitor can be omitted, the development cost is saved, the conducted electromagnetic interference is effectively reduced, and the reliability of the product is improved.
Fig. 4 is a schematic structural diagram of an embodiment of a filter circuit of a power adapter of the present invention, and in particular, is a schematic structural diagram of an embodiment of a positive-negative bus differential mode inductance symmetric common mode filter circuit. Fig. 4 can show the principle of a circuit for improving the noise immunity of positive and negative bus differential mode inductors. As shown in fig. 4, the positive and negative bus differential mode inductance symmetric common mode filter circuit includes: the protection circuit, the rectification circuit, the first electrolytic capacitor, the filter inductor and the second electrolytic capacitor are sequentially connected with a live wire L and a zero line N of an alternating current power supply. The first electrolytic capacitor, the filter inductor and the second electrolytic capacitor are all differential mode devices, and cost is low.
The protection circuit consists of a piezoresistor and a protective tube and is used for overvoltage protection at the alternating current input end of electrical equipment.
The rectification circuit is internally composed of 4 rectifier diodes or a single rectifier bridge, and the unidirectional pulsating direct-current voltage is output by controlling the on-off of different diodes by utilizing the unidirectional conduction characteristic of the diodes.
In the first electrolytic capacitor and the second electrolytic capacitor, the positive electrodes of the first electrolytic capacitor and the second electrolytic capacitor are metal foils (such as aluminum foils or tantalum foils), metal oxide films (such as aluminum oxide or tantalum pentoxide) attached to the positive electrodes are dielectrics, and the negative electrodes are made of conductive materials, electrolytes and other materials, so that the cost is relatively low. By utilizing the charging and discharging characteristics of the rectifier circuit, the pulsating direct current voltage rectified by the rectifier circuit is changed into relatively stable direct current voltage, and the rectifier circuit has the functions of energy storage, voltage stabilization and filtering.
In the scheme of the invention, the capacitance value of the first electrolytic capacitor and the second electrolytic capacitor ranges from 5 to 30 muF, and an appropriate capacitance value is selected according to the output voltage. Generally, the sum of the capacitance values of the first electrolytic capacitor and the second electrolytic capacitor is greater than twice the value of the output voltage. The capacitance values of the two capacitors are distributed through the EMI test result.
In the scheme of the invention, the filter inductor after the rectifying circuit consists of two differential mode inductors with the same size, and the nominal inductance value is between 110 microhenries (mu H) and 680 mu H. Generally, a nickel-zinc ferrite magnetic core is adopted, and the initial magnetic conductivity is 100-1000. By optimizing the filter inductance, the single-side inductance (common mode inductance in the example shown in fig. 2) in the correlation scheme is changed into the double-side inductance (a pair of differential mode inductances in the example shown in fig. 4), that is, a pair of symmetric differential mode inductances are connected in series on the positive bus and the negative bus at the output side of the rectifier circuit, and the differential mode inductances are lower in initial permeability and higher in high-frequency noise suppression capacity due to the material of the magnetic core.
Fig. 5 is a schematic diagram of a curve of a filtering effect test result using the filter circuit shown in fig. 4, and specifically, 8.95dB of margin is actually measured at a position where the terminal disturbance voltage is 2.48 MHz. By using the filter circuit of the scheme of the invention, the test result of conducted EMI is better and the effect is obvious.
The examples shown in fig. 3 and 5 can show the results of conducted EMI testing with scan frequencies from 150kHz to 30 MHz. Of the four curves from top to bottom, the first and second curves are the limits of quasi-peak detection (QP) and mean detection (AV), respectively. The third curve represents the quasi-peak scan for the prototype EMI and the fourth curve represents the mean scan for the prototype EMI. The national standard requires that the EMI scan results cannot be higher than the standard limit, i.e. the first curve and the second curve.
Since the processes and functions implemented by the power adapter of this embodiment substantially correspond to the embodiments, principles, and examples of the apparatus shown in fig. 1, reference may be made to the related descriptions in the foregoing embodiments without details in the description of this embodiment.
Through a large number of tests, the technical scheme of the invention is adopted, a pair of differential mode inductors capable of symmetrically filtering are connected in series on the positive bus and the negative bus of the power adapter, and a pair of electrolytic capacitors are arranged on the front side and the rear side of the pair of differential mode inductors, so that the common mode noise of the power adapter is inhibited, the electromagnetic interference and the transmission path of the power adapter are effectively inhibited from the interference noise transmission path, and the filtering effect is good.
According to an embodiment of the present invention, there is also provided an electromagnetic interference suppression method for a power adapter corresponding to the power adapter, as shown in fig. 6, which is a schematic flowchart of an embodiment of the method of the present invention. The electromagnetic interference suppression method of the power adapter can comprise the following steps: step S110 to step S130.
In step S110, overvoltage protection is performed on the input ends of the live line and the neutral line of the ac power supply through a protection unit.
In step S120, ac power input from the live line and the neutral line of the ac power supply is rectified by the rectifying unit, and unidirectional pulsating dc voltage is output to the positive and negative buses.
At step S130, the electromagnetic interference carried in the unidirectional pulsating direct current voltage is suppressed by an electromagnetic interference suppression unit, so as to achieve suppression of electromagnetic interference of the power supply of the electrical device.
The protection unit (such as a protection circuit), the rectification unit (such as a rectification circuit) and the electromagnetic interference suppression unit are arranged at the input ends of a live wire and a zero wire of an alternating current power supply of the power adapter. The electromagnetic interference suppression unit is arranged on the positive bus and the negative bus of the output end of the rectification unit.
Therefore, by adopting the protection unit (such as a protection circuit), the rectification unit (such as a rectification circuit) and the electromagnetic interference suppression unit, the EMI of the high-frequency switch circuit in the power adapter can be suppressed starting from the interference noise propagation path, and the electromagnetic interference of the power adapter and the electromagnetic interference propagation path can be effectively suppressed.
In some embodiments, the electromagnetic interference suppressing unit includes: the device comprises a differential mode inductance module and an electrolytic capacitor module. The differential mode inductance module and the electrolytic capacitor module are both arranged on a positive bus and a negative bus of the output end of the rectifying unit.
In step S130, the electromagnetic interference suppression unit suppresses the electromagnetic interference carried in the unidirectional pulsating direct current voltage, which includes the following two aspects:
in a first aspect, the unidirectional pulsating dc voltage is subjected to common mode rejection by a differential mode inductance module.
In some embodiments, the differential mode inductance module comprises: a first differential mode inductance and a second differential mode inductance. And the first differential mode inductor is arranged on a positive bus in the positive and negative buses at the output end of the rectifying unit. And the second differential mode inductor is symmetrical to the first differential mode inductor and is arranged on a negative bus in the positive and negative buses at the output end of the rectifying unit.
Specifically, symmetrical differential mode inductors are connected in series on the positive bus and the negative bus of the power adapter, so that the positive bus and the negative bus are balanced, and a common mode rejection effect is generated. The filter inductor behind the rectifying circuit consists of two differential mode inductors with the same size, and the nominal inductance value is between 110 microhenries (mu H) and 680 mu H. Generally, a nickel-zinc ferrite magnetic core is adopted, and the initial magnetic conductivity is 100-1000. By optimizing the filter inductance, the unilateral inductance (such as common mode inductance) in the related scheme is changed into bilateral inductance (such as a pair of differential mode inductances), namely, a pair of symmetric differential mode inductances are connected in series on a positive bus and a negative bus at the output side of the rectifying circuit, and the differential mode inductance has lower initial permeability and stronger inhibition capability on high-frequency noise due to the material of a magnetic core.
In the second aspect, the unidirectional pulsating direct current voltage is subjected to voltage stabilization and filtering treatment through an electrolytic capacitor module.
Specifically, the problem of poor differential mode filtering effect of the common mode choke coil is solved by adopting a combination of an electrolytic capacitor (such as a first electrolytic capacitor and a second electrolytic capacitor) and a symmetrical filtering differential mode inductor connected in series on a positive bus and a negative bus (namely, a differential mode inductor is distributed and connected in series on the positive bus and the negative bus), and adjusting device parameters, namely adjusting the device parameters of the electrolytic capacitor (such as the first electrolytic capacitor and the second electrolytic capacitor) and the differential mode inductor, so that an X capacitor can be omitted, the development cost is saved, the conducted electromagnetic interference is effectively reduced, and the reliability of the product is improved.
In some embodiments, the electrolytic capacitor module comprises: a first electrolytic capacitor and a second electrolytic capacitor. The first electrolytic capacitor is positioned on one side of the differential mode inductance module, which is close to the rectifying unit, and is arranged between a positive bus and a negative bus in the positive bus and the negative bus at the output end of the rectifying unit. The first electrolytic capacitor is positioned on one side, far away from the rectifying unit, of the differential mode inductance module and is arranged between a positive bus and a negative bus in the positive bus and the negative bus at the output end of the rectifying unit.
Specifically, electrolytic capacitors (e.g., a first electrolytic capacitor and a second electrolytic capacitor) are employed as differential mode filter capacitors. In the first electrolytic capacitor and the second electrolytic capacitor, the positive electrodes of the first electrolytic capacitor and the second electrolytic capacitor are metal foils (such as aluminum foils or tantalum foils), metal oxide films (such as aluminum oxide or tantalum pentoxide) attached to the positive electrodes are dielectrics, and the negative electrodes are made of conductive materials, electrolytes and other materials, so that the cost is relatively low. By utilizing the charging and discharging characteristics of the rectifier circuit, the pulsating direct current voltage rectified by the rectifier circuit is changed into relatively stable direct current voltage, and the rectifier circuit has the functions of energy storage, voltage stabilization and filtering.
The capacitance value of the first electrolytic capacitor and the second electrolytic capacitor ranges from 5 to 30 muF, and an appropriate capacitance value is selected according to the output voltage. Generally, the sum of the capacitance values of the first electrolytic capacitor and the second electrolytic capacitor is greater than twice the value of the output voltage. The capacitance values of the two capacitors are distributed through the EMI test result.
Since the processes and functions implemented by the method of the present embodiment substantially correspond to the embodiments, principles, and examples of the power adapter, reference may be made to the related descriptions in the foregoing embodiments without being detailed in the description of the present embodiment.
Through a large number of tests, the technical scheme of the embodiment is adopted, a pair of differential mode inductors capable of symmetrically filtering are connected in series on the positive bus and the negative bus of the power adapter, and a pair of electrolytic capacitors are arranged on the front side and the rear side of the pair of differential mode inductors, so that the common mode noise of the power adapter is restrained, the problem that the differential mode filtering effect of the common mode choke coil is poor is solved, an X capacitor can be omitted, the development cost is saved, the conducted electromagnetic interference is effectively reduced, and the reliability of the product is 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. An electromagnetic interference suppression apparatus for a power adapter, comprising: the input ends of a live wire and a zero line of an alternating current power supply of the power adapter are provided with a protection unit, a rectification unit and an electromagnetic interference suppression unit; the electromagnetic interference suppression unit is arranged on the positive bus and the negative bus of the output end of the rectification unit; wherein the content of the first and second substances,
the protection unit is configured to perform overvoltage protection on input ends of a live wire and a zero wire of the alternating-current power supply;
the rectifying unit is configured to rectify alternating currents input from a live line and a zero line of the alternating current power supply and output unidirectional pulsating direct current voltage to a positive bus and a negative bus;
the electromagnetic interference suppression unit is configured to suppress electromagnetic interference carried in the unidirectional pulsating direct current voltage so as to suppress electromagnetic interference of a power supply of electrical equipment.
2. The apparatus for suppressing electromagnetic interference of a power adapter according to claim 1, wherein the protection unit includes: a piezoresistor and a fuse tube; the piezoresistor and the protective tube are arranged at the input ends of the live wire and the zero line of the alternating current power supply.
3. The apparatus of claim 1, wherein the rectifying unit comprises: a rectifier module or a rectifier bridge; the rectification module includes: and the diode rectifying module.
4. The apparatus according to any one of claims 1 to 3, wherein the EMI suppression unit comprises: a differential mode inductance module and an electrolytic capacitor module; wherein the content of the first and second substances,
the differential mode inductance module is configured to perform common mode rejection on the unidirectional pulsating direct current voltage;
the electrolytic capacitor module is configured to perform voltage stabilization and filtering processing on the unidirectional pulsating direct current voltage.
5. The apparatus for suppressing electromagnetic interference of a power adapter as claimed in claim 4, wherein the differential mode inductance module comprises: a first differential mode inductance and a second differential mode inductance; wherein the content of the first and second substances,
the first differential mode inductor is arranged on a positive bus in positive and negative buses at the output end of the rectifying unit;
and the second differential mode inductor is symmetrical to the first differential mode inductor and is arranged on a negative bus in the positive and negative buses at the output end of the rectifying unit.
6. The apparatus of claim 4, wherein the electrolytic capacitor module comprises: a first electrolytic capacitor and a second electrolytic capacitor; wherein the content of the first and second substances,
the first electrolytic capacitor is positioned on one side, close to the rectifying unit, of the differential mode inductance module and is arranged between a positive bus and a negative bus in the positive bus and the negative bus at the output end of the rectifying unit;
the first electrolytic capacitor is positioned on one side, far away from the rectifying unit, of the differential mode inductance module and is arranged between a positive bus and a negative bus in the positive bus and the negative bus at the output end of the rectifying unit.
7. A power adapter, comprising: the electromagnetic interference suppressing apparatus of a power adapter as claimed in any one of claims 1 to 6.
8. A method for suppressing electromagnetic interference of a power adapter is characterized by comprising the following steps:
performing overvoltage protection on input ends of a live wire and a zero line of the alternating current power supply through a protection unit;
rectifying alternating current input from a live wire and a zero line of the alternating current power supply through a rectifying unit, and outputting unidirectional pulsating direct current voltage to a positive bus and a negative bus;
through an electromagnetic interference suppression unit, suppressing electromagnetic interference carried in the unidirectional pulsating direct current voltage so as to suppress the electromagnetic interference of a power supply of electrical equipment;
the protection unit, the rectification unit and the electromagnetic interference suppression unit are arranged at the input ends of a live wire and a zero wire of an alternating current power supply of the power adapter; the electromagnetic interference suppression unit is arranged on the positive bus and the negative bus of the output end of the rectification unit.
9. The method of claim 8, wherein the EMI suppression unit comprises: a differential mode inductance module and an electrolytic capacitor module;
through electromagnetic interference suppression unit, restrain the electromagnetic interference who carries in the one-way pulsation direct current voltage, include:
common mode suppression is carried out on the unidirectional pulsating direct current voltage through a differential mode inductance module;
and carrying out voltage stabilization and filtering treatment on the unidirectional pulsating direct current voltage through an electrolytic capacitor module.
10. The method of claim 9, wherein the step of suppressing the electromagnetic interference of the power adapter,
the differential mode inductance module comprises: a first differential mode inductance and a second differential mode inductance; the first differential mode inductor is arranged on a positive bus in positive and negative buses at the output end of the rectifying unit; the second differential mode inductor is symmetrical to the first differential mode inductor and is arranged on a negative bus in the positive and negative buses at the output end of the rectifying unit;
the electrolytic capacitor module comprises: a first electrolytic capacitor and a second electrolytic capacitor; the first electrolytic capacitor is positioned on one side, close to the rectifying unit, of the differential mode inductance module and is arranged between a positive bus and a negative bus in the positive bus and the negative bus at the output end of the rectifying unit; the first electrolytic capacitor is positioned on one side, far away from the rectifying unit, of the differential mode inductance module and is arranged between a positive bus and a negative bus in the positive bus and the negative bus at the output end of the rectifying unit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110156488.7A CN112994440A (en) | 2021-02-04 | 2021-02-04 | Electromagnetic interference suppression device and method of power adapter and power adapter |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110156488.7A CN112994440A (en) | 2021-02-04 | 2021-02-04 | Electromagnetic interference suppression device and method of power adapter and power adapter |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN112994440A true CN112994440A (en) | 2021-06-18 |
Family
ID=76347150
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202110156488.7A Pending CN112994440A (en) | 2021-02-04 | 2021-02-04 | Electromagnetic interference suppression device and method of power adapter and power adapter |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN112994440A (en) |
Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN204012694U (en) * | 2014-08-14 | 2014-12-10 | 四川长虹电子部品有限公司 | Anti-lightning surge protection circuit and anti-lightning power supply adaptor |
| US20170170734A1 (en) * | 2015-12-15 | 2017-06-15 | Google Inc. | Two stage structure for power delivery adapter |
| CN106887826A (en) * | 2017-03-23 | 2017-06-23 | 深圳市福瑞康电子有限公司 | A kind of power supply adaptor with excess temperature and input overvoltage double protection function |
| CN206865350U (en) * | 2017-03-30 | 2018-01-09 | 深圳创维数字技术有限公司 | A kind of filter circuit and power supply adaptor |
| CN207070030U (en) * | 2017-06-22 | 2018-03-02 | 江苏沃姆克科技有限公司 | The power-supply filter that a kind of differential mode and common mode coexist |
| CN210867503U (en) * | 2019-11-14 | 2020-06-26 | 中科汇安科技成都有限公司 | Integrated filtering assembly |
| CN211710627U (en) * | 2020-02-20 | 2020-10-20 | 北京新能源汽车股份有限公司 | Electromagnetic interference suppression module, battery pack and electric automobile |
-
2021
- 2021-02-04 CN CN202110156488.7A patent/CN112994440A/en active Pending
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN204012694U (en) * | 2014-08-14 | 2014-12-10 | 四川长虹电子部品有限公司 | Anti-lightning surge protection circuit and anti-lightning power supply adaptor |
| US20170170734A1 (en) * | 2015-12-15 | 2017-06-15 | Google Inc. | Two stage structure for power delivery adapter |
| CN106887826A (en) * | 2017-03-23 | 2017-06-23 | 深圳市福瑞康电子有限公司 | A kind of power supply adaptor with excess temperature and input overvoltage double protection function |
| CN206865350U (en) * | 2017-03-30 | 2018-01-09 | 深圳创维数字技术有限公司 | A kind of filter circuit and power supply adaptor |
| CN207070030U (en) * | 2017-06-22 | 2018-03-02 | 江苏沃姆克科技有限公司 | The power-supply filter that a kind of differential mode and common mode coexist |
| CN210867503U (en) * | 2019-11-14 | 2020-06-26 | 中科汇安科技成都有限公司 | Integrated filtering assembly |
| CN211710627U (en) * | 2020-02-20 | 2020-10-20 | 北京新能源汽车股份有限公司 | Electromagnetic interference suppression module, battery pack and electric automobile |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US11062837B2 (en) | Planar transformer, power conversion circuit, and adapter | |
| WO2017211104A1 (en) | Emi filter and power emi filter access circuit | |
| US9887592B2 (en) | Power transmission device and power reception device | |
| CN109941128A (en) | A kind of electric car wireless charging technology voltage optimization method of field coupling formula | |
| CN203554278U (en) | A household electrical appliance and an EMI filter circuit thereof | |
| CN101272086B (en) | EMC equipment | |
| CN112994440A (en) | Electromagnetic interference suppression device and method of power adapter and power adapter | |
| CN216311573U (en) | Stable transformer | |
| CN212992292U (en) | Filter circuit for high-voltage direct current input | |
| CN111934538B (en) | Shielding structure, circuit and power adapter | |
| EP2797091A1 (en) | Transformer and power supply using the transformer | |
| Zhao et al. | Electromagnetic Compatibility | |
| KR102589292B1 (en) | Electromagnetic Interference Filter | |
| CN114006522B (en) | Inductance-capacitance network unit and DC-DC converter | |
| CN220325315U (en) | Charging circuit and charging device | |
| CN104244482A (en) | Low-cost induction cooker EMC control circuit | |
| Jeong et al. | A terminal ground filter between cable and chassis for reduction of conducted emissions at a home appliance | |
| CN219436862U (en) | Electromagnetic interference protection power supply conversion circuit | |
| CN111614094A (en) | Electromagnetic interference filter circuit | |
| Sulaeman et al. | Source and Load Impedance Mismatch Analysis of a Power Line Filter in Microgrid Application | |
| Chand et al. | EMC evaluation and analysis of UPS | |
| CN213937738U (en) | Power supply circuit for improving electromagnetic interference of coffee machine | |
| Gong et al. | Three-dimensional parasitics cancellation in EMI filters with Power Sandwich construction | |
| CN217563546U (en) | Power supply circuit and electronic equipment | |
| CN213426017U (en) | Electromagnetic interference filter circuit structure, switching power supply and fan heater electronic controller |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| RJ01 | Rejection of invention patent application after publication | ||
| RJ01 | Rejection of invention patent application after publication |
Application publication date: 20210618 |