CN113794389A - Ethernet power supply filtering and safe starting device - Google Patents

Ethernet power supply filtering and safe starting device Download PDF

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Publication number
CN113794389A
CN113794389A CN202110857279.5A CN202110857279A CN113794389A CN 113794389 A CN113794389 A CN 113794389A CN 202110857279 A CN202110857279 A CN 202110857279A CN 113794389 A CN113794389 A CN 113794389A
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CN
China
Prior art keywords
rectifier bridge
module
output end
capacitor
mode inductor
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Pending
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CN202110857279.5A
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Chinese (zh)
Inventor
沈远哲
吴晟
胡忠强
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Zhejiang Guangpo Intelligent Technology Co ltd
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Zhejiang Guangpo Intelligent Technology Co ltd
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Priority to CN202110857279.5A priority Critical patent/CN113794389A/en
Publication of CN113794389A publication Critical patent/CN113794389A/en
Pending legal-status Critical Current

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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
    • H02M7/12—Conversion of ac power input into dc power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M7/21—Conversion of ac power input into dc power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
    • H02M7/217—Conversion of ac power input into dc power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only
    • H02M7/219—Conversion of ac power input into dc power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only in a bridge configuration
    • 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
    • H02M1/36—Means for starting or stopping converters
    • 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

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Rectifiers (AREA)

Abstract

The invention discloses a power supply filtering and safe starting device for an Ethernet, which solves the problems of damage of a starting capacitor, electromagnetic EMI noise and electric leakage safety certification caused by repeated plugging and unplugging of an Ethernet power supply network in the prior art. According to the invention, the filtering module is adopted to suppress the electromagnetic EMI noise of the Ethernet, the starting module provides the high-voltage-resistance starting capacitor bank and the combined filter, the grounding module limits the leakage current and provides an internal electromagnetic EMI noise loop at the same time, the electromagnetic EMI noise in the system can be guided to flow back in the system, and the electromagnetic compatibility problem of other systems caused by the overflow of the noise is prevented.

Description

Ethernet power supply filtering and safe starting device
Technical Field
The invention relates to the field of hardware, electromagnetic compatibility and safety regulation, in particular to a power over Ethernet filtering and safety starting device.
Background
Poe (power Over ethernet) refers to a technology that can provide dc power for some IP-based terminals (such as IP phones, wireless lan access points AP, network cameras, etc.) while transmitting data signals for such devices, without any modification to the existing ethernet cat.5 wiring infrastructure. Ethernet, also known as a local area network-based Power Over LAN (POL) or Active Ethernet (Active Ethernet), sometimes referred to simply as Power over Ethernet, is a recent standard specification for simultaneously transferring data and electrical Power using existing standard Ethernet transmission cables and maintains compatibility with existing Ethernet systems and users. A complete PoE system comprises two parts, namely a Power Sourcing Equipment (PSE) and a Power receiving Equipment (PD).
The technical scheme of the existing power receiving end equipment is as follows: as shown in FIG. 7, after electricity is taken from center taps 1-4 of a network transformer, positive PD power supply and negative PD power supply are output through rectifier bridge stacks A and B. At the moment, the rectified power supply charges the starting capacitor, and the protection device clamps the voltage of the sudden wave at the moment of electrifying the starting capacitor. After the voltage at the two ends of the starting capacitor is detected by the PD chip, the PD chip works and supplies power through the PWM system power supply positive direction and the PWM system power supply negative direction. The PWM system outputs to the positive output power supply and the negative output power supply on the load side. The cross-over capacitance guides the electromagnetic EMI noise loop between the PWM system and the load.
The prior art has the following defects: power over ethernet systems introduce electromagnetic EMI noise issues that are not present in ethernet networks. The existing Ethernet power supply scheme has the following defects: 1) the electromagnetic EMI noise problem and the electric leakage safety certification problem cannot be simultaneously considered. The leakage current is increased only by increasing the capacitance of the cross-over capacitor, but the performance requirement of electromagnetic EMI can not be satisfied without increasing the capacitance of the cross-over capacitor. 2) And a protection device is required to be added for carrying out surge protection on two ends of the starting capacitor, so that the cost is high and the size is large.
Disclosure of Invention
The invention provides an Ethernet power supply filtering and safety starting device for overcoming the problems of damage of a starting capacitor, electromagnetic EMI noise and leakage safety certification caused by repeated plugging and unplugging of an Ethernet power supply network in the prior art.
In order to achieve the purpose, the invention adopts the following technical scheme:
a power over Ethernet filtering and safe starting device comprises a filtering module, wherein the input end of the filtering module is connected with a rectifier bridge stack, the input end of the rectifier bridge stack is respectively connected with the output end of a network transformer through four center taps, the output end of the filtering module is connected with a PD chip, the output end of the PD chip is connected with a PWM system, the output end of the PWM system is connected with a load,
the filter module comprises a common-mode inductor and a starting module, the starting module comprises a series capacitor bank and a grounding module, the input end of the common-mode inductor is connected with the output end of the rectifier bridge stack, the output end of the common-mode inductor is connected with the starting module, and the grounding module is further connected with a load.
The common mode inductor is used for filtering electromagnetic EMI noise of Ethernet, the two capacitors are connected in series to provide a PD chip starting capacitor, the common mode inductor and a differential mode inductance parasitic on the common mode inductor can form first-order filtering, the grounding module is used for limiting leakage current, and meanwhile, the flow direction of the electromagnetic EMI noise in the system can be guided.
Preferably, the common-mode inductor comprises a common-mode inductor L3, the series capacitor bank comprises a capacitor C14 and a capacitor C38, the rectifier bridge stack comprises a rectifier bridge D21 and a rectifier bridge D27,
the positive input end of a common-mode inductor L3 is connected with the positive output end of a rectifier bridge D21 and the positive output end of a rectifier bridge D27 respectively, the negative input end of the common-mode inductor L3 is connected with the negative output end of a rectifier bridge D21 and the negative output end of a rectifier bridge D27 respectively, the positive output end of the common-mode inductor L3 is connected with one end of a capacitor C14 and the positive electrode of a PD chip power supply respectively, the negative output end of the common-mode inductor L3 is connected with one end of a capacitor C38 and the negative electrode of the PD chip power supply respectively, and the other ends of the capacitor C14 and the capacitor C38 are connected with a grounding module.
Preferably, the grounding module is a safety grounding point.
The grounding module is a safety point on a printed circuit board, changes the traditional mode and replaces the original capacitor bridged between the PWM system and the power output negative. The electromagnetic EMI noise in the system can be guided to flow back in the system by multiplexing with the serially connected starting capacitor, and the electromagnetic compatibility problem of other systems caused by the overflow of the noise is prevented.
Preferably, the connection part of the PWM system and the load is a negative pole of the power output, and the negative pole of the power output is grounded.
Preferably, the common mode inductor includes a differential mode inductance, and the parasitic differential mode inductance and the series capacitance constitute a first-order filter.
When external electromagnetic EMI noise in the Ethernet enters the power over Ethernet system along the center taps 1-4, different forms of filter devices are encountered.
For common mode noise, the common mode inductor provides a common mode high impedance, which can block the external entering common mode noise; for differential mode noise, a first-order filter is formed by the differential mode inductance parasitic on the common mode inductor and two capacitors at the rear end, and the differential mode noise is fully filtered.
Meanwhile, the two capacitors connected in series replace the traditional PD starting capacitor, the voltage withstanding capability of the starting capacitor is improved in a mutual series connection mode, and the starting capacitor is prevented from being damaged by the impact voltage at the moment of plugging and unplugging for many times. Meanwhile, the cut-off frequency design of a first-order filter can be carried out by adjusting the capacitance values of the two series capacitors, and the filter has a filtering effect on internal and external noises.
Preferably, the model of the common-mode inductor L3 is DLW5BTM102TQ 2.
Preferably, the models of the rectifier bridge D21 and the rectifier bridge D27 are DF 10S-D.
Therefore, the invention has the following beneficial effects:
1. the invention adopts a filtering module, a starting module and a grounding module. The filtering module suppresses Ethernet electromagnetic EMI noise, the starting module provides a high-voltage-withstanding starting capacitor set and a combined filter, and the grounding module limits leakage current and provides an internal electromagnetic EMI noise loop;
2. the filtering module can inhibit electromagnetic EMI noise outside the PWM system and inside the PWM system, and forms a first-order filter with the capacitors connected in series; the series resistor is simultaneously used as a starting module to provide a starting capacitor for the PD chip, and can also simultaneously form first-order filtering with the parasitic differential mode inductance of the common mode inductor;
3. the grounding module is a safety point on a printed circuit board, changes the traditional mode, replaces the original capacitor bridged between a PWM system and a power output negative, is multiplexed with a series-connected starting capacitor, can guide electromagnetic EMI noise inside the system to flow back in the system, and prevents the electromagnetic compatibility problem of other systems caused by noise overflow.
Drawings
Fig. 1 is a block diagram of the structure of the present embodiment.
Fig. 2 is a schematic circuit diagram of the network transformer according to the present embodiment.
Fig. 3 is a schematic circuit diagram of the bridge rectifier of the present embodiment.
Fig. 4 is a schematic circuit diagram of the filter module according to the present embodiment.
Fig. 5 is a schematic circuit diagram of the PD chip and its peripheral circuits according to the present embodiment.
Fig. 6 is a schematic circuit diagram of the PWM system and the load according to the present embodiment.
Fig. 7 is a block diagram of a related art structure.
In the figure: 1. the circuit comprises a filtering module 101, a common-mode inductor 102, a starting module 103, a grounding module 2, a network transformer 201, a first center tap 202, a second center tap 203, a third center tap 204, a fourth center tap 3, a rectifier bridge stack 4, a PD chip 5, a PWM system 6 and a load.
Detailed Description
The invention is further described with reference to the following detailed description and accompanying drawings.
Example (b):
the embodiment provides a power over ethernet filtering and safety starting device, as shown in fig. 1, which includes a network transformer 2, a bridge rectifier 3, a filtering module 1, a PD chip 4, a PWM system 5, and a load 6, which are connected in sequence.
2-6, the filter module 1 includes a common mode inductor 101 and a start module 102, the start module 102 includes a series capacitor bank and a ground module 103, the common mode inductor 101 includes a common mode inductor L3, the series capacitor bank includes a capacitor C14 and a capacitor C38, the rectifier bridge stack includes a rectifier bridge D21 and a rectifier bridge D27, the common mode inductor 101 counts differential inductance, the parasitic differential inductance and the series capacitor bank form a first-order filter,
the positive input end of a common mode inductor L3 is respectively connected with the positive output end of a rectifier bridge D21 and the positive output end of a rectifier bridge D27, the negative input end of the common mode inductor L3 is respectively connected with the negative output end of the rectifier bridge D21 and the negative output end of the rectifier bridge D27, the positive output end of the common mode inductor L3 is respectively connected with one end of a capacitor C14 and the positive electrode of a PD chip power supply, the negative output end of the common mode inductor L3 is respectively connected with one end of a capacitor C38 and the negative electrode of the PD chip power supply,
the other end of the capacitor C14 and the other end of the capacitor C38 are connected to the grounding module 103.
In the embodiment, after the power is removed from the first center tap 201, the second center tap 202, the third center tap 203 and the fourth center tap 204 of the network transformer 2, the PD power positive and the PD power negative are output through the rectifier bridge stack 3, the rectified power charges the starting module 102, the PD chip 4 operates to output the PWM system power positive and the PWM system power negative after the PD chip 4 detects the voltages at the two ends of the starting module 102, the PWM system power positive and the PWM system power negative are supplied through the PWM system power positive and the PWM system power negative PWM system 5, the PWM system outputs the output power positive and the output power negative at the load side, the grounding module 103 is multiplexed with the series capacitor group of the series starting module 102 through the safety grounding point on the printed circuit board, instead of the conventional way of using a cross-over capacitor in the prior art in fig. 7, the electromagnetic EMI noise inside the system can be guided to flow back into the system to prevent the noise from overflowing, causing other system electromagnetic compatibility problems.
The common mode inductor is used for filtering electromagnetic EMI noise of the Ethernet, the two capacitors are connected in series to provide a PD chip starting capacitor, and the common mode inductor and a differential mode inductance parasitic on the common mode inductor can form first-order filtering; one printed circuit board point is used to limit leakage current while also directing the flow of electromagnetic EMI noise within the system.
When external electromagnetic EMI noise enters an Ethernet power supply system along one to four central taps in the Ethernet, the common-mode inductor provides a common-mode high impedance for common-mode noise of different types of filter devices, so that the external common-mode noise can be blocked; for differential mode noise, a first-order filter is formed by the differential mode inductance parasitic on the common mode inductor and two capacitors at the rear end, and the differential mode noise is fully filtered.
Meanwhile, the two capacitors connected in series replace the traditional PD starting capacitor, the voltage resistance of the starting capacitor is improved in a mutual series connection mode, the starting capacitor is prevented from being damaged by the instantaneous impact voltage of power-on in multiple plugging and unplugging, the cut-off frequency design of a first-order filter is carried out by adjusting the capacitance values of the two capacitors connected in series, and the internal and external noises are filtered.
A safety point on a printed circuit board changes the traditional mode, replaces the original capacitor bridged between a PWM system and a power output negative, is multiplexed with a series starting capacitor, can guide electromagnetic EMI noise inside the system to flow back in the system, and prevents the electromagnetic compatibility problem of other systems caused by noise overflow.
The above embodiments are described in detail for the purpose of further illustrating the present invention and should not be construed as limiting the scope of the present invention, and the skilled engineer can make insubstantial modifications and variations of the present invention based on the above disclosure.

Claims (7)

1. A power over Ethernet filtering and safe starting device is characterized by comprising a filtering module (1),
the input end of the filter module (1) is connected with a rectifier bridge stack, the input end of the rectifier bridge stack is connected with the output end of a network transformer through four center taps respectively, the output end of the filter module (1) is connected with a PD chip, the output end of the PD chip is connected with a PWM system, the output end of the PWM system is connected with a load,
the filtering module (1) comprises a common-mode inductor (101) and a starting module (102), the starting module (102) comprises a series capacitor bank and a grounding module (103),
the input end of the common mode inductor (101) is connected with the output end of the rectifier bridge stack, the output end of the common mode inductor (101) is connected with the starting module (102), and the grounding module (103) is also connected with a load.
2. A power over Ethernet filtering and security activation device in accordance with claim 1,
the common-mode inductor (101) comprises a common-mode inductor L3, the series capacitor bank comprises a capacitor C14 and a capacitor C38, the rectifier bridge stack comprises a rectifier bridge D21 and a rectifier bridge D27,
the positive input end of a common mode inductor L3 is respectively connected with the positive output end of a rectifier bridge D21 and the positive output end of a rectifier bridge D27, the negative input end of the common mode inductor L3 is respectively connected with the negative output end of the rectifier bridge D21 and the negative output end of the rectifier bridge D27, the positive output end of the common mode inductor L3 is respectively connected with one end of a capacitor C14 and the positive electrode of a PD chip power supply, the negative output end of the common mode inductor L3 is respectively connected with one end of a capacitor C38 and the negative electrode of the PD chip power supply,
the other end of the capacitor C14 and the other end of the capacitor C38 are connected with the grounding module (103).
3. A power over ethernet filtering and secure boot device according to claim 1 or 2, characterized in that said grounding module (103) is a secure grounding point.
4. A power over ethernet filtering and safety startup device according to claim 1, wherein the connection of the PWM system and the load is the negative pole of the power supply output, which is grounded.
5. A power-over-ethernet filtering and security startup device according to claim 1, characterized in that the common-mode inductance (101) accounts for differential mode inductance, the parasitic differential mode inductance and the series capacitance set forming a first order filter.
6. A power over ethernet filtering and safety starter as claimed in claim 2, wherein said common mode inductor L3 is model DLW5BTM102TQ 2.
7. A power over ethernet filtering and safety starter as claimed in claim 2, wherein said rectifier bridge D21 and rectifier bridge D27 are model DF 10S-D.
CN202110857279.5A 2021-07-28 2021-07-28 Ethernet power supply filtering and safe starting device Pending CN113794389A (en)

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Application Number Priority Date Filing Date Title
CN202110857279.5A CN113794389A (en) 2021-07-28 2021-07-28 Ethernet power supply filtering and safe starting device

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Application Number Priority Date Filing Date Title
CN202110857279.5A CN113794389A (en) 2021-07-28 2021-07-28 Ethernet power supply filtering and safe starting device

Publications (1)

Publication Number Publication Date
CN113794389A true CN113794389A (en) 2021-12-14

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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101651408A (en) * 2009-06-10 2010-02-17 上海爱瑞科技发展有限公司 Filtering module inhibiting common mode noise and differential mode noise
CN101707435A (en) * 2009-05-13 2010-05-12 海洋王照明科技股份有限公司 EMI filter circuit and LED power supply driving circuit using same
CN102970147A (en) * 2012-11-30 2013-03-13 迈普通信技术股份有限公司 Ethernet power supply equipment and method for suppressing electromagnetic radiation
CN203554278U (en) * 2013-10-16 2014-04-16 广东美的制冷设备有限公司 A household electrical appliance and an EMI filter circuit thereof
CN110460449A (en) * 2018-05-08 2019-11-15 杭州海康威视数字技术股份有限公司 Repeater and method of supplying power to

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101707435A (en) * 2009-05-13 2010-05-12 海洋王照明科技股份有限公司 EMI filter circuit and LED power supply driving circuit using same
CN101651408A (en) * 2009-06-10 2010-02-17 上海爱瑞科技发展有限公司 Filtering module inhibiting common mode noise and differential mode noise
CN102970147A (en) * 2012-11-30 2013-03-13 迈普通信技术股份有限公司 Ethernet power supply equipment and method for suppressing electromagnetic radiation
CN203554278U (en) * 2013-10-16 2014-04-16 广东美的制冷设备有限公司 A household electrical appliance and an EMI filter circuit thereof
CN110460449A (en) * 2018-05-08 2019-11-15 杭州海康威视数字技术股份有限公司 Repeater and method of supplying power to

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