How to Optimize the Transformer Design in Poe Power Supply

Power over Ethernet - Ethernet power supply technology refers to a way in which power supply equipment PSE (power sourcing equipment) transmits power to power receiving equipment PD (power device) through network cable. Typical applications, for example, take the PSE switch as the core and connect many PD devices through network cables, such as access point, IP phone and IP camera. PSE completes the signal and power transmission to PD.

Poe power supply has the following advantages: convenient installation and expansion: network cable transmits signal and power, and there is no need to configure power interface around PD equipment remote management: one PSE device provides power for multiple PD devices, which is convenient for remote power management low cost: signal line and power line are combined into one, eliminating one power line, so network cable is not only the carrier of signal transmission, It also plays the role of power transmission, so the wiring cost is reduced good compatibility: it is not limited by the power grid standards of various countries, and the unified Poe protocol ensures that PD equipment can be compatible with any PSE worldwide

From the perspective of circuit architecture, the PSE on the left transmits DC 44-57v to PD, and the PD on the right cooperates with step-down circuit to convert the power supply into required power. PSE and PD are connected through RJ45 interface and up to 100m twisted pair.

IEEE 802.3af, IEEE 802.3at and

Ieee802.3bt three Ethernet power supply standards. In particular, the IEEE 802.3bt standard was released in 2019, which greatly increased the power supplied by Poe. PSE provides 90W power. After passing through 100m network cable, the received power of PD reaches 71w. This class 8 power level is mainly used in the power supply system of small base stations. Moreover, 802.3bt standard is downward compatible with 802.3af and 802.3at standards; When the 802.3bt PD is connected to the low-power 802.3af and 802.3at PSE, it will work in the low-power state, that is, "degraded".

In this process, the lower power PD is connected to the higher power PSE, and the equipment is not damaged. The following handshake process is mainly experienced when the PSE supplies power to the PD:

Pictures from the Internet

The picture comes from the network, and the chart comes from the inside of shunluo

In the circuit architecture of PD equipment, three parameters are mainly concerned: size, efficiency and EMC. Then how to connect the requirements of PD equipment and the design requirements of transformer.

//3.1 optimized size

key points of design 1: reduce the size of the transformer with high frequency. In a circuit board, it can be seen that the larger the volume is the transformer, so reducing the size of the transformer can save the size of the board. High frequency can reduce the size of transformer and power transmission of transformer, so the frequency from 200 kHz to 300 kHz to 500 kHz can reduce the volume of transformer. Design point 2: CCM working mode reduces device size design point 3: primary side feedback reduces size

Pictures from the Internet

3.2 improving efficiency

EMC measures the interference of noise source on sensitive equipment, including conduction and radiation composition. On the one hand, reduce the interference source, on the other hand, optimize the coupling path.

In order to reduce EMI, first confirm the noise source in the circuit. The noise source is divided into conduction noise source and radiation noise source. The conducted noise source is generally low-frequency noise within 30MHz, which is generated by the change of electric field; The conduction noise source is mainly the switching action of the power tube, which will lead to the sudden change of MOS source level voltage, which will lead to the transformer transmitting the sudden change of voltage to the secondary side. Increasing the driving resistance of MOS can reduce the switching speed, but the driving loss will increase; Or increase the absorption circuit to reduce the high-frequency oscillation. Stray parameters of transformer have a great impact on EMI. For example, transformer CP (primary winding electric field) affects voltage spike and current ripple.

The radiated noise source is the noise above 30m, which is the interference of spatial magnetic field and consists of high-frequency current loop. High frequency loop refers to the primary side loop and secondary side loop of transformer. During PCB layout, the loop path should be reduced to reduce noise, or small capacitance in parallel should be added.

3.3 shunluo electronic transformer

Shunluo electronics has a strong transformer design team. In the transformer design of Poe power supply, it comprehensively optimizes the transformer design from the perspective of size, efficiency and EMC to meet the customized needs of customers. Shunluo electronics has a fully automatic transformer production line to ensure the reliability and consistency of products and short delivery cycle. You are welcome to place an order.

Editing: JQ

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How to Solve the Fault of LED Display Screen
How to Solve the Fault of LED Display Screen
How to solve the flower screen fault of LED display? There are many reasons why the flower screen of full-color LED display can not be displayed normally. Here is a summary of how to solve the flower screen of full-color LED display.If the new screen is powered on, it may be that the control card settings are not scanned correctly, or the cable is not inserted correctly (check the cable from the control card to the first board). This problem will also occur if the 5V power supply is connected incorrectly.If this phenomenon is suddenly found after using for a period of time, in addition to the failure of the control card, the biggest possibility is that the board is flooded and burns the chip or power supply.Also, you can try a display connected to a DVI interface. First, check whether the DVI output port of the graphics card has a normal signal. The DVI interface resolution of general lingxingyu card is 1024 * 768. The reason for the LED display screen may also be the problem of the graphics card or the driver. Try to unplug the network cable of the receiving card behind the display screen and press the debugging button on the receiving card to see whether the screen body scanning is normal.In addition, other reasons for the flower screen of full-color LED display are also provided for your reference:1. LED display flower screen cannot be displayedSolution: check whether the power supply of the electronic display screen is normal and whether there is 220V strong current input2. The display of LED electronic display screen is abnormal, and the flower screenresolvent:(1) Whether the parameter setting of LED control card is correct and whether there is signal transmitted to the LED control card of electronic display screen;(2) Check whether the communication line communicates normally and whether the LED control card has signal input;(3) Whether the 5V power supply of LED control card is normal;3. Part of the screen body of the electronic display screen is abnormal, such as black screen and flower screenSolution: check whether the screen power supply with abnormal display works normally; Signal transmission line fault; Single module failure of screen body.A. There is a problem with the output1. Check whether the line from the output interface to the signal output IC is connected or short circuited.2. Check whether the clock latch signal of the output port is normal.3. Check whether the cascade output data port between the last drive IC is connected with the data port of the output interface or short circuited.4. Poor heat dissipation of the chassis leads to the rise of the temperature of the graphics card.Solution: eliminate the heat dissipation problem.Check whether the fan operates normally, add oil to the fan, clean the dust in the chassis, and eliminate the fault after solving the heat dissipation problem.5. Reinstallation of the system, graphics card or display does not support high resolution.resolvent:(1) Restart the computer, press F8 continuously, in the Advanced Startup menu, select "safe mode" and enter to log in to the system, then enter the display setting under windows, select the 16 color status, click the "apply" button and click the "OK" button.(2) Restart the computer. In the normal mode of windows, enter the device manager, delete the graphics card driver, and restart the computer.
Screen Printing Machines  Useful Tips to Choose the Best
Screen Printing Machines Useful Tips to Choose the Best
The younger and the antique are starting to understand the importance of making a fashion statement. Garment producers churn out more modern strategies and technology to meet the needs of the prevailing era. Screen-printing happens to be the brand new "fad" for the general public. For the time being, we will speak certain tactics to help you discover the fine on line bulk display screen printing providers.Why should you opt for on-line bulk screen-printing? The reasons vary i can highlight some of them in this passage. Actually, each person who has the proper type of machinery will be able to execute display screen printing beautifully. However, the catch lies someplace else. The design imprinted on the apparel has to be specific. The complete belief revolves round capturing the eye of by using standers! on the net, you will encounter various display screen-printing services who will offer the first-class of the designs for a viable pricing. How does that sound?Please be aware the "bulk" element associated with on-line display screen printing. in case you want to print a design on 300 tee shirts, then these service vendors will be of sizeable help. The greater the printing order, the profitable the prices will emerge as. Secondly, you can pick the designs from the consolation of your property. The usual technique is to spend a main part of the day hunting round for the high-quality Screen Printing Machine service to your location. Now, with the assist of the internet, you just need to spend a few minutes to select the finest designs in your garments. You can even pay for the printing task thru credit playing cards. Do you comprehend the simplicity associated with the bulk screen-printing procedures?In case you are willing to spend even extra time, you may permit your imagination run and supply upward thrust to amazing display screen printing designs. In fact, most of the people of the cyber residents seek custom screen-printing carriers at the net. The vantages are manifold in case you are willing to experiment with this paradigm. Sure online screen printing vendors will offer loose transport offerings for bulk orders. The way with which you spend your tough-earned money is solely depending on you.The smart will always choose such approaches because it saves them time in addition to money. You might come upon some online assets that strain at the importance of owning a display-printing device. Supply it a few idea and you may comprehend that there's no need to spend money on one such machine in particular for home users. If you want to make a dwelling out of display screen printing, then expending on a screen printer and the essential accessories will grow to be rather viable. Clever selections play an crucial role in your lifestyles!Given current technology, could TV display screens double as video camera sensors?Making this work technically would be a Manhattan project; there's no reason to make such extreme effort when there's a simpler way to get it done. Selfie-grade cameras like the one on the face of your phone cost less than a dollar in million quantity. Microphones are even cheaper. Simply incubate a social movement that creates some sort of reason some people might want one on their TV. Encourage every TV maker to put it on every TV, all in the name of populism. We pretty much already have this with several social media habits, like cell phones tracking your location. For instance Google Maps tracks your location even in the background, nominally to monitor traffic flow and present local attractions, but also usable by police. Those are things you can turn off if you apply both technical skill and diligence, however you need to apply both pretty liberally, and when you do, and the police have reason to notice, it makes you look guilty and prejudices juries.Eventually it becomes a thing that is on by default, like Google Maps' tracking; you must go to technical extremes to turn it off, and very few people bother. Those who do, the fact that they do is interesting in and of itself.Since the last Microsoft update to Windows 10, my display screens keep switching to a darkened version. Sometimes I can recover my preferred brightness by restarting, but not always. How can I fix this?It is possible that you have have activated "Dark Mode." Easy to turn off.How to Enable Dark Mode in Windows 10 or Turn it OffAnother possibility is that the driver for the "brightness sensor" changed, if your displays have one. Maybe try to disable auto brightness adjustment?How to disable automatic brightness adjustment on Windows 10. The other possibility is mis-set or overly aggressive power plan that dims the screen too quickly. htmlSince the last Microsoft update to Windows 10, my display screens keep switching to a darkened version. Sometimes I can recover my preferred brightness by restarting, but not always. How can I fix this?Since the last Microsoft update to Windows 19, my display screens keep switching to a darkened version. Sometimes I can recover my preferred brightness by restarting, but not always. How can I fix this?
Liu Zuohu: Yijia's New Product Will Be Equipped with an Exclusive Customized New Display Screen
Liu Zuohu: Yijia's New Product Will Be Equipped with an Exclusive Customized New Display Screen
On the evening of April 22, Liu zuohu, CEO of Yijia technology, disclosed more information about Yijia's new products on his microblog. He said that the new products would use a new and exclusive customized display screen. Liu zuohu further talked about the impact of the screen on the user experience: "the screen is the man-machine interface that users contact most and feel most directly every day. A good screen is very important to create the best user experience."Figure: Liu zuohu microblogThe screen is very important for a mobile phone product. Liu zuohu said: "we have invested nearly 100 million yuan in R & D to customize a unique display dedicated to Yijia. People in the industry know that the screen is one of the most expensive devices in mobile phones, and the screen cost of Yijia's new product is 2-3 times that of the screen used in ordinary flagship machines."Yijia has always adhered to the product concept of "no burden" and is committed to building Android flagship boutique mobile phones. Yijia has extremely high requirements for product hardware configuration and software optimization. Yijia mobile phone adopts the current top configuration in hardware selection, and fully releases the potential energy of hardware through software optimization and adjustment. The combination of software and hardware provides users with a light and smooth use experience. "Lightness and fluency" is also a common label on all generations of mobile phones.Liu zuohu tweeted on April 17 that the new Yijia product will lead the industry into a new era of "smooth" experience. This product is also the "smoothest Yijia mobile phone" he has ever used. One plus new products are approaching. Liu zuohu's new product topic on his microblog makes netizens look forward to it more and more. On April 23, Liu zuohu will also announce the date of one plus new product launch on his personal microblog, which is worth looking forward to!
What Would Make Your Computer Freeze Up and Display a Screen with Lines on It?
What Would Make Your Computer Freeze Up and Display a Screen with Lines on It?
viris1. What are the disadvantages and advantages of a crt display screen?CRT are huge monsters. But LCD'S are small and USAULLY have a better image2. How to use laptop as a display screen for Raspberry Pi3? [closed]The assumption is that you want to "see" the RPi graphical screen on your laptop. Consider setting up a Virtual Network Console (VNC). A VNC server on the RPi and a VNC client on the laptop. (If all you want is the console (text only) then the simpler SSH approach mentioned by Ingo should work.)3. How to make my computer display the screen full size?adjust your screen resolution... if you had adjust it to high and still the same.. get a video card the has a highest resolution.4. My 1st generation iPod display screen is partially blank. Why?Try resetting it be shifting the hold button back and forth once and then holding the center and play button5. How do I control my laptop computer display screen?Go to Start - Control Panel - Display - Advanced In advanced make sure your DPI setting is set to Normal 96dpi and not 120 I think this is what I had to do.6. The inside display screen lights up but is a blank screen. My outside scteen works just fine.?You have a couple options here...the simplest one would be to claim insurance on your phone, pay the diductable and t-mobile will mail you a new phone...thats is if you have insurance...if you dont then you will have to buy a new phone at full price....i think the 6103 retails at $199.99. Also try and remove the battery and put it back in and power up the phone. ..that works sometimes. You can also purchace parts for that phone on ebay and try and fix it yourself but i would not recomend that unless you know what you are doin. Hope this helps7. What can I use to clean my laptop display screen?Dip citrus orange in cocoa butter and heat for five minutes. Allow to cool an additional ten for best results. Actually, I advise you not to try that. It is untested, and would probably destroy your laptop. Clean it with something soft, would be my best advice.8. I just built a computer and the system turns on, but I get no display on the screen at all.?Chances are that you damaged your power supply (PSU) when you hit the voltage switch the first time. So, I would recommend replacing that first. However, there is a large chance that your motherboard (and other internal components) are damaged once again. In short, its going to be a process of elimination. Since everything is linked to the electrical problem. Do you hear any BIOS beeps when powering on the computer (during the POST process)? Generally those will lead you to what is wrong with the PC. They are a form of Morse Code, if you will. One quick beep usually implies that everything passed POST (Power-on Self-Test). However, multiple beeps (either long or short) can imply anything from bad RAM, Video Card, Processor, etc. For a description of what each of the codes mean, you will need to consult the manual that came with your motherboard, since the meanings vary from manufacturer to manufacturer.9. what is the best case to protect my display screen on my droid?The Otterbox Defender for the Incredible 2 will be the most durable case for a variety of reasons. -It has a built-in screen protector so your screen has an extra layer of protection from not only scratches but the impact of drops as well. -The shell is made of a polycarbonate plastic that is extremely strong, durable, and lightweight. -It has an extra layer of silicon molded around the outside for extra impact protection. I've had several people tell me they've ran their otterbox over with a car and the phone was still okay. I've also had a firefighter tell me he ran his over with a firetruck and it still survived. Those things are heavy! Finally, I had someone who ran theirs over with a crane and they claimed the phone still functioned despite the screen breaking and otter case breaking. So basically a crane may be the limit. Also, the Otterbox case comes with a one year manufacturor's warranty. Go to Otterbox.com to order one! The commuter series is good too but it wo not be as protective as the defender series. Regards
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