PoE technology exploded in 2010. The industry in 2010 is also known as the first year of China’s security HD. The first year of HD refers to the start of the popularization of network HD applications. PoE is also the time to enter the vision of China’s weak engineers. We began to recognize the IEEE802.3af and IEEE802.3at. We put the PoE switch in line with the international standard protocol, called the standard PoE switch.

At the same time, there is an inexpensive solution, which is the barbaric practice of loading DC power directly to the network cable, and we call it a non-standard PoE switch. Non-standard PoE switches mix in with PoE switches because of their low price. Since 2012-2016, Chinese standard PoE switch manufacturers have been promoting and educating the market to identify “standard” and “non-standard.” With the industry’s maturity, non-standard PoE switches have been recognized by users who only choose non-standard PoE switches when seeking meager costs. Therefore, non-standard PoE switches have become an embarrassing product in the PoE market. Most of the non-standard-based PoE switch vendors have gone bankrupt or switched to other businesses. A kind of single-chip PoE switch with a partial identification function has started to mix in the industry again. Today Mr. Hua will talk to you about how many problems are waiting for you in the MCU PoE switch and hope that more user friends will know and better choose the standard PoE switch products they want through our exchange of topics in this issue.

What is MCU PoE Switch?

Standard PoE products port power supply conform to IEEE802.3af 44-57V (15.4W), IEEE802.3at 50-57V (30W), IEEE802.3bt 52-57V (60-90W) protocols, all with standard PoE power supply chips. The standard PoE power supply voltage and process strictly follow specific specifications, which protect the PD throughout the power-on, detection, and power supply process. The microcontroller is a program written in 2018 and 2019 to imitate the regular PoE chip to run the protocol! There is no corresponding hardware support. It is first issued a 12V DC power supply to detect a 24.9K resistor at the PD end, and after detection, it directly boosts to 48V, during which there is no graded protection process. Once the MCU connects to AC power, 12V DC power immediately transmits to the powered device, which can easily burn out the device when the powered device connects to a voltage matching network terminal.

Spend more money

MCU PoE switch and standard PoE switch the most significant cost difference is still professional PoE primary control PSE chip, followed by supporting hardware circuit vacancies. The cost is much lower than professional standard PoE switch products than non-standard PoE switch is only a cheap to play the role of imitation of a tiny MCU. According to the standard PoE switch, most of the current industry business is selling single-chip PoE switch products. And with the ordinary distinguish non-standard and standard PoE switch voltage detection method, the essential detection can not be because the voltage used is 48VDC. Solution: disassemble the machine to check whether the PoE switch PSE chip, standard PSE chips are Microsemi, Texas Instruments, Linear Tech, IC PLUS Corp, National Semiconductor, Maxim Realtek, the chip is surrounded and accompanied by more supporting circuits.

No monitoring program, risk of burning equipment

The standard PoE switch will monitor the voltage, and the current power supply changes in real-time after the power supply is started. When there is any abnormality in the power supply, the port will be cut off in time to effectively protect the power supply and the receiving end of the equipment. The wire core of the network cable is about 0.5mm copper core conductive medium. In the process of power supply is very susceptible to external electromagnetic environment, the formation of inrush current and inrush voltage, to the PSE side and PD side to bring some damage. Suppose there is no effective monitoring mechanism for the PoE power supply at the PSE side and no real-time equalization measures. In that case, it is straightforward to cause damage to the power supply side and the receiving side, and in severe cases, it may cause a fire. MCU PoE switches and non-standard PoE switches bring us the same potential risk.

System instability and frequent self-reboot

The main components of PoE switch products are divided into three.

• First, the communication unit, the leading communication solutions including Broadcom, VITESSE, Marvell, IC PLUS, Realtek, etc.
• Second is the PoE control unit PSE, the top PSE power supply solutions including Microsemi, Texas Instruments, Linear Tech, IC PLUS Corp, National Semiconductor, Maxim, Realtek, etc…
• Third, the AC to DC converts the power supply unit, mainly using variable voltage, rectification, protection, and other circuits and devices.

The system stability of PoE switch products is closely related to these three parts, and the shortcomings of any one unit may cause the instability of PoE switches. The cottage model of the single-chip PoE switch in the PSE part significantly destroys the stability of the PoE switch and destroys the original standard architecture of the PoE switch. The experience brought to the customer is that the MCU PoE switch loses power for no reason during the application, and the product restarts for no reason. It makes the communication and power supply service intermittent and significantly destroys the quality of the terminal network equipment. Because of the low price of choosing a single-chip PoE switch and bringing endless after-sales and field maintenance, it is a nightmare for weak engineers.

PD has single recognition and poor compatibility

MCU PoE switches are elementary in the way they identify PD devices. Can not do PSE chip accuracy, in the single-chip simulation identification PD program, is designed and tested for a brand, a series, a model of PD, with a very narrow PD recognition. Therefore, the choice of single-chip PoE switch users often encounters the ability to power this brand of cameras, for another brand of cameras can not be powered. Compatibility is extremely poor, bringing great trouble and inconvenience to the engineers who install it on site.

No control flow program, no power supply situation.

MCU PoE switch lacks port power supply control and constraint mechanism, and the power supply to the terminal device belongs to the random state. Can not do port power supply management, so there are often tests when the camera is loaded usually, the installation to the site lacks port power. Even in the application process, of power supply is insufficient. Port power supply power in a random state, the front-end application of the weak power engineers to master the product characteristics bring significant obstacles.

Can not support IEEE802.3af/at/bt

In the rapid development of industrial IoT. Industrial PoE switches, standard PoE switches, and other products widely used in various projects. HoweVision‘s industrial PoE switches, PoE switches manufactured by the company, can widely support any standard manufacturers PD equipment, welcomed by overseas users. howeVision why can do this, the most fundamental reason is the standard, IEEE802.3af, IEEE802.3at, IEEE802.3bt three major PoE international standards, so that complex PoE electronic products can cross the country, can cross the brand, a perfect match for use. And MCU PoE switches have no standard, no protocol. Overseas PoE users do not welcome MCU PoE switch products.

POE switch life is short, no more than 18 months

If the single-chip machine can do the effect of PSE, still need professional PoE chip manufacturers colossal investment in the development of PSE chip? There is another problem that is not easy to find: the need for time to verify. The product application life and the standard PoE switch regular use of life is more than five years. The average failure-free time is more than ten years. And MCU POE is unstable system PoE products, since the beginning of 2018 since the market, to the end of 2019 user feedback, the average service life is less than 18 months, significantly lower than the life of the standard PoE switch.

Conclusion: HoweVision says communication, I am Mr. Hua, 100% technology, 100% originality, talk about PoE technology and stories, and jointly promote communication technology to a broader future! Today’s “microcontroller PoE, in the end, how many problems waiting for you” to share here, Mr. Hua wants to tell you, microcontroller PoE switch as much as possible not to touch, how many more problems, no one can know. If you have encountered the single-chip PoE switch to bring you trouble, you are welcome to send a message. Thank you for checking; more PoE stories for you to read, see you again next time!