Preface
PoE power supply technology refers to a method of transmitting power and data through network cables, which is mainly composed of network cables, power supply ends, and power receiving ends. Compared with traditional power supply methods, PoE technology is easier to deploy, and only one network cable is required to complete the transmission of power and data. After more than ten years of development, the speed of PoE switches has been continuously improved, from the initial 100 Gigabit and Gigabit to the current 10 Gigabit, and the maximum power supply power has gradually increased to 90W. This technology can easily meet the power and data transmission needs of a variety of devices, including IP phones, IP webcams, wireless APs, small indoor base stations, and more. The wide application of PoE technology provides a more flexible and convenient solution for the connection and management of network devices, which helps to improve the efficiency and reliability of transmission.
The PoE chip that appears in the article
When the charging head network sorted out the previous dismantling cases, it was found that 5 Netcom products were equipped with PoE chips recently. Some of the parameters of the four chips that appear in the article are shown in the figure, and the details will be introduced to you below.
Texas Instruments TPS23861
TI Texas Instruments TPS23861 is an IEEE 802.3at four-port Power-over-Ethernet PSE controller in a TSSOP-28 package that supports four-port PoE power control. TPS23861 is able to automatically detect a valid signed power delivery device (PD), determine the power supply demand based on classification, and apply power. Supports classification of two types of PD events. TPS23861 supports both DC disconnect and external field-effect transistor (FET) architectures, allowing designers to balance size, efficiency, and solution cost needs.
The unique pinout enables a 2-layer PCB design with clear upper and lower separation of logic grouping and I2C and power pins. This provides best-in-class thermal performance, Kelvin accuracy, and low build costs. In addition to the automatic operating mode, the TPS23861 can be semi-automatic with I2C control for precise monitoring and intelligent power management. In both semi-automatic and automatic mode, the 400ms TPON specification value is guaranteed.
Application examples
TP-LINK standard PoE injector TL-POE170S
TP-LINK standard PoE injector TL-POE170S adopts a straight board design, and the black glossy surface of the shell looks very temperamental. There are IN and OUT prompts next to the network cable interfaces at both ends of the power supply, which can be used after wiring and powering, which is simple and convenient.
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Silan SD4952B
Silan Micro SD4952B is a PD and DC/DC controller based on IEEE 802.3af standard in SOP-16 package. The PD controller part of the chip provides characteristic resistance detection, power grading, and surge current limiting functions for the powered devices in the PoE Power over Ethernet system, and it integrates a power MOSFET with a withstand voltage of 100V on-resistance of 0.6Ω, and built-in current limiting protection, undervoltage protection, and overtemperature protection. The DC/DC controller has a built-in 200V power MOSFET, adopts the primary side control (PSR) mode, is suitable for the Flyback topology, provides an accurate constant voltage control loop, works in PWM+PFM mode, and has high system efficiency and good EMI characteristics.
Application examples
Long-view gun-type high-definition network surveillance camera
This camera is a gun-type design with IP67 waterproof capability to meet the requirements of outdoor use. Built-in Sony backlight sensor for clearer night videos. The camera supports 1080P output, and the AI intelligent analysis function can carry out face detection, intrusion detection and other functions, and supports transmission through the network interface, connected to the DVR.
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Marui MK3614
The Morgis MK3614 is a highly integrated, single-chip Power-over-Ethernet controller for powering IEEE802.3 AF/AT devices. The chip integrates power device detection, current limiting, load disconnection detection and operating current level.
The MK3614 integrates an 80V/0.3Ω power MOS transistor and a current sense resistor, as well as an intelligent protection circuit, and supports an output of 30W power. It is equipped with LED indicator to indicate the working status and supports a variety of working modes. The MK3614 is available in a thermally enhanced ESOP-8 package with minimal external components.
Application examples
Tenda Gigabit AT standard Ethernet PoE injector
This Gigabit Ethernet PoE injector is designed in a white strip enclosure with an AC power outlet at one end and two network cable ports at the other end. By using this power supply, it is possible to convert network cables that do not support PoE power supply to PoE power supply output. The output power of this power supply is 53.5V 0.6A, the power supply standard is IEEE 802.3 AT, and it supports power supply to devices below 30W, and supports gigabit speeds.
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Teardown Report: Tenda Gigabit AT Standard Ethernet PoE Injector
PeerSafe PoE Power Supply IC AS7800
The AS7800 is a high-precision off-line switching power supply IC with an integrated 200V withstand voltage, 0.5Ω MOS transistor and 12W output power in SOP-7 package. The AS7800 uses primary-side feedback, the constant current value and output power are externally set, and the built-in constant current control and peak current control are built-in.
In addition, the AS7800 has built-in line voltage drop compensation, which has good load regulation, and can work with frequency reduction during light loads, resulting in lower power consumption. The chip also provides power-on soft-start function and self-resettable protection functions including cycle-by-cycle current limiting protection, VDD over-voltage protection, VDD over-voltage clamping, under-voltage protection, etc., with high system efficiency and good EMI performance.
Application examples
Skyworth 4 million intelligent dual-light full-color network camera
The camera launched by Skyworth Security has 4 million pixels and has IP66 protection level to meet the needs of outdoor applications. The camera supports 2K resolution video output, built-in microphone and fill light. The camera is equipped with a 100 Gigabit network interface to provide power supply for PoE, which is more convenient for installation and deployment.
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Teardown report: SKYWORTH 4 million intelligent dual-light full-color network camera
ZTE 4 million pixel HD smart camera
ZTE's camera is 400W pixels, with a sealed case, which is dustproof and waterproof to meet outdoor use. The camera has cloud storage and motion detection, and has a built-in IR fill light and a white LED fill light. The camera is equipped with a 100 Gigabit network interface, PoE power supply, and comes with a PoE power supply for easy installation and use.
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Teardown report: ZTE 4 million pixel HD smart camera
Summary of the charging head network
Charging head network has learned that at present, a variety of Netcom products are equipped with PoE chips with different performance, which play an important role in power supply and data transmission. The chips mentioned in the article, such as Texas Instruments' TPS23861, Silan Micro's SD4952B, and Maoruixin's MK3614, not only support power supply, but also have intelligent management and protection functions, providing a stable and reliable power supply environment for equipment. It effectively simplifies the wiring and management process of the equipment and reduces the daily maintenance cost.
As IoT technology continues to evolve, the demand for PoE technology will grow further. In the future, PoE chips are expected to achieve higher power output and more intelligent management functions, providing stronger support for the development of mobile phone communications, monitoring and security, smart cities and other fields, and promoting the construction and progress of a digital society.