Power over Ethernet for power management silicon components
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Ethernet “refers to the use of a variety of standard IEEE802.3 LAN (LAN) system. Ethernet is the application of a workplace agreement, for example, by high-speed data cable to the desktop PC and connect the central file server. Data Terminal , wireless access points, network cameras and phones connected to the Ethernet ports of any of the equipment has to have its own power, which can be battery power can also be a separate AC outlet. and a more attractive idea is can at the same time, power and data to any connected to the Ethernet equipment. If the transmission is designed to make use of existing Ethernet cables, can be 100% backwards compatibility, it is better
This is included in the IEEE802.3af Power over Ethernet (PoE) standard can be done. The new standard in 2003, 6 menstrual IEEE approval for Ethernet transmit and receive signal power.
The advantages of PoE are:
● applications only need a set of wires, cables has become easier, lower cost.
● save AC adapter socket, and after the work environment more safe, clean, cost be reduced accordingly.
● Applications can be easily moved from one another.
● When the AC main line power failure, an uninterruptible power supply to ensure that the application of electricity required.
● remote monitoring and control can be connected to the Ethernet equipment.
Power over Ethernet which has allowed rapid progress as a new technology, which fundamentally changed the type of equipment, low-power power supply. There are more power-driven equipment through Ethernet. Today, there are two main types of PoE power devices become a leading force in sales growth, they are: wireless LAN access points and VoIP phones. The former compound growth rate of 38%, and in 2007 reached 15 million (Source: iSuppli), and support enterprise-class network which in 2007 is expected to be reached three million. Of power in turn drives the demand requirements of the existing Ethernet switch can support PoE. This can be shown in the “middle style” program to achieve. Is expected by 2007, the number of such equipment will grow to 800 million, growth rate of 68%.
In this case, the original Ethernet switch through the “middle style” Power-over-Ethernet hub to twisted-pair LAN cable into the power, the realization of PoE. Ethernet switch will be combined with the new “half-way” approach for the adoption of high-speed data cable to connect the power device (PD) power. Of these electrical equipment can be a network of cameras, VoIP phones, wireless LAN access points and other equipment. Uninterruptible power supply (UPS) to the main power supply to provide backup electrical power.
Power management devices used in Ethernet switches and Power over Ethernet “-style half-way” hub conversion voltage and current, as well as electrical equipment in the DC-DC converters.
Ethernet switch in the power management device
Up-to-date through the Ethernet switch 24 or 48 independent ports provide PoE for the electrical equipment connected to the following non-PoE-compatible system. Each device has its own power 48V power supply, each of PD up to 15.4W, respectively, by the Ethernet switch management.
IEEE802.3af PoE standard allows the maximum power consumption of equipment in the 13W or so – taking into account the long-distance transmission cables have a certain degree of power loss, Ethernet switch to provide power 15.4W. End-use electrical equipment when the 48V power supply voltage range 36 ~ 57V, the voltage reaches the maximum allowed twice about switching voltage (such as peak signal switches, etc.), require the use of a power switch for 100V rated VDS discrete MOSFET.
PoE controller generally refers to “hot swap” controller. The function of this type of IC are:
● Separation of independent control of the four PoE ports.
● Detection of electrical equipment and effective connections.
● Monitoring of the MOSFET under steady-state current (through the low-ohm resistor sensor).
● PD when connected to the port on the influx of current and thermal control MOSFET.
● When the PD disconnect, a low-current disconnect function.
In common mode, once the power supply port, PD port by-pass capacitor voltage power supply, external MOSFET power scattered is very small. This shows that a small MOSFET will be able to meet this need. However, IEEE802.3af there are a number of other needs, such as the surge current is turned on and electrical equipment are not compatible with the issue of ports, which need a lot of energy in the instantaneous spread of the MOSFET. That is why the use of discrete MOSFET integrated solutions rather than the causes.
Ethernet switch MOSFET also called for the closure of the leakage when the volume is lower. Asking for a port IEEE802.3af absolute maximum amount of leakage can not exceed 12 basis, this figure including the MOSFET and other circuit protection of the leakage path of leakage current. Philips Semiconductors of the MOSFET design to meet this requirement.
Battery has become the key mobile office applications
At present, the mobile office concept has already become a reality. In order to meet the needs of mobile and mainstream manufacturers are introducing more powerful, more stable system of ultra-thin notebook PCs, and notebooks accounted for 10% of the overall price -15% of the battery performance, but also more and more manufacturers concern.
In fact, the value of the battery often underestimated, and even a lot of people in the time to buy laptop battery had simply ignored the problem completely. However, from the perspective of mobile office, but in the practical application of the battery often play an extremely important role. According to the relevant person in charge of NEC, at present, a common ultra-thin notebook battery time between 2-3 hours, a good brand can be achieved for about four hours. NEC S820 will be able to provide electricity five hours time, and the S820 weighs only 1.36Kg, the fuselage is only 16.6 millimeters thick. At the same time, with a backup battery, S820’s life will be a staggering 11.8 hours.
Looking at the market most of ultra-thin notebook computers, cell expansion have not been able to achieve “full portable,” and after loading so that the lower part of the formation of convex body, that affects the body and reduces the appearance of the portable , and for users This is a fly in the ointment. NEC was the first to put forward a “no protruding objects” Smoothing the concept of battery design, the S820 is designed to extend the battery very thin flat-shaped, S820 Ultra Low Voltage CPU, the motherboard to use a large number of high-quality low-power components , as well as through high-quality CPU power management features with the control, reduce unnecessary power consumption, so as to achieve a minimum energy. Smoothing these unique battery design that is available once the evaluation was very high, is considered the appearance of laptop battery “revolutionary” design.
There analysis of the industry, with the ever-increasing Internet bandwidth and the increasing popularity of wireless networks, mobile notebook PC will become the most widely used, which includes not only people existing “mobile office” concept, entertainment, communications, and other day-to-day non-business mobile applications will also be popular, as the energy source of laptop battery is bound to become the top priority. Experts predict that in the near future, there will be more vendors to join the main energy-saving technologies and notebook battery R & D ranks, with new material made of small size, high-capacity, long time, a high end portable battery products laptop battery will become the main trend of the application.
Fuel cell vehicles 4 years after the start, the recent launch first hybrid vehicle
In 2003, China’s energy consumption level has been flat and Japan, will surpass Japan this year, after the United States to become the second largest energy consumption power. China’s oil consumption in total energy consumption accounted for about 25%, which accounted for gasoline consumption in the car around 70%. According to projections, by 2020 China will have a car full of vehicle ownership is the amount of 5 times the energy consumption can only sustain the current 2-fold, research alternative energy sources is urgent car.
As a large city, how to develop the city’s environmental protection and energy saving cars have become a major issue. According to the officers revealed that the city will soon launch a hybrid car, is expected to launch long-term light-fuel vehicles. 2008-2010, the city of light fuel vehicles is expected to start.
At present, the city of CNG (compressed natural gas), about 150 buses are being used, LPG (liquefied petroleum gas) are more than 10,000 taxi cars. According to a three-year environmental protection plan, the city of CNG buses in future will be about 3000. — 863 research projects and go beyond the fuel cell vehicle on the 2nd through the Ministry of Science and Technology in a recent inspection, which will also further developed a variety of models, is expected to extend the study to the next five-year plan.
According to international forecasts, from 2010 to 2015, the world will be a major fuel cell vehicle production, vehicle production will be a new revolution. China’s fuel cell vehicles is expected in 2008 Olympics and the World Expo 2010 will take place during the model run.
