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USB Power Delivery Specification (USB-PD) Introduction Jan 15, 2018

With the increase of smart phone functions, the power consumption becomes faster and faster, and people are getting hungry for the efficiency of cell phone charging and the reduction of power consumption. With the long-awaited USB Type-C standard released, USB-PD protocol has also entered the public view, this new charging protocol subverts the awareness of USB charging inefficiency.


Alleged USB-PD protocol, can carry 3A or 5A of current, transmission power can reach 100W, while the interface defines a dedicated channel for power transfer protocol communication, charging and receiving devices can be completed between the intelligent adaptive Charge adjustment, improve charging efficiency.


So what is USB-PD?

The "USB Power Delivery Specification (USB PD)" is a standard that uses the USB interface to provide 100W of power and aims to provide users with a more robust power-supply solution. USB 2.0 only for portable terminal drive and built-in rechargeable battery charging purposes, "USB Battery Charging" standard although to improve the supply of electricity, but only 7.5W of power supply.


Currently, the USB PD is available in five "10", 18W, 36W, 60W and 100W "specs" at 5V, 12V and 20V and current ratings of 1.5A, 2A, 3A and 5A. This flexible configuration allows various electronic devices Can be through a USB cable to meet the power needs, not only for mobile devices, and even notebooks, monitors, direct power supply, even more powerful is that it can achieve two-way charging, that is, two computers with USB cable can be connected Charge each other.


USB-IF (Universal Interface Industry Consortium) has set out the USB PD standard, 7.5W still only 5V power supply, but 10W, 18W 5V introduced outside the 12V, 60W and 100W is introduced 20V. Although the power supply will be expanded to 100W, there are still cable differences, the standard USB cable has long been the standard 100W power supply, but for mobile devices commonly used Micro-USB, due to the smaller connector, the physical limitations Under, can only supply 60W, can not reach 100W.


Similarly, the new USB-IF C-connector is a small mobile connector, the same can not be up to 100W power supply, the limit is 60W. In addition, unpredictable Powered USB estimates will also gradually fade out, only a few applications will continue to adopt. USB power supply once up to 60W, 100W, the next step may be achieved by printers, scanners, desktop monitors, etc., can be changed to USB power supply, which means that the future for notebooks, printers and other change , No longer need to discard the transformer, but can be used to reduce e-waste.


In fact, if you look carefully at this table is not difficult to find, this distribution can actually be divided into three types. Which 10W only 5V @ 2A output, that is, the current increase up only, which belongs to the most basic USB PD port. And then 18W and 36W belong to a grade, USB port will not only provide 5V will also provide 12V power supply, which for some external HDD, car power supply and other equipment for power supply. The third category is to provide 5V / 12V / 20V USB port, this type can provide an external HDD, automotive equipment, power supply, you can also give laptop, external monitor power supply.


It is worth mentioning that, whether it is not the most common USB PD port, the wire is definitely going to be over again. In addition, also need to pay attention to support 100W output only Standard A and Standard B standard connector, Micro can only support 60W.


USB-PD system design level also need to move forward

USB-PD to break the existing charging voltage limit, laptop, tablet manufacturers can design different products according to the power supply program. However, the introduction of new generation USB-PD specifications for electronic devices requires the use of new cables and connectors and the testing of related safety and protocol. Mainly consider the USB upgrade to the high power charging, the traditional cable can not fully meet the USB-PD voltage / current rating, and the device internal circuitry and user safety will have a certain impact, so the future USB cable And connectors are required to increase the ID pin, to enhance the circuit protection.


In addition, the USB-PD connector must be downward compatible to support existing USB products. The USB PD specification that supports power delivery will be set as the next-generation new standard, which is likely to change the way electronic products are used because the device will no longer need to be plugged into a separate power supply. The USB can provide data to the device while it is available Up to 100W power supply, which is 10 times stronger than today's USB power supply, and more efficient in power transfer conversion process, reducing energy waste caused by heat.


For power supply solutions providers, the technical challenge of developing USB-PDs is the selection of peripheral components, taking into account the power supply and consumption aspects, and putting more emphasis on 5,12 and 20 volts or different current specifications Multiple hardware and software development resources to improve the existing USB interface, 5 volt VBus power cord, support for voltage levels up to 12 or 20 volts.


USB PD not only has industrial significance, but also has a number of social significance. USB PD means further globalization. Past the world adopted different analog TV standards such as NTSC US regulations, PAL European regulations, the connector also has the United States RCA terminals, Japan S-terminals, which are the differences between the national portal, and now is gradually to OTT, Internet Network specifications and HDMI connector uniform. Similarly, all over the world adopt different frequency, different voltage, different connector power outlet, these differences make the end user must go abroad with universal adapter, if the transformer is damaged, stolen, can only find the original factory to re- Purchase.


Summary: The emergence of USB PD, will have the opportunity to unify the following applications of 100W power, and USB power supply has been gradually integrated into life. The future with laptops to countries are no longer need to bring the transformer, as long as with a USB cable, or even built-in retractable USB cable, greatly enhance the convenience