On the origin and specification of power delivery
In the past, the charging devices of the products were mostly used by various brands with their own interfaces, resulting in a lot of waste when replacing the devices. Due to the popularity of USB, most products in the market transmit data through this interface, which makes people want to improve the power supply capacity of USB. In the past, even though USB battery charging 1.2 (bc1.2) could only provide 7.5W (5V 1.5A) at most, it took a long time for electronic products to charge. Origin and specification of PD fast charging
Usb-if (USB implementers Forum) published the first version of USB power delivery Specification Revision 1.0 (version 1.0) in 2012, which greatly improved the power supply capacity to 100W (20V, 5a). With the addition of more functions, the specification is constantly updated, and now comes to USB power delivery Specification Revision 3.1 (later referred to as PD and PD spec). New usb-c specification: support up to 240W power, need to upgrade cable
With the market becoming more and more mature, type-C interface has gradually become the mainstream in the market, and most products support PD. These products use configuration channel (CC) pin to transmit PD communication information and protocol, and power supply through VBUS pin. Let's understand the concept of PD through the summary of historical articles. Change the charging design, using USB PD and type-c
On May 25, the usb-if Association released the v2.1 version of USB type-C cable and interface standard, in which the chapter on power supply capability was specially updated. USB pd3.1 standard puts the original USB pd3.0 content into standard power range (SPR), and the maximum power remains 100W; At the same time, extended power range (EPR) is added, and the maximum power is expanded from 100W to 240W. What is the relationship between USB C, USB PD and USB 3.1? picture
According to the data released by usb-if Association, in the extended power range EPR, three fixed voltage ranges of 28V, 36V and 48V and three adjustable voltage supply (AVS) are added
Among them, the maximum current level remains unchanged at 5A; The power of 100-140w is 28V AVS, and the voltage range is 15v-28v; Over 140W to 180W, the power is 36V AVS, and the voltage range is 15v-36v; Over 180W to 240W is 48V AVS, and the voltage range is 15v-48v.
Under the USB pd3.1 standard, USB type-C cable is divided into two specifications: 20V ordinary cable and 50V EPR cable. When the power output exceeds 100W, not only the 5A cable of EPR (extended power) needs to be used, but also the EPR specific information handshake between source, sink and cable can be used to enter EPR from SPR; If the cable is a captive cable fixed to the charger, you only need to shake hands between the source and sink. For details, you can refer to the technical literature published by GRL in history: the origin and specifications of PD fast charging; According to the role of power supply end and power consumption end, power can be broadly divided into the following three types:
Discussion on USB pd3.1 fast charging specification
At the same time, it has the functions of source and sink, and RP and RD are set on CC pin at the same time
The two ends of the butt joint are detected by CC and VBUS to see if there is a suitable device connected: because the voltage level is greatly increased, the safety problem is very important, and EPR puts forward higher requirements for the safety regulations of connectors and cables. It is necessary to pay attention to the provisions of IEC 62368 on limited power supply (LPS). It is worth noting that in the formulation of this USB pd3.1 specification, Huawei, Xiaomi, Lucent precision, huinengtai and other domestic companies have actively participated in it, and made important contributions to the new standard, which has been written into the enterprise directory of standard drafting
At present, the industry standard USB PD charging protocol based on USB type-C is only open to 100W. Although it is enough for most mobile phones and entry-level game laptops, it is still not enough for E-sports laptops that are frequently used to be more than 150W or even 240W. With the opening of USB PD 3.1 to 240W by this association, it means that in addition to a few over frequency E-sports laptops, In the future, USB PD will provide sufficient power, so it can be used in high-performance PC, large screen display, printer with USB, etc. even, USB PD will become a unified standard power supply interface, and the day when USB type-C will unify the charging of laptop has come!