With the update and iteration of smart phone charging technology, the charging power has developed from 5W to 240W. The interface specification, wire and charger apparently look the same. Why is it so different? In particular, the wire specifications are all usb-c data cables on the surface. The price difference is several times. When it is used with a 100W charger, the power cannot reach the maximum output value. How can the charging be so slow?
In fact, the standard usb-c wire also has a "performance grading" system in terms of charging. The most common specifications are 3A wire and 5A wire. Now, the charging head network introduces why these two data lines affect the charging power of the system from the aspect of charging wire.
Wire shape
Usb-c interface is the most common quick charging interface in the market at present. There are many types of usb-c wire, mainly including usb-c to usb-c, usb-a to usb-c and usb-c to lightning. Since usb-c to lightning is not a universal wire, this article will not discuss it in detail. It will mainly explain usb-c to usb-c and usb-a to usb-c.
E-marker chip
According to the USB specification, the USB Pd / usb-c point-to-point connection system includes three participants: source, sink and wire.
During each connection, in order to avoid blind people feeling like elephants, the devices will conduct "Information Negotiation" through the wire, so as to know whether the other end of the wire is a mobile phone or a charger or a computer, determine whether the other end is a power supply or a power receiving device, communicate the power supply specification / power receiving specification, data transmission rate specification and other key information.
As an important bridge for carrying information communication and participating in power transmission, usb-c wire can be added with "e-marker" chip in the terminal head to participate in "Information Negotiation" as a third party.
E-marker chip is "optional". For safety reasons, the current of wire rod without e-marker chip is limited to 3a to avoid safety problems caused by overheating of high resistance and large current; The maximum current transmission of the whole fast charging system is also 3A for the wire with 3A e-marker chip; Using the wire of 5A e-marker chip, the maximum current transmission of the whole fast charging system can reach 5A.
It can be seen from the table that the maximum power transmission specifications of data lines are mainly divided into two types, 60W / 100W, which are divided into 3A wire / 5A wire according to the current. Except for lightning data lines, the power transmission performance of other data lines is not directly related to the data transmission performance. If you want to obtain a fast charging performance higher than 60W (3a), a 100W (5a) cable is necessary. You should read the product description clearly when you buy it. If you buy it wrong, the power will be limited and can not be used more than 60W (3a).
3A wire
3A wire is one of the most widely used wires in the market, and there is no obvious mark on the wire appearance and terminal. It can be understood from the literal meaning of "3A", the maximum transmission current value is 3a, which is calculated based on the maximum voltage of 20V of USB pd3.0, and the maximum allowable fast charging power is 60W.
Generally, 3A wire rod will not be added with e-marker chip, and it is also designed and manufactured according to the power specification in terms of contact gold plating, wire core thickness and cost control.
60W fast charging power is sufficient for ordinary mobile phones, tablets, switch game consoles and ultrabooks, and the price is relatively low. Many chargers lower than 60W are equipped with 3A wire as standard.
5A wire
Compared with 3A wire, the current transmission specification of 5A wire is nearly doubled, and the requirements for all aspects of wire are more stringent. In terms of appearance, the word "5A" will be clearly marked on the outer package and the terminal head and net tail of 5A wire for the convenience of users. It can be understood from the literal meaning of "5A", the maximum transmission current value is 5a, which is calculated based on the maximum voltage of 20V of USB pd3.0, and the maximum allowable fast charging power is 100W.
5A wire must have a built-in 5A e-marker chip. During the "Information Negotiation" between power supply equipment and power receiving equipment, the key parameter that the wire supports 5A is obtained, and the whole set of fast charging system can break through the limitation of 3A current transmission. The production, design and manufacturing process of 5A wire rod are more complex. The gold plating of the joint is thicker, the shrapnel is wider, and the wire core is thicker. In addition, cotton thread and lubricating powder are usually added to improve the flexibility and avoid too hard wire body.
100W fast charging power can be used for flagship fast charging mobile phones, high-performance notebooks, high-power power power banks and other equipment with higher requirements. In terms of price, manufacturers are more willing to pay attention to the appearance design and anti-wear tensile design on 5A wire rod to improve the durability of products. The price of 5A wire rod is also rising.
As early as 2016, the charging head network has conducted electrical performance tests on a number of wires. It can be seen from the internal resistance test of voltage drop that the resistance value of the two 5A cables is as low as 0.06 Ω, which is far lower than that of other ordinary cables. When passing through large current, the voltage drop is lower, the energy loss is less, and it is not easy to heat.
Q&A
The charging head network collects and answers some common user questions.
Can 3A wire and 5A wire be mixed?
In most cases, wires can be mixed with each other, but there is a gap in charging speed. For example, for devices and chargers that support 10v5a, the power will be limited to 10v3a after using 3A wire; For devices and chargers that support 20v5a, the power will be limited to 20v3a after using 3A wire, and so on.
Very few notebooks have strict requirements. It is mandatory to charge notebooks above 20v3.25a, that is, above 65W; If a 3A cable is used, the notebook only detects 20v3a, that is, 60W, and will refuse to charge.
5A wire is so good. Is 3A wire still worth buying?
Only buy the right ones, not expensive ones, and correctly purchase fast charging [accessories] according to the equipment in your hand( https://microsoft.pvxt.net/Xx07X ) OK. 5A wire rod has high specification, which is mainly used for high-power and high current equipment. Its wire body is stronger and will not be so soft; 3a is easy to store and coil, and the price of 3A will be cheaper.
Why is it rare for 5A wire rod to have an ultra long style such as 2m?
Generally speaking, the ultra long cables of 2M and 3M in the market are 3A wires, and 5A wires are usually only 0.3-1m. Because the longer the wire is, the greater the accumulated resistance will be, resulting in a greater voltage drop, and the high current fast charging will consider the voltage drop value, so the 5A wire generally will not have an ultra long wire.
Does it support 5A current when you buy 5A wire?
Generally speaking, the equipment supports 5A high current fast charging and adopts USB PD universal fast charging standard. With a charger with 5A or 5A PPS voltage output and 5A eMarker wire, 5A current can be achieved. However, some devices use private fast charging protocols, and the cables and chargers encrypt the communication content. Such devices can only purchase their own fast charging wires.
Does the lightning line have to be 5A current?
Lightning 3 wire, lightning 4 wire and USB4 wire are all 5A current.
What current line is usb-c to lightning?
C2l is an encrypted wire. Although there is a communication chip in the terminal head, its wire material specification and manufacturing process only support the upper limit of 3A current. At present, the highest c2l charging "power" device is ipad Pro, about 33W (15v2.2a), the highest charging "current" device is iphone 13 Pro max, about 27W (9v3a).
Is there a direct relationship between the data transmission speed of 3A cable and 5A cable?
There is no direct relationship. There are either 3a 10Gbps cables or 5A 480mbps cables. The data transmission performance specifications are separate from the power transmission performance specifications and have no direct relationship.
Charging head network Summary
In this charging talk, I shared with you the specific differences between 3A wire rod and 5A wire rod. They are different in manufacturing process, material specification, price and flexibility. For users with more than 3A power transmission equipment, 5A wire can get a better fast charging experience. If you don't have a need for fast charging with large current, it's OK to buy 3A line. Well, the above is the whole content of this charging talk. If you have any topic you want to talk about next time, please leave a message and tell the editor. See you next time.