What is the difference between 5a and 3a charging cables?

Difference: 1. The 5A data line allows a larger current to pass per unit time, so the 5A charging speed is faster than the 3A data line at the same voltage; 2. The 3A data line can support 3a and below When charging mobile phones, you cannot charge mobile phones that support more than 3a. A 5A data cable can charge mobile phones that support 5a and below, but cannot charge mobile phones that support more than 5a. The price of 3 and 5A data cables is generally higher than that of 3A data cables.

The operating environment of this tutorial: HarmonyOS 2 system, HONOR V30 mobile phone.

With the update and iteration of smartphone charging technology, the charging power has developed from 5W to the current 240W. The interface specifications, wires, and chargers obviously look similar on the surface. Why are they so different? Especially the cable specifications. On the surface, they are all USB-C data cables. The price difference is several times. When used with a 100W charger, the power cannot reach the maximum output. Why is charging still so slow?

In fact, standard USB-C cables also have a "performance grading" system in terms of charging. The most common specifications are 3A cables and 5A cables.

The difference between 5A and 3A data cables

1. The difference between 3a fast charging and 5a fast charging lies in the different charging speeds and the internal materials of the two. Differently, the resistance of 3a is larger than that of 5a, so the current passing through per unit time is smaller. At the same voltage, 5a charges faster than 3a.

2. Suitable for different scenarios: 3a fast charging can charge mobile phones that support 3a or below, but cannot charge mobile phones that support more than 3a, while 5a fast charging can charge mobile phones that support 5a or below, but cannot charge mobile phones that support more than 5a. of charge.

3. Different prices: 5a charges faster, but the price is also higher.

Expand knowledge:

Cable form

The USB-C interface is currently the most popular one on the market. There are many common fast charging interfaces, and there are many types of USB-C cables. There are three main types: USB-C to USB-C, USB-A to USB-C, and USB-C to Lightning. Since USB-C to Lightning It is not a universal cable, and this article will not discuss it in detail. It mainly explains USB-C to USB-C and USB-A to USB-C.

E-Marker chip

According to the USB specification, in the USB PD / USB-C point-to-point connection system, it is included There are three participants, power supply equipment (Source), power receiving equipment (Sink), and wires.

At every connection, in order to avoid blind people trying to figure out the elephant, the devices will conduct "information negotiation" through the cable to know whether the other end of the cable is a mobile phone, a charger or a computer, and to determine whether the other end of the cable is powering or receiving power. Key information such as electrical equipment, communication power supply specifications/power receiving specifications, data transmission rate specifications, etc.

As the USB-C cable serves as an important bridge for information communication and participation in power transmission, the "E-Marker" chip can be added to the terminal head to participate in the "information negotiation" as a third party.

The E-Marker chip is "optional". For safety reasons, the current of wires without E-Marker chips is limited to 3A to avoid safety problems caused by high resistance and large current overheating; while using 3A E- With Marker chip wires, the maximum current transmission of the entire fast charging system is also 3A; using 5A E-Marker chip wires, the maximum current transmission of the entire fast charging system can reach 5A.

As can be seen from the table, the maximum power transmission specifications of data lines are mainly divided into two types, 60W / 100W. According to the current division, they are 3A wire / 5A wire, except 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 fast charging performance higher than 60W (3A), a 100W (5A) cable is necessary. Please read the product description clearly when purchasing. If you buy the wrong one, the power will be limited and cannot exceed 60W (3A).

3A wire

3A wire is one of the most widely used wires on the market. There is no obvious marking on the appearance of the wire or the terminals. From the literal meaning of "3A", we can understand that its maximum transmission current value is 3A. Calculated based on the USB PD3.0 maximum voltage of 20V, its maximum withstand fast charging power is 60W.

3A wires generally do not add E-Marker chips, and are designed and manufactured according to this 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 below 60W come standard with 3A wires. .

5A wire

Compared with 3A wire, the current transmission specifications of 5A wire are nearly doubled, and the requirements for all aspects of the wire are more stringent. In terms of appearance, 5A wires are generally clearly marked with the word "5A" on the outer packaging and at the end of the terminal net for easy identification by users. From the literal meaning of "5A", we can understand that its maximum transmission current value is 5A. Calculated based on the USB PD3.0 maximum voltage of 20V, its maximum withstand fast charging power is 100W.

5A wire must have a built-in 5A E-Marker chip. During the "information negotiation" process between the power supply device and the powered device, it is obtained that the wire supports 5A, a key parameter. The entire set of fast charging Only then can the system break through the 3A current transmission limitation. The production design and manufacturing process of 5A wires are more complex. The connectors are thicker gold-plated, the spring pieces are wider, and the wire cores are thicker. Cotton thread, lubricating powder, etc. are usually added to improve flexibility and avoid excessive hardness of the wire body.

100W fast charging power can be used in higher-demand devices such as flagship fast-charging mobile phones, high-performance notebooks, high-power power banks, etc. In terms of price, manufacturers are more willing to spend time on 5A wires for appearance design, The anti-wear and tensile design improves product durability, and the price of 5A wires has also increased.

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