Why are there still notebooks using the traditional “round charging port”?

The popularity of the PD protocol and USB-C interface, and the emergence of gallium nitride semiconductor materials in recent years have greatly improved the charging experience of electronic devices. A multi-port charging head and a few charging cables can recharge most electronic devices, bringing a "cross-platform" charging experience.

With this trend getting more and more popular, many traditional notebook manufacturers have also begun to follow, and they have equipped their own high-end thin and light notebooks with full-featured USB-C interface (even Thunder 3, Thunder 4), although the transmission protocol is different, But their common point is to support the PD fast charge protocol.

The transmission capacity of the full-featured USB-C interface is weaker than that of Thunderbolt 3 (and Thunderbolt 4), but it also supports PD fast charging, DP video output and data transmission, but its use cost (including cables, docking stations, etc.) is far Below thunder and lightning. As for the relationship between Raiden and USB-C, you can move to " USB-C under the Great Unification also hides "several sins" ", this article will not be too much ink. Unless otherwise specified, the USB in the article -C interface refers to full-function USB-C.

However, laptops in the price range of 3,000 yuan to 5,000 yuan are a little bit "conservative", and basically retain the traditional DC charging interface. A slightly more "fashionable" manufacturer will spare a USB-C interface. More still provide USB-A form interface, progress is slightly slow.

▲ Traditional laptop charger. Picture from: windowsreport

It is a general trend for notebook computers to become thinner and lighter, but it does not seem to include chargers. For some brand products, chargers are still "urinary bag-like". It is not convenient to wear a transformer on a wire.

The question is, why do these traditional notebook computer manufacturers still retain the DC interface instead of embracing the PD fast charge protocol and the USB-C interface?

Traditional laptop charger "silly big black rough"

Let's start with the shortcomings of traditional laptop chargers.

The shape of the traditional laptop charger (DC interface) is roughly similar, and it is divided into the input line, the charger body, and the output line connector. This form of external power supply was invented by Toshiba in 1985, and used this to promote notebook computers to the public, which can be said to be an "old tradition".

Subsequently, the products of major PC manufacturers continued to follow this form and gradually became the mainstream, and the form has not changed. There is no harm if there is no comparison. In 2001, there was also a compact power adapter released with Apple PowerBook G4. Its size and weight are the same as the current MacBook charger.

The biggest advantage of the Apple charger is actually that the traditional charger is divided into two. The transformer is directly connected to the plug and plugged into the socket together. Similar to a mobile phone, the notebook does not have to be dragged with a "urine bag" at any time (of course, it can also be connected The extension cord returns to the traditional state).

In comparison, the traditional notebook DC charger is really big and heavy, the key is not convenient, and in the face of the "consumer's voice" does not seem to want to change.

In addition, due to the large number of manufacturers, the charging head specifications and transformer output specifications of their products are different (but the power is around 65W), which means that the chargers of different products cannot be exchanged, and there is a certain risk. Mobile phone chargers are very similar.

Is it better to use PD fast charge protocol?

The current PD fast charging protocol and USB-C interface can just make up for the shortcomings of traditional chargers, solve the heavy and large volume, and do not need to drag the "urine bag" to charge.

Is there no disadvantage to the PD fast charge protocol? The answer is of course no, PD fast charging also has many shortcomings, some of which make traditional manufacturers hesitate.

From a macro point of view, the PD protocol is actually somewhat similar to traditional DC charging, and both are the product of technological development. The PD fast charging protocol is a fast charging specification formulated by the USB-IF organization. To put it simply, it has several characteristics, the maximum output power is 100W (20V 5A), the interface form is USB-C, and the power transmission direction can be freely changed.

As mentioned earlier, the power of traditional laptop power supplies is mostly around 65W, but some gaming laptops and high-performance laptops may exceed 100W. The PD protocol charging head cannot meet their high-power requirements.

For the sake of beauty, many notebooks use an all-metal body, and almost all PD charging heads are not grounded, so you will often be charged (static/leakage). Although it is not harmful, it is enough to make you lose your elegance. For static electricity/leakage, the current solution is still a "urine bag". Many manufacturers will equip a three-hole adapter for grounding, and Mac users can also solve it by connecting the included power extension cord.

Another point is that before fast charging, the charger needs to communicate with the device, and only after the correct identification will the (protocol) handshake start fast charging. In other words, using PD protocol fast charge requires such a communication and handshake process, which is very complicated. On the contrary, the traditional DC power supply is much simpler, with only two levels of positive and negative, and it can be charged when connected, which is simple, convenient and stable.

In actual use, the DC interface is actually more convenient than the USB-C interface. The round shape of the DC interface not only supports "universal" blind insertion, it is more convenient to plug and unplug, and it is also more durable.

Not changing the USB-C is actually to save money?

In addition to the trade-offs made by manufacturers between the advantages and disadvantages of DC interface and PD fast charging, there is actually a purely commercial factor that is cost considerations. Compared with the traditional DC charging interface, the PD fast charging protocol is a technology that has only appeared in recent years, and the cost of the USB-C interface is slightly higher than that of the DC interface.

The full-featured USB-C interface can not only support PD fast charging, but also video output and data transmission, so it has higher requirements for electromagnetic shielding. In order to support high power of about 65W, better circuit design and more Scientific wiring and so on.

At the same time, the replacement of an interface in the original form of the notebook means that the existing production line must be upgraded, and the motherboard and mold must be replaced accordingly, which are hidden costs. For high-end thin and light notebooks with a price range of about 10,000 yuan, manufacturers may actively follow up with full-featured USB-C interfaces (even with Thunderbolt 3 and Thunderbolt 4), but they will be available on mid-range notebooks that cost more than a baht. Scruples.

Only for charging, the DC interface and the USB-C interface have their own advantages and disadvantages, and they have not completely reversed to the USB-C interface of the PD protocol. From a practical point of view, it is reasonable for many manufacturers to retain the traditional DC interface.

However, most of the products that retain the DC interface are traditional manufacturers. Relatively speaking, their resistance to transformation is greater than that of the new Internet manufacturers. They must take into account the different layout of the product line and control the "hidden cost."

USB-C form interface is the optimal solution

The epidemic in early 2020 created demand for distance education and home office work, which in turn stimulated the PC market. According to Canalys research data, the PC market in the fourth quarter of 2020 increased by 35% year-on-year, and the first quarter of 2021 is expected to surge by 43%. Among them, notebook computers are the main growth force.

Facing the favorable market this year, many traditional manufacturers have made efforts to revise their own product strategies. For example, Lenovo's Xiaoxin series has been out of the circle with extremely high cost performance and launched many sincere products. Coupled with the recent emergence of the Intel EVO certification platform, the dull notebook market has become active again. Among these new products, the full-featured USB-C interface is more and more common, and the DC interface appears less and less frequently.

▲ Full-featured USB-C has gradually become the mainstream interface. Picture from: pcworld

On the whole, the development trend of notebooks is becoming thinner and lighter, and the interface will be more streamlined. The USB-C interface with multiple functions of power supply, video output, and data transmission is more in line with the development trend. Smart phones, earphones, cameras, etc., the interfaces of many electronic devices are unified towards USB-C. You can get a cross-platform connection experience with only one USB-C cable, which is not possible with traditional DC interfaces. of.

Going back to the original question, the notebook retains the traditional DC interface. One is because the PD fast charge protocol and USB-C interface do not bring overwhelming advantages at this stage, and the other is due to cost. But taking a long-term view, the full-featured USB-C interface has been laid out in the future, while the DC power interface only lives in the present.

In the near future, the DC interface may enter history like VGA and RJ45 interfaces, and what replaces them is the multifunctional USB-C interface.

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