Common interface standards can improve the convenience of life, such as powering desk lamps, drones, TVs, printers, external GPUs and even sweepers
First of all, the power is not pulled up casually. Power is equal to voltage * current, neither of which can be amplified casually. The current is actually limited by fire safety. With the same resistivity, the higher the current, the hotter the wire will be. If the heat exceeds the natural heat dissipation capacity, it will heat up, and it will burn if the temperature rises high. Therefore, the maximum current is limited by the resistivity of the entire wire. This whole line includes the cable itself and the plugs on both sides and the sockets connected to it. There is still room for adjusting the cable thickness and fineness. The plug and socket are regulated according to the standard and cannot be adjusted. If the adjustment exceeds the allowable error range, it is not easy to use. Therefore, the current agreement to 5A is already very large. Physically, all core wires can be used up to about 10A, and they have to be made of very expensive materials, which will not be easy to use. The voltage is limited by physical safety, that is, the risk of breakdown. Of course, it also involves fire prevention and protection against electric shock. Simply put, you feel that the line is insulated, but it can only isolate a limited voltage. If it exceeds the voltage, it may break down and discharge. In the shortest case, it will cause the line to short-circuit and burn the equipment, and in the worst case, it will catch fire. The limiting factor of the maximum voltage is mainly the plug and socket, because the standard plug design determines the line width and the distance between the golden finger, the voltage difference is very limited. The voltage currently given is 20V, which is actually almost the peak value under safe conditions. After all, considering the safety of the human body, it is about 30V. So in fact, the current PD standard basically provides the upper limit of the power that a line can provide, which is about 100W. Of course, it’s not impossible to have crazy stack technology to increase the total power. For example, a total of 24 lines of USB Type-C, if I use all 6 groups to supply power, I am afraid it can indeed exceed 300W (but it can’t exceed that much, the cable The total power is still limited). But what is the point of doing so? It also provides 300W of power, and the cost of an ordinary mains cable is only about one-tenth of that of a USB Type-C cable of the same power. Manufacturers and consumers need a USB Type-C cable that can supply power because it can solve power supply and high-speed data at the same time with one cable, which is simple and convenient. At the same time, applications that only require a power supply function or only a data function can use part of the hardware to reduce the total investment. But this demand or the corresponding benefits are not available everywhere. For example, why do I need to use high-power USB Type-C for desk lamps? Is there a situation that requires desk lamps and other equipment to transmit data? Is there a situation where a single wire is required for the desk lamp and other equipment? Taking a step back, how much power does the desk lamp have, can’t 100W satisfy it? As for drones, why do we need 300W? Ordinary battery packs simply cannot be charged with such high power. TVs and printers are fixed devices, why do they need to use USB Type-C to power them? They should be able to power my mobile devices with USB to reduce the total cost. In fact, many products also do this. The same is true for an external GPU. The GPU most likely needs to be connected to a display device. If the display device is not too big to be moved, it may not need an external GPU. As long as the display device supplies power to it—but USB Type-C can afford it. The power is not enough. At this time, using independent power supply will not cause obvious inconvenience, so you have to plug the external GPU into the mains and then supply power to the mobile device. Anyway, in the final analysis, the answer to this question is basically a combination of two reasons: too expensive, no one buys it.