How to connect external power to a usb hub. Why is there not enough power for USB devices?
Consumers of data storage products often experience that their devices do not have enough power from the USB connector. Because of this, devices do not work as they should - they are constantly turned off, periodically disappear from the list of drives, or do not turn on at all. Moreover, this happens, as always, according to the law of meanness, at the most inopportune moment, when you urgently need to gain access to your data. The article will discuss how to provide your portable hard drive with good power.
I’ll make a reservation right away that this problem occurs with the USB 2.0 port, since the more modern version of USB 3.0, according to the specification, has a higher output power, which is quite sufficient for the start-up and operation of the drive.
So, what to do if there is a lack of nutrition.
There are two options. The first one is simple: you need to find a very short USB cable- about 15-20 cm. According to my experience, losses on such cables are minimal, therefore HDD It will work even from an old USB port.
Usually such a wire can be bought at one of the computer markets or shops, and in addition, a well-known manufacturer of portable products likes to put such wires in their product kits Western Digital. The chance that a short cable will fix the problem is quite high. In addition, such a “cord” is convenient to carry with you, it is lightweight and does not take up much space even in a tiny purse or small handbag.
Option two - you'll have to fork out a little. You need to buy a device that will feed your hard drive. There are also two ways here. You can take an internal solution or an external one. The first is suitable for owners of desktop computers, the second - for owners of laptops and other portable equipment.
An external solution includes purchasing a USB hub (hub) for 4-7 ports with an external power supply that has enough power to power devices in all ports at once.
The advantage of this solution is its versatility. It can be used with a laptop, a desktop, or any device in general. If necessary, such a hub can easily be thrown into a bag and taken to work / to a friend / to the country, etc. However, there are also disadvantages, although not significant. Firstly, there is an extra occupied outlet. It may seem that I am being picky, however, as practice shows, sockets become clogged with devices quite quickly, and soon there may not be enough of them. Secondly, this is extra space on the table and a bunch of additional wires. For lovers of minimalism, and simply order on the table, this option will not seem the best.
The internal solution is much better in this regard. Purchase a three-inch internal USB splitter powered by a Molex connector. This device also has a card reader, so in addition to everything you get a memory card reader, which is a definite plus. Since no power supply is required (electricity comes from the computer's power supply), such devices are usually very cheap. Their price rarely exceeds 250-350 rubles.
In this case, the solution is very elegant - it does not take up space on the table, there are no extra wires, everything is at hand. It will be especially convenient for those users who do not have front USB ports on the computer case (only on the rear panel). The downside is that such a device will only work with desktops, and also only if you have a free internal connector on the motherboard. It should be noted that in modern motherboards such internal connectors are a dime a dozen.
Why is there not enough power for USB devices?
What is the cause of food shortage? The USB 2.0 port at a voltage of 5 Volts is capable of delivering a current of only 0.5 Amperes. That is, the power of one port will be 2.5 Watts. Starting current hard drive also amounts to 0.5 (and sometimes a little more) Ampere. If the computer's power supply (like itself) is not new, then it may not output 5 volts, but, say, 4.6-4.8 volts. That is, the total power may decrease, limiting the power supply to the hard drive that is already working at the limit. A long wire has more resistance than a short one, which also reduces the power supply to the hard drive. Fortunately, manufacturers of portable hard drives take into account this problem and put hard disks with less consumption. True, this does not have the best effect on speed characteristics.
A more modern USB 3.0 connector according to the specification has a current of 0.9 Amperes (almost 2 times more previous version). Therefore, such devices do not have problems with power supply. In addition, this connector provides higher data transfer speeds. Since there is backward compatibility, a USB 3.0 device can be plugged into a USB 2.0 port without any problems. In this case, it will work in compatibility mode at lower speeds. Therefore, I recommend buying hard drives with USB 3.0. Even if your computer does not have this modern connector, it will be a good foundation for the future. When it appears, you will see a significant increase (3-4 times) in speed.
If you have any questions, write them in the comments.
There are so many USB devices for various purposes these days: fans, lamps, kettles and coffee makers, heated slippers, etc. They try to connect almost everything to USB; they charge smartphones and tablets. Some of the devices use USB for their primary purpose, but most new products use USB as a five-volt power source.
a lack of USB connectors permitted using hubs that branch not only the interface, but also the power bus. And simple USB interface splitters in the form of passive hubs can be found in hundreds, if not thousands of varieties. Sometimes they are created in the form of elaborate figures; there are no limits to design ideas here.
Along with conventional (simple) hubs, there are also USB hubs on the market that are equipped with an additional external or built-in power supply. Why such a decision is being promoted, now we’ll figure it out.
The lack of free USB ports for connecting external devices most often occurs precisely because the computer user connects to USB connector s various devices, the need for which is highly doubtful. Standard USB connectors from four pieces, brought outside the computer case in a standard configuration south bridge a chipset with at least two basic (root) hubs should be enough for almost any application.
The need to expand the number of devices connected to a computer is often built into the external devices. Card readers that have USB hubs on board are no exception. And in other devices, a hub is often placed simply as a buffer circuit element to reduce the load on the computer. Such devices have the ability to connect their own power supply or recharge from the second and subsequent USB ports of the computer.
Hubs with external power supply are designed to connect devices that are critical to power from the computer bus via a USB connector. Load limit USB port included in the specification and is no more than half an ampere in the standard of specification number two. And for the purpose of saving, including batteries in laptops, most often manufacturers computer equipment they build power supply circuits in which standard load current values are not provided.
It is not always and there is no need to supply a device with so much energy from each connector that the device does not need it. Overspending due to redundancy turns into an expensive implementation of the final product. Therefore, in order to save money, power supply circuits are made in such a way that it is sufficient to power the buffer elements of external device circuits.
For example, a mouse or flash drive does not require a power supply of two or more watts. Printers connected to computers and laptops via USB also have a separate power supply. Since in no way from one bus USB connector fail to provide power to the printer or multifunction device (MFP).
Smart people themselves realize that they cannot rely on “protection from fools” and download USB ports, and even more so overload, while stupidly being guided by the specification standard USB interface. Therefore, when connecting devices, they take care of turning on the external power supplies of devices and hubs, without experimenting and testing fate to see if they will “withstand or not withstand” the load.
The external (additional) power supply of the hub provides load distribution for the USB interface connector. Thus, the load on the circuits of the main (motherboard) board of a computer or laptop remains within acceptable values. This protects an expensive product from failure due to overloading of buffer circuit elements, power distribution buses and other components.
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