Many times it happens to us that we connect a peripheral to the USB port and we find that it does not charge well. Sometimes it may be that the problem is with the charging cable or even the peripheral itself, but there are times when it is advisable to check if the USB ports of the PC provide the necessary power.
Today we usually use USB ports as the standard connector for various types of peripherals on our PCs, whether they are printers, mice, keyboards, microphones, etc. One of the advantages of these ports being that they can also feed said peripherals, making a power supply unnecessary.
A quick refresher on the USB port
The USB port is a high-speed serial port that among its peculiarities is the fact of incorporating a charging pin that serves to power the peripherals. This feature is found in all USB ports regardless of their form factor and is one of the greatest attractions it has, which reduces the amount of power supplies that we have to have around our computer.
This allows what we traditionally call hotplugging or hot plugging, which allows you to connect the peripherals in full operation of the PC and that the operating system not only recognizes them, but also can use them without problems immediately and without the need for reboots. . This capacity is also known as plug & play or connect and go, but many times it happens that the USB port does not give enough power and therefore the peripheral usually comes with an external power supply.
Other times it depends on the specifications of the USB hub, not all of them give the same power and have the same capacity, so we may find that a specific USB port does not have enough power.
How much power do the USB ports on my PC give?
To check this, we do not need to install any new software and we do not need to use any special hardware for it. You just have to type the following in the Windows search bar: devmgmt.msc . Which will bring up the device manager.
Once you are there select universal bus controllers, double click and then select USB root hub, but do it with the right mouse button selecting properties. The following window should appear:
Within the same properties window of the USB root hub select details and in the drop-down menu of that tab select “Energy Data”, which will give you information on how much electrical energy the root hub transmits to the different peripherals. This goes from D0 to D3, with D0 being the one that gives the most energy and D3 the one that gives the least energy.
Why do USB ports use multiple power modes?
Keep in mind that the USB port supports various states depending on the situation in which the peripherals are. These modes mark how much energy said peripheral needs at that moment. For example, a peripheral that goes to sleep will not need as much as an active one. Neither is a peripheral turned off the same as disconnected from the USB port.
That is why USB hubs use state machines that distribute power to the different USB ports depending on the state, in general and unless we are using a USB-C port with fast charging, the specifications are as follows:
- A USB peripheral with battery can use up to 500 mA to charge it, this means that it can draw 2.5 W of power to charge such peripherals.
- If the peripheral is in sleep then the USB port operates at 2.5 mA.
- The voltage between the different ports does not add up, but the amperage does.
Use USBDeview
It may happen that despite the fact that the USB root hub is specified for a certain power level, but due to some problem in the controllers, the energy that is transmitted to the USB ports is much lower.
To check it at the software level we will use USBDeview, a totally free and easy-to-use application, which has a version for x86 CPUs with 64-bit support and another for 32-bit CPUs. Check your PC’s CPU first to download the correct version. This will come to you in a Zip that you must unzip in a folder.
You can use any unzipping application to unzip the entire folder, once there double click on the USBDeview.exe file. This will start the application, so it is totally portable and you can use it on any PC.
Move the bottom bar of the window to the right until you find the Power column, where you can obtain the consumption of the peripheral face, from there you can check how many milliamps each peripheral connected to the USB ports consumes.
USB peripherals draw power in blocks of 100 mA for USB 2.0 peripherals and 150 mA for USB 3.0 peripherals. So we can check if the peripherals receive enough power.
Use a USB voltmeter
The third option to check if the USB ports give enough power is to use hardware. Do not worry, you will not have to open the computer for this, but you will only need to use a USB voltmeter like the following:
You just have to connect the voltmeter to the USB port you want to measure and it will automatically give the information in the USB port you want to measure. And in the event that you want to measure a USB C port, you can choose the following option:
With them you will be able to check if the USB ports of your PC work correctly when giving power to the peripherals. They will also help you to check if the problem is in the peripherals and to check how much energy they consume.
One recommendation that we make is to test the USB voltmeter on other PCs or devices with this type of ports and compare them with the ones you get on your PC to check if the power given by the USB ports to each peripheral and device is adequate and therefore the requested by the peripherals themselves.