Introduction: USB Extension With External Power Supply

USB (Universal Serial Bus) has been the standard communication for devices between PC and other devices, later USB became the standard for mobile phones and other electronics. Since the standardization a lot of devices have switched their voltage rating to 5V logic and many devices continue using the standard as USB continues to grow faster and faster.

But the problem with the 5V power supply is, it is limited in power, standard USB 2.0 supply 2A across all the USB lanes. For most device 2A would be sufficient but there are devices that would need more power to run smoothly.

I personally have a lot of external HDD that require 3A of power, but my laptop USB ports don't provide it sufficient power same goes with the Raspberry Pi. The solution to this problem is to provide external power source to these devices so they can get enough power to run as intended.

So in this instructable I'm going to show you How to build an external USB Extension with external power supply.

Step 1: All That You Need to Get Started

To follow along with this instructable you will need, two male USB extensions or connectors, this the end of the cable you plug into the PC and one USB female connector this is similar to the USB connector you find on your PC. You will need a PCB to solder all the components in, You can also try this project on a breadboard, before you actually move to a breadboard.

Furthermore, you will need an external power supply for 5v and 3A or grater, if you are using more than 3A you will need an extra fuse of the device rating. Optional Components include an LED and resistor to indicate when the circuit is turned ON.

So here is the total list of components

  • USB Male Connectors
  • USB Female Connector
  • 5v 3A (or above) Power supply
  • 3A fuse Optional
  • PCB
  • Connecting Wires
  • 3v LED Optional
  • 1k Resitor Optional

Step 2: Measuring the Current

You can start off by noting down how much current your USB device is consuming, most of the devices have the current rating printed on the device itself or the Box it came in, but if you are not sure you can use a multi-meter to calculate the power consumed.

This can be measured by tapping the 5v terminal of the USB cable and adding the multi-meter in series with it, take a note of the current rating and you should purchase a Power supply of the same rating.

Step 3: Circuit

The Circuit is simple the External Power supply is given via tapping the 5V lane and ground lane of the USB Line or Cable. So this makes the External device not drag any power from the PC and draw power from the external power supply based on the rating of the device. You can refer to the circuit above to make the connections.

If you are using a power supply rated at a higher current rating than the device needs you can, can add a fuse to the 5V lane to prevent the external device from dragging excess power. The fuse should be rated the same as that of the external device being powered.

Step 4: Further More

Optional you can add a resistor and LED to the 5V line and the GND so the LED lights up indicating that the external drive is dragging power from the external power supply.

You should now be able to plug the USB extension to your PC and you should notice the external device in my case my HDD not power on until I add an external power source to the other USB male connector.

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