What is the name of this kind of DC power connection?
DC output connectors aren't limited to just two pins, depending on the requirements of the device being powered. A good example is your typical ATX power supply in a computer. There can be several separate voltages (sometimes called lines or rails) such as +12V, +5V, +3.3V, and so on. In an LED driver application, it is possible that two different voltages are being supplied with a common ground. There can also be conductors used for feedback, regulation, and proprietary usage, such as a laptop that verifies the power supply being used is of the appropriate wattage or brand.

It's also just as possible and likely that the third pin isn't used at all. The manufacturer may have chosen the connector simply to ensure that some other power supply, with a more common connector (such as a barrel jack), isn't used. In constant-current devices, such as LED strips, it's important to use a constant-current supply instead of a switching supply (SMPS).

As Lior stated in his/her answer, it appears to be a proprietary connector. However, you might be able to find something that matches or is close enough with some of the following terms:


circular connector
Mini DIN connector
push-pull (as opposed to screw, bayonet, and twist &mdash; the flat ridge prevents all but push-pull type)


Note that if you just want to extend the cable, you may find it cheaper, easier, and quicker to cut the cable, insert the desired extra length, solder and heat shrink both ends of the splice. Just ensure that you connect the same conductors together and use the same (or thicker) gauge of wire. Keep in mind that adding a substantial length could cause extra power dissipation.