USB as an Analog/RF Port

Michael Hopkins is the Founder and CEO of CurrentRF.

Most people associate USB and its hardware as a digital and system data transfer protocol only. Thinking of USB in terms of analog and RF has only recently been a subject of interest in USB design, a necessity with the advent of USB 3 speeds and protocols. In fact, RF effects become dominant in the data transfer speeds involved within USB 3. There is current technology and methodology available today that allows server and network device USB ports, normally thought of as digital and system data transfer ports, to be used as analog/RF pickup ports for system noise and power reduction.

If we open and ignore the data lines used for any flavor of USB, and focuse only on the resident +5V power and ground lines, we will see a rich source of RF frequencies of significant magnitude. Energy harvesting techniques can be employed to recover this resident, generated energy. Utilizing an AC-coupled spectrum analyzer of sufficient bandwidth, will result in frequency spikes and noise related to USB data transfers. However, “coupled in” frequencies and noise energies are also related to other aspects of servers and network devices.

LDOs (low drop out regulators) and switch mode regulators, commonly used in data center and business devices today, do little to contain processing and clock noise energies. This noise, or dynamic power dissipation, is sufficiently high frequency in nature to couple through the system almost unimpeded.

The Earth only receives a portion of the sun’s radiated energy, so only a portion of this server and network device generated noise couples to the USB port +5V line. Thus, with this coupled in noise, a portion of radiated noise energy can be picked up and processed back into the system as usable, “green” power. This energy, captured and recycled, acts to reduce the load current on system voltage regulators, lessening the power drawn from either the wall plug or batteries. CurrentRF can recover and recycle this radiated, high frequency noise, visible at the server and network USB ports, saving power and money in data center and business networks and servers.

The USB port, then, becomes the “eyes into the system” and serves as an RF pickup of radiated energy from processors, memory, graphics cards, HDDs, SSDs, and internet activity, etc. This energy is normally ignored and treated by the industry as “throw away” and waste. If captured and recycled, even at a partial level, it proves to be a substantial source of generated energy; and if used, can result in substantial power savings and TCO reduction in data centers.

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