Much has been written about wireless component connectivity. The most recent publicity surrounds the "WirelessHD" initiative - an incipient standard for wirelessly interconnecting signal processing components to an HDTV display. This is a great concept except one big cord remains - the power cord.

Wireless power has been a much sought-after technology since Nikola Tesla first demonstrated the possibilities in the early 1900's. Inductive battery recharging technologies have recently been aggressively explored for cordless cell phone applications, but have not been seriously commercialized. However, a recent exciting innovation being developed by Atomics Unlimited, a Canoga Park, California, based company, promises to not only solve the problem of providing high power without wires but also to eliminate the necessity for recharging.

The solution uses what can be best described as a "nuclear battery," called aptly by the company an "Atomic Power Cell" (APC). These are individual cells using electromagnetic energy generated by radioactive pellets to produce the power needed by the devices in which they are installed - such as HDTV displays.

The use of such "atomic" batteries has been studied for sometime and has been successfully deployed on a very small scale, producing only microwatts of power.

The Atomics Unlimited approach is the first utilization of nuclear power for medium duty applications ranging from in-home electronics devices to appliances. Here is how it works:

The power cell consists of very small spherical pellets, approximately one micron in diameter, of enhanced uranium (U-235) material housed in an eight-inch long elliptical capsule with a two-inch minor diameter (see illustration). The U-235 is chemically recovered from "spent" power rods used in nuclear power plant reactors. The uranium pellets are coated with a carbon moderator that acts to slow down neutrons emitted by the uranium. The carbon moderating is necessary not only to minimize the harmful affect of neutron emission, but also to maintain the atomic "chain-reaction" produced when the pellets are compressed in the capsule.

When the pellets are physically compressed and sealed in the capsule, the neutron maintained atomic reaction generates vast amounts of electromagnetic energy, mostly in the form of X-rays (30 Phz - 30Fhz). This X-radiation impinges on an array of wide-band rectifiers printed on the outer edge of the capsule. These rectifiers covert the radiated energy to direct current (DC) that is coupled to the output terminals via the connected load. An internal power regulator circuit limits the terminal voltage to 20 volts @ 60 amps.

The capsule walls are composed of a lead epoxy impregnated carbon-fiber material that arts as a shield to prevent harmful radioactive particles and X-radiation from escaping. Although some heat is generated, it is effectively dissipated by metal fins (not illustrated).

The APC is designed to produce constant power for the useful life of the product it is serving, although the cell can be replaced by a trained technician. If the cell is removed and/or the internal circuitry malfunctions, it will cease to function, producing no terminal voltage. Further, if the container is punctured or compromised in any way, the cell is automatically disabled. The individual pellets themselves are harmless unless ingested.

Look for scaled down versions of the APC technology to be powering small electronics devices, such as cell phones, within the next five years. Perhaps your next HDTV will be APC powered.

Ed
April 1, 2008