The ideal diode...how the POWER-GATE battery isolator became the best.

H. Frank Fogleman is a DC power management expert and the inventor of the internationally patented POWER-GATE arrayed MOSFET technology.  He resides in Rancho Santa Fe, California.

When George Westinghouse set up AC power transmission systems in America, he was primarily concerned with providing power to remote locations for lighting homes without using gas or kerosene lamps. That was going well, but people wanted to use the available power to recharge batteries powering radios and vehicles. Yes, there was the Baker electric car like the one that President Monroe had introduced to the White House; one catch, to convert the AC to DC, a rectifier was needed….. a rectifier to conduct during the positive part of the line voltage and block during the negative half of each cycle, making it suitable for recharging storage batteries.

The first wide-spread use of AC rectification was the use of mercury vapor tubes to produce Direct Current for the “Third rail” excitation for railways. The mercury vapor rectifier soon became deployed in room-sized units that remained in service for decades. There were much smaller units used in photography and metal treating facilities.              

Next came copper-oxide and selenium rectifiers for lower current applications

in the 1950’s.  Germanium diodes were used for low voltage ( 40 to 100 ) applications which only required current capacity in the fractional ampere range.

Then silicon diodes became available offering much higher blocking voltage ratings with a substantial increase in current capacity. The down-side was (and still is) the forward voltage drop which results in high heat dissipation in multi-amp applications. They are still in wide-spread use today mounted on extremely large heat sinks and often require additional air cooling fans. The Schottky diode hit the market in the late eighties with a lower voltage drop but a jump in cost and reduction in current capability.

At the end of the century, MOSFET rectifiers were introduced, but price and other factors prevented them from becoming the success developers envisioned.  That was when I found a need for a superior rectifier in DC power management applications. 

Looking at what was commercially available, I could see that the engineers using MOSFETS didn’t have thermodynamic experience.  At this point, a large array of MOSFETS was successfully engineered and the POWER-GATE concept was born. Patents were issued in countries around the world and Perfect Switch, LLC set out to market the arrayed MOSFET devices in the form of rectifiers, relays, and OR’ing devices. POWER-GATE devices are smaller, lighter, and more efficient than any other competing technology.  Early adopters of this new technology include tough vehicular applications including military and fleet utility, aircraft, marine, and communications markets.