Due to size and layout considerations, it is not always practical to install enough limiting resistors to handle all of this dissipation. Even if the resistors are of the high-energy type and can withstand short bursts of arcing, they may not withstand continuous arcing conditions. Protection is provided by an arc counting circuit that suppresses the generation of HV when the number of arcs exceeds a safe limit within a specified period of time. This technique allows reasonable average power dissipation in the limiting resistor. Our arc sensing circuits provide power protection with thresholds in microseconds without excessive "nuisance" tripping. After a power trip, automatic reset is usually completed within 5 seconds. As an option, the power supply can be permanently latched. Resetting the power supply can be accomplished via an external signal. The arc quench feature suppresses the converter for a fixed period of time after each arc. This allows the arc to be extinguished.

Although the primary purpose of an arc sensing circuit is to protect the power supply, in some applications it can also protect the load driven by the power supply. For example, for ion sources that typically provide external series resistors, the arc counting feature is not required. However, the arc is quickly extinguished by an "arc quenching" characteristic that protects the ion source from damage. The arc induction characteristics' suppression duration, sensitivity and frequency can be custom modified for any application, as long as the parameters remain within the range required to maintain power protection. If using an external