Patent ID: 7009406

Claim:
An arc fault detector for a circuit comprising: a current shunt resistor coupled in series with said circuit; and an arc discriminator comprising an amplifier sensing a first voltage on a first side of said current shunt resistor, sensing a second voltage on a second side of said current shunt resistor, and producing a first signal proportional to a current flow through said current shunt resistor, said arc discriminator further comprising a change detector receiving said first signal as input and producing an arc fault detection signal as output when said change detector detects a change in said first signal indicative of a presence of an arc fault in said circuit; wherein said change detector comprises a first splitter receiving said first signal as input and providing a second and a third signal as outputs, a delay circuit receiving said second signal as input and producing a delayed signal having a predetermined delay as output, a reference circuit receiving said third signal as input and producing a reference signal as output, and a comparator receiving said delayed signal and said reference signal as inputs, and producing said arc fault detection signal as an output when a difference between said reference signal and said delay signal satisfies a predetermined criteria.