Fail safe digital fuel ignition system

Claim 1

A fail safe control system for operating a fuel burner with three separate fuel burner functions by using digital signal processing, including: power terminals adapted to be connected to a source of alternating current potential to energize said control system; power conversion means connected to said terminals to receive power from said source of alternating current potential and having a plurality of output potentials; said output potentials including at least two potentials which are separated in phase from each other; power supply means having an input connected to a first of said potentials and including voltage output means which is negative with respect to a reference potential for said control system; two digital clock means each having input means and output means with said clock means each energized from a different one of said two potentials to provide said clock means with output clock pulses at their respective output means and with said output clock pulses being separated in time from one another; spark gap means for positioning ignition sparks for said fuel burner and for flame detection; fuel burner control circuit means connected to said spark gap means to sense the presence or absence of flame; said fuel burner control circuit means including digital signal processing means and being powered from said power supply means; said fuel burner control circuit means connected to said two digital clock means to process digital signals in response to said two digital clock means; said fuel burner control circuit means having three output means with a first and a second of said output means clocked by a first of said digital clock means while a third of said output means is clocked by a second of said digital clock means; three gated solid state switch means with each switch means connected to control a separate one of said fuel burner functions with said switch means each powered by a potential that is positive with respect to said reference potential; and each of said switch means having gate means connected to the outputs of said fuel burner control circuit means; said fuel burner control circuit means controlling said solid state switch means by said digital signals which are separated in time by said two digital clock means.