Patent ID: 6060719
Filing Date: 2000-05-09
Classification: F23N

Abstract:
An optical flame sensor, comprising:a photodiode flame sensor operating in a photovoltaic short circuit mode designed to produce a low output current electrical signal when a flame is detected;a transconductance amplifier operating in said photovoltaic short circuit mode connected via a transistor to said flame sensor, said transconductance amplifier including a feedback network designed to conduct said low output current from said flame sensor causing said transconductance amplifier to output a voltage high signal;voltage comparator circuitry designed to compare said transconductance amplifier voltage high signal with a threshold voltage signal in order to develop a logic level output signal for input to a processor, andtest circuitry designed to provide a test signal, said test signal designed to interrupt said low output current from said flame sensor in order to interrogate the functionality of said flame sensor during a test pulse.