Patent ID: 6573482
Filing Date: 2003-06-03
Classification: G05D,H01L,H05B

Abstract:
A heating device comprising:a heater for heating an object to be heated; a power supply circuit for supplying electric power from a power source to the heater; a power switch for switching on and off a power output from the power source; an output control circuit for controlling the power output from the power source to the heater; a relay for switching on and off the operation of the power supply circuit in accordance with signals outputted from the output control circuit; and a failure detecting circuit for detecting an operational failure of the heating device; wherein the failure detecting circuit includes: a first monitor for monitoring the operation of an ON/OFF contact in the power switch; a second monitor for detecting ON/OFF signals transmitted from the power control circuit to the relay; and a third monitor for detecting an output voltage on a secondary side of the relay.