Patent ID: 8483989

Claim:
An apparatus for estimating a temperature of a heating element mounted on an electronic printed circuit board, comprising: a first temperature detector installed at a position away from the heating element by a first distance and adapted to produce an output indicative of temperature of the installed position; a second temperature detector installed at a position away from the heating element by a second distance greater than the first distance and adapted to produce an output indicative of temperature of the installed position; a cooling device adapted to be operative to cool the heating element: a cooling operation determiner that determines whether the cooling device is operative; and a heating element temperature estimator that estimates the temperature of the heating element based on temperatures detected from the outputs produced by the first and second temperature detectors using a first equation when the cooling device is determined to be inoperative, and using a second equation when the cooling device is determined to be operative; wherein the cooling device comprises a blower that produces cooled air to be supplied to the heating element, and the cooling operation determiner includes: a third temperature detector installed at a position upstream of the heating element in flow of the cooled air and adapted to produce an output indicative of temperature of the installed position; and a fourth temperature detector installed at a position downstream of the heating element in flow of the cooled air and adapted to produce an output indicative of temperature of the installed position; and the cooling operation determiner determines that the cooling device is operative when the detected temperature of the third temperature detector is lower than a value obtained by subtracting a predetermined temperature from the detected temperature of the fourth temperature detector.