Patent ID: 8265799

Claim:
A dynamic rotation speed control circuit that controls the dynamic rotation speed of a fan provided in a computer, comprising: a first reception unit for receiving “ambient temperature” which is a temperature of surroundings where the computer is installed; a second reception unit for receiving “first device temperature” which is a temperature of a first device provided in the computer; a third reception unit for receiving “second device temperature” which is a temperature of a second device provided in the computer; and a fan rotation speed indicating unit for determining the rotation speed of the fan based on a comparison between the ambient temperature, first device temperature, and second device temperature which are received by the first to third reception units and a fan rotation speed description table describing a relationship between the respective temperature and fan rotation speed and instructing the fan to rotate at the determined rotation speed, wherein: the fan rotation speed description table includes a plurality of individual tables for each of ambient temperature segments, and the fan rotation speed indicating unit selects one of the plurality of individual tables that corresponds to the received ambient temperature, determines a first rotation speed based on a comparison between the selected individual table and first device temperature received by the second reception unit, determines a second rotation speed based on a comparison between the selected individual table and second device temperature received by the third reception unit, and instructs the fan to rotate at a higher one of the first and second rotation speeds.