TEMPERATURE CONTROL CIRCUIT OF CENTRAL PROCESSING UNIT

PROBLEM TO BE SOLVED: To provide a temperature control circuit for a CPU capable of changing the clock frequency and power supply voltage for the CPU while the operation standard of the CPU is satisfied. SOLUTION: A comparator circuit 8 compares the temperature of a CPU 1 measured by a CPU temperature sensor 2 with temperature information stored preliminarily in a ROM 6. A CLK (clock)/power supply control circuit 9 performs an operation switching a clock frequency from a high frequency to a low frequency when the comparison in the circuit 8 indicates the temperature of the CPU 1 becomes higher and next switches a power supply voltage from a high voltage to a low voltage when a timer 12 counts up. When the temperature of the CPU 1 becomes lower, the circuit 9 performs an operation switching the power supply voltage from a low voltage to a high voltage and next switches the clock frequency from a low frequency to a high frequency when a timer 13 counts up.