PURPOSE: To output a variable clock from a VCO and to improve the operating efficiency of a system, by detecting an environmental temperature around logical elements of the system, sampling a detected temperature signal, and controlling the oscillating frequency of the VCO.
CONSTITUTION: A single or a plurality of temperature sensors 4a, 4b are arranged around each logical element of an operating circuit 5 and a storage circuit 6 constituted with LSIs and thelike, and the sensors 4a, 4b detect the environmental temperature around the logical elements. The temperature detected at the sensors 4a, 4b is sample-held at an A/D converter 1 and converted into a digital signal. Through sample holding, a maximum temperature signal is applied to the VCO3 via LPF2, the oscillating frequency of the VCO3 is controlled according to the maximum temperature signal from the LPF2, the clock from the VCO3 takes the synchronism of the circit 5, 6, no cooler is required and the operating efficiency of system can be improved.
KANEKO AKIRA
KUBOTA KATSUHISA
