Microprocessor Frequency Control Method Under Thermal and Energy Savings Constraints

This paper describes a method and a prototype of an integrated circuit of a temperature-controlled oscillator to address problems with overheating of high-performance processors working under thermal and energy saving constraints. Some theoretical considerations about the method are provided. Structure and measurement results of a circuit designed and fabricated in UMC CMOS 0.18 μm (1.8 V) are presented. The circuit consists of a set of proportional to absolute temperature sensors, a temperature comparator and maximum temperature detection circuit, a controlled ring oscillator, and additional blocks to manage the processor according to the presented method. The main aim of the circuit is to optimize the processor performance for a specified temperature limit, based on dynamic scaling of the operating frequency. The tuning is continuously and instantaneously performed by a signal from a sensor indicating maximum temperature directly measured in the silicon die.