Dynamic Voltage and Frequency Scaling in an Embedded Microcontroller SoC

Given energy as the limiting factor in a low-power battery-driven embedded microcontroller (MCU), energy-efficient operation is critical. Low-energy microcontrollers benefit from comparable performance and longer lifetimes when compared to microcontroller cores without energy saving schemes. Dynamic voltage and frequency scaling (DVFS) has been proposed in [1] as a novel technique to provide optimal performance given application requirements in a microcontroller. This project involved the design of a similar structure which will be integrated onto the Wireless Integrated Microsystems (WIMS) MCU described in [2], which is targeted for embedded sensor applications. The WIMS MCU employs a three-stage pipeline with 32 kB of on-chip SRAM and a 512-byte low-power loop cache. The MCU is driven by an on-chip MEMS-LC clock generator which can scale frequency in just over one cycle of MCU operation. With VDD at 1.8V, the WIMS MCU runs at 100MHz.