Clock-Voltage Co-Regulator With Adaptive Power Budget Tracking for Robust Near-Threshold-Voltage Sequential Logic Circuits

This paper presents a post-regulation power management integrated circuit for energy harvesting applications. It incorporates a power budget tracking mechanism to adaptively control the power consumption of a near-threshold-voltage microcontroller based on the time-varying available input power. In addition, the proposed integrated circuit adapts the clock frequency of the microcontroller to the supply voltage under the time-varying input available power to prevent timing violations for the sequential logics of the microcontroller. A prototype shows the adaptive power budget tracking can correct timing violations with only 6.26uA quiescent current. It also properly operates sequential logic circuits at as low as 188mV supply voltage and 1.61MHz clock without interruption when powered by a solar energy harvester under the light illuminance range of 1000-6000lx. This adaptive power tracking structure enables the near-threshold-voltage microcontroller to maintain a continuous operation at optimized processing speed under the varying power condition without violating the timing requirements.