A cycle-accurate energy estimator for CMOS digital circuits

Cycle-accurate energy estimation is very useful in reducing the energy consumption in the CMOS digital circuits, which was reported in [1]-[3]. This paper introduces a measurement-based energy estimator, describes a new energy calculation method for the CMOS circuits. We found that instead of representing all load capacitance as a capacitor to ground, we should separate the capacitance to ground and that to supply for the precise energy estimation. The verification of the measurement system and calculation method was done through the experiment for the inverter with a known load capacitance. Then, we measured the base cost of the instructions of an ARM7 processor, and 4-bit counters implemented with an Altera's APEX20K FPGA.