The design and implementation of a low-power clock-powered microprocessor

We describe the design and implementation of a 16-bit clock-powered microprocessor that dissipates only 2.9 mW at 15.8 MHz based on laboratory measurements. Clock-powered logic (CPL) has been developed as a new approach for designing and building low-power VLSI systems that exploit the benefits of supply-voltage-scaled static CMOS and energy-recovery CMOS techniques. In CPL, the clock signals are a source of ac power for the other large on-chip capacitive loads. Clock amplitude and waveform shape combine to reduce power. By exploiting energy recovery and an energy-conserving clock driver, it is possible to build ultra-low-power CMOS processors with this approach. We compare the CPL approach with a conventional, fully dissipative approach for a processor with a similar ISA and VLSI architecture which was designed using the same set of VLSI CAD tools. The simulation results indicate that the CPL microprocessor would dissipate 40% less power than the conventional design.