However, as Minima gets closer to market with its mixed software and hardware intellectual property approach to the market it appears to have pulled back from earlier sub-threshold voltage discussion and instead talks about the benefits of near-threshold voltage operation.
Minima offers ultra-wide dynamic voltage and frequency scaling (DVFS) and a framework to change the frequency and/or operating voltage of a processor based on active system function parameters and software calls. Minima is claiming that even at near-threshold voltages of down to 0.4V the energy savings over all applications when both dynamic margining and ultra-wide DVFS are deployed is up to 15x to 20x lower energy compared to a nominal voltage design.
Minima inserts timing and voltage monitors along paths to monitor power and performance during operation. If a critical path monitor is activated by a voltage drop, whether due to process variation, temperature conditions, or variability or aging, then software and dynamic feedback responds by temporarily slowing the path for a clock cycle, or until conditions allow a resumption of previous performance. The OS-controlled middleware acts like an automatic braking system that adjusts to conditions. Instead of driving based on worst-case assumptions, Minima goes as quickly as possible at a given voltage and only slows operation or increases voltage when necessary – and only for as long as necessary.
This also means that Minima IP can work with conventional gate libraries rather than libraries made robust for low-voltage operation. Minima claims that its light-touch, real-time, interactive approach can take any existing processor or DSP into the microwatt power consumption range.
The technology has been applied in silicon with two semiconductor test-chip runs and one chip, a RISC with crypto accelerator, has been taped out. Minima and Arm are partnering to produce a low-power implementation of a Cortex-M3 processor core, which is available without paying an up-front licensing fee through ARM's DesignStart program. But it should also be noted that Minima Processor is also a founding member of the RISC-V Foundation, which promotes open processor hardware.