Tremendous progress has been made in improving System-on-a-Chip (SoC) energy efficiency through the application of fundamental low power design techniques such as clock gating and voltage scaling. However, as SoC complexity has grown and geometries continue to shrink it has become increasingly difficult to squeeze further improvements from these techniques. In particular, voltage scaling of synchronous circuits has stalled due to process variation.
NanoWatt has taken a fresh look at power efficiency and has developed techniques to achieve additional savings by focusing on enabling further voltage reduction and resolving SoC level issues.
Beginning about 2011, sensor hubs are being rapidly introduced to manage the challenges associated with Internet of Things (IoT), solar, smart home, and electric vehicles. Sensor Hubs are initially targeted at inertial and light level sensors, but the applications are set to expand rapidly as ubiquitous sensing begins to take hold. Sensor Hubs offload tasks from a general purpose processor, and may be able to complete the work using 100x less energy. Low duty cycle is one technique for reducing energy with sensor hubs. In addition, supply voltage can be further reduced, once issues related to process variation are solved. Although asynchronous architectures have been around for some time, they have seen little implementation at 1.0V and above. NanoWatt Design has unique solutions that are aimed at 0.6V and below, and fundamentally address the process variation issues.
Transistor and gate level optimizations are no longer sufficient for building energy-efficient designs. The major differentiation and advances today occur at the architecture level. Yet, building an effective and efficient architecture requires broad and deep knowledge in Low Power Design. NanoWatt has extensive experience in the many facets of Low Power Design that enable architectural optimizations for DSPs, communications processors, and wireless devices. This Low Power Design expertise has led to a variety of architecturally optimized designs, including for example an asynchronous floating point unit (FPU), a MSP430 microcontroller targeted at wireless sensor nodes, and a multi-core vision processor.
Many DSPs today utilize an array of cores - dozens to hundreds - to achieve overall performance goals through parallelization. However, power management of arrays of cores has lagged behind until now. NanoWatt has developed patent pending control and communication technology enabling voltage and frequency scaling (DVFS) of each of the cores independently of all the other cores, no matter how many cores there are. Double-digit energy improvements have been demonstrated over the entire array of cores for a challenging application. Since DVFS is programmable for each individual core, higher energy savings will be seen for lighter applications. This technology, termed Switchable Synchronous to Asynchronous dynamic voltage and frequency Scaling (SSAS), is scalable to any number of cores.
On-chip communication networks, sometimes referred to as Networks on Chip (NoCs), have become increasingly important as overall SoC complexity has grown. The NoC can significantly impact overall SoC reliability, power consumption, and throughput. NanoWatt has applied asynchronous signaling technologies to NoC design, demonstrating simpler, faster operation. One key attribute of the Asynchronous NoC (ANoC) is that it does not require routing synchronizers. In typical SoC designs, hundreds or even thousands of synchronizers may be eliminated from the end design, leading to dramatic improvement in reliability (MTBF); reduction in power; and improvements in latency and area.