Merged logic-memory architectures and applications

点击翻译按钮获取中文摘要

Logic enhanced memories are being shown to improve power consumption, performance and reduce cost of various digital systems.  Beyond the obvious advantage of integrating more functions to build a system on a chip (SoC), logic enhanced memories offer internal memory bandwidths that would require tens or hundreds of standard memory chips to match. Power is saved by making more effective use of memory cycles and reducing inter-chip communication.  Two ways my lab employs logic-enhanced memories are for Single Instruction stream Multiple Data stream (SIMD) computing and for internet routing.     Computational RAM is one such SIMD parallel processor architecture, which has been patented, licenced to Canadian Industry and commercialized.  Suitability of this existing architecture will be determined for new applications.  Variations on this architecture will be designed for a number of applications.     Through a collaboration with MIT Lincoln Labs, we had one 3-dimensional integrated circuit built and have been invited to participate in future runs of their 3D SOI IC process.  Because the substrate is not electrically connected to the silicon-on-insulator circuits, the substrate can be removed through etching and the circuits from many wafers can be stacked in a small volume.  The need for bonding pads is replaced by small 1.5 micrometre vias between layers.  New architectures are required to fully exploit this new IC technology.     Ternary Content Addressable Memories (TCAMs) are a popular solution for storing internet routing table address prefixes and searching them at high speed.  In adding logic into the memory array at each cell, we are evaluating an alternative that requires the optimal number of bits of memory (half plus one) to achieve the same task, requires fewer transistors and performs searches faster.  For high capacity routing in the backbone of the internet, we are investigating a logic-enhanced memory that can search for route entries for a large number of packets in parallel.     Logic enhanced memories have advantages in bandwidth, power consumption and system performance.