In this study, a simple and effective memory system required for the implementation of an AI chip is proposed. To implement an AI chip, the use of internal or external memory is an essential factor, because the reading and writing of data in memory occurs a lot. Those memory systems that are currently used are large in design size and complex to implement in order to handle a high speed and a wide bandwidth. Therefore, depending on the AI application, there are cases where the circuit size of the memory system is larger than that of the AI core. In this study, SDRAM, which has a lower performance than the currently used memory system but does not have a problem in operating AI, was used and all circuits were implemented digitally for simple and efficient implementation. In particular, a delay controller was designed to reduce the error due to data skew inside the memory bus to ensure stability in reading and writing data. First of all, it verified the memory system based on the You Only Look Once (YOLO) algorithm in FPGA to confirm that the memory system proposed in AI works efficiently. Based on the proven memory system, we implemented a chip using Samsung Electronics’ 65 nm process and tested it. As a result, we designed a simple and efficient memory system for AI chip implementation and verified it with hardware.

With the increasing use of multi-purpose artificial intelligence of things (AIOT) devices, embedded field-programmable gate arrays (FPGA) represent excellent platforms for deep neural network (DNN) acceleration on edge devices. FPGAs possess the advantages of low latency and high energy efficiency, but the scarcity of FPGA development resources challenges the deployment of DNN-based edge devices. Register-transfer level programming, hardware verification, and precise resource allocation are needed to build a high-performance FPGA accelerator for DNNs. These tasks present a challenge and are time consuming for even experienced hardware developers. Therefore, we propose an automated, collaborative design process employing an automatic design space exploration tool; an automatic DNN engine enables the tool to reshape and parse a DNN model from software to hardware. We also introduce a long short-term memory (LSTM)-based model to predict performance and generate a DNN model that suits the developer requirements automatically. We demonstrate our design scheme with three FPGAs: a zcu104, a zcu102, and a Cyclone V SoC (system on chip). The results show that our hardware-based edge accelerator exhibits superior throughput compared with the most advanced edge graphics processing unit.