An Overview of Energy-Efficient Hardware Accelerators for On-Device Deep-Neural-Network Training

Deep Neural Networks (DNNs) have been widely used in various artificial intelligence (AI) applications due to their overwhelming performance. Furthermore, recently, several algorithms have been reported that require on-device training to deliver higher performance in real-world environments and protect users’ personal data. However, edge/mobile devices contain only limited computation capability with battery power, so an energy-efficient DNN training processor is necessary to realize on-device training. Although there are a lot of surveys on energy-efficient DNN inference hardware, the training is quite different from the inference. Therefore, analysis and optimization techniques targeting DNN training are required. This article aims to provide an overview of energy-efficient DNN processing that enables on-device training. Specifically, it will provide hardware optimization techniques to overcomes the design challenges in terms of distinct dataflow, external memory access, and computation. In addition, this paper summarizes key schemes of recent energy-efficient DNN training ASICs. Moreover, we will also show a design example of DNN training ASIC with energy-efficient optimization techniques.