1. Fully On-Chip MAC at 14 nm Enabled by Accurate Row-Wise Programming of PCM-Based Weights and Parallel Vector-Transport in Duration-Format.
- Author
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Narayanan, P., Ambrogio, S., Okazaki, A., Hosokawa, K., Tsai, H., Nomura, A., Yasuda, T., Mackin, C., Lewis, S. C., Friz, A., Ishii, M., Kohda, Y., Mori, H., Spoon, K., Khaddam-Aljameh, R., Saulnier, N., Bergendahl, M., Demarest, J., Brew, K. W., and Chan, V.
- Subjects
PHASE change memory ,DEEP learning ,ARTIFICIAL intelligence ,PHASE change materials - Abstract
Hardware acceleration of deep learning using analog non-volatile memory (NVM) requires large arrays with high device yield, high accuracy Multiply-ACcumulate (MAC) operations, and routing frameworks for implementing arbitrary deep neural network (DNN) topologies. In this article, we present a 14-nm test-chip for Analog AI inference—it contains multiple arrays of phase change memory (PCM)-devices, each array capable of storing 512 $\times $ 512 unique DNN weights and executing massively parallel MAC operations at the location of the data. DNN excitations are transported across the chip using a duration representation on a parallel and reconfigurable 2-D mesh. To accurately transfer inference models to the chip, we describe a closed-loop tuning (CLT) algorithm that programs the four PCM conductances in each weight, achieving <3% average weight-error. A row-wise programming scheme and associated circuitry allow us to execute CLT on up to 512 weights concurrently. We show that the test chip can achieve near-software-equivalent accuracy on two different DNNs. We demonstrate tile-to-tile transport with a fully-on-chip two-layer network for MNIST (accuracy degradation ~0.6%) and show resilience to error propagation across long sequences (up to 10 000 characters) with a recurrent long short-term memory (LSTM) network, implementing off-chip activation and vector-vector operations to generate recurrent inputs used in the next on- chip MAC. [ABSTRACT FROM AUTHOR]
- Published
- 2021
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