PhaseMAC: A 14 TOPS/W 8bit GRO Based Phase Domain MAC Circuit for in-Sensor-Computed Deep Learning Accelerators

Abstract

PhaseMAC (PMAC), a phase domain Gated-Ring-Oscillator (GRO) based 8bit MAC circuit, is proposed to minimize both area and power consumption of deep learning accelerators. PMAC composes of only digital cells and consumes significantly smaller power than standard digital designs, owing to its efficient analog accumulation nature. It occupies 26.6 times smaller area than conventional analog designs, which is competitive to digital MAC circuits. PMAC achieves a peak efficiency of 14 TOPS/W, which is best reported and 48% higher than conventional arts. Results in anomaly detection tasks are demonstrated, which is the hottest application in the industrial IoT scene.

An 8-bit Ring-Amplifier Based Mixed-Signal MAC Circuit With Full Digital Interface and Variable Accumulation Length

“…A timedomain signal processing circuit is also proposed to implement MAC function. For instance, gated ring oscillator (GRO) based analog MAC in [5] realizes a highly areaefficient solution. However, the inherent nonlinearity of the voltage-to-frequency conversion in VCO may prevent its usage for a general-purpose neural network computation.…”