Cyclical sensing integrate-and-fire circuit for memristor array based neuromorphic computing

The brain-inspired, spike-based neuromorphic system is highly anticipated in the artificial intelligence community due to its high computational efficiency. The recently developed memristor-crossbar-array technology, which is able to efficiently emulate the plasticity of biological synapses and accommodate matrix multiplication, has demonstrated its potential for neuromorphic computing. To facilitate the computation, a high-speed integrate-and-fire circuit (IFC) and a counter were previously developed to efficiently convert the current from the memristor array into rate-coded spikes. However, the linear dynamic range of the circuit, which is limited by its responding speed, is challenged when the input intensity and the conductance of the memristor array are both high simultaneously. In this paper, a novel cyclical sensing scheme is developed that can significantly extend the linear dynamic range of the original IFC. Meanwhile, the power efficiency of the IFC can also be increased. The circuit simulation results indicated that the cyclical sensing IFC was able to efficiently and accurately facilitate the matrix multiplication when it was integrated with a 32×32 memristor crossbar array. With the optimized crossbar array structure and its peripheral circuits, the developed cyclical sensing IFC has shown great promise in accelerating matrix multiplication in spike-based computing systems.