Experimental Body-input Three-stage DC offset Calibration Scheme for Memristive Crossbar

Abstract

Reading several ReRAMs simultaneously in a neuromorphic circuit increases power consumption and limits scalability. Applying small inference read pulses is a vain attempt when offset voltages of the read-out circuit are decisively more. This paper presents an experimental validation of a three-stage calibration scheme to calibrate the DC offset voltage across the rows of the memristive crossbar. The proposed method is based on biasing the body terminal of one of the differential pair MOSFETs of the buffer through a series of cascaded resistor banks arranged in three stages- coarse, fine and finer stages. The circuit is designed in a 130 nm CMOS technology, where the OxRAM-based binary memristors are built on top of it. A dedicated PCB and other auxiliary boards have been designed for testing the chip. Experimental results validate the presented approach, which is only limited by mismatch and electrical noise.EU H2020 grant 687299 NeuRAM3EU H2020 grant 824164 HERMESEU H2020 grant 871501 NeurONNEU H2020 grant 871371 MeM-ScalesSpanish Ministry of Economy and Competitiveness TEC2015-63884-C2-1-P (COGNET)Spanish Ministry of Economy and Competitiveness G0086 ICONUniversidad de Sevilla (España) VI PPI