Write and read circuit for memristor analog resistance switching

Abstract

Size scaling CMOS transistors are known to improve cost, speed, and power per chip that results in high performance IC. However, too small transistor size can degrade transistor performance thus become limitation to CMOS scaling. One way to overcome this limitation is by incorporating CMOS with memristor; a device that offers small size, low power, nonvolatile characteristic with switching ability and is compatible with CMOS technology. In this research, memristor resistance write circuit (RWC) and read circuit (RRC) are presented. A pulse-coded memristor programming method is adopted in RWC design. It uses 2 sets of switches to decreases or increases resistance by supplying positive or negative pulse. Plus, the longer width of supply signal, the bigger changes of resistance. Next, two types of RRC are presented; voltage read circuit and current read circuit. Former circuit consists of trans-impedance amplifier and resistor. Output voltage from amplifier expresses memristor resistance value. When voltage supply is negative pulse, memristor resistance increases thus V out gradually decreases and otherwise. Latter circuit consists of amplifier and CMOS transistor to read the current from memristor that express memristor resistance. When memristor resistance changes, the current also changes. Set of current mirror is added to enable memristor current to be copied to other circuit. A current sample and hold circuit is added to keep current information when there is no voltage supply. Result shows first RWC successfully program resistance of memristor either to increase or decrease. Second, voltage read circuit can express resistance value in voltage form but have negative output voltage that not very applicable. Third, current read circuit can give current output based on memristor resistance and applicable with other circuits.