MULTINARY MEMORY AND METHOD FOR RECORDING TO PHASE-CHANGE TYPE RECORDING MEDIUM FOR IT

摘要

By controlling the number of times electric pulse is applied to a phase-change type recording medium so as to control the stepwise change of the resistance value, multinary information is recorded according to the difference in resistance values. The electric pulse stepwise changes its resistance value by the first application means for changing the phase-change type recording medium from a high resistance state to a low resistance state and second application means for changing it from the low resistance state to the high resistance state. According to a difference between the information which has been recorded and the information to be recorded, an electric pulse required for changing to the information to be written is selected and its number of application times is calculated. The present invention provides a multinary memory appropriate for a simple circuit configuration with high integration.