Write driver circuit for controlling a write current applied to a phase change memory based on an ambient temperature

摘要

A programming method which controls the amount of a write current applied TO Phase-change Random Access Memory (PRAM), and a write driver circuit realizing the programming method. The programming method includes maintaining a ratio of a resistance of the PCM in the higher resistance state to a resistance of the phase change material (PCM) in the lower resistance state constant or substantially constant independent of an ambient temperature. The ratio may be maintained by increasing, decreasing or keeping the same a reset current and/or a set current.