Providing current for phase change memories

摘要

A programmable current source for a phase change memory allows a single current source to controllably provide the current for reading and writing both set and reset bits. In addition, the current source can vary the current based on the characteristics of a particular run of wafers. In one embodiment, a plurality of current generators may be selectively operated to generate the desired additive output current that is needed for a particular operation such as reading or writing set or reset bits.