Patent ID: 8054675

Claim:
A variable write method for resistance random access memory (RRAM), the method comprising: setting a write counter to zero; reading a resistance value across an RRAM cell, if the resistance value indicates that the RRAM cell is in a desired data state, then the write method is complete, otherwise: applying a first write pulse across the RRAM cell, the first write pulse having a first write pulse duration and incrementing the counter by one; reading a resistance value across the RRAM cell, if the resistance value indicates that the RRAM cell is in the desired data state, then the write method is complete, otherwise: applying a second write pulse across the RRAM cell, the second write pulse has a second write pulse duration being greater than the first write pulse duration and incrementing the counter by one; and reading a resistance value across the RRAM cell, if the resistance value indicates that the RRAM cell is in the desired data state, then the write method is complete, otherwise, subsequent write pulses are applied across the RRAM cell, each subsequent write pulse has a write pulse duration being greater than a previous write pulse duration and incrementing the counter by one.