Patent ID: 8848431

Claim:
A magnetic field sensing system comprising: a magnetoresistive random access memory (MRAM) cell comprising a magnetic switching threshold; a write line associated with the MRAM cell and configured to conduct a write current so as to induce a write magnetic field proximate to the MRAM cell, wherein the write magnetic field has a magnitude that is less than the magnetic switching threshold of the MRAM cell; a switching element electrically connected in series with the write line and configured to provide the write current from a write current source; and a control module configured to: control at least one of the write current source or the switching element to provide the write current from the write current source through the write line, such that the magnitude of the write magnetic field is less than the magnetic switching threshold of the MRAM cell, after initiating the provision of the write current through the write line, determine a magnetic state of the MRAM cell, and determine a characteristic of an external magnetic field incident upon the MRAM cell based at least in part on the determined magnetic state of the MRAM cell.