Patent ID: 8692546

Claim:
A magnetic field sensor, comprising: at least two magnetic field sensing elements; and a switching circuit coupled to the at least two magnetic field sensing elements, wherein the switching circuit is configured to couple the at least two magnetic field sensing elements into a normal mode configuration when the magnetic field sensor is in a normal mode of operation, and wherein the switching circuit is configured to couple the at least two magnetic field sensing elements into a diagnostic mode configuration when the magnetic field sensor is in a diagnostic mode of operation, wherein the at least two magnetic field sensing elements are configured to generate a magnetic field signal comprising: a measured-magnetic-field-responsive signal portion responsive to an external magnetic field and substantially unresponsive to a diagnostic magnetic field when coupled in the normal mode configuration; and a diagnostic-magnetic-field-responsive signal portion responsive to the diagnostic magnetic field and substantially unresponsive to the external magnetic field when coupled in the diagnostic mode configuration, wherein the magnetic field sensor is operable to generate a diagnostic output signal from the magnetic field sensor when in the diagnostic mode of operation, wherein the diagnostic output signal is capable to indicating results of a self-test of the at least two magnetic field sensing elements and a self-test of processing circuits coupled to the at least two magnetic field sensing elements.