Magnetic field sensor and related techniques that inject a synthesized error correction signal into a signal channel to result in reduced error

A magnetic field sensor, comprising:

• a plurality of magnetic field sensing elements configured to generate a respective plurality of x-y output signals, wherein each one of the x-y output signals is responsive to a magnetic field in an x-y plane;
• a sequence switches circuit coupled to receive the plurality of x-y output signals and configured to generate a sequential signal comprised of sequential ones of the plurality of x-y output signals, wherein the sequential signal comprises a time waveform comprising a respective fundamental frequency component and an error component;
• an angle calculation module having an input node and an output node, wherein the angle calculation module is configured to generate an x-y angle value at the output node of the angle calculation module that is indicative of an angle of the magnetic field in an x-y plane;
• an angle processing channel coupled between the sequence switches circuit and the angle calculation module, wherein the angle processing channel comprises:
• an electronic filter having an input node and an output node, wherein the electronic filter is configured to generate a filtered signal at the output node of the electronic filter;
• and
• a summing circuit having first and second input nodes and an output node, wherein either:
• the first input node of the summing circuit is coupled to the sequential signal, the output node of the summing circuit is coupled to the input node of the electronic filter, and the output node of the electronic filter is coupled to the input node of the angle calculation module, or
• the input node of the filter is coupled to the sequential signal, the first input node of the summing circuit is coupled to the filtered signal, and the output node of the summing circuit is coupled to the input node of the angle calculation module, wherein the magnetic field sensor further comprises:
• an error correction signal generator circuit having an output node, the error correction signal generator circuit for generating an error correction signal at the output node of the error correction signal generator, wherein the output node of the error correction signal generator circuit is coupled to the second input node of the summing circuit, wherein the summing circuit is configured to generate a signal at the output node of the summing circuit with a corrected error component smaller than the error component of the sequential signal;
• and
• a sine look up table memory coupled to the error correction processor and configured to store a plurality of sine values, wherein the error correction signal is generated by selecting sequential ones of the plurality of sine values, wherein the error correction signal comprises a respective frequency component having a frequency equal to an integer multiple of the fundamental frequency component of the sequential signal.