Circuits and Methods for Processing Signals Generated by a Circular Vertical Hall (CVH) Sensing Element in the Presence of a Multi-Pole Magnet

A magnetic field sensor, comprising:

• a CVH sensing element comprised of a plurality of vertical Hall elements, wherein each one of the plurality of vertical Hall elements is arranged upon a common circular implant region in the first surface of the semiconductor substrate, wherein the plurality of vertical Hall elements is configured to generate a plurality of x-y output signals responsive to a magnetic field having a direction component parallel to the x-y plane, wherein the CVH sensing element is configured to generate a CVH output signal comprised of the plurality of x-y output signals;
• a clock generator configured to generate a first clock signal and a second clock signal;
• and
• an angle sensing circuit coupled to receive the CVH output signal and configured to generate an x-y angle signal representative of an angle of the direction component of the magnetic field, wherein the angle sensing circuit comprises:
• a multiplexer coupled to receive the CVH output signal at a first input and coupled to receive the first clock signal at a second input and configured to generate a first multiplexed output signal comprised of the CVH output signal at some times and comprised of the first clock. signal at other times;
• a comparator coupled to receive a signal representative of the first multiplexed output signal and configured to generate a comparison signal, wherein the comparison signal has state transitions representative of zero crossings of the CVH output signal at some times and state transitions representative of state transitions of the first clock signal at other times;
• a counter coupled to receive the comparison signal, coupled to receive a signal representative of the first clock signal, and coupled to receive a signal representative of the second clock signal, wherein the counter is configured to generate a second multiplexed output signal comprised of a first count signal at some times and comprised of a second count signal at other times;
• and
• a combining module coupled to receive a signal representative of the second multiplexed output signal and configured to generate the x-y angle signal as a difference between the first count signal and the second count signal.

A method of position sensing, comprising:

• generating, with a CVH sensing element, a plurality of x-y output signals responsive to a magnetic field having a direction component parallel to the x-y plane, wherein the CVH sensing element is configured to generate a CVH output signal comprised of the plurality of x-y output signals;
• generating a first clock signal and a second clock signal;
• and
• generating an x-y angle signal representative of an angle of the direction component of the magnetic field, wherein the generating the x-y angle signal comprises:
• generating a first multiplexed output signal comprised of the CVH output signal at some times and comprised of the first clock signal at other times;
• generating a comparison signal from. the first multiplexed output signal, wherein the comparison signal has state transitions representative of zero crossings of the CVH output signal at some times and state transitions representative of state transitions of the first clock signal at other times.
• generating a second multiplexed output signal with a counter coupled to receive the comparison signal, coupled to receive a signal representative of the first clock signal, and coupled to receive a signal representative of the second clock signal, wherein the second multiplexed output signal is comprised of a first count signal at some times and comprised of a second count signal at other times;
• and
• generating the x-y angle signal as a difference between the first count signal and the second count signal.