US Patent 9605978 Off-axis magnetic field angle sensors

Embodiments relate to magnetic field angle sensing systems and methods. In an embodiment, a magnetic field angle sensing system configured to determine a rotational position of a magnetic field source around an axis, comprises N sensor devices arranged in a circle concentric to an axis, wherein N>1 and the sensor devices are spaced apart from one another by about (360/N) degrees along the circle, each sensor device comprising a magnetic field sensing device having a sensitivity plane comprising at least one reference direction of the magnetic field sensing device, wherein the magnetic field sensing device is sensitive to a magnetic field component in the sensitivity plane and configured to provide a signal related to a (co)sine of an angle between the reference direction and the magnetic field in the sensitivity plane; and circuitry coupled to the N sensor devices and configured to provide a signal indicative of a rotational position of a magnetic field source around the axis determined by combining the signals from the magnetic field sensing devices of the N sensor devices, wherein the circuitry is configured to (i) interpret the signal of the N sensor devices as angle values, (ii) add integer multiples equivalent to 360° to selective ones of the N angle values to result in at least one monotonously rising or falling sequence of all N corrected values in a single clockwise or counter-clockwise direction of angular positions of respective ones of the N sensor devices, and (iii) average these corrected values.