A system for determining angular position includes a magnet having at least four poles and an axis of rotation, wherein the magnet produces a magnetic field. A first magnetic field sensor produces a first output signal and a second magnetic field sensor produces a second output signal in response to the magnetic field. The magnetic field sensors are operated in a saturation mode in which the magnetic field sensors are largely insensitive to the field strength of the magnetic field. Thus, the first output signal is indicative of a first direction of the magnetic field and the second output signal is indicative of a second direction of the magnetic field. Methodology performed by a processing circuit entails combining the first and second output signals to obtain a rotation angle value of the magnet in which angular error from a stray magnetic field is at least partially canceled.

A power steering apparatus assists steering of a vehicle by conferring torque generated by an electric motor to a steering mechanism. The apparatus includes a steering column with linked upper and lower steering shafts. An angle sensor (AS) includes a gear and magnet to measure the steering shaft angle. A torque sensor (TS) measures the relative shift angle between the upper and lower steering shaft and includes a multi-pole ring magnet and a magnetic flux conductor. The TS and AS are arranged such that the AS magnet influences the TS measurement creating a steering shaft angle depending error signal. The steering mechanism is arranged such that a zero crossing of an envelope curve of the error signal is given for the neutral position of the steering apparatus or a range of the steering position in which the steering angle is less than a threshold angle limit.

A control unit includes a detection device that includes: a multi-turn detection unit capable of continuing detection of a rotation position of multiple rotations of a steering shaft driven by a motor without power supply from outside; a position detector detecting the rotation position in one rotation of the rotor; a count calculator calculating multiple rotation position information related to the rotation position of multiple rotations based on a detection value of the multi-turn detection unit; and an angle calculator calculating a motor rotation angle related to the rotation position in one rotation based on a detection value of the position detector. The multi-turn detection unit is disposed at a position different from the motor, thereby detection of the rotation position of multiple rotations is continuable even when a supply of electric power from outside is interrupted.

A position sensing system for a rotating object may include analog conditioning circuitry, analog to digital converter circuitry, and a controller. The analog conditioning circuitry may identify a half cycle of an analog input signal received from a sensor, which has a variable period and a variable magnitude. The analog to digital converter circuitry may process the input signal during the variable period. The controller may control the analog to digital converter circuitry to compare a magnitude of the identified half cycle of a first variable period of the input signal to a magnitude of the identified half cycle of a second variable period of the input signal. The controller may generate an output signal when a difference between the magnitude of the identified half cycle of the first variable period and the magnitude of the identified half cycle of the second variable period is greater than a predetermined threshold.

Provided is an angle detection device including: a correction signal calculator configured to generate corrected signals from a sine signal and a cosine signal acquired from an angle detector; and an angle calculator configured to calculate an angle signal for a rotary machine from the corrected signals. When one of the sine signal and the cosine signal is defined as a first detection signal, and another one thereof is defined as a second detection signal, the correction signal calculator calculates a corrected first detection signal and a corrected second detection signal, and the angle calculator calculates the angle signal for the rotary machine from the corrected first detection signal and the corrected second detection signal.

A rotational angle detection device includes a magnet with n pole pairs (where n3) provided to be integrally rotatable with a rotating body; magnetic detection parts including first and second magnetic detection parts; a corrected signal generation part generating first and second corrected signals; and a rotational angle detection part detecting the rotational angle of the rotating body based on the first and second corrected signals. The waveform of the first and second detection signals have a phase difference of 90 from each other. The corrected signal generation part adds the first sensor signals and adds the second sensor signals. The region at the perimeter of the magnet includes first through nth regions, and at least two of the first and second magnetic sensor parts are positioned in different regions from each other among the first through nth regions.

Systems, methods, and apparatuses for magnetic field sensors with self-test include a detection circuit to detect speed and direction of a target. One or more circuits to test accuracy of the detected speed and direction may be included. One or more circuits to test accuracy of an oscillator may also be included. One or more circuits to test the accuracy of an analog-to-digital converter may also be included. Additionally, one or more IDDQ and/or built-in-self test (BIST) circuits may be included.

A rotary movement position sensor is presented that includes a first sensor output, a second sensor output, a first signal processing unit, a second signal processing unit, a first system output providing the output of the first signal processing unit or of the second signal processing unit, and a second system output providing the output of the second signal processing unit or of the first signal processing unit. A swapping unit that swaps the first signal processing unit between the first sensor output and first system output to the second sensor output and second system output and simultaneously swaps the second signal processing unit from the second sensor output and second system output to the first sensor output and first system output and vice versa. A method for detecting errors in a position sensor system is also presented.

Magnetic sensor modules, systems and methods are provided, configured to detect a rotation speed of an object. A magnetic sensor module includes a plurality of sensor elements configured to generate measurement values in response to sensing a magnetic field, the plurality of sensor elements being grouped into three pairs; and a sensor circuit configured to generate a first shifted differential measurement signal based on the measurement values received from a first shifted pair of sensor elements, a central differential measurement signal based on the measurement values received from a central pair of sensor elements, and a second shifted differential measurement signal based on the measurement values received from a second shifted pair of sensor elements, and generate an output signal based on detecting the first shifted differential measurement signal, the central differential measurement signal, and the second shifted differential measurement signal crossing at least one threshold.

An absolute encoder is driven by backup power from an external battery for backup. The absolute encoder includes: a clock generator configured to generate backup clock pulses at intervals of a predetermined period when the backup power is supplied; an analog signal generation circuit configured to operate according to the clock pulse so as to detect a displacement position of a motor and generate an analog signal corresponding to the detected displacement position; a comparator configured to operate according to the clock pulse so as to compare the analog signal with a predetermined voltage; and a clock control circuit configured to control the clock generator to change the pulse width of the clock pulse.