摘要:
A first detection unit has first and second detection circuits. A second detection unit has third and fourth detection circuits. Output signals of the second and fourth detection circuits differ from output signals of the first and third detection circuits in phase, respectively, by an odd number of times ¼ the signal period. The output signal of the third detection circuit differs from the output signal of the first detection circuit in phase by an integer multiple of ⅙ the signal period other than an integer multiple of ½ the signal period. A rotating field sensor generates a first signal based on the output signals of the first and third detection circuits, generates a second signal based on the output signals of the second and fourth detection circuits, and calculates a detected angle value based on the first and second signals.
摘要:
The angle-of-rotation sensor apparatus of the invention comprises a shaft supported rotatably about an axial center, a permanent magnet fixed to one end face of the shaft, and a magnetic field sensor device located in opposition to the permanent magnet at a constant spacing. The permanent magnet used is in a cuboidal shape and magnetized in the minor axis (X) direction at the rectangular surface opposing to the magnetic field sensor device. The minor axis side is defined as the X direction and the major axis side as the Y direction. Given the opposing surface of the same area, the area where the angle distribution of the magnetic field emitted out of the permanent magnet can be placed in a uniform direction is made so wide that the tolerance range for axial alignment errors between the magnetic field sensor device and the permanent magnet can be enlarged.
摘要:
A rotating field sensor includes a first detection circuit that outputs a first signal indicating the intensity of a component of a rotating magnetic field in a first direction, a second detection circuit that outputs a second signal indicating the intensity of a component of the rotating magnetic field in a second direction, and an arithmetic circuit that calculates a detected angle value based on the first and second signals. Each of the first and second detection circuits includes at least one MR element row. Each MR element row is composed of a plurality of MR elements connected in series. Each MR element has a magnetization pinned layer. The plurality of MR elements forming each MR element row include one or more pairs of MR elements. Magnetization directions of the magnetization pinned layers in two MR elements making up a pair form a predetermined relative angle other than 0° and 180°.
摘要:
A field generation unit generates a rotating magnetic field including a first partial magnetic field in a first position and a second partial magnetic field in a second position. The first and second partial magnetic fields differ in direction by 180° and rotate in the same direction of rotation. A first detection unit located in the first position has first and second detection circuits whose output signals differ in phase by ¼ the period. A second detection unit located in the second position has third and fourth detection circuits whose output signals differ in phase by ¼ the period. A detected value of the angle that the direction of the rotating magnetic field in a reference position forms with respect to a reference direction is calculated based on a first signal generated from the output signals of the first and third detection circuits and a second signal generated from the output signals of the second and fourth detection circuits.
摘要:
A magnetic sensor for detecting a direction of an external magnetic field comprises: a bridge circuit configured to provide an output that changes in accordance with the direction of the external magnetic field, the bridge circuit including four resistance element sections, each of which comprises at least one magnetoresistance effect element; and two resistors connected to respective output terminals of the bridge circuit. The ratio of the resistance of each of the resistors to that of the bridge circuit is at least 2 when the resistance of each of the resistance element sections is at a minimum corresponding to a change in magnetoresistance.
摘要:
A rotation angle sensor includes a magnet that rotates about a rotation axis. The magnet has an end face perpendicular to the rotation axis and has a magnetization in a direction perpendicular to the rotation axis. The rotation angle sensor further includes a magnetic sensor that faces the end face of the magnet and detects a magnetic field produced by the magnet. The magnet includes a plate-shaped portion including the end face, and a ring-shaped portion that is located on a side of the plate-shaped portion farther from the end face and coupled to the plate-shaped portion. The plate-shaped portion does not include any hollow through which the rotation axis passes, whereas the ring-shaped portion includes a hollow through which the rotation axis passes.
摘要:
A field generation unit generates a rotating magnetic field including a first partial magnetic field in a first position and a second partial magnetic field in a second position. The first and second partial magnetic fields differ in direction by 180° and rotate in the same direction of rotation. A first detection unit detects, in the first position, a first angle that the direction of a first applied field forms with respect to a first direction. The first applied field includes the first partial magnetic field as its main component. A second detection unit detects, in the second position, a second angle that the direction of a second applied field forms with respect to a second direction. The second applied field includes the second partial magnetic field as its main component. A detected value of the angle that the direction of the rotating magnetic field in a reference position forms with respect to a reference direction is calculated based on detected values of the first and second angles.
摘要:
A magnetic sensor includes a first detection unit and a second detection unit. The first detection unit calculates a first detection angle which is a detected value of a first angle that a direction of an external magnetic field in a first position forms with respect to a first direction. The second detection unit calculates a second detection angle which is a detected value of a second angle that the direction of the external magnetic field in a second position forms with respect to a second direction. The first detection angle includes a first angular error. The second detection angle includes a second angular error. The first angular error and the second angular error differ in phase by an odd number of times ½ of the error period.
摘要:
A magnetic sensor includes a bridge circuit with a first, a second, a third, and a fourth resistor annularly and electrically connected together in this order, and a compensation resistor. The compensation resistor is connected to a first point between the fourth resistor and the first resistor. The first to fourth resistors include a first to fourth tunnel magneto-resistance element, respectively. Each of the magnetization directions in the magnetization fixed layers in the second and fourth magneto resistance elements is opposite to the magnetization direction in the magnetization fixed layer in the first magneto resistance element. The magnetization direction in the magnetization fixed layer in the third magneto resistance element is the same as the magnetization direction in the magnetization fixed layer in the first magneto resistance element. The resistance of the compensation resistor varies with a period of 180 degrees with respect to a rotation angle of the external field.
摘要:
The method according to the present invention includes the steps of: sequentially applying a plurality of different voltages to an MR element and sequentially detecting output signals from the MR element; and eliminating the MR element as a defective product when an evaluation value, based on a difference of SN ratios of the output signals from the MR element respectively obtained for each applied voltage, is less than a threshold value, and selecting the MR element as a non-defective product when the evaluation value is greater than or equal to the threshold value.