Abstract: In a current sensor for detecting an electric current flowing in a current path, a magnetic field generating element generates a second magnetic field perpendicular to a first magnetic field generated by the electric current of the current path, and a magnetic sensor generates at least one of a first signal containing a sine value according to an angle defined between the second magnetic field and a synthetic magnetic field composed of the first magnetic field and the second magnetic field and a second signal containing a cosine value according to the angle. A signal processing unit includes a calculation circuit that calculates a tangential value according to the angle using the at least one of the first signal and the second signal, and outputs a sensor signal containing the tangential value.

Abstract: A current sensor includes: a magneto electric conversion element; and a magnetic field concentrating core applying a magnetic field caused by a measurement object current to the magneto electric conversion element. A planar shape of the magnetic field concentrating core perpendicular to a current flowing direction is a ring shape with a gap. The magneto electric conversion element is arranged in the gap. A part of a conductor for flowing the current is surrounded by the magnetic field concentrating core. The magnetic field concentrating core includes two first magnetic members and at least one second magnetic member, which are stacked alternately in the current flowing direction. Parts of the two first magnetic members adjacent to each other via the one second magnetic member are opposed to each other through a clearance or an insulator.

Abstract: A current sensor for measuring a current flowing through a conductor includes a sensor substrate, a magnetoelectric converter formed on a surface of the sensor substrate and configured to output a signal changing with an applied magnetic field, and a magnetic shield that surrounds the sensor substrate and the conductor to magnetically shield the inside from the outside. The output signal of the magnetoelectric converter changes with a magnetic filed applied along the formation surface of the sensor substrate. The magnetic shield has at least one gap for reducing magnetic saturation in the magnetic shield. The gap and the sensor substrate are located at the same height in a z-direction orthogonal to the formation surface of the sensor substrate.

Abstract: A moving object detection apparatus includes a current mirror circuit including first and second transistors connected in parallel between a power source and ground and having gates connected to a ground-side terminal of the first transistor, first and second magnetoresistive elements having pin layers and respectively arranged between the first and second transistors and the ground, a constant voltage circuit, a voltage output circuit having third and fourth transistors respectively arranged between the first and second transistors and the first and second magnetoresistive elements and respectively applying constant voltages to the first and second magnetoresistive elements based on output of the constant voltage circuit when the output of the constant voltage circuit is applied to gates of the third and fourth transistors, and a fifth transistor arranged between the second and fourth transistors to operate according to a potential of a power-source-side terminal of the fourth transistor.

Abstract: A magnetic sensor includes a detection portion that includes first and second magnetic resistance elements. Each of the first and second magnetic resistance elements includes a pinned layer whose magnetic direction is fixed in a predetermined direction and a free layer whose magnetic direction changes in accordance with an external magnetic field. A resistance value of each of the first and second magnetic resistance elements changes in accordance with an angle between the magnetization direction of the pinned layer and the magnetization direction of the free layer. The first and second magnetic resistance elements are connected in series in a state where the magnetization directions of the pinned layers are perpendicular to each other. The detection portion outputs a middle point voltage of the first and second magnetic resistance elements as a detection signal.

Abstract: A current sensor includes: a magneto electric conversion element; and a magnetic field concentrating core applying a magnetic field caused by a measurement object current to the magneto electric conversion element. A planar shape of the magnetic field concentrating core perpendicular to a current flowing direction is a ring shape with a gap. The magneto electric conversion element is arranged in the gap. A part of a conductor for flowing the current is surrounded by the magnetic field concentrating core. The magnetic field concentrating core includes two first magnetic members and at least one second magnetic member, which are stacked alternately in the current flowing direction. Parts of the two first magnetic members adjacent to each other via the one second magnetic member are opposed to each other through a clearance or an insulator.

Abstract: A moving object detection apparatus includes a current mirror circuit including first and second transistors connected in parallel between a power source and ground and having gates connected to a ground-side terminal of the first transistor, first and second magnetoresistive elements having pin layers and respectively arranged between the first and second transistors and the ground, a constant voltage circuit, a voltage output circuit having third and fourth transistors respectively arranged between the first and second transistors and the first and second magnetoresistive elements and respectively applying constant voltages to the first and second magnetoresistive elements based on output of the constant voltage circuit when the output of the constant voltage circuit is applied to gates of the third and fourth transistors, and a fifth transistor arranged between the second and fourth transistors to operate according to a potential of a power-source-side terminal of the fourth transistor.

Abstract: A current sensor for measuring a current flowing through a conductor includes a sensor substrate, a magnetoelectric converter formed on a surface of the sensor substrate and configured to output a signal changing with an applied magnetic field, and a magnetic shield that surrounds the sensor substrate and the conductor to magnetically shield the inside from the outside. The output signal of the magnetoelectric converter changes with a magnetic filed applied along the formation surface of the sensor substrate. The magnetic shield has at least one gap for reducing magnetic saturation in the magnetic shield. The gap and the sensor substrate are located at the same height in a z-direction orthogonal to the formation surface of the sensor substrate.

Abstract: In a current sensor for detecting an electric current flowing in a current path, a magnetic field generating element generates a second magnetic field perpendicular to a first magnetic field generated by the electric current of the current path, and a magnetic sensor generates at least one of a first signal containing a sine value according to an angle defined between the second magnetic field and a synthetic magnetic field composed of the first magnetic field and the second magnetic field and a second signal containing a cosine value according to the angle. A signal processing unit includes a calculation circuit that calculates a tangential value according to the angle using the at least one of the first signal and the second signal, and outputs a sensor signal containing the tangential value.

Abstract: A signal processing circuit for a rotation detector includes a rotational direction determining portion, an effective edge determining portion, a normal-rotation pulse request holding portion, a reverse-rotation pulse request holding portion, an output request signal outputting portion, a pulse outputting portion, a first resetting portion, and a second resetting portion. When one of the holding portions holds an output request signal, the pulse outputting portion outputs a pulse based on the output request signal. When the other one of the holding portions holds an output request signal and then a condition for holding the output request signal that is already held by the one of the holding portions is satisfied in a state where the one of the holding portions holds the output request signal, the second resetting portion resets the output request signal held by the other one of the holding portion.

Abstract: A signal processing circuit for a rotation detector includes a normal-rotation pulse request holding portion, a reverse-rotation pulse request holding portion, a resetting portion, and a waiting time switching portion. When an output of one of a normal-rotation pulse and a reverse-rotation pulse is finished and a waiting time elapses, the resetting portion resets an output request signal of the one of the normal-rotation pulse and the reverse-rotation pulse held by one of the pulse request holding portions. The waiting time switching portion sets the waiting time to a first waiting time when one of the pulse request holding portions holds the output request signal, and the waiting time switching portion sets the waiting time to a second waiting time longer than the first waiting time when both the pulse request holding portions hold the output request signals.

Abstract: In the normal rotation direction, a change in the main sensing signal caused by a front edge is defined as a signal change caused by an effective edge, and a change in the main sensing signal caused by a back edge is defined as a signal change caused by an ineffective edge. In the reverse direction, a change in the main sensing signal caused by the back edge is defined as a signal change caused by an effective edge, and a change caused by a front edge is defined as a signal change caused by an ineffective edge. Regardless of the rotation direction, a detection signal generating circuit generates a detection signal including falling-edge changes and rising edge changes caused by the effective edge and ineffective edge respectively. When the direction is changed, the signal change on the detection signal is prohibited. As a result, gear tooth detection discrepancies are prevented.

Abstract: A rotation detection sensor for detecting both rotational position and direction of a rotating body with a gear includes a magnet, multiple magnetic sensors, a rotational position detection circuit, and a rotational direction detection circuit. The magnet produces a magnetic field directed to a gear tooth of the rotating body. When the rotating body rotates, the magnetic sensors output sensor signals shifted in phase from each other. The rotational position detection circuit performs a differential operation on the sensor signals received from at least two magnetic sensors and outputs a rotational position signal. The rotational direction detection circuit outputs a rotational direction signal based on the position signal and the sensor signal received from at least one of the at least two magnetic sensors.

Abstract: A signal processing circuit for a rotation detector includes a normal-rotation pulse request holding portion, a reverse-rotation pulse request holding portion, a resetting portion, and a waiting time switching portion. When an output of one of a normal-rotation pulse and a reverse-rotation pulse is finished and a waiting time elapses, the resetting portion resets an output request signal of the one of the normal-rotation pulse and the reverse-rotation pulse held by one of the pulse request holding portions. The waiting time switching portion sets the waiting time to a first waiting time when one of the pulse request holding portions holds the output request signal, and the waiting time switching portion sets the waiting time to a second waiting time longer than the first waiting time when both the pulse request holding portions hold the output request signals.

Abstract: A signal processing circuit for a rotation detector includes a rotational direction determining portion, an effective edge determining portion, a normal-rotation pulse request holding portion, a reverse-rotation pulse request holding portion, an output request signal outputting portion, a pulse outputting portion, a first resetting portion, and a second resetting portion. When one of the holding portions holds an output request signal, the pulse outputting portion outputs a pulse based on the output request signal. When the other one of the holding portions holds an output request signal and then a condition for holding the output request signal that is already held by the one of the holding portions is satisfied in a state where the one of the holding portions holds the output request signal, the second resetting portion resets the output request signal held by the other one of the holding portion.

Abstract: In the normal rotation direction, a change in the main sensing signal caused by a front edge is defined as a signal change caused by an effective edge, and a change in the main sensing signal caused by a back edge is defined as a signal change caused by an ineffective edge. In the reverse direction, a change in the main sensing signal caused by the back edge is defined as a signal change caused by an effective edge, and a change caused by a front edge is defined as a signal change caused by an ineffective edge. Regardless of the rotation direction, a detection signal generating circuit generates a detection signal including falling-edge changes and rising edge changes caused by the effective edge and ineffective edge respectively. When the direction is changed, the signal change on the detection signal is prohibited. As a result, gear tooth detection discrepancies are prevented.

Abstract: A rotation detection sensor for detecting both rotational position and direction of a rotating body with a gear includes a magnet, multiple magnetic sensors, a rotational position detection circuit, and a rotational direction detection circuit. The magnet produces a magnetic field directed to a gear tooth of the rotating body. When the rotating body rotates, the magnetic sensors output sensor signals shifted in phase from each other. The rotational position detection circuit performs a differential operation on the sensor signals received from at least two magnetic sensors and outputs a rotational position signal. The rotational direction detection circuit outputs a rotational direction signal based on the position signal and the sensor signal received from at least one of the at least two magnetic sensors.

Abstract: A rotation detector is positioned to face a rotating object such as a crankshaft of an internal combustion engine. The rotation detector includes a sensor chip mounted on a portion extending from a holder and a magnet for supplying a biasing magnetic field to the sensor chip. Rotation of the rotating object is detected by sensing changes in the magnetic field in which the sensor chip is positioned. A projection is formed on an end surface of the holder while a depression is formed on an end surface of the magnet, and the projection and the depression are tightly engaged with each other to thereby correctly position the magnet relative to the holder. In this manner, the sensor chip is correctly and accurately positioned relative to the biasing magnet. Thus, deviations in rotation detection are minimized, and detection accuracy of the detector is improved.

Abstract: A rotation detection device includes a cover member having an opening end, and a sensor body member which has a mounting portion protruding from a mounting-portion protrusion surface and a joint portion positioned around the mounting-portion protrusion surface. The opening end of the cover member is joined to the joint portion of the sensor body member in such a manner that a magnet is housed in the cover member and the mounting-portion protrusion surface is covered by the cover member. A magnetism detection unit is fixedly mounted to the mounting portion and arranged in the magnet. One of the joining surface of the opening end of the cover member and the joining surface of the sensor body member has at least one of a flange-shaped portion and a bent portion. The other of the joining surfaces has a shape corresponding to that of the one thereof.

Abstract: A rotation detection device includes a cover member having an opening end, and a sensor body member which has a mounting portion protruding from a mounting-portion protrusion surface and a joint portion positioned around the mounting-portion protrusion surface. The opening end of the cover member is joined to the joint portion of the sensor body member in such a manner that a magnet is housed in the cover member and the mounting-portion protrusion surface is covered by the cover member. A magnetism detection unit is fixedly mounted to the mounting portion and arranged in the magnet. One of the joining surface of the opening end of the cover member and the joining surface of the sensor body member has at least one of a flange-shaped portion and a bent portion. The other of the joining surfaces has a shape corresponding to that of the one thereof.