AMR speed and direction sensor for use with magnetic targets

A movement sensor comprising:

• a multi-pole linear magnet;
• a semiconductor substrate;
• a first magnetic sensor formed on the semiconductor substrate, wherein the first magnetic sensor is configured to produce a first output signal in response to movement of the multi-pole linear magnet, and wherein the first magnetic sensor comprises:
• a first magnetoresistor, a second magnetoresistor, a third magnetoresistor, and a fourth magnetoresistor that are concentric to each other to define a first centroid representing a first center of mass associated with the first, second, third, and fourth magnetoresistors;
• a second magnetic sensor formed on the semiconductor substrate and positioned directly adjacent to the first magnetic sensor, wherein the second magnetic sensor comprises:
• a fifth magnetoresistor, a sixth magnetoresistor, a seventh magnetoresistor, and an eighth magnetoresistor that are concentric to each other to define a second centroid representing a second center of mass associated with the fifth, sixth, seventh, and eighth magnetoresistors;
• and
• a first resistor, wherein a first end of the first resistor is both directly connected to a first end of the first magnetoresistor and directly connected to a first end of the third magnetoresistor, wherein a second end of the first resistor is directly connected to a source connector, wherein the first resistor comprises a negative temperature coefficient material, and wherein the first magnetoresistor and the third magnetoresistor comprise a positive temperature coefficient material,
• wherein:
• the first magnetic sensor and the second magnetic sensor are aligned on the semiconductor substrate along a line that is perpendicular to a surface of the multi-pole linear magnet,
• the second magnetic sensor is arranged at a predetermined angle with respect to the first magnetic sensor,
• the second magnetic sensor is configured to produce a second output signal in response to the movement of the multi-pole linear magnet,
• the predetermined angle is configured to produce a difference in phase between the first and second output signals in response to the movement of the multi-pole linear magnet,
• the first, second, third, and fourth magnetoresistors are radially symmetric about the first centroid and the fifth, sixth, seventh, and eighth magnetoresistors are radially symmetric about the second centroid, and,
• the first centroid and the second centroid are disposed at spaced apart locations along a lateral axis of the multi-pole linear magnet that is orthogonal to a longitudinal axis of the multi-pole linear magnet, such that the first and second magnetic sensors are not concentric to each other.

A movement sensor comprising:

• a multi-pole ring magnet;
• a semiconductor substrate;
• a first magnetic sensor formed on the semiconductor substrate, wherein the first magnetic sensor is configured to produce a first output signal in response to movement of the multi-pole ring magnet, wherein the first magnetic sensor comprises a first magnetoresistor, a second magnetoresistor, a third magnetoresistor, and a fourth magnetoresistor that are concentric to each other to define a first centroid representing a first center of mass associated with the first, second, third, and fourth magnetoresistors, wherein the first magnetoresistor, the second magnetoresistor, the third magnetoresistor, and the fourth magnetoresistor are arranged to form a first Wheatstone bridge;
• a first resistor, wherein a first end of the first resistor is both directly connected to a first end of the first magnetoresistor and directly connected to a first end of the third magnetoresistor, wherein a second end of the first resistor is directly connected to a source connector, wherein the first resistor comprises a negative temperature coefficient material, and wherein the first magnetoresistor and the third magnetoresistor comprise a positive temperature coefficient material;
• and
• a second magnetic sensor formed on the semiconductor substrate and positioned directly adjacent to the first magnetic sensor, wherein the second magnetic sensor produces a second output signal in response to the movement of the multi-pole ring magnet, wherein the second magnetic sensor comprises:
• a fifth magnetoresistor, a sixth magnetoresistor, a seventh magnetoresistor, and an eighth magnetoresistor that are concentric to each other to define a second centroid representing a second center of mass associated with the fifth, sixth, seventh, and eighth magnetoresistors,
• wherein the first centroid and the second centroid are disposed at spaced apart locations along a radius of the multi-pole ring magnet, the radius extending orthogonally from a rotational axis of the multi-pole ring magnet, such that the first and second magnetic sensors are not concentric to each other, and
• wherein the first, second, third, and fourth magnetoresistors are radially symmetric about the first centroid and the fifth, sixth, seventh, and eighth magnetoresistors are radially symmetric about the second centroid.