Multi-axis integrated Hall magnetic sensors

Conventional Hall magnetic sensors respond only to the magnetic field component perpendicular to the surface of the sensor die. Multi-axis sensing capability can be provided in the following two ways: (a) by integrating magnetic flux concentrators on the die, and (b) by using vertical Hall devices. Here we review the most important two-and three-axis integrated Hall magnetic sensors based on these concepts. Their applications include mapping of magnetic fields and sensing angular position

Integrated planar fluxgate sensor

Planar magnetic sensor, made in particular via CMOS techniques on a semiconductor substrate (1) of for example parallelepiped shape. It includes an amorphous ferromagnetic core (10) in the shape of a Greek cross which occupies the two diagonals of the square defined by the outer contour (90) of the excitation coil (9), the latter being made in the form of a planar winding of square shape. One thus measures, via flat detection coils (70, 80 and 71, 81) which are mounted in series and in a differential arrangement, the two orthogonal components (H1, H2) of the external magnetic field (Hext)

A low-cost inductive proximity sensor for industrial applications

The paper presents an inductive proximity sensor with fully integrated electronics. The sensor with the compact hybrid configuration is composed of a sensing flat coil and an integrated electronic interface. The sensor exhibits a longitudinal resolution of 120 nm for an aluminum target position up to 500 µm from the sensing coil. The total working range is from 100 µm to 1200 µm. The temperature drift of the sensor is less than 400 ppm/°C. The sensor power consumption is 125 mW and the active sensor dimensions are 1.5mm x 1.5mm x 1.2mm

Magnetic detector made on a semiconductive substrate

Excitation circuit is formed by a single planar coil of an essentially square shape (9) with the magnetic core (10) in the f of a diagonal cross with the legs (101, 102) extending towards the corners of the square defined by the outer circumference (90) the coil. The arrangement allows the two planar components (H1, H2) of an external magnetic field (Hext) to be measured

Hall sensor array

Integrated circuit Hall sensor system comprising a plurality of elementary blocks (EB), each elementary block including a Hall cell (4), a differential pair (8) of an input stage of a Differential Difference Amplifier (DDA), and terminals (12a, 12b), wherein the terminals (12a, 12b) are placed laterally on opposing outer sides of each elementary block parallel to a Y axis and the plurality of elementary blocks are arranged in a juxtaposed manner to form at least one row (6a, 6b) extending along an X axis orthogonal to the Y axis and interconnected by the terminals

Orthogonal fluxgate magnetic field sensor

Orthogonal fluxgate sensor for measuring an external magnetic field Hext, comprising a conductor for carrying an excitation current lexc, a ferromagnetic material adapted to saturate in the presence of a magnetic field generated by the excitation current, and at least one pick-up coil adapted to detect variations in the magnetic field in the vicinity of the magnetic material. The excitation conductor comprises a substantially linear elongated portion of conductive, non-magnetic material, forming an excitation rod (6). The magnetic material surrounds the excitation rod in the form of a cladding (8)

Fluxgate-type magnetic microsensors for wide linear measuring range

In this paper, we present a microfabricated fluxgate sensor for wide linear measuring range applications. The sensor consists of an electroplated copper excitation rod surrounded by an electroplated Permalloy core layer, and has planar pick-up coils for signal detection. Fabricated sensors are tested in orthogonal and parallel operation modes. The effects of operation modes and excitation conditions are compared. A linear operating range of ±900 μT is proved in the orthogonal mode, whereas the same sensor has much lower linear range in the parallel mode. The use of the sensor in a contactless current measurement application is also presented

Integrated Hall Microsystem with Current Re-Use

A new architecture of a Hall microsystem for low-power applications is presented. The innovation in this paper lies in the re-use of the electric current for biasing of several parts in the microsystem permitting substantial reduction of the current consumption. In this manner, four Hall devices were embedded into a differential difference amplifier, and signal treatment techniques for 1/f noise suppression were implemented to the system. The microsystem integrated in a standard 0.8 um double-poly, double-metal CMOS process exhibits an output sensitivity of 37.5 V/T and a magnetic field resolution of 500 nT/√Hz at 1 Hz. Its current consumption was reduced by 45% down to 2.4 mA compared to a similar Hall microsystem with conventional architecture having separated biasing of the sensing part and the electronic part

An orthogonal fluxgate-type magnetic microsensor with electroplated Permalloy core

In this paper, we present a new microfabricated orthogonal fluxgate sensor tructure. The sensor consists of an electroplated copper excitation rod surrounded by an electroplated Permalloy layer and has planar pick-up coils for signal detection. The use of electroplating leads to a low-cost fabrication process and the use of planar pick-up coils provides easy integration with CMOS processes. The fabricated sensor has an excitation independent linear range of ±200uT, a sensitivity of 510 uV/mT, and an average power dissipation of 8.1mW for 100 mA-peak sinusoidal excitation current at 100 kHz frequency. The equivalent magnetic noise is 95 nT/√Hz at 1 Hz, and the RMS noise is 215 nT for 10 Hz bandwidth