08-03-2012, 03:46 PM
isoloop magnetic coupler
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INTRODUCTION
A coupler is an an electronic circuit which is used to couple or (isolate) two pieces of an electronic equipment or two different euipments.
The couplers transmit signals and data between two circuits without any electrical connection.
conventional optocouplers take up a lot of space,are slow and have limitation on temperature range.Their age is also less.
Isoloop magnetic couplers are similar to optocoupler in many ways. They are galvanically isolated data couplers with integrated signal conversion in a single IC.My presentation will give a brief study about “ISOLOOP MAGNETIC COUPLERS”.
OTHER SIMILAR DEVICES
Mechanical Relays can also provide isolation, but even small relays tend to be fairly bulky compared with ICs. Because relays are electro-mechanical, they are not as reliable and are only capable of relatively low speed operation.
Transformer is similar, but only for AC but Magnetic coupler can be used for DC.
Where small size, higher speed and greater reliability are important, a much better alternative is to use a magnetic coupler. It consists of an on chip microscopic coil that generates a magnetic field and a GMR sensor that detects that field.A thin film of dielectric is used for galvanic isolation.
MAGNETIC COUPLER
Magnetic couplers transmit signals via a magnetic field, rather than a photon transmission, across a thin film dielectric that provides the galvanic isolation. As is true of opto couplers, magnetic couplers are unidirectional and operate down to DC. But in contrast to opto couplers, magnetic couplers offer the high-frequency performance of an isolation transformer, covering nearly the entire combined bandwidth of the two conventional isolation technologies.
PHYSICS OF GIANT MAGNETORESISTANCE
Large magnetic field dependent changes in resistance are possible in thin film ferromagnet / nonmagnetic metallic multilayers. The phenomenon was first observed in France in 1988, when changes in resistance with magnetic field of up to 70% were seen. Compared to the small percent change in resistance observed in anisotropic magneto resistance, this phenomenon was truly ‘giant’ magneto resistance.
The spin of electrons in a magnet is aligned to produce a magnetic moment. Magnetic layers with opposing spins (magnetic moments) impede the progress of the electrons (higher scattering) through a sandwiched conductive layer. This arrangement causes the conductor to have a higher resistance to current flow.