Electricity: measuring and testing – Magnetic – Displacement
Reexamination Certificate
2001-08-27
2003-09-09
Tran, Minh Loan (Department: 2826)
Electricity: measuring and testing
Magnetic
Displacement
C324S251000, C327S511000
Reexamination Certificate
active
06617846
ABSTRACT:
TECHNICAL FIELD OF THE INVENTION
This invention relates generally to the field of electronics and, more specifically, to a method and system for isolated coupling.
BACKGROUND OF THE INVENTION
Integrated circuits are used for numerous applications. For example, isolation coupling can be accomplished using integrated circuits. Isolation coupling is utilized when two data systems need to communicate with each other, but a physical connection of conductive material is not possible or desired.
There are many desired characteristics for isolation coupling devices or systems. One is that the isolation coupling system accommodates both direct current and alternating current from low to high frequencies. In addition, fast communication speed and higher levels of device integration are also important. Furthermore, users of isolation coupling systems or devices desire systems occupying a small space, while requiring low power consumption and reducing unwanted external and internal effects (i.e. parasitics) to a minimum. It is also desired that isolation coupling systems and devices be produced in a cost-effective manner.
Various systems and devices have been used for isolation coupling. Capacitive coupling using capacitors is one common method. However, a problem with capacitive coupling is that it is very expensive and it cannot accommodate direct current. Another common method for isolation coupling utilizes transformers. Transformers use coils for transferring voltages. A problem with transformers is essentially the same as capacitive coupling in that they are very expensive and cannot handle direct current or low frequency alternating.
An additional method for isolation coupling is optocoupling. Optocouplers use photodiodes in which signals are transmitted by a photon field. A problem with optocouplers is that they are very expensive and can only handle alternating current signals up to approximately ten megahertz. Giant magnetoresistors (“GMRs”) are also used for isolation coupling. GMRs use magnetic sensors that utilize a change in resistance to couple two isolated systems. GMRs are not quite as expensive as transformers, capacitive coupling systems, or optocouplers, but they are expensive, and they require magnetic shielding. One of the main reasons they are expensive is the fabrication costs resulting from the many semiconductor fabrication layers required for GMRs.
SUMMARY OF THE INVENTION
The challenges in the field of electronics continue to increase with demands for more and better techniques having greater flexibility and adaptability. Therefore, a need has arisen for a new method and system for isolated coupling.
In accordance with the present invention, a method and system for isolated coupling is provided that addresses disadvantages and problems associated with previously developed methods and systems.
A method for isolatively coupling an input signal to an output signal, where the input signal is a first voltage differential, comprises generating a magnetic field that is indicative of the input signal in at least one magnetic sensor in an integrated circuit by generating a current through a conductor in the integrated circuit. The current is generated by applying the first voltage differential across the conductor, which is proximate the magnetic sensor. A second voltage differential between two points of the magnetic sensor is generated by providing a current through the magnetic sensor in a direction having a component transverse to the magnetic field. A signal, indicative of the second voltage differential, is produced as the output signal, thereby isolatively coupling the input signal to the output signal.
An integrated circuit incorporating an isolation coupler is disclosed. The integrated circuit comprises at least one region of conductive material formed in a semiconductor substrate. The region of conductive material is electrically connected to a plurality of conductive nodes that are operable to allow measurement of a voltage difference arising due to a magnetic field acting on the region of conductive material. The region of conductive material is operable to receive a current from a current source and operable to generate a current through the region of conductive material. At least one isolation layer is disposed outwardly from the semiconductor substrate. A conductive layer is disposed outwardly from the isolation layer, and is operable to receive an input signal and operable to conduct a current to generate the magnetic field.
Embodiments of the invention provide numerous technical advantages. For example, a technical advantage of one embodiment of the present invention is that the single chip, or portion thereof, used for isolated data communication is capable of measurement of direct current (“DC”) and alternating current (“AC”) from low frequencies up to very high frequencies due parallel path open loop operation. Another technical advantage of one embodiment of the present invention is that the single chip, or portion thereof, has less parasitic capacitance associated with it. An additional technical advantage of one embodiment of the present invention is that the single chip, or portion thereof, is cheaper than previous methods and apparatuses used for isolated coupling.
Other technical advantages are readily apparent to one skilled in the art from the following figures, descriptions, and claims.
REFERENCES:
patent: 4292595 (1981-09-01), Smith
patent: 4801883 (1989-01-01), Muller et al.
patent: 5694040 (1997-12-01), Plagens
patent: 5831426 (1998-11-01), Black, Jr. et al.
Myers, John, et al., “GMR Isolators,”Nonvolatile Electronics, Inc., © 1998, pp. 1-7.
Carvajal Fernando D.
Hayat-Dawoodi Kambiz
Brady III W. James
Moore J. Dennis
Telecky , Jr. Frederick J.
Texas Instruments Incorporated
Tran Minh Loan
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