Method and system for isolated coupling

• US 20020027488A1
• Filed: 08/27/2001
• Published: 03/07/2002
• Est. Priority Date: 08/31/2000
• Status: Active Grant

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: Hayat-Dawoodi, Kambiz, Carvajal, Fernando D.
• Granted Patent: US 6,617,846 B2
• Time in Patent Office: Days
• US Class Current: 335/78
• CPC Class Codes: H04B 5/22 Capacitive coupling
• CPC Class Codes: H04B 5/73 for taking measurements, e.g. using sensing coils
• CPC Class Codes: H04B 5/75 for isolation purposes
• CPC Class Codes: H10B 61/00 Magnetic memory devices, e.g. magnetoresistive RAM [MRAM] devices
• CPC Class Codes: H10N 59/00 Integrated devices, or assemblies of multiple devices, comprising at least one galvanomagnetic or Hall-effect element covered by groups H10N50/00 - H10N52/00 MRAM devices H10B61/00

Abstract

A method for isolatively coupling an input signal to an output signal, where the input signal is a first voltage differential, comprises three steps. Step one calls for 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. Step two requires generating a second voltage differential between two points of the magnetic sensor by providing a current through the magnetic sensor in a direction having a component transverse to the magnetic field. Step three calls for providing a signal indicative of the second voltage differential as the output signal, thereby isolatively coupling the input signal to the output signal.

Claims

1. A method for isolatively coupling an input signal to an output signal, the input signal being a first voltage differential, the method comprising:

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 generated by applying the first voltage differential across the conductor, the conductor being disposed proximate the magnetic sensor;

generating a second voltage differential between two points of the magnetic sensor by providing a current through the magnetic sensor in a direction having a component transverse to the magnetic field; and

providing a signal indicative of the second voltage differential as the output signal, thereby isolatively coupling the input signal to the output signal.

2. The method of claim 1 further comprising:

capacitively coupling the first voltage differential to a third voltage differential to produce a second signal indicative of the third voltage differential; and

selecting the output signal chosen from the group consisting of the signal and the second signal based on the frequency of the input signal.

3. The method of claim 1 wherein the magnetic sensor is a Hall element.

4. The method of claim 3 wherein the Hall element comprises an n-well formed in a semiconductor substrate.

5. The method of claim 1 wherein the conductor is copper.

6. The method of claim 1 further comprising arranging the conductor such that the magnetic field generated by the conductor produces a negative voltage difference on a first magnetic sensor and a positive voltage difference on a second magnetic sensor.

7. The method of claim 1 further comprising manufacturing the magnetic sensor with a surface area less than approximately 1000 μ

m².

8. A method for isolatively coupling an input signal to an output signal in an integrated circuit, the method comprising:

providing first and second conductive plates operable to receive the input data signal;

providing at least one magnetic sensor having a region of conductive material, the magnetic sensor operable to receive a current from a current source and to conduct the current through the region of conductive material;

electrically connecting a plurality of conductive nodes to the conductive material, the conductive nodes operable to allow measurement of a voltage difference arising due to a magnetic field acting on the region of conductive material;

electrically connecting a conductor at one end to the first conductive plate and electrically connecting the other end to the second conductive plate;

positioning the conductor proximate the magnetic sensor, the conductor operable to conduct a current generated by the input signal thereby generating the magnetic field;

receiving the input signal resulting in a first differential voltage between the first and second conductive plates;

capacitively coupling the first differential voltage to a second differential voltage along a first parallel path to produce a first output signal representative of the input signal using a first amplifier and a first comparator;

magnetically coupling the first differential voltage to a third differential voltage along a second parallel path to produce a second output signal representative of the input signal by measuring the voltage difference across the magnetic sensor due to the magnetic field generated by the current produced by the first voltage differential and producing a second output signal representative of the input signal using a second amplifier and a second comparator; and

creating an output signal chosen from the group consisting of the first output signal and the second output signal.

9. The method of claim 8 wherein the magnetic sensor is a Hall element.

10. The method of claim 8 wherein the region of conductive material comprises an n-well formed in a semiconductor substrate.

11. The method of claim 8 wherein the conductor is copper.

12. The method of claim 8 wherein providing at least one magnetic sensor comprises providing two magnetic sensors, wherein the conductor is arranged such that the magnetic field generated by the conductor produces a negative voltage difference on one of the magnetic sensors and a positive voltage difference on the other magnetic sensor.

13. The method of claim 8 further comprising manufacturing the magnetic sensor with a surface area less than approximately 1000 μ

m².

14. The method of claim 8 wherein capacitively coupling comprises the first and second conductive plates being separated from third and fourth conductive plates by an isolation layer, wherein the third and fourth conductive plates are electrically connected to the first amplifier.

16. The integrated circuit of claim 15 wherein the region of conductive material is an n-well.

17. The integrated circuit of claim 15 wherein the conductive layer comprises:

a first conductive plate;

a second conductive plate spaced apart from the first conductive plate; and

a conductor connecting the first conductive plate to the second conductive plate.

18. The integrated circuit of claim 15 wherein at least one region of conductive material comprises two regions of conductive material, and wherein the conductive layer is arranged such that the magnetic field generated by the conductive layer produces a negative voltage difference on one of the regions of conductive material and a positive voltage difference on the other region of conductive material.

19. The integrated circuit of claim 15 wherein the conductor is copper.

20. The integrated circuit of claim 15 further comprising a passivation layer disposed outwardly from the conductive layer.

21. The integrated circuit of claim 15 further comprising a conductive plate separated from the conductive layer by a portion of the isolation layer, wherein the conductive plate is disposed below the conductive layer and contained in a material chosen from the group consisting of the semiconductor substrate and the isolation layer.

15. An integrated circuit incorporating an isolation coupler comprising:

at least one region of conductive material formed in a semiconductor substrate, the region of conductive material electrically connected to a plurality of conductive nodes 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 operable to receive a current from a current source and to generate a current through the region of conductive material;

at least one isolation layer disposed outwardly from the semiconductor substrate; and

a conductive layer disposed outwardly from the isolation layer operable to receive an input signal and to conduct a current to generate the magnetic field.