Two-terminal linear sensor

• US 8,773,123 B2
• Filed: 09/22/2011
• Issued: 07/08/2014
• Est. Priority Date: 03/06/2008
• Status: Active Grant

• Current Assignee: Allegro Microsystems Incorporated (Sanken Electric Company Limited)
• Original Assignee: Allegro Microsystems Incorporated (Sanken Electric Company Limited)
• Inventors: Doogue, Michael C., Lamarre, Jonathan, Thomas, Monica J.
• Primary Examiner(s): LEDYNH, BOT L
• Application Number:
  US13/239,587
• Publication Number:
  US 20120013327A1
• Time in Patent Office: 1,020 Days
• Field of Search: 324/251
• US Class Current: 324/251
• CPC Class Codes: G01D 5/145 influenced by the relative movement between the Hall device and magnetic fields see G01R33/06
• CPC Class Codes: G01R 33/0023 Electronic aspects, e.g. circuits for stimulation, evaluation, control; Treating the measured signals; calibration G01R33/0017 takes precedence
• CPC Class Codes: G01R 33/0035 Calibration of single magnetic sensors, e.g. integrated calibration
• CPC Class Codes: G01R 33/07 Hall effect devices
• CPC Class Codes: G01R 33/09 Magnetoresistive devices

Abstract

A magnetic field sensor includes a linear magnetic field sensor to produce a voltage proportional to a sensed magnetic field and an interface having only two terminals for external connections. The two terminals of the interface include a power supply terminal and a ground terminal. The interface includes a voltage-controlled current generating device that is connected between the two terminals and is controlled by the voltage to provide a current signal that is proportional to the sensed magnetic field.

Claims

1. A circuit comprising:

a linear magnetic field sensor comprising an integrated circuit having only two terminals, one a power supply terminal and the other a ground terminal, wherein a current proportional to a magnetic field sensed by the linear magnetic field sensor is provided at at least one of the power supply terminal and the ground terminal; and

a current sensing device, connected to the linear magnetic field sensor, usable to measure the current provided by the linear magnetic field sensor.

2. The circuit of claim 1, wherein the current sensing device is connected between the power supply terminal and a power supply.

3. The circuit of claim 2 wherein the linear magnetic field sensor comprises a voltage-controlled current generating device operable as a voltage-controlled current sink.

4. The circuit of claim 1, wherein the current sensing device is connected between the ground terminal and ground.

5. The circuit of claim 4 wherein the linear magnetic field sensor comprises a voltage-controlled current generating device operable as a voltage-controlled current source.

6. The circuit of claim 1 wherein the current sensing device comprises a resistor.

7. The circuit of claim 1 wherein the linear magnetic field sensor comprises a Hall-effect element to sense the magnetic field.

8. The circuit of claim 1 wherein the linear magnetic field sensor comprises a magnetoresistive element to sense the magnetic field.

9. A method comprising:

using a linear magnetic field sensor to produce a current that is proportional to a sensed magnetic field, the linear magnetic field sensor comprising an integrated circuit having only two terminals including a power supply terminal and a ground terminal, wherein the current is provided at at least one of the power supply terminal and the ground terminal; and

measuring the current.