Methods and apparatus for a current sensor having fault detection and self test functionality

• US 9,383,425 B2
• Filed: 12/28/2012
• Issued: 07/05/2016
• Est. Priority Date: 12/28/2012
• Status: Active Grant

• Current Assignee: Allegro Microsystems Incorporated (Sanken Electric Company Limited)
• Original Assignee: Allegro Microsystems Incorporated (Sanken Electric Company Limited)
• Inventors: El Bacha, Georges, Milano, Shaun D., Kerdraon, Thomas, Gaboury, Michael, Doogue, Michael C.
• Primary Examiner(s): Phan, Huy Q
• Assistant Examiner(s): RHODES-VIVOUR, TEMILADE S
• Application Number:
  US13/730,100
• Publication Number:
  US 20140184200A1
• Time in Patent Office: 1,285 Days
• Field of Search: 324/202
• US Class Current: 1/1
• CPC Class Codes: B60L 1/00 Supplying electric power to auxiliary equipment of vehicles circuit arrangements for charging batteries H02J7/00
• CPC Class Codes: G01H 1/00 Measuring characteristics of vibrations in solids by using direct conduction to the detector G01H9/00, G01H11/00 take precedence
• CPC Class Codes: G01R 1/00 Details of instruments or arrangements of the types included in groups G01R5/00 - G01R13/00 and G01R31/00 constructional details particular to electromechanical arrangements for measuring the electric consumption G01R11/02
• CPC Class Codes: G01R 31/2829 Testing of circuits in sensor or actuator systems testing of apparatus for measuring electric or magnetic variables G01R35/00; testing of indicating or recording apparatus G01D; in airbag systems B60R21/0173; checking gas analysers G01N33/007; monitoring or fail-safe circuits for electromagnets H01F7/1844
• CPC Class Codes: G01R 33/072 Constructional adaptation of the sensor to specific applications
• CPC Class Codes: G01R 35/00 Testing or calibrating of apparatus covered by the other groups of this subclass
• CPC Class Codes: H01L 2224/05554 being square
• CPC Class Codes: H01L 2224/48247 connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 2224/49171 Fan-out arrangements
• CPC Class Codes: H02H 1/00 Details of emergency protective circuit arrangements

Abstract

Methods and apparatus for an integrated circuit having a magnetic sensing element, a fault detection module including circuitry to detect a fault condition and to self-test operation of the circuitry to detect the fault. The integrated circuit includes a fault pin to indicate the fault condition.

Claims

1. An integrated circuit, comprising:

a sensing element;

fault detection module coupled to the sensing element, the fault detection module including circuitry to detect and output a fault condition and circuitry to perform self-test operation of the circuitry to detect the fault condition; and

a fault pin to output the fault condition and to receive a self-test command,

wherein the fault condition includes a magnetic field is above a first threshold and/or below a second threshold,

wherein the self-test is terminated before completion when the magnetic field is above a flux threshold, and

wherein the self-test operation is initiated only when the magnetic field is below a certain level associated with no magnetic field present.

2. The integrated circuit according to claim 1, wherein the sensing element comprises a magnetic sensing element.

3. The integrated circuit according to claim 2, wherein the magnetic sensing element comprises a Hall element.

4. The integrated circuit according to claim 2, wherein the magnetic sensing element comprises a magnetoresistance element.

5. The integrated circuit according to claim 1, wherein the fault condition includes a current level above a threshold.

6. The integrated circuit according to claim 1, wherein the integrated circuit comprises a linear current sensor.

7. The integrated circuit according to claim 1, wherein the integrated circuit comprises a magnetic field sensor.

8. The integrated circuit according to claim 1, wherein a self-test initiation signal comprises a given voltage level applied for at least a given time duration.

9. The integrated circuit according to claim 8, wherein the given voltage level comprises about vcc/2.

10. The integrated circuit according to claim 1, wherein the integrated circuit outputs a result of the self-test on the fault pin.

11. The integrated circuit according to claim 10, wherein the result comprises a voltage level indicative of pass/fail for the self-test.

12. The integrated circuit according to claim 1, wherein the fault detection module comprises a first comparator to detect a first fault condition and a second comparator to detect a second fault condition.

13. The integrated circuit according to claim 12, wherein the first fault condition includes a current level below a first threshold, and the second fault condition includes a current level above a second threshold.

14. The integrated circuit according to claim 1, wherein the integrated circuit comprises a package having exactly four pins.

15. The integrated circuit according to claim 1, wherein the integrated circuit comprises a package having a thickness of less than 1.1 mm.

16. The integrated circuit according to claim 1, wherein the fault detection module comprises a programmable window comparator.

17. The integrated circuit according to claim 1, wherein the integrated circuit comprises a linear current sensor.

18. The integrated circuit according to claim 1, further comprising a three-phase power system, wherein the integrated circuit is disposed in a core of an element in the three-phase power system.