Methods and apparatus for sensor diagnostics

Patent metadata

Field	Value
Publication number	US-11313899-B2
Application number	US-201916655657-A
Country	US
Kind code	B2
Filing date	Oct 17, 2019
Priority date	Dec 26, 2013
Publication date	Apr 26, 2022
Grant date	Apr 26, 2022

Abstract

Methods and apparatus for providing an integrated circuit having a drive current source, a magnetic sensing element coupled to the drive current source, the magnetic sensing element having first and second differential outputs, and first and second current elements to provide respective currents in relation to the drive current source, wherein the first current element is coupled to the first differential output and the second current element is coupled to the second differential output. In illustrative embodiments, an IC output can output a voltage corresponding to the currents of the first and second current elements.

First claim

What is claimed is:

1. An integrated circuit, comprising:
a magnetic sensing element;
a coil disposed in proximity to the magnetic sensing element;
a self test module coupled to ends of the coil to exercise an analog signal path including from the magnetic sensing element to an integrated circuit (IC) output, wherein the analog signal path includes a direct signal path from the magnetic sensing element to the IC output for detecting a fault in any circuit element from the magnetic sensing element to the IC output, wherein the IC output is configured to output a signal for normal operation of the IC and a signal for diagnostic operation of the IC;
a threshold module having a normal operation voltage level switchpoint output and a diagnostic voltage level switchpoint output, wherein the threshold module is configured to output one of the normal operation voltage level switchpoint output and the diagnostic voltage level switchpoint output at a given time; and
a comparator to receive first and second inputs, wherein the first input is configured to receive one of the normal operation voltage level switchpoint or the diagnostic voltage level switchpoint, wherein the diagnostic voltage level switchpoint corresponds to exercising the analog signal path, and the second input is configured to receive a signal from the magnetic field sensing element.

2. The integrated circuit according to claim 1 , wherein the magnetic sensing element comprises a Hall element disposed on a silicon substrate common to the integrated circuit.

3. The integrated circuit according to claim 1 , wherein the magnetic sensing element comprises a magnetoresistive element disposed on a silicon substrate common to the integrated circuit.

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

5. The integrated circuit according to claim 1 , wherein the self test module includes a first current source coupled to one end of the coil.

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 switch.

8. The integrated circuit according to claim 1 , wherein the integrated circuit comprises a switch coupled between the coil and ground.

9. The integrated circuit according to claim 1 , wherein the integrated circuit comprises a switch coupled between the coil and a system diagnostic module.

10. The integrated circuit according to claim 1 , wherein the integrated circuit comprises a switch coupled to the coil to turn on and off current through the coil.

11. The integrated circuit according to claim 1 , wherein the integrated circuit comprises a switch coupled to the coil to turn on and off current through the coil for controlling a pulse width modulation of the IC output during self-test of the integrated circuit.

12. The integrated circuit according to claim 1 , further including a die supported by a leadframe having a region cutout from the leadframe, wherein the location of the magnetic sensing element is aligned with the region to reduce Eddy currents.

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

14. The integrated circuit according to claim 1 , wherein the self-test module is configured to generate a pulse width modulation (PWM) signal on the IC output during diagnostic operation.

15. The integrated circuit according to claim 1 , wherein a signal on the IC output is deflected an amount proportional to current through the coil.

16. The integrated circuit according to claim 15 , further including first and second current sources coupled to ends of the coil to enable the current to flow in either direction.

17. A method, comprising:
locating a coil in proximity to a magnetic sensing element forming a part of an integrated circuit;
coupling a self test module to ends of the coil to exercise an analog signal path including from the magnetic sensing element to an integrated circuit (IC) output; and
exercising the analog signal path from the magnetic sensing element to the IC output,
wherein the self test module is coupled to ends of the coil to exercise an analog signal path including from the magnetic sensing element to an integrated circuit (IC) output, wherein the analog signal path includes a direct signal path from the magnetic sensing output to the IC output for detecting a fault in any circuit element from the magnetic sensing element to the IC output, wherein the IC output is configured to output a signal for normal operation of the IC and a signal for diagnostic operation of the IC;
employing a threshold module having a normal operation voltage level switchpoint output and a diagnostic voltage level switchpoint output, wherein the threshold module is configured to output one of the normal operation voltage level switchpoint output and the diagnostic voltage level switchpoint output at a given time; and
employing a comparator to receive first and second inputs, wherein the first input is configured to receive one of the normal operation voltage level switchpoint or the diagnostic voltage level switchpoint, wherein the diagnostic voltage level switchpoint corresponds to exercising the analog signal path, and the second input is configured to receive a signal from the magnetic field sensing element.

18. The method according to claim 17 , further including coupling a first current source of the self test module to one end of the coil.

19. The method according to claim 18 , further including controlling the first and second current sources to verify operation of the integrated circuit, including comparator switchpoints.

20. The method according to claim 18 , further including controlling the first and second current sources to verify operation of the integrated circuit, including deflecting the IC output in proportion to current in the coil.

21. The method according to claim 17 , further including applying a constant current to the coil and verifying a deflection on the IC output proportional to a gain of the analog signal path.

22. The method according to claim 17 , further including verifying a zero field operation of the IC output.

23. The method according to claim 17 , further including employing a die supported by a leadframe having a region cutout from the leadframe, wherein the location of the magnetic sensing element is aligned with the region to reduce Eddy currents.

24. The method according to claim 17 , wherein the integrated circuit comprises a switch coupled between the coil and ground.

25. The method according to claim 17 , wherein the integrated circuit comprises a switch coupled between the coil and a system diagnostic module.

26. The method according to claim 17 , wherein the integrated circuit comprises a switch coupled to the coil to turn on and off current through the coil.

27. The method according to claim 17 , wherein the integrated circuit comprises a switch coupled to the coil to turn on and off current through the coil for controlling a pulse width modulation of the IC output during self-test of the integrated circuit.

Assignees

• Allegro Microsystems Llc

Inventors

• Milano Shaun D
• El Bacha Georges
• Doogue Michael C
• Haas David J
• Delmain Gregory
• Gaboury Michael
• Taylor William P

Classifications

• H10W90/756

  between a chip and a stacked lead frame, conducting package substrate or heat sink · CPC title

• H10W74/00

  Encapsulations, e.g. protective coatings · CPC title

• G01R33/091 Primary

  Constructional adaptation of the sensor to specific applications · CPC title

• G01R31/3187

  Built-in tests · CPC title

• G01R33/072

  Constructional adaptation of the sensor to specific applications · CPC title