Inductive proximity sensor and related methods

• US 20030164697A1
• Filed: 01/16/2003
• Published: 09/04/2003
• Est. Priority Date: 07/20/2000
• Status: Active Grant

• Current Assignee: Honeywell Control Systems Limited (Honeywell International Inc.)
• Original Assignee: Honeywell Control Systems Limited (Honeywell International Inc.)
• Inventors: Hardie, David
• Granted Patent: US 7,719,262 B2
• Time in Patent Office: Days
• US Class Current: 324/207.15
• CPC Class Codes: H03K 17/9512 using digital techniques
• CPC Class Codes: H03K 17/9547 with variable amplitude
• CPC Class Codes: H03K 2217/94026 Automatic threshold calibration; e.g. threshold automatically adapts to ambient conditions or follows variation of input
• CPC Class Codes: Y10T 29/49105 Switch making

Abstract

An inductive proximity sensor or switch and a method of using same. The sensor or switch includes an Application Specific Integrated Circuit (“ASIC”) and a plurality of external components. The ASIC is implemented in CMOS technology and has an oscillator. A switch point of the sensor or switch is predetermined by selection of a bias voltage to a potential node of the oscillator.

Claims

1. An inductive proximity sensor having at least one Complementary Metal Oxide Semiconductor (CMOS) component.

2. A sensor as claimed in claim 1, wherein the inductive proximity sensor comprises an inductive proximity switch.

3. A sensor as claimed in claim 1, wherein the inductive proximity sensor includes a plurality of CMOS components.

4. A sensor as claimed in claim 2, wherein the inductive proximity sensor comprises a proximity switch having a digital output.

5. A sensor as claimed in claim 2, wherein an output of the inductive proximity sensor is analogue.

6. A sensor as claimed in claim 1, wherein the CMOS component(s) are selected from one or more of:

transistors, resistors, capacitors, fusible links, polyfuses.

7. A sensor as claimed in claim 1, wherein the CMOS component(s) is/are made at least partly from silicon.

31. An ASIC (Application Specific Integrated Circuit) for use in the inductive proximity sensor of claim 1.

33. An apparatus including an inductive proximity sensor according to claim 1.

8. A method of manufacturing an Application Specific Integrated Circuit (ASIC) for use in or as an inductive proximity sensor, the method including the step of forming one or more components of the ASIC by Complementary Metal Oxide Semi-conductor (CMOS) methodology.

9. An inductive proximity switch having an oscillator, a switch point of the inductive proximity switch being predetermined by selection of a bias voltage to a potential node of the oscillator.

10. A switch as claimed in claim 9, wherein the selection of the bias voltage adjusts a gain or amplitude on the detection head.

11. A switch as claimed in claim 9, wherein the oscillator comprises at least part of an Application Specific Integrated Circuit (ASIC) forming at least part of the inductive proximity switch.

32. An ASIC (Application Specific Integrated Circuit) for use in the inductive proximity switch of claim 9.

34. An apparatus including an inductive proximity switch according to claim 9.

12. A method of setting a switch point of an inductive proximity switch by selecting a bias voltage to a potential node of an oscillator of the inductive proximity switch.

13. An inductive proximity sensor including an oscillator and means for substantially maintaining an output voltage from the oscillator, the maintenance means comprising temperature compensation means.

14. A sensor as claimed in claim 13, wherein the inductive proximity sensor comprises an inductive proximity switch.

15. A sensor as claimed in claim 13, wherein the temperature compensation means acts to maintain the output voltage if and when a temperature of the oscillator varies, in use.

16. A sensor as claimed in claim 13, wherein the temperature compensation means provide a temperature compensation signal which may be applied to a node of the oscillator.

17. A sensor as claimed in claim 13, wherein the temperature compensation means comprises a temperature compensation circuit.

18. A sensor as claimed in claim 17, wherein the inductive proximity sensor provides a bandgap reference block circuit which acts to provide a bandgap reference block circuit voltage which is substantially constant with temperature, and which produces a variation signal indicative of any change applied to the temperature compensation circuit and so to the oscillator.

19. A method of maintaining an output voltage from an oscillator of an inductive proximity sensor comprising the steps of:

providing temperature compensation means;

establishing a temperature compensation signal from the temperature compensation means; and

maintaining the output voltage by means of the temperature compensation signal.

20. An inductive proximity sensor including an oscillator and wherein, in use, a bias voltage of the oscillator is selected by means of a plurality of successive approximation steps.

21. A sensor as claimed in claim 20, wherein the inductive proximity sensor comprises an inductive proximity switch.

22. A sensor as claimed in claim 20, wherein the inductive proximity sensor includes an n-bit converter which suitably changes a voltage applied to a control node of the oscillator.

23. A sensor as claimed in claim 20, wherein the inductive proximity sensor includes an analogue-to-digital (a-to-d) converter.

24. A method of selecting a bias voltage of an oscillator of an inductive proximity sensor including the steps of carrying out a plurality of successive approximation steps.

25. An inductive proximity sensor wherein an output functionality of the inductive proximity sensor is programmed or selected by application of a predetermined voltage to a power supply input of the inductive proximity sensor.

26. A sensor as claimed in claim 25, wherein the inductive proximity sensor comprises an inductive proximity switch.

27. A sensor as claimed in claim 25, wherein the application of the predetermined voltage causes one or more fuses to fuse or blow.

28. A sensor as claimed in claim 25, wherein the predetermined voltage is applied to code signal processing means which produce a code signal which is applied to a plurality of fuses so as to fuse or blow one or more of the fuses thereby setting a functionality of the inductive proximity sensor.

29. A sensor as claimed in claim 28, wherein the functionality is selected from sink open, source open, sink closed, or source closed.

30. A method of programming or selecting a functionality of an inductive proximity sensor including the step of applying a predetermined voltage to a power supply input of the inductive proximity sensor.

35. A method of programming or selecting a functionality of an inductive proximity sensor.