Inductive proximity sensor and related methods

• US 7,719,262 B2
• Filed: 01/16/2003
• Issued: 05/18/2010
• Est. Priority Date: 07/20/2000
• Status: Expired due to Fees

• Current Assignee: Honeywell Control Systems Limited (Honeywell International Inc.)
• Original Assignee: Honeywell International Inc.
• Inventors: Hardie, David
• Primary Examiner(s): NGUYEN, LONG T
• Application Number:
  US10/345,206
• Publication Number:
  US 20030164697A1
• Time in Patent Office: 2,679 Days
• Field of Search: 327/50, 327/51, 327/77, 327/78, 327/517, 307/116, 307/652, 324/76.11, 324/179, 324/685, 324/207.13, 324/207.15, 324/207.22, 324/207.26
• 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 comprising:

a programmable Application Specific Integrated Circuit (ASIC) wherein said programmable ASIC is capable of being programmed by an automatic program control sequence initiated by application of a predetermined supply voltage to said inductive proximity sensor, said automatic program control sequence programmed to set a finished functionality of said inductive proximity sensor based upon a magnitude of said predetermined supply voltage and said automatic program control sequence is further programmed to set a sense distance of said inductive proximity sensor based upon a position of a target relative to said inductive proximity sensor.

2. The sensor of claim 1, wherein said programmable ASIC is capable of operating with a voltage of at least 30 volts.

3. The sensor of claim 1, wherein said programmable ASIC comprises a voltage regulator, an oscillator, a demodulator, a threshold switch, a bandgap reference circuit, a temperature compensation circuit, an auto programming and trim control circuit, a driver stage, a turn-on turn-off and short circuit delay circuit, a short detection circuit, a thermal protection circuit, a source output stage and a sink output stage.

4. The sensor of claim 3, wherein said programmable ASIC is connected by a plurality of pins to a plurality of circuitry components within said inductive proximity sensor circuit.

5. The sensor of claim 4, wherein said auto programming and trim control circuit provides an output that is input to said source output stage and wherein said thermal protection circuit comprises an output that is input to said driver stage, and wherein said driver stage provides at least one output that is input to said sink output stage, wherein said sink output stage generates an output that provides load data.

6. The sensor of claim 2, wherein said programmable ASIC comprises at least one Complementary Metal Oxide (CMOS) component.

7. The sensor of claim 6, wherein said programmable ASIC operates in at least one of two modes, including at least a programming mode or at least a normal mode.

8. The sensor of claim 7 wherein said programmable ASIC is utilized within a host proximity switch having a digital output.

9. The sensor of claim 7, wherein an output of said inductive proximity sensor is analogue.

10. The sensor of claim 7, wherein said at least one CMOS component is selected from at least of one of the following types of CMOS components:

transistors, resistors, capacitors, fusible links, and/or polyfuses.

11. The sensor of claim 2, wherein said host proximity switch comprises an oscillator, such that a switch point associated with said host proximity switch is predetermined by a selection of a bias voltage to a potential node of said oscillator.

12. The sensor of claim 11, wherein said selection of said bias voltage adjusts a gain or amplitude on a detection head of said inductive proximity sensor circuit.

13. The sensor of claimed in claim 3, wherein said temperature compensation circuit maintains an output voltage from said oscillator.

14. The sensor of claim 13, wherein said temperature compensation circuit acts to maintain said output voltage if and when a temperature of said oscillator varies, in use.

15. The sensor of claim 13, wherein said temperature compensation circuit provides a temperature compensation signal which is, in use, applied to a node of said oscillator.

16. The sensor of claim 3, wherein said bandgap reference circuit acts to provide a bandgap reference circuit voltage which is substantially constant with temperature, and which produces a variation signal indicative of any change applied to said temperature compensation circuit and to said oscillator.

17. The sensor of claim 10 further comprising an n-bit converter, which suitably changes a voltage, applied to a control node of said oscillator.

18. A method of programming an inductive proximity sensor comprising:

applying a predetermined supply voltage to said inductive proximity sensor;

initiating an automatic program control sequence of an ASIC of said inductive proximity sensor by said predetermined supply voltage;

setting a finished functionality of said inductive proximity sensor based upon a magnitude of said predetermined supply voltage; and

setting a sense distance of said inductive proximity sensor by positioning a target relative to said inductive proximity sensor at said sense distance when said predetermined supply voltage is applied to said inductive proximity sensor.

19. The method of claim 18 wherein said inductive proximity sensor is mounted in a working location prior to programming said inductive proximity sensor.

20. The method of claim 18 wherein said predetermined supply voltage initiates an internal timing sequence which iterates through an n-bit weighting thereby optimizing a switch setting of said inductive proximity sensor.