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Apparatus and method for low power position sensing systems

Imported: 23 Feb '17 | Published: 22 Oct '02

Dany Paul Delaporte

USPTO - Utility Patents

Abstract

A very low power quadrature position sensing system that includes a first sensor, which defines a starting point of a first channel. First sensor is coupled to a first square wave generator. A second sensor, in quadrature with first sensor, defining a starting point of a second channel, with second sensor coupled to a second square wave generator. The system further includes a moving member having a magnetized surface with a magnetic distribution disposed on the magnetized surface. The magnetized surface is sensed by the first sensor, and the second sensor during movement by the moving member, the first sensor generates a high signal forming a rising edge of a square wave generated by the first square wave generator and the first sensor generates a low signal forming a falling edge of a square wave generated by the first square wave generator, and during movement of the moving member, the second sensor generates a high signal forming a rising edge of a square wave generated by the second square wave generator and the second sensor generates a low signal forming a falling edge of the square wave generated by the second square wave generator. A method for very low power quadrature position sensing includes the determination of a first set of sensed signals using a first sensor and the determination of a second set of sensed signals using a second sensor. The method includes the derivation of a first sequence of square waves from the first set of sensed signals. The method further includes the derivation of a second sequence of square waves from the second set of sensed signals that are in quadrature with the first sequence of square waves. The method also includes the generation of a redundancy sequence signal using a redundancy circuit that comprises a switch.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will now be described, by way of an example, with references to the accompanying drawings, in which:

FIG. 1 is a schematic diagram illustrating sensors installed in a vehicle;

FIG. 2 is a schematic diagram depicting an exemplary embodiment of the sensor assembly;

FIG. 3 is circuit diagram illustrating an exemplary embodiment of the sensor assembly with the sensors initiating input;

FIG. 4 is a circuit diagram of another embodiment with the sensors initiating input;

FIG. 5 is a side view of the exemplary diagram of the sensor assembly;

FIG. 6 is an application using the present invention;

FIG. 7 is a time diagram showing relationships between inputs and outputs of the present invention;

FIG. 8 is a diagram showing the periodical nature of the output signals generated by the device of the present invention.

FIG. 9 is a circuit diagram of another embodiment with two channels and the sensors providing input;

FIG. 10 is a circuit diagram of another exemplary embodiment with two channels and the sensor providing input;

FIG. 11 is a circuit diagram of an exemplary embodiment of a discrete inverter stage;

FIG. 12 is a logic symbol of an exemplary alternate embodiment of a dual set-reset latch;

FIG. 13 is a schematic diagram depicting an alternative embodiment of a sensor assembly and;

FIG. 14 is a high level block diagram of an exemplary embodiment.

Claims

1. A position sensing system, comprising:

2. The position sensing system as in claim 1, further comprising:

3. The position sensing system as in claim 2, further comprising:

4. The position sensing system as in claim 3, wherein said first and said second signal transform circuitry include CMOS gates designed to be in the off non-active state until said first sensor and said second sensor generate voltage pulses.

5. The position sensing system as in claim 4, wherein said movable member is a shaft of an electric motor coupled to a liftgate of a vehicle, said electric motor providing an urging force for manipulating a position of said liftgate.

6. The position sensing system as in claim 2, wherein said first signal transform circuitry comprises a first NAND gate having an input and an output having said input coupled to said first sensor and said output coupled to said first input of said first latch means;

7. The position sensing system as in claim 2, further comprising:

8. The position sensing system as in claim 7, wherein said switch comprises a transistor.

9. The position sensing system as in claim 1, further comprising:

10. The position sensing system as in claim 2, wherein, said first latch means comprises a set-reset latch.

11. The position sensing system as in claim 3, wherein, said second latch means comprises a set-reset latch.

12. The position sensing system as in claim 2, wherein, said first sensor is a zero power sensor capable of generating a voltage pulse as said magnetized surface moves with respect to said first sensor.

13. The position sensing system as in claim 2, wherein,said second sensor is a zero power sensor capable of generating a voltage pulse as said magnetized surface moves with respect to said second sensor.

14. The position sensing system as in claim 1, wherein said first sensor and said first square wave generator exhibit a total quiescent operation current of less than one milliampere.

15. The position sensing system as in claim 1, wherein said quiescent operation current is less than ten microamperes.

16. The position sensing system as in claim 1, wherein said second sensor and said second square wave generator exhibit a total quiescent operation current of less than one milliampere.

17. A position sensing system for a vehicle, comprising: a first sensor defining a starting point of a first channel with said first sensor coupled to a first square wave generator;

18. A position sensing system as in claim 17, wherein said vehicle door is a sliding door of a van.

19. The position sensing system as in claim 17, wherein said moving member is a shaft of an electric motor, said electric motor being configured and positioned to provide an urging force to said vehicle door.

20. The position sensing system as in claim 17, wherein said moving member is a hinge pin of said vehicle door.

21. The position sensing system as in claim 17, wherein the location of said first and second sensors in relation to the moving member at a starting position is n*(one period of the magnetic field)+¼ period of the magnetic field of said moving member, where n is the number of magnetic pole pairs.

22. A method for position sensing comprising: