Sensor arrangement and method for operating a sensor arrangement

• US 9,217,652 B2
• Filed: 05/05/2011
• Issued: 12/22/2015
• Est. Priority Date: 05/05/2010
• Status: Active Grant

• Current Assignee: ams AG (Ams-Osram AG)
• Original Assignee: ams AG (Ams-Osram AG)
• Inventors: Riedmueller, Kurt, Oswald, Thomas
• Primary Examiner(s): Phan, Huy Q
• Assistant Examiner(s): Split, James
• Application Number:
  US13/101,995
• Publication Number:
  US 20110273173A1
• Time in Patent Office: 1,692 Days
• Field of Search: 324/202, 324/207.12, 324/207.24, 324/207.25, 324/244, 324/251, 324/252, 702 85-107
• US Class Current: 1/1
• CPC Class Codes: G01D 18/008 with calibration coefficients stored in memory
• CPC Class Codes: G01D 5/145 influenced by the relative movement between the Hall device and magnetic fields see G01R33/06

Abstract

A sensor arrangement comprises at least one magnetic-field sensor (SM1). A signal-processing unit (PROC) is set up to determine a minimum signal (MIN) and a maximum signal (MAX) of the magnetic-field sensor (SM1) over the full scale range (FSR) of the sensor arrangement. An adjustment circuit (DSPL) is set up to generate a correction signal (COR) as a function of the minimum and maximum signals (MIN, MAX). A first combination means (ADD1) couples the first magnetic-field sensor (SM1) on the input side to the adjustment circuit (DSPL) and connects the magnetic-field sensor (SM1) on the output side to a signal output (OUT).

Claims

1. A linear position detector, comprising:

at least one magnetic-field sensor that generates sensor signals;

a signal-processing unit configured to determine, during an initialization routine of the linear position detector, a minimum signal and a maximum signal of the at least one magnetic-field sensor over a linear full scale range of the linear position detector as a function of a magnetic-field source movable linearly along a movement axis relative to the linear position detector; and

wherein the signal-processing unit has a signal input and an offset output, the offset output providing an offset signal,

the at least one magnetic-field sensor is connected to a first switching device that is configured to generate a first phase signal and second phase signal from the sensor signals of the at least one magnetic-field sensor,

the first and second phase signals are associated with a change in a direction of a Hall current through the at least one magnetic-field sensor,

an adjustment circuit that is set up to generate a correction signal as a function of the minimum and maximum signals or first and second phase signals,

the correction signal is inverted synchronously with the first and second phase signals,

the signal-processing unit is configured to derive the offset signal from the sensor signals or first and second phase signals of the at least one magnetic-field sensor,

a first combination means effectively couples, on an input side, the at least one magnetic-field sensor to the offset output and connects, on an output side, to the signal input, and

a second combination means is connected to the offset output and the adjustment circuit on an input side of the second combination means, and is coupled on an output side to the first combination means such that the correction signal and the offset signal are superimposed on the sensor signals or first and second phase signals of the at least one magnetic-field sensor.

2. The linear position detector according to claim 1, wherein the signal-processing unit is connected by means of a signal output to a computation unit, and wherein the computation unit is coupled by means of an interface to the adjustment circuit.

3. The linear position detector according to claim 1, wherein the adjustment circuit comprises a comparison means that compares the minimum signal with a lower linear full scale range limit, and the maximum signal with an upper linear full scale range limit.

4. The linear position detector according to claim 1, wherein the at least one magnetic-field sensor comprises:

a sensor array including a first magnetic-field sensor and a second magnetic-field sensor, and

a selection means, by means of which the first or second magnetic-field sensor can be selected as a function of the minimum and maximum signal.

5. A method for operating a linear position detector, the method comprising:

determining, during an initialization routine of the linear position detector, a minimum signal and a maximum signal of a magnetic-field sensor generating sensor signals over a linear full scale range of the linear position detector as a function of a magnetic-field source movable linearly along a movement axis relative to the linear position detector;

changing a direction of a Hall current through the magnetic-field sensor to generate a first phase signal and a second phase signal from the sensor signals of the magnetic-field sensor;

deriving an offset signal from the sensor signals or first and second phase signals of the magnetic-field sensor;

generating a correction signal as a function of the minimum signal and the maximum signal or the first and second phase signals; and

correcting the sensor signals or first and second phase signals of the magnetic-field sensor with a combination of the correction signal and the offset signal such that the correction signal and the offset signal are superimposed on the sensor signals or first and second phase signals of the magnetic-field sensor,

wherein the correction signal is inverted synchronously with the first phase signal and second phase signal of the magnetic-field sensor.

6. The method according to claim 5, wherein:

the minimum signal is compared with a lower linear full scale range limit, and the maximum signal is compared with an upper linear full scale range limit, and

the correction signal is generated as a function of the comparison of the minimum signal with the lower linear full scale range limit and the maximum signal with the linear upper full scale range limit.