Magnetic absolute position sensor having a Wiegand module

Patent metadata

Field	Value
Publication number	US-10222236-B2
Application number	US-201615278247-A
Country	US
Kind code	B2
Filing date	Sep 28, 2016
Priority date	Sep 28, 2015
Publication date	Mar 5, 2019
Grant date	Mar 5, 2019

Abstract

The present disclosure relates to an absolute position sensor. In one example, the absolute position sensor includes a Wiegand module and a control electronic that enable the absolute position sensor to operate in either a non-autonomous mode or an autonomous mode. In the autonomous mode there is no external energy available and a position sensor is supplied with energy by the Wiegand module.

First claim

The invention claimed is:

1. Absolute position sensor comprising:
a Wiegand module, which is composed from a Wiegand wire with a coil that surrounds the Wiegand wire;
a measurement substrate, which defines a measurement plane, and which comprises a plurality of Hall elements, wherein the Hall elements are arranged on the measurement substrate such that their active areas, which are sensitive to a magnetic field, extend in the measurement plane or form a part of the measurement plane;
a permanent magnet arrangement, which is movable in a movement plane, which is parallel to the measurement plane, relative to the Wiegand module and to the measurement substrate in one direction as well as in a direction that is opposite to said one direction, wherein
upon a movement of the permanent magnet arrangement in said one direction, the coil of the Wiegand module generates a voltage pulse, if a north pole or a south pole of the permanent magnet arrangement is located at a first position, and upon a movement of the permanent magnet arrangement in said opposite direction, the coil of the Wiegand module generates the voltage pulse, when the north pole or the south pole of the permanent magnet arrangement is located at a second position that is different from the first position;
a micro-controller; and
a processing electronic system, which is arranged on the measurement substrate and which comprises at least a control electronic, a volatile data memory and a non-volatile data memory as well as the Hall elements, which are realized in a common integrated circuit on the basis of identical integration technology; wherein
the control electronic is configured
(i) in a non-autonomous mode, in which the position sensor is supplied with external energy, to deliver output signals of a group of the Hall elements to the micro-controller for determining a precise position of the permanent magnet arrangement with respect to a reference position, and to determine a value, which corresponds to a number of repeating motion sequences of the permanent magnet arrangement, for storing in the volatile or non-volatile data memory either on the basis of an output signal of at least one of the Hall elements or to obtain such a value from the micro-controller, and
(ii) in an autonomous mode, in which no external energy is available and the position sensor is supplied with energy, which is provided from the Wiegand module, to determine the value, which corresponds to the number of repeating motion sequences of the permanent magnet arrangement, on the basis of an output signal of at least one of the Hall elements as well as to store the value in the volatile data memory, and to transfer the value, which is stored in the volatile data memory, to the non-volatile data memory, if the energy that is available in the autonomous mode falls below a threshold value.

2. Position sensor according to claim 1 , wherein
the identical integration technology is a CMOS integration technology.

3. Position sensor according to claim 1 , wherein the volatile data memory is a register and the non-volatile data memory is an EEPROM.

4. Position sensor according to claim 1 , wherein
the volatile data memory comprises n bits and the non-volatile data memory comprises m memory blocks, each having at least n bits; and
the processing electronic system is configured to transfer the stored value from the volatile data memory to one of the m memory blocks and to change said one of the m memory blocks.

5. Position sensor according to claim 4 , wherein the processing electronic system is configured to transfer the stored value from the volatile data memory to one of the m memory blocks so long, until an examination of said one of them memory blocks yields that at least one memory cell, which corresponds to one of the n bits, of the memory block has a malfunction and to subsequently change over said one of the m memory blocks.

6. Position sensor according to claim 4 , wherein the processing electronic system is configured to perform an examination of said one of the m memory blocks to the effect whether at least one memory cell, which correspond to one of the n bits, of one of the m memory blocks has a malfunction, and subsequently to replace the memory cell, which has the malfunction, by a reserve memory cell of said one of the m memory blocks, and to change over said one of the m memory blocks, if a specified number of memory cells of the storage blocks has the malfunction.

7. Position sensor according to claim 1 , wherein the processing electronic system is configured to determine a presence and an absence of the voltage pulse of the Wiegand module, and to switch on at least those electronic elements, which are necessary for the determination and the storage of the value, which corresponds to the number of repeating motion sequences.

8. Position sensor according to claim 7 , wherein
the processing electronic system is configured to switch off again those electronic elements after the storing of the value, which corresponds to the number of repeating motion sequences.

9. Position sensor according to claim 1 , wherein
the processing electronic system is configured to transfer the value, which is stored in the volatile data memory, into the non-volatile data memory, if a time period after the occurrence of the voltage pulse exceeds a time period limit.

Assignees

• Avago Tech Int Sales Pte Lid
• Mehnert Walter
• Theil Thomas

Inventors

• Mehnert Walter
• Theil Thomas

Classifications

• G01D5/145 Primary

  influenced by the relative movement between the Hall device and magnetic fields (see G01R33/06) · CPC title

• G01D5/142 Primary

  using Hall-effect devices (measuring magnetic variables using Hall-effect or other galvanomagnetic devices G01R33/06) · CPC title

• G01D5/2497

  Absolute encoders (G01D5/2454 takes precedence) · CPC title