Systems and methods for offset reduction in sensor devices and systems
Embodiments relate to systems and methods for reducing errors in sensor devices and systems. In embodiments, the sensor devices comprise magnetic field sensor devices, such as ordinary or vertical Hall sensor devices, and the error to be reduced is a residual offset error, though in other embodiments other sensor devices can be used and/or other types of errors can be targeted for reduction or elimination. In one embodiment, at least two such sensor devices not electrically coupled with one another are sequentially operated in a spinning current-type mode such that an individual output signal from each of the at least two sensor devices is obtained. A total output signal can then be calculated, such as by averaging or otherwise combining the individual output signals from each sensor device.
1. A sensor system comprising:
a plurality of sensor devices positioned proximate each other such that each of the plurality of sensor devices is configured to sense essentially the same condition;
control circuitry configured to operate each of the plurality of sensor devices in at least one partial spinning current mode comprising at least two phases to obtain a partial spinning current output signal in each phase by selectively coupling a first of the plurality of terminals of each sensor device as a supply terminal and a second of the plurality of terminals of each sensor device as a signal terminal in each phase such that, in sequential phases, current flows in different directions in each sensor device and different ones of the plurality of terminals of each sensor device are signal terminals; and
output circuitry configured to determine a system output signal from partial spinning current output signals of the at least two phases of each of at least two of the plurality of sensor devices, wherein the output circuitry is further configured to compare the partial spinning current output signals of the plurality of sensor devices to determine a distribution of the partial spinning current output signals.
2. The sensor system of claim 1 , wherein the output circuitry is configured to determine a system output signal from summing the partial spinning current output signals of at least two of the plurality of sensor devices.
3. The sensor system of claim 1 , wherein the output circuitry is configured to determine a system output signal from averaging the partial spinning current output signals of at least two of the plurality of sensor devices.
4. The sensor system of claim 1 , wherein the plurality of sensor devices comprise Hall effect sensor devices.
5. The sensor system of claim 4 , wherein the Hall effect sensor devices comprise vertical Hall effect sensor devices.
6. The sensor system of claim 4 , wherein a first of the Hall effect sensor devices comprises at least one of the same terminals a second of the Hall effect sensor devices, wherein the first and second Hall effect sensor devices are operated in different phases.
7. The sensor system of claim 1 , wherein the plurality of sensor devices are arranged on the same semiconductor die.
8. The sensor system of claim 1 , wherein the plurality of terminals comprises at least three terminals.
9. The sensor system of claim 1 , wherein the distribution is used to determine a residual offset error affecting at least one of the plurality of sensor devices.
10. The sensor system of claim 1 , wherein the output circuitry is further configured to omit from the determination of the system output signal at least one sensor device partial spinning current output signal that is an outlying signal within the distribution.
11. The sensor system of claim 1 , wherein the control circuitry is configured to omit from operation in a subsequent spinning current mode at least one sensor device having a partial spinning current output signal that is an outlying signal within the distribution.
12. The sensor system of claim 11 , wherein the output circuitry is configured to determine the distribution during a manufacturing test and store a result of the test in a non-volatile memory.
13. The sensor system of claim 1 , wherein the output circuitry is configured to carry out the comparison periodically.
14. The sensor system of claim 1 , wherein the output circuitry is configured to carry out the comparison at least one of stochastically, upon a request, or upon an input.
15. The sensor system of claim 1 , wherein the control circuitry is configured to operate each of the plurality of sensor devices sequentially in a spinning current mode.
16. The sensor system of claim 1 , wherein the control circuitry is configured to operate at least two of the plurality of sensor devices simultaneously in a spinning current mode.
17. A method of operating a sensor system comprising a plurality of sensor devices arranged proximate one another such that each of the plurality of sensor devices is configured to sense essentially the same condition, each sensor device comprising a plurality of terminals, comprising:
operating a first sensor device of the plurality of sensor devices in a spinning current mode comprising at least two clock phases by selectively coupling a first terminal of the first sensor device as a supply terminal and a second terminal of the first sensor device as a signal terminal such that, in sequential clock phases, current flows in different directions in at least a portion of the first sensor device and different ones of the plurality of terminals of the first sensor device are the signal terminal;
determining a partial spinning current output signal of the first sensor device in each of the at least two clock phases of the operating of the first sensor device;
operating at least a second sensor device of the plurality of sensor devices in the spinning current mode;
determining a partial spinning current output signal of the at least second sensor device in each of the at least two clock phases of the operating of the at least the second sensor device;
comparing the partial spinning current output signals of the first sensor device and the at least second sensor device to determine a distribution of the partial spinning current output signals; and
determining a sensor system output signal based on the partial spinning current output signals of the first sensor device and the at least second sensor device.
18. The method of claim 17 , wherein determining a sensor system output signal comprises summing the partial spinning current output signals of the first sensor device and the at least second sensor device.
19. The method of claim 18 , wherein determining a sensor system output signal comprises averaging the partial spinning current output signals of the first sensor device and the at least second sensor device.
20. The method of claim 17 , further comprising omitting from the determining of the sensor system output signal at least one partial spinning current output signal of the first sensor device or the at least second sensor device that is an outlying signal within the distribution.
21. The method of claim 17 , further comprising omitting from operation in at least one clock phase of a subsequent spinning current mode at least one of the first sensor device or the at least second sensor device having a partial spinning current output signal that is an outlying signal within the distribution.
22. The method of claim 17 , wherein the comparing is carried out during manufacturing of the sensor system.
23. The method of claim 17 , wherein the comparing is configured to be carried out periodically.
24. The method of claim 17 , wherein the comparing is configured to be carried out at least one of stochastically, upon receiving a request, or upon receiving an input.
25. The method of claim 17 , wherein the operating of the first sensor device and the operating of the at least a second sensor device is carried out sequentially.
26. The method of claim 17 , wherein the operating of the first sensor device and the operating of the at least a second sensor device at least partially overlaps in time.
27. The method of claim 17 , wherein the at least two clock phases of the first sensor device and the at least two clock phases of the at least a second sensor device are interleaved.
28. The method of claim 17 , wherein the plurality of sensor devices comprises Hall effect sensor devices.