Packaged sensor with integrated offset calibration
A mechanism is provided to field adjust offset values for packaged sensors incorporated in devices. Embodiments provide for a processor in the sensor package to measure current environmental conditions and set a zero offset for the sensors in the package in light of those current environmental conditions. In this manner, any changes in the sensor over the sensor's lifetime and current environmental conditions that can affect functioning of the sensor can be accounted for in operational measurements taken by the device.
1. A method for setting an offset calibration for a sensor in a sensor package comprising a sensor, a memory, and a processor, the method comprising:
placing the sensor package in a standby mode;
detecting a current sensor measurement;
storing, in the memory, a current sensor value corresponding to the current sensor measurement;
setting, by the processor, the current sensor value as an operational offset value, if the current sensor value is less than or equal to an adjusted maximum offset value, wherein the adjusted maximum offset value is determined using a factory-set offset value.
2. The method of claim 1 further comprising:
setting the sensor in a low noise mode prior to said detecting the current sensor measurement.
3. The method of claim 2 wherein setting the sensor in the low noise mode comprises operating the sensor at or near a maximum sampling rate for the sensor.
4. The method of claim 3 further comprising:
setting the sensor to an operational sampling rate subsequent to setting the current sensor value as the operational offset value.
5. The method of claim 4 further comprising placing the sensor package out of standby mode subsequent to said setting the sensor to the operational sampling rate.
6. The method of claim 1 further comprising:
receiving, by the processor, a signal to initiate the offset calibration, wherein said receiving occurs prior to performing said detecting the current sensor measurement.
7. The method of claim 1 further comprising:
transmitting, by the processor, an indication that the current sensor value is greater than the adjusted maximum offset value, if the current sensor value is greater than the adjusted maximum offset value.
8. The method of claim 1 , wherein the adjusted maximum offset value is further determined using one or more of a board mount offset, a package stress offset, and long-term drift calculation.
9. A sensor device package comprising:
a sensor device;
a processor coupled to the sensor device and configured to
perform an offset calibration of the sensor device to determine an offset value using current environmental conditions experienced by the sensor device, and
interpret sensor data in light of the offset value subsequent to said offset calibration; and
a molded encapsulant forming a cavity package around the sensor device and the processor.
10. The sensor device package of claim 9 wherein the sensor device comprises a pressure sensor and the current environmental conditions comprise a fluid pressure externally applied to the pressure sensor.
11. The sensor device package of claim 9 wherein the processor is further coupled to an external processor located external to the sensor device package, and configured to receive a signal from the external processor to conduct said performing the offset calibration.
12. The sensor device package of claim 9 wherein the processor is configured to perform the offset calibration by virtue of being further configured to
place the sensor package in a standby mode;
detect a current sensor measurement of the current environmental conditions;
store, in a memory coupled to the processor, a current sensor value corresponding to the current sensor measurement;
set the current sensor value as an operational offset value, if the current sensor value is less than or equal to an adjusted maximum offset value, wherein
the adjusted maximum offset value is determined using a factory-set offset value, and
the factory-set offset value is stored in the memory.
13. The sensor device package of claim 12 wherein the processor is configured to perform the offset calibration by virtue of being further configured to
set the sensor in a low noise mode prior to detecting the current sensor measurement.
14. The sensor device package of claim 13 wherein the processor is configured to set the sensor in the low noise mode by virtue of being further configured to operate the sensor at or near a maximum sampling rate for the sensor.
15. The sensor device package of claim 14 wherein the processor is configured to perform the offset calibration by virtue of being further configured to set the sensor to an operational sampling rate subsequent to setting the current sensor value as the operational offset value.
16. The sensor device package of claim 15 wherein the processor is configured to perform the offset calibration by virtue of being further configured to place the sensor package out of standby mode subsequent to said setting the sensor to the operational sampling rate.
17. A system comprising the sensor device package of claim 9 .