Digital calibration methodology applied to a sensor microsystem
This paper presents the application of a complete digital calibration methodology to the improvement of a Hall sensor-based current measurement microsystem. It is a step-by-step illustration of how generic calibration techniques and circuits can be used on a practical example. At system-level, the microsystem is analyzed and its imperfections identified. The circuit is designed so that for each imperfection to be cancelled, detection and compensation nodes are identified. To these nodes, generic digital calibration circuits are connected to perform continuous background calibration. In the presented current measurement microsystem, the use of this methodology reduced the sensitivity drift down to 50 ppm/degrees C, which is 10 times less than the state of the art.