Two-dimensional magnetic microsensor with on-chip signal processingfor contactless angle measurement

The reported CMOS microsystem is the key element for accurate angle measurements. In combination with a permanent magnet, it is used for various wear free angular positioning control systems for automotive and industrial applications covering the full 360° range. The integrated system includes a two-dimensional (2-D) magnetic microsensor (30×30 μm² active area), offset compensation, and signal conditioning circuitry. A novel approach for the angle calculation is presented using an on-board incremental ADC. A bitstream representing the angular position of the applied permanent magnet is provided at the system output. The system achieves a 1° angular resolution with 9 mW power consumption and a permanent magnet of 100 mT. The chip is fabricated in a generic 2-μm, double-poly, double-metal CMOS process and covers an area of 2.6×4.1 mm²