A Low Cost Readout And Processing Circuit For Integrated Cmos Geomagnetic Sensors

This paper presents a readout and processing circuit that is integrated with CMOS geomagnetic sensor based on Hall Effect. Due to the demanding requirement in battery-powered chip, a low cost of area and power consumption design was implemented. The technique of chopper-stable structure and bipolar input transistor were adopted to reduce noise and offset. A low power dual-slope ADC follows the readout front-end and output digital output, whose integrator adopts a chopper amplifier to get improvement on precision. On chip oscillator increases the practicability of the whole circuit. The prototype circuit technology. The experimental result shows that with a supply of 3.3V, the whole power is 2.1mW and the sensitivity is 20nV/LSB