A magnetic sensor with current-controlled sensitivity and resolution

In this paper we present a novel split-current magnetic sensor (bulk Hall plate operated in the current mode) with onchip circuitry, fabricated in an industrial 2 pm CMOS process. The sensor consists of a low-doped resistive path with one input and three output terminals. The on-chip circuit controls the biasing of the sensor, calculates the difference between the currents flowing through the outer output terminals and provides an output voltage proportional to the applied magnetic field. We demonstrate that the sensitivity and the noise performance of the proposed device can be tuned by changing the ratio between the bias cur;rents applied to the input and to the central output terminal, while keeping the power consumption constant. Supporting numerical simulations based on a finite-element method and experimental results on an integrated prototype are reported as well.