A continuous-time ripple reduction technique for spinning-current Hall sensors

The intrinsic offset of Hall sensors can be reduced with the help of the spinning-current technique, which modulates this offset away from the signal band. The resulting offset ripple can then be removed by a low-pass filter, which, however, limits the sensor´s bandwidth. This paper presents a ripple-reduction technique that does not require a low-pass filter. Measurements on a Hall sensor system implemented in a 0.18μm CMOS process show that the technique can reduce the residual ripple by at least 40dB - to the same level as the sensor´s noise.