A simple signal conditioner for Tunneling Magneto-resistance based angle sensor

This paper presents a novel and simple signal conditioning scheme for Tunneling Magneto-resistance (TMR) based angle sensors. The output of TMR angle sensors vary as a sine/cosine function of the sensing angle. The developed signal conditioner accepts and processes the sine/cosine natured outputs of the angle sensor with the help of a simple phase demodulator and renders a linear direct-digital angle measuring system with full circle range. The working principle as well as the analysis of the signal conditioner is reported. The performance of the scheme is tested and verified using simulation and emulation studies. The error obtained from the signal conditioner circuit during emulation is less than 0.13 %. Further, the circuit was tested with a prototype TMR angle sensor IC unit built. Test results show that the worst-case error in angle measurement is within admissible limits.