A Hall Sensor Analog Front End for Current Measurement With Continuous Gain Calibration

This paper presents a new technique for continuously calibrating the sensitivity of a current measurement microsystem based on a Hall magnetic field sensor. An integrated reference coil generates a magnetic field for calibration. Using a variant of the chopper modulation, the spinning current technique, combined with a second modulation of the reference signal, the sensitivity of the complete system is continuously measured without interrupting normal operation. Modulation and demodulation schemes allowing the joint processing of both external and reference magnetic fields are proposed. Additional techniques for extracting the very low reference signal are presented. The implementation of the microsystem is then discussed. Finally, measurements validate the calibration principle. A thermal drift lower than 50 ppm/degC is achieved. This is 6-10 times less than in state-of-the-art implementations. Furthermore, the calibration technique also compensates drifts due to mechanical stresses and ageing

[1]  A. Bilotti,et al.  Monolithic magnetic Hall sensor using dynamic quadrature offset cancellation , 1997, IEEE J. Solid State Circuits.

[2]  Dragan Manic.  Drift in silicon integrated sensors and circuits due to thermo-mechanical stresses , 2000 .

[3]  Sandra Bellekom,et al.  Influence of mechanical stress on the offset voltage of Hall devices operated with spinning current method , 1999 .

[4]  Marc Pastre,et al.  High-precision DAC based on a self-calibrated sub-binary radix converter , 2004, 2004 IEEE International Symposium on Circuits and Systems (IEEE Cat. No.04CH37512).

[5]  Gabriele Grandi,et al.  A magnetic field transducer based on closed-loop operation of magnetic sensors , 2002, Industrial Electronics, 2002. ISIE 2002. Proceedings of the 2002 IEEE International Symposium on.

[6]  Michel Demierre,et al.  Improvements of CMOS Hall microsystems and application for absolute angular position measurements , 2003 .

[7]  Maher Kayal,et al.  Highly sensitive Hall magnetic sensor microsystem in CMOS technology , 2002, IEEE J. Solid State Circuits.

[8]  Alberto Bilotti,et al.  Chopper-stabilized amplifiers with a track-and-hold signal demodulator , 1999 .

[9]  Janez Trontelj,et al.  CMOS integrated magnetic field source used as a reference in magnetic field sensors on common substrate , 1994, Conference Proceedings. 10th Anniversary. IMTC/94. Advanced Technologies in I & M. 1994 IEEE Instrumentation and Measurement Technolgy Conference (Cat. No.94CH3424-9).

[10]  S. Middelhoek,et al.  AUTOCALIBRATION OF SILICON HALL DEVICES , 1996 .

[11]  Qiuting Huang,et al.  A fully integrated, untrimmed CMOS instrumentation amplifier with submicrovolt offset , 1999 .

[12]  Zoran Randjelovic.  Low-power high sensitivity integrated hall magnetic sensor microsystems , 2000 .

[13]  D. Draxelmayr,et al.  A chopped Hall sensor with programmable "true power-on" function , 2004, Proceedings of the 30th European Solid-State Circuits Conference.

[14]  Janez Trontelj.  Optimization of integrated magnetic sensor by mixed signal processing , 1999, IMTC/99. Proceedings of the 16th IEEE Instrumentation and Measurement Technology Conference (Cat. No.99CH36309).

[15]  Radivoje Popovic,et al.  Short and long-term stability problems of Hall plates in plastic packages , 2000, 2000 IEEE International Reliability Physics Symposium Proceedings. 38th Annual (Cat. No.00CH37059).

[16]  Marc Pastre,et al.  A Hall Sensor Analog Front End for Current Measurement With Continuous Gain Calibration , 2007 .

[17]  D. Draxelmayr,et al.  A self-calibrating Hall sensor IC with direction detection , 2003 .