Periodic Report Summary - IHACS (Wide-band, self-calibrating, CMOS-integrated HALL magnetometer for current sensing applications)
The IHACS project aims at the development of a new family of very compact, galvanically isolated, open-loop, wide-band, self-calibrating current sensors. The sensors are based on sophisticated multi-axes CMOS HALL magnetometers with no ferromagnetic parts that employ a new technique for sensitivity stabilization against temperature effects. The scientific and technological objectives of the proposed project are summarized in the sequel:
1. The development of a multi-axes magnetometer for pulsed-current sensing applications to exhibit unique performance characteristics with regard to: a) the extended current measuring range that is specified at 5kA with 0.02% resolution, b) the ultra-wide bandwidth that ranges from DC up to at least 1MHz, and c) the current alteration rate that is specified at 10GA/sec.
2. To design the aforementioned magnetometer in such a way to enable mounting as close as 10mm to current carrying conductors, called hereafter bus-bars. The latter condition, combined with the requirements stated previously, imposes the following specifications: a) 100mT flux-density measuring range with 0.02% resolution and b) 200kT/sec flux-density alteration rate.
3. To completely integrate the aforementioned magnetometer in a standard 0.35µm CMOS process with chip dimensions smaller than 3 x 3 mm2, in order to achieve unique characteristics with regard to: a) dimensions, b) spatial sensing resolution, c) performance-cost ratio, d) reproducibility, and e) production yield.
4. To develop a novel sophisticated temperature stabilization technique for HALL magnetometers that would allow for continuous-time calibration of magnetometer sensitivity assuring stability over the industrial temperature range extending from -25decC to +150degC.
5. To design, model, manufacture, and experimentally evaluate a series of flux-shaping devices to provide for proper magnetic field filtering and sensitivity boosting.
The contribution of IHACS partners is the combination of well-known physical principles and devices with sophisticated VLSI circuit design techniques, for the development of a new family of CMOS integrated current sensors with unique characteristics at competitive cost. IHACS consortium makes use of advanced modelling techniques, as well as special experimental equipment - much of which is tailor-made for the purposes of the project - to test, evaluate, and optimise the performance of the aforementioned systems.
Until now (month 24), IHACS consortium has delivered: a) The final version of the silicon integrated CMOS magnetometer that implements a patented, innovative, continuous calibration technique, b) The final version of the current sensor that employs magneto-dynamic effects for flux shaping and sensitivity boosting, and c) tailor-made measuring equipment for testing purposes. The aforementioned devices comply with IHACS objectives and specifications fulfilling, IHACS DoW up to date.