Title :
Hall cell geartooth sensor with 15 gauss sensitivity
Author :
Close, J.P. ; DeVito, L.M. ; Quinn, D.E.
Author_Institution :
Analog Devices, Wilmington, MA, USA
Abstract :
A monolithic sensor for detecting time-varying magnetic fields, which combines precision analog circuits with a Hall cell, is described. The device withstands the rigorous environment of an automobile engine ignition control system where it detects teeth on a rotating ferrous wheel. The open-collector digital output responds to field changes of 15+or-1 G over a -55 degrees C to 150 degrees C range. Yield is improved by laser trim of silicon chromium resistors, eliminating the process dependence of Hall cell sensitivity. An AC-coupling scheme using an external 1- mu F capacitor rejects system offsets of several hundred G while allowing full sensitivity with signals as slow as 4 Hz. Other features include controlled startup and shutdown behavior and insensitivity to system noise. The 110-transistor. 10.700-mil/sup 2/ device is packaged in a 4-pin SIP, and operates on a single 5- to 16-V supply.<>
Keywords :
Hall effect transducers; automotive electronics; electric sensing devices; magnetic field measurement; -55 to 150 degC; 15 G; AC-coupling scheme; Hall cell; SIP; automobile engine ignition control system; controlled shutdown; controlled startup; geartooth sensor; laser trim; open-collector digital output; system offsets; time-varying magnetic fields; Analog circuits; Automobiles; Control systems; Engines; Gaussian processes; Ignition; Magnetic sensors; Sensor phenomena and characterization; Teeth; Wheels;
Conference_Titel :
Solid-State Circuits Conference, 1990. Digest of Technical Papers. 37th ISSCC., 1990 IEEE International
Conference_Location :
San Francisco, CA, USA
DOI :
10.1109/ISSCC.1990.110214
