US 11,680,996 B2
Methods and apparatus for magnetic sensor having integrated coil
Gary T. Pepka, Pembroke, NH (US); and William P. Taylor, Amherst, NH (US)
Assigned to Allegro MicroSystems, LLC, Manchester, NH (US)
Filed by Allegro MicroSystems, LLC, Manchester, NH (US)
Filed on Sep. 20, 2017, as Appl. No. 15/709,739.
Application 15/709,739 is a continuation of application No. 13/468,478, filed on May 10, 2012, granted, now 9,817,078.
Prior Publication US 2018/0011150 A1, Jan. 11, 2018
Int. Cl. G01R 33/00 (2006.01); G01R 33/09 (2006.01)
CPC G01R 33/0017 (2013.01) [G01R 33/0035 (2013.01); G01R 33/09 (2013.01)] 19 Claims
OG exemplary drawing
 
1. A magnetic sensor integrated circuit (IC) package, comprising:
a die;
sensor circuitry formed in a device layer of the die to generate an output signal for the sensor IC package;
an integrated coil to generate a magnetic field; and a magnetoresistive magnetic field sensing element on the die to detect changes in the magnetic field generated by the coil as a result of the presence of a ferromagnetic target,
wherein the sensor circuitry is configured to process the changes in the magnetic field generated by the coil, wherein the magnetoresistive magnetic field sensing element generates an output signal corresponding the detected changes in the magnetic field generated by the coil, and wherein the sensor circuitry is configured to receive the output signal from the magnetoresistive magnetic field sensing element and to process the output signal from the magnetoresistive magnetic field sensing element for generating the output signal for the sensor IC package,
wherein the sensor circuitry is configured to use less power for closer airgaps and more power for larger airgaps.