US 12,276,687 B2
Methods and systems for estimating coil impedance of an electromagnetic transducer
Emmanuel Marchais, Dripping Springs, TX (US); and Jon Hendrix, Wimberley, TX (US)
Assigned to Cirrus Logic Inc., Austin, TX (US)
Filed by Cirrus Logic International Semiconductor Ltd., Edinburgh (GB)
Filed on May 8, 2020, as Appl. No. 16/870,401.
Claims priority of provisional application 62/944,090, filed on Dec. 5, 2019.
Prior Publication US 2021/0174777 A1, Jun. 10, 2021
Int. Cl. G01R 27/26 (2006.01); G01L 1/16 (2006.01)
CPC G01R 27/2611 (2013.01) [G01L 1/16 (2013.01)] 43 Claims
OG exemplary drawing
 
1. A method comprising:
selecting, based on whether an electromagnetic load is in a first condition or a second condition, a measurement technique from a plurality of impedance measurement techniques for measuring an impedance of the electromagnetic load, wherein:
in the first condition, the electromagnetic load has been stimulated to produce haptic vibration in response to a haptic event but prior to motion of the electromagnetic load; and
in the second condition, the electromagnetic load is in motion in response to the haptic event after stimulation; and
performing the selected measurement technique to generate an estimate of the impedance of the electromagnetic load.