公开(公告)号：US20180335458A1

公开(公告)日：2018-11-22

申请号：US15598582

申请日：2017-05-18

Applicant: Cirrus Logic International Semiconductor Ltd.

Inventor： John L. Melanson ,  Anindya Bhattacharya ,  Axel Thomsen ,  Eric Smith ,  Vamsikrishna Parupalli ,  Mark May ,  Johann Gaboriau ,  Junsong Li

IPC: G01R27/26 ,  H03M3/00

CPC classification number: G01D5/24 ,  G01R27/2605

Abstract: Sensing electronics may be used to measure capacitance of components, such as speakers in mobile devices. A sensing circuit may include a charge-sense front end with sine wave excitation, an analog-to-digital conversion block, and a digital demodulator. The component being measured by the sensing electronics may be excited by a high-frequency sine wave excitation. The digitization of the output from the component may be performed using a bandpass filter synchronized with the excitation signal by centering the bandpass filter near (e.g., within 5% of) the frequency of the excitation signal.