The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.

The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.

Date of Patent:
Jun. 11, 2019

Filed:

Sep. 23, 2016
Applicant:

Apple Inc., Cupertino, CA (US);

Inventors:

John Stephen Smith, Cupertino, CA (US);

Manu Agarwal, Cupertino, CA (US);

Christian M. Sauer, Cupertino, CA (US);

Assignee:

Apple Inc., Cupertino, CA (US);

Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G06F 3/045 (2006.01); G01L 1/20 (2006.01); G01L 1/22 (2006.01);
U.S. Cl.
CPC ...
G06F 3/045 (2013.01); G01L 1/205 (2013.01); G01L 1/225 (2013.01);
Abstract

Several techniques for driving a force sensor to reduce common mode offset are disclosed. The force sensor can include at least one set of individual strain sensitive structures formed on or in a surface of a substrate. Each set of individual strain sensitive structures can include one or more strain sensitive structures. At least one external resistor is operably connected in series between a first output of one or more transmitter channels and at least one set of strain sensitive structures. The external resistor(s) effectively increases the resistances of the strain sensitive structures to reduce the common mode offset. Additionally or alternatively, one or more signal generators may be connected to one or more transmitter channels. Each signal generator is configured to produce one or more signals that is/are designed to reduce common mode offset.


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