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.
Patent No.:
Date of Patent:
May. 26, 2020
Filed:
Nov. 19, 2018
Applicant:
Apple Inc., Cupertino, CA (US);
Inventors:
Roderick B. Hogan, San Francisco, CA (US);
Troy A. Murphy, San Jose, CA (US);
Nathan A. Johanningsmeier, San Jose, CA (US);
Assignee:
APPLE INC., Cupertino, CA (US);
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
H03F 3/217 (2006.01); H03F 1/56 (2006.01); H04R 3/00 (2006.01); H03F 3/183 (2006.01);
U.S. Cl.
CPC ...
H03F 3/217 (2013.01); H03F 1/56 (2013.01); H03F 3/183 (2013.01); H04R 3/00 (2013.01); H03F 2200/03 (2013.01); H03F 2200/33 (2013.01); H03F 2200/387 (2013.01); H03F 2200/471 (2013.01); H03F 2200/481 (2013.01);
Abstract
An audio amplifier has a first H bridge and a second H bridge, to drive a speaker as a load. The second H bridge drives the speaker through resistors for increased output impedance. Control logic operates the first H bridge as a class D amplifier for larger amplitudes of audio signal, and operates the second H bridge as a class D amplifier for smaller amplitudes of audio signal. Other aspects are also described and claimed.