公开(公告)号：US20200106406A1

公开(公告)日：2020-04-02

申请号：US16195546

申请日：2018-11-19

Applicant: Apple Inc.

Inventor： Roderick B. Hogan ,  Troy A. Murphy ,  Nathan A. Johanningsmeier

IPC: H03F3/217 ,  H03F3/183 ,  H03F1/56 ,  H04R3/00

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.

公开(公告)号：US10666209B2

公开(公告)日：2020-05-26

申请号：US16195546

申请日：2018-11-19

Applicant: Apple Inc.

Inventor： Roderick B. Hogan ,  Troy A. Murphy ,  Nathan A. Johanningsmeier

IPC: H03F3/217 ,  H03F1/56 ,  H04R3/00 ,  H03F3/183

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.