AS3412 datasheet(25/84 Pages) AMSCO

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ams Datasheet

Page 25

[v1-00] 2016-Apr-06

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AS3412 − Detailed Description

Integrated Music Bypass Switch

If the AS3412 is switched off, the device features a unique

integrated music bypass function. The bypass switches can be

used to replace a mechanical switch to bypass the music signal

in off mode or if the headset runs out of battery. Figure 29 shows

the basic music playback path of the AS3412 with a full battery.

In this mode the line input signal is feed to the headphone

amplifier. The integrated bypass switches are automatically

disabled in this operation mode.

Figure 29:

Bypass Mode Inactive

Bypass Mode Active: This block diagram shows the general music playback path of AS3412 with the integrated

music bypass switches disabled.

Figure 30 shows the AS3412 in off mode with an empty battery.

This is basically the same use case as no battery at all. In this

mode the internal bypass switch becomes active. The

headphone amplifier is not powered because the headset has

run out of battery and the bypass switch becomes active. Thus

the music signal coming from the 3.5mm audio jack is routed

through the ANC chip, without any power source connected to

the device, to the speakers.

Music Bypass

TRSDA/BYPL

TRSCL/BYPR

AGND

LINL

LINR

100%

3.5mm audio jack

HPR

HPL

AS3412 Datasheet(PDF) 25 Page - ams AG