LG MG810c Service Manual page 29

3. H/W Circuit Description
3) Acoustic Function
SPKP1
SPKP2
SPKN1
SPKN2
MICBIAS
MICIP
MICIN
EARP
EARN
HSMICBIAS
HSMIC
HSOVMID
HSOL
HSOR
AUXI
AUXO
The voice link is composed of two part. One is Up-link. The other is Down-link.
i. Up-link path.
A voice signal is converted to electrical signal with Microphone. The converted electrical voice signal is
amplified and converted to digital signal in ABB(TWL3016, TI). The converted digital data is encoded
to GSM voice standard in DBB(Calypso +).
The audio signal from main microphone goes to MICP of ABB and the voice signal from head-set to
HSMIC of ABB. The bias voltage for microphone is 2V for main mic. and 2.5V for head-set mic, which
bias voltage is generated in ABB(MICBIAS, HSBIAS)
A6
B6
A7
B7
C9
B12
A12
A8
B8
B10
HSBIAS
A11
B9
A9
A10
B11
C8
Figure 13. Voice circuits of ABB(TWL3014)
MAIN_MIC_CKTs
MICBIAS
MICP
C120
L106
MICN
0.1u
100nH
100p C312
C124 100p
VA306
EVLC14S02050
Figure 14. Main Mic. Circuits.
MICBIAS
NA
C111
L104
100nH
L105
100nH
C116 C117
4.7u
100p 100p
C115
L104
100nH
C125
C313
100p
100p
C126
VA307
10u
EVLC14S02050
- 28 -
MICP
MICN
NA
C112
HSMIC
R129 0
HSOL
HSOR
R130 0
C118
100p
MIC101
1
OUT
2
G1
3
G2
4
PWR
5
G3
SP0102BE3