BM28723AMUV
Description of Function
17 Small Signal Input Detecting Function
There is a function which detects the audio data input of a non-signal or a small signal. This function is used in order to reduce
the standby power consumption of an audio set.
If the signal below a setting detection level continues in both L channel and R channel, a small signal detection flag will
become High. A detection result can be read from command 0x72[0].
The point which acts as a monitor of the small signal becomes input data of audio DSP block.
I2S
DSP
Peak Detector
(Lch)
Peak Detector
(Rch)
Counter
Flag
0x72 [0]
NOSIG_DET_FLAG
Figure 66. Block Diagram of Small Signal Input Detecting
Detection level setting
Default=0x00
Select Address
0x70[4:0]
Explanation of Operation
Level
-103dB
-93dB
-91dB
-87dB
-84dB
-80dB
-79dB
-78dB
Level
-77dB
-76dB
-75dB
-74dB
-73dB
-72dB
-71dB
-70dB
Level
-69dB
-68dB
-67dB
-66dB
-65dB
-64dB
-62dB
-60dB
Value
0x00
0x01
0x02
0x03
0x04
0x05
0x06
0x07
Value
0x08
0x09
0x0A
0x0B
0x0C
0x0D
0x0E
0x0F
Value
0x10
0x11
0x12
0x13
0x14
0x15
0x16
0x17
Detection time setting
Default=0x0
Select Address
0x71[1:0]
Value
0x0
Explanation of Operation
42.7ms
85.4ms
170.7ms
341.4ms
0x1
0x2
0x3
Caution: Sampling frequency is value of fS=48kHz. In the case of fS=44.1kHz, it will be about 1.09 times the setting value.
Detection flag read-back (Read Only)
Select Address
0x72[0]
Value
0x0
Explanation of Operation
Not detecting
Detecting
0x1
www.rohm.com
TSZ02201-0C1C0E900720-1-2
31.Aug.2018 Rev.001
© 2018 ROHM Co., Ltd. All rights reserved.
57/79
TSZ22111 • 15 • 001
ROHM [ ROHM ]
