A question about the power of ADAU1761
Dear Sir
We concern the power of ADAU176. As discussed in the datasheet, the ADAU1761 is a low power processor that supports stereo 48 kHz record and playback at 14 mW from a 1.8 V analog supply. However, when a 40-order digital filter program whose sampling rate is 48KHz, is running at the EVAL-ADAU1761Z under the condition that all unnecessary jumpers are unconnected, the power of ADAU1761 is more than 56mW. So I have a question that how do you test the power of ADAU1761？Could you provide a power test demo for me? Any recommendations about the power of ADAU 1761 can be provided？
Best Regards！
Audio Signal Processors
SigmaDSP Audio Processors
adau1761
The power consumption of each device varies greatly depending on how it is used.
The 14 mW playback mode in the datasheet refers to using the serial input and routing it to the DAC directly, bypassing the DSP.
Likewise, the 14 mW record mode in the datasheet refers to using the ADC input and routing it directly to the serial output, bypassing the DSP.
Using the DSP, the power consumption will increase. As more instructions are executed in the program, the power consumption increases linearly. You can see this in Figure 22 in the datasheet.
I did a basic test where I made a "pass-through" program in the DSP that would route the ADC inputs to the DAC outputs. In this case, the total power consumption was 23 mW, as you can see below.
ADAU1761 Low Power Tests
State
Iavdd (mA)
Vavdd (V)
Pavdd (mW)
Idle power on (PLL off)
0.5
1.8
0.9
Default program in to out
12.928
1.8
23.2704
Lowest power (DSP idle)
1.82
1.8
3.276
Lowest power (no MCLK)
1.24
1.8
2.232
Also, the register settings for each section of the chip will change the power consumption. Be sure to turn off things that you don't need, or put them into low power mode, or mute audio paths that are not in use.
Attached is the project file where I achieved 23 mW analog-to-analog.
Thank you for your reply. I obtained a lot of information from your helps. However, I still have a question. As illustrated in the datasheets, both the power of record and playback are 7 mW, so the min power of ADAU1761 is 14mW. Howeve, the power of your low power test Project is upper to 23mW. Is there any skills to reduce the power?
Hello,
An analog-to-analog path (ADC - serial out - serial in - DAC) will consume roughly 14 mW, but this bypasses the DSP.
By using the DSP, the power consumption increases. As the DSP program size increases, the power consumption increases as well.
If you are using the DSP core, then it will be difficult to get the power below 20 mW.
In order to help lower the power consumption, you can disable different functionality in the device using the register control window in SigmaStudio. You'll need to experiment with disabling or muting paths or functional blocks that are not in use in order to lower the power consumption.
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