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Hi, Zach,
Sorry that we missed your post!
I took the liberty to split it off the old thread ().
The section of the data sheet titled, "AUTOMATIC GAIN CONTROL" starting on page 13 has an excellent overview of the operation of this IC.
The following section, titled, "TPA2028D1 AGC AND START-UP OPERATION" starting on page 21 has an excellent step-by-step tutorial on the programming of the device.
If you are still having issues after reviewing this, please post the I2C data you are writing to the device, and we will see if we see any obvious issues.
-d2
Hi Zach,
I made some tests with the EVM. The maximum gain you can get can be configured as your register settings. By setting AGC compression to 1:1 and disable the output limiter, you can be able to change the gain of the amplifier in register 0x05.
I followed this small sequence and then changed the values of 0x05 to confirm the volume change.
Reg. 0x07 Data 0xCO
Reg. 0x06 Data 0xBA
Reg. 0x05 Data 0x1E
If the Compression is disabled, fixed gain is adjustable only from 0dB to 30dB.
Regards,
-Diego Meléndez López
Audio Applications Engineer
Hi Diego,
I reviewed the evaluation board this morning and I have a few questions regarding the results of initial testing. My procedure was the same as on my platform: Set the compression ratio to turn of AGC, turn off output limiting and then adjust fixed gain. See the screen shot below for the settings.
I noticed that when I set the fixed gain to max (30dB), over the course of several seconds, the volume increases. It appears that the volume slowly increases up to the value of fixed gain as I repeatedly play a sample sound. Could you explain why this change is occurring? I was under the impression that by disabling the AGC, the amp volume could be directly set by fixed gain. To what can I attribute this change in volume?
Thank you for your help,
Zach
"I noticed that when I set the fixed gain to max (30dB), over the course of several seconds, the volume increases. It appears that the volume slowly increases up to the value of fixed gain as I repeatedly play a sample sound. Could you explain why this change is occurring? I was under the impression that by disabling the AGC, the amp volume could be directly set by fixed gain. To what can I attribute this change in volume?"
Have you solved this problem ?