Other Parts Discussed in Thread: TAS5717
I am using one channel of a TAS5727 amplifier as a mono output. I designed the filter based on App note SLOA119B and using components that would fit in the space we had on the board. The schematic for the output filter is as follows:
The PVDD inputs of the TAS5727 are being supplied by a 17.5V power supply.
We decided to try switching to BD Modulation to test power consumption and ripple differences between the modulation schemes. To do this, I removed C43. Registers 0x11 through 0x14 were set according to table 16 on page 46 of the datasheet. Register 0x20 was also set accordingly.
The result of doing this was that the sound quality at the output is greatly improved with BD modulation. In AD mode, there is a constant white noise component when the amplifier is turned on. In BD mode, this white noise is gone and the audio is better.
My understanding is that changing the modulation scheme should not effect the sound quality of the output, but could have other effects on the power supply and emissions. One thing I noticed when looking at the output ripple on the 17.5V power supply is that the ripple increased when using BD modulation.
Can anyone provide an explanation as to why changing the modulation scheme would have such a great effect on the audio quality? Are there other register settings that might need to be changed or adjusted to improve audio quality for the AD modulation scheme?
Any feedback on this would be appreciated.
Thank You,
Ben Missele