TAS5717 signal saturation

Hi, Eric,

Welcome to E2E, Thanks for your interest in our products!.

Can you plase let me know the frequency of the square signal you are getting?, if it is about 380KHz, the signal you are looking is the remnant of the PWM carrier. Also, could you please let me know the register configuration used to program the amplifier?.

Regards,

  -Diego Meléndez López
   Audio Applications Engineer

Hi Diego.
So, after getting it working with the TAS57XX Graphical Development Environment, I am now so far unsuccessfully trying to get the part on-board working. I have tried unsuccessfully to get the I2C code output from the tool above. At a minimum, all I did was set the Master Volume(r7), Ch1Vol1(8) and 2(9), and unchecked the Shutdown(reg?). On the Shutdown, the tool says its register 0x46, the documentation differs, but is not clear. What would be the minimum commands to accomplish this, or even better, capture the Tools I2C output in a file? There is a I2C logging box, but I can't find where it logs it to.
thanks
Eric

Hi, Eric,

The basic configuration to get the amplifier running is the next:

#Osc Trim
x1b 00
#Exit Shutdown
x05 00
#Master Volume 0dB
x07 00 c0

The I²C logging tool is useful to track down any changes made during the configuration of the amplifier. When enabled, any action you make with the GUI is written in a log file called diagnostics.cfg located in C:\Program Files\Texas Instruments Inc\TAS57XX GDE\ProcessFlows\TAS57XX. 

Best Regards,

  -Diego Meléndez López
   Audio Applications Engineer

Thanks for that info. I have carefully checked all my signals, and after a minor correction, I have the part accepting the I2C commands. I see the I2S at the inputs, but the outputs are at 3.3V, with PVDD=15V. The surrounding parts are copied from the dev board. Reset and PDN are high. The only difference is : I use Reg4=0x06, as you and I worked out when doing this on the dev board. I've tried with and w/o this difference. Any ideas?
Eric

Hi, Eric,

This seems weird, Is the 3.3V signal in the output present before or after LC filter?. After configuring the amplifier and exit shutdown, you should see a signal of about ½ PVDD after the LC filter if no audio is streaming. Can you please check the output signal before LC filter?, after exit shutdown you should see a 50% duty cycle PWM in the output pins. This information would help us finding the cause of the issue. 

Best Regards,

  -Diego Meléndez López
   Audio Applications Engineer

Weired, no kidding. I've written software so I can now write 1 and 2 byte registers, and read registers of n bytes. Writing and reading going per spec, with :
(all read correct, per spec on initialization)
register write read startup sequence of instructions
1B 00 C0
05 00 00
04 06 06 (this is the setting for my I2S input)
07 00 00 00 00
08 00 00 00 00
09 00 00 00 00

Matching the discovery board input, I have SCK and MCK shorted.
Reading the error status register . . .
02 82 MCLK and OVERxxx FLAGS
I have no loads on the output at this time,
I'd send a schematic in pdf, if you give me a site or other method to send it to you.

I tested(jumpered) the I2S going into the part, over to the Discovery board, with Graphical Dev control, and the output works and sounds fine, just like before. I2S is good going in.
Eric

Also, fyi: PDN is high. PVDD = 14V. HPSDN(33) is low.

Uh-OH, I just noticed, I made a probable big boo boo. I shorted BST_n to Output N, not cap coupled. Probably got distracted when entering schematic. What would this do? Any idea? Would this destroy the part? I'll correct now.
Eric

Hi, Eric,

Thanks for the feedback, please let us know if you have further questions.

Best Regards,

  -Diego Meléndez López
   Audio Applications Engineer