TAS5828M: Output signals: Depending on load ...

hi, Edwin

when without connecting load, the output current is small, which also lead to the voltage drop through mosfet and inductor is small.

1. you can take a measure the current go through inductor.

2. what is your inductor Isat current, if it is not enough, which might lead to more higher ripple current be generated.

3. AGAIN be set to 0x06, can you share me how you calculate the value, if your PVDD is 23.6v, it seems like you should use 04 as your AGAIN setting.

tks.

jess

Hi Jesse,

Some answers:
1. The inductor current is very difficult to measure. But the design guarantees the correct function: 24V - 10 Ohm load - 10uH/10A inductor from Würth (the same type you recommend in the datasheet)
2. 10A saturation current ... cannot be a problem.
3. Yes of course. I can increase the output voltage span but I prefer the 20V span. And I will have more than 1V to the rails on both side (better whon a power supply just outputs 23V). But why should it get better when AGAIN is set to 23.3V span?

Best regards,
Edwin

hi Edwin

if the PVDD is 24v, usually we config AGIN as 20log(24/29.5) = -1.8dB.

if you want 20v span, AGIN should be -3.38dB.

can you share me your schematic?

you can refer below link for gain setting.

https://www.ti.com/lit/an/slaa894/slaa894.pdf?ts=1688004901454&ref_url=https%253A%252F%252Fwww.ti.com%252Fproduct%252FTAS5805M%253FkeyMatch%253DTAS5805M%2526tisearch%253Dsearch-everything%2526usecase%253DGPN-ALT

can you share me you schematic, we can check whether other problem have.

tks.

jesse

Hi Jesse,

Here is the schematic. Nothing special, quite the same as in the datasheet ...

The major question for me is the difference depending on the load. Because the 10 Ohm load can't be to hard for the very low output impedance of the switches.

And: What should I do for gain setting?
* Gain to full voltage span and reduce the maximum (digital) output values to 90%?
* Gain to 20V span ond full digital output values?

This document you recommend (slaa894) is about tuning the IC. But I just have a I2C communication between the DSP and the TAS and I don't reprogram the DSP setup.

Thanks and best regards,
Edwin

hi Edwin

i found that you are using pbtl mode and the code you config manully?

not using our PPC3 software.

if yes, it would be better use below attached file.

/cfs-file/__key/communityserver-discussions-components-files/6/tas5828_5F00_ini_5F00_code.cfg

tks

jess

Hi Jess,

Yes, pbtl-mode and manual configuration.

These are the config values (left addr, right value):

{ 0x01, 0x11 }, /* RESET_CTRL: reset */
{ 0x01, 0x00 }, /* RESET_CTRL: relinquish from reset */
{ 0x02, 0x04 }, /* DEVICE_CTRL_1: 384 kHz, PBTL (mono), bd mode */
{ 0x03, 0x02 }, /* DEVICE_CTRL_2: normal operation, start with hi z ... switch to play mode after complete initialization */
{ 0x04, 0x03 }, /* PVDD_DROP_DETECTION_CTRL1: keep playing but output pvdd detection, output detection result using 16 samples */
{ 0x05, 0x4C }, /* PVDD_DROP_DETECTION_CTRL2: detection voltage about 9V */
/* digital interface: most registers remain in reset values */
{ 0x28, 0x00 }, /* SAP_CTRL1: standard values, 16 bit data */
{ 0x33, 0x00 }, /* SAP_CTRL1: standard i2s but just 16 bit word length */
/* behaviour stuff */
{ 0x50, 0x03 }, /* AUTO_MUTE_CTRL: enable in standard time */
{ 0x54, 0x1F }, /* AGAIN to 5V mode */

The higher output voltage is set later when the 24V  are measured ... I am always starting with 5V output.

Well, how can I use the attached file? I do not use the EVM. Is there a documentation file describing all the registers? Where can I find this?

And, finally:

I just measured the output signals with a 10 Ohm load and 6.7 Ohm load ... as I have written, I cannot understand this ...

Best regards,
Edwin

Hi Jesse,

My office email address is just a mail forwarding ... normally I use the gmail system ... I hope receiving a mail from a gmail account is no problem.

Best regards,
Edwin

Hi Edwin

i can receive your email.

but if keep using gmail, some forbidden will happen.

i generated some code according to your situation, can you confirm whether they can let the output waveform be normal.

btw, for i haven't config any limitation in below file, so too large volume might lead to large output power.

please pay attention to the input signal volume.

1. PBTL initial code.

/cfs-file/__key/communityserver-discussions-components-files/6/5828_5F00_initial_5F00_code.cfg

2. stereo 2.0 + manually set PBTL

 /cfs-file/__key/communityserver-discussions-components-files/6/5828_5F00_initial_5F00_code_5F00_2.0.cfg

tks

jesse