Pam8403 class d module

[NWS]

Hi all
Is anyone knows how is the pam8403 output waveform?
Can we get spwm wave of this module when we don't connect lc low pass filter?
My idea is get spwm from this module and send that wave to another half/full bridge to get high power.
What do you think about it?

I attached pam8403 datasheet.

 

[jean-paul]

Regardless if your idea will be fruitful or not: you better use PAM8406 as it simply is a better version.

 

[Mark Tillotson]

You'll inherit the poor distortion figures of the PAM8403/6 doing that and lose the protection features, but its perfectly possible and you don't need to know what the waveform is, just pass each wire to a half-bridge to buffer it, so 4 half-bridges are needed for stereo bridged topology.


As for noise, that depends on how much of the noise of the PAM chip is jitter related, jitter cannot be reduced. Putting less load on the chip may improve its noise performance a little anyway.

 

[jean-paul]

Are the poor distortion figures not nearly the same compared to those of PAM8403? When both are used in class D THD+N is comparable AFAIK but PAM8406 can deliver more just a bit more power at more or less the same THD+N.

Even if they would perform the same it is more important that you can find PAM8406 on a way better PCB made by LOSC that has film input caps, CLC power supply filtering and full output filtering at just a slightly higher price. Almost all the other available boards don't have these features. If the output filtering does not suit you then you can remove that and you still have the other enhancements giving a better result.

I don' t see a difference in "protection features"? These chips are almost equal with PAM8406 being e more recent development with some refinements.

 

[NWS]

Thanks for helping.

I'l start testing with pam8403's module but i use pam8406 in the next testing

The problem is sound output's ground connecting.
I think Pam8403 have isolated ground for outputs
In this type how connect pam8403's output to halfbridge's input?
Driver of halfbridge need ground and input signal
I attached two diagram for connecting pam8403's output to (ir2104+irf540)halfbridge driver.


And
If the pam8403's output wave is any wave except spwm,my halfbridge don't work.
If the output wave is sine, my amp will change to class ab!

If anyone have this modules please test output wave in oscilloscope to i see(with 0% and 50% of volume to see changing dutycycle)

Thanks a lot my friends.

 

[NWS]

This is the schematic of pam8403(that use for module)

 

[NWS]

This is the schematic of pam8403(that use for module)

 

[NWS]

I know something about pam8403's output
I just need to know hos is the output wave
I'l test it soon and share result

 

[NWS]

I tested class d pam8403 module to get spwm wave and power up it with ir2104 halfbridge.
It works
But as pam8403's output is differental,i need to change output from differental to single ended mode.
Is anyone knows how i do it?