Need help on this TDA7293 schematic

[Elkaid]

I've edited this schematic taken from a magazine which has taken it from the TDA7294 datasheet and tried to adapt it to TDA7293.

I would simply like to have your feedback about it. I'm not very sure about the bootstrap / bootloader stuff and an some expert's comments about the schematic in general would be more than welcome.

Thank you !

[halojoy]

Originally posted by Elkaid
I've edited this schematic taken from a magazine which has taken it from the TDA7294 datasheet and tried to adapt it to TDA7293.
Thank you !

First.
Here is download of TDA7293 datasheet TDA7293 PDF Datasheet

TDA7293 is almost the same IC as TDA7294 or TDA7294S
So I guess the circuits are about the same too.

Here is RECOMMENDED application
You always get less problems when staying with recommended circuit.
It is when you start tweak and think you can
make it 10 times better, than the professional people
you can get into some little troubles.
Like burning a couple of ICs and stuff!
Do not underestimate those who write the Datasheet for these
BIG companies. They are certainly no dumb-heads!

I would not say it is impossible to improve
with some few % percent or promille.
Or something like that

I recommend you to download TDA7293 datasheet - It is already hard to find on the Webb -
Read all of it. How you can modify component values ...
Do not take the SHORTCUT:
staying WITHOUT KNOWLEDGE about the Component you are going to use.

Here is recommended normal application for TDA7293:

[halojoy]

Some projects Using TDA7293 and 7294

Endstufen - UB Elektronik

Ultich Böhmke Elektronik
----------------------------------
Endstufe 100
Datenblatt für Rev. 1.10 (789KB) Platine wird nicht mehr ausgeliefert!
Datenblatt für Rev. 1.11 (1,5MB) neueste Auflage

DMOS-Endstufe 100 W (bis 300 W durch Brücke/Parallelschaltung) mit TDA 7293. Gute Meßwerte und Super-Klang. Sehr kompakter Aufbau für vielseitige Anwendung, insbesondere BiAmping und Aktivlautsprecher.
------------------------------
Output Endstage 100
100W (300W bridged/parallel) with TDA7293
for you who doesn't know Deutsch (halojoy does!)

He also have some "VorVerstärker" PreAmplifiers.

Hier ist das Bild von "Endstufe 100"

Here is the image of "EndStage 100"

[MikeTuriel]

I have had problems with the TDA7293 in configuration mainly and slave.
With a power supply of +/- 49v without audio signal, to obtain 100 W. The bank of electrolitics is of 30000uf for rail.
I did equally to the of ST's application note, and when it works, the specifications of the manufacturer are fulfilled, but often when I put it in on the IC slave burns.
Does someone know because this happens?

[sixtek]

Hey,

+/-49V and 30.000uF/rail?!
That's too much!
Use +/-40V rails with max. 10.000uF PSU capacitors.

[MikeTuriel]

Originally posted by sixtek
Hey,

+/-49V and 30.000uF/rail?!
That's too much!
Use +/-40V rails with max. 10.000uF PSU capacitors.

But at the time are they lies ST's specifications?
They say that the IC supports +/-60v without signal.
With +/-40v I do not obtain 100W

There is a difference between the ST application notes, I am going to try with it (the inputs of the IC slave now are connected to -V and before to mass)

Bye.

[FastEddy]

" ... With +/-40v I do not obtain 100W " ... And you don't get quite the high 10% distortion at full power, either.

sixtek: " ... Use +/-40V rails with max. 10.000uF PSU capacitors. ..." ... but don't forget those snubbing caps ... the factory suggested sckemo suggests as little as 1000 uF per rail, but note those 100 nF snubbing caps (0.1 uF) ... be sure they are the plastic / MKT / polystyrene type =

[MikeTuriel]

Velleman Kits uses 20000uF for rail, and i'm use the this it is not the problem for the burns when power on. And I use them 100nf MKT.

[FastEddy]

I have a couple of Velleman PSU modules for use in low profile rack mount chassis and they have (10,000 uF X 2) = 20,000 uF per rail, as you say ... quite inexpensive as I recall and they have the diode bridge plus LED power indicators ... ... a nice fit for the TDA7293 ... there is also some solder points for the 100nF plastic snubbing caps, but I would put them closer to the chip amp, rather than on the PSU module ...

Oops! these particular Velleman PSU filter modules should not be used with more than +/- 40 VDC rails as the caps have an absolute max rating of 50 VDC ...

[MikeTuriel]

www.velleman.be/downloads/0/manual_k8040.pdf