TDA7293:Input & Output Optimization with T Shaped Feedback

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#21
KSTR
Thanks for your reply. I had exactly the same idea (I have a nice toroid transformer) but I had no idea about the gauge for the wire for the biffilar extra winding.
If the required current is less than 100mA then two TL431 will be OK. Have you made a dedicated pcb or you modified something known in the relevant threads ? Any link please ?

Elias
 
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#22
KSTR said:
Catch diodes (Schottky type) are really recommended to connect from the output stage supply to the input stage supply pins to prevent the output stage supply ever becoming larger than the input supply (eg during startup) which kills the chip instantly.
Click to expand...

Although i never had such issue with my 7294 build but it's good to have such diodes for protection...

tda7293~2.jpg
 
#23
Elias Zacharopoulos said:
KSTR
Thanks for your reply. I had exactly the same idea (I have a nice toroid transformer) but I had no idea about the gauge for the wire for the biffilar extra winding.
If the required current is less than 100mA then two TL431 will be OK. Have you made a dedicated pcb or you modified something known in the relevant threads ? Any link please ?

Elias
Click to expand...
Sadly, no. This all happened like at least 20years ago and it was a quick hack job to check if it is worth the effort. IMHO, it's not worth it, at least not for a production circuit. It didn't measure any better and it didn't sound better to me either, provided the main supply is low ripple (at least on the negative supply, see note above).
 
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