TDA7264 overload protection?
 

I have a TDA7264 amp I built a few years ago mostly from parts I had laying around.
I'm using two 19V switching supplies to get my two power rails and it has worked very well over the years.
I am currently driving two speakers which claim a nominal impedance of 6 ohms. I realize this is pushing the envelope with 19V rails.


Last night I was pushing the system pretty hard and actually had the amplifier mute it self momentarily three times. Each time was for around 5 seconds.
I'm curious if this is an indication of the thermal protection kicking in, or something else? 5 seconds seems awfully short if its a thermal issue.


Thank you for your time.

Chris J



https://sphotos-a.xx.fbcdn.net/hphot..._4004746_n.jpg

https://sphotos-b.xx.fbcdn.net/hphot..._4795885_n.jpg

It could well be thermal.

When you think of the dynamics, the chip itself buried within the package can heat up very rapidly indeed and that heat can't be transmitted to the tab and heatsink quick enough to prevent thermal limiting. 5 seconds seems quick but is plently of time for an overheated few millimeters of silicon to cool via the tab if the overload were transient and the tab and heatsink are relatively cool.

hey guy, would you happen to have the schematics for this???