TDA7264 overload protection?

thetube0a3 · 05:39 PM

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

Mooly · 25th July 2012, 06:16 PM

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.

mechatronics · 10th August 2012, 12:37 AM

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

25th July 2012, 05:31 PM	#1
thetube0a3 diyAudio Member Join Date: May 2008	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 Last edited by thetube0a3; 25th July 2012 at 05:39 PM.

25th July 2012, 06:16 PM	#2
Mooly diyAudio Moderator Join Date: Sep 2007	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. __________________ ------------------------------------------------------- *A simulation free zone.* *Design it, build it, test it.*

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10th August 2012, 12:37 AM	#3
mechatronics diyAudio Member Join Date: Aug 2012	hey guy, would you happen to have the schematics for this???