TDA7375V current limiter?

[danielgpsalmeida]

Posted on December 23, 2012 at 23:13

Good night,

I've mounted a TDA7375V power amplifier on a breadboard with a 3ºC/W heatsink, and with a 16.5V/4A power suplly, the amplifier is in bridge configuration and driving 6 ohm speakers, the circuit is similar to the circuit available in the datasheet but has 1uF input capacitors, 100uF SVR and 2000uF/100nF as rail capacitors. The amplifier as a preamplifier and the signal ground is connected to this ground path, the power supply is the same. The regulators are one for TDA7375V and the other one for the preamplifier. When the amplifier is at high volumes, and the output is clipping the amplifier switches on and off very quickly making very strange noises, can this be current limiting, with 6 ohm speakers? Without the preamplifier and with the suggested circuit the same happens even with other power supplies.Thank you very much for your atention,Best regards,Daniel Almeida

[Nickname16491_O]

Posted on January 10, 2013 at 10:46

Hello Daniel,

If we exclude overheating, 

intermittency at high volume may be caused by one (or more) of the following causes:

- excess ripple due to unregulated supply voltage. In order to verify this you could monitor the supply voltage line and even the SVR pin (muting occurs if it goes low). - T

he (nominal) 6 Ohm speaker is critical because its min impedance is actually lower and the L/C content is very high. Again, the SVR pin status should be monitored to verify if it goes low. If so, the TDA7375 – AV version has better ability to drive complex load and probably is free from this effect

Call me again if you have other questions

Best Regards

Luigi Crespi – ST Application Engineer

[danielgpsalmeida]

Posted on January 11, 2013 at 00:58

Thank you very much for your help.

Can I use STA540 instead of TDA7375AV or I can have the same problems?Best regards,Daniel AlmeidaLisbon

[danielgpsalmeida]

Posted on January 11, 2013 at 01:03

The power supply is regulated using LM338T with improved ripple rejection circuit and works fine with TDA7297.

Best regards,Daniel AlmeidaLisbon