Hello everyone,
I've designed a multislope VI limiter protection to use with LM4702C (using complementary pair BUZ900P/905P). The design is based on a figure of Randy Slone's book High-Power Audio Amplifier Construction Manual . I've tested the circuit using TINA and it performs very well, protecting the output devices against short circuit and other conditions of low impedance loads. As thermal overload protection I'll use two transistor similar to the ones found in the figure attached. My question is:
The priciple of this protection circuit (multislope VI limiter) is to divert current from the source (which I think that's a current source like a feedback current source or some equivalent), if I divert current from the source transistors the device could be damaged or the circuit are current limited?
About the thermal protection circuit it's a simple transistor (BJT) that if the temperature limit imposed by the NTC is overpassed starts diverting current from the 5V source thru the resistor Rmute, when the current on mute pin is lower then 1mA the device mutes the output signal, giving time to the NTC and the output transistors to lower the temperature, but this kind of protection can damage the mute pin, or produce unpleasent sounds at normal working temperatures?
Thank you very much for your atention,
Best Regards,
Daniel Almeida