LM4702 OPS thermal protection, using muting pin

Daniel Almeida

Hello Dear Members of TI E2E forum,

I'm projecting a power amplifier using TI's LM4702, and I need thermal protection and S/C protection for the output transistors.

I've made this design, but I don't know if it's the best solution.

There's any TI part to protect class AB output stages and speakers like TA7317?

Best regards,

Daniel Almeida

Lisbon

snam117.TSC

over 10 years ago

0 Don Dapkus over 10 years ago

TI__Guru**** 189401 points

Hi, Daniel,

Cool! Discrete protection circuitry can be a little bit tricky at times.

Maybe someone in the Community can share their experiences with you.

Let us know how this works if you built it.

-d2

0 Stuart Ralston over 10 years ago

Prodigy 40 points

Your VI limiter is not quite right (you have both sides going to P+), and the thermal cut-off circuit would be much easier to implement with a thermostat (switch) than a thermistor. Hope this helps.

0 Daniel Almeida over 10 years ago in reply to Stuart Ralston

Expert 1010 points

Thank you for your help,

Yes, you're right a thermostat is much easier to implement. In the lower side the VI limiter should be connected to P-, I forget to change it.

Best regards,

Daniel Almeida

Lisbon

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LM4702 OPS thermal protection, using muting pin