Very Simple, Almost Universal, Speaker Protection Circuit

Hi all,

Testing and preparation is now complete, so the group buy is now open at



Fran
 
Hello,

I have a few questions that I hope are not too invasive.

Can you clarify why the circuit must be run from the same rails as the main amplifier? If one rail goes down, does the protection circuit immediately open the relay? My last question is, what kind of failure conditions will trip the circuit to open the relays?

Appreciated!
 
Can you clarify why the circuit must be run from the same rails as the main amplifier? If one rail goes down, does the protection circuit immediately open the relay?

Yes, and precisely for that reason.

Also the relay MOSFETs are protected from excessive voltage during switching of inductive load by clamping diodes to both rails.

My last question is, what kind of failure conditions will trip the circuit to open the relays?

Loss of any one of the rails, differential DC voltage at the amplifier output.

The working principle of the DC trigger is very similar to post #5. Difference is in the details.


Patrick
 
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This is what I did a while ago, seems to work fine, does not false trigger even on 50V 5hz ( simulation ). Disadvantage it takes around 0.5 sec to trigger ( not a problem for subwoofers I think ) . Uses separate supply. Relay turns on on fault . Can be used to short the Speaker relay coil. or be modified to latch after "fault detected ".

Thoughts ?.
 

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