Buzzer protection circuit.

[Argail]

Hi, everyone,

I've tried to search for an already written post, but without any success.

I'm looking to study the problem of "feedback voltage" from a piezo diaphragm after a shock, but don't really understand how to make that. I want to drive the buzzer in differential mode +/-9 V with a sort of charge pump from 3V, in fact a cmos driver. On some piezo diaphragm "datasheet" there is a section which tell to protect the LSI circuit from those feedback volatage.

The shock intensity on those piezo will generate a corresponding voltage peak (made some measurement with an oscilloscope, more than 50V could be produced) and I think there is a relation between the voltage generated, the time of this pulse and the capacity of the piezo diaphragm. Those informations should determine the amount of energy generated, but how?

After determining the energy produced, how can determine if a protection is required and which protection is the best, and how to size it.

There are standard ESD protection on those devices (clamping diodes?), but will they work for this problem?

Any help will be greatly appreciated

Best regards.

 

[vinodstanur]

i think capacitors could do the job of prevention.

 

[Argail]

Thanks for the info, you will put the capacitor in parallel to the Buzzer connecting the two wires which drives the Piezo together?