Hi all, first post on the forum.
I would like to drive several hundred piezoelectric buzzer discs with as little components as possible. In one polarity all the discs can be charged at once, the other polarity individual discs need to be actuated. I could use a h bridge for each buzzer but do not need the ability to actuate individually both directions.
I am wondering if anyone has a better idea than having to use a ton of h bridges.
Thanks
Joe

 

I don't understand about "polarity"?

What is the application?

 

I don't understand about "polarity"?

What is the application?

What I mean by polarity is just the two leads of the piezoelectric, modelled as an unpolarized capacitor. I want to charge all of them together one way (convex) then individually charge them concave. The application is difficult to explain, in short popping tiny balls up in the air. I have successfully bench tested this and now what to drive the piezos from a mcu.

 

How often do you need to repeat this charge/reverse-charge process, and what is the charged voltage?

 

Maximum 5hz, 60v

 

Something like this :-

 

TS is trying to build an ultrasonic acoustic levitator.

https://blog.hackster.io/tinylev-is-an-acoustic-levitator-you-can-build-at-home-79b1b4f052bb

 

Something like this :-
View attachment 168189

That looks great! thanks so much. I have replaced the NPNs with N-FETs so I can drive from a 3.3V output port expander and the top switch is a P-FET, seems to work. I want to power the circuit from a 3.7V battery and although I have made a boost circuit 3.7V->70V before I don't know where to start with making an isolated one (DC supply with center tap is the terminology?), any tips?

I also had an idea that I could use an inductor instead of an isolated DC supply to reset all the piezos to a concave state when the field collapses in the inductor, couldn't quite visualize the circuit.

 

I have replaced the NPNs with N-FETs

What voltage rating FETs are you using? If you're discharging a piezo from +60V down to -60V in a circuit similar to the one I posted you'd need the FETs to withstand >120V.

I don't know where to start with making an isolated one

Isolated from what?

 

What voltage rating FETs are you using? If you're discharging a piezo from +60V down to -60V in a circuit similar to the one I posted you'd need the FETs to withstand >120V.

Isolated from what?

These ones https://uk.rs-online.com/web/p/mosfets/1655867/

I dont know the correct terminology (Dual DC supply ), Basically i'm having trouble going from a dual bench power supply to a dual boost circuit because of the common ground. 3.7V->70V Any tips?

 

Sorted, replaced the second supply with a H bridge. Seems to work, going to design an anti shoot through circuit for safety.