I need to achieve 110dB at 25khz from a Piezo Transducer. According to the datasheet, the resonant frequency of the Piezo is 25khz and at 10 vrms it will produce 110dB.
I will be using an MSP430G2553 controller's PWM pins to bit-bang it.
Currently, though, I am using an Arduino Mega 2560 to do a 'push-pull'. I have connected the 2 pins of the transducer to 2 separate PWM pins on the arduino and am using a library that synchronizes the PWM output on the 2 pins so that they are opposite of each other. This gives full motion to the piezo instead of having it vibrate between 0 – 3.3v, it oscillates between -3.3v->3.3v. This doubles the voltage and got my output from 50dB up to 80dB. However, I need to get up to 110dB.
So, the big question again is: How do I increase the volume up to 110dB ? (Basically, I need to achieve -5v -> +5v instead of -3.3v -> +3.3v) How do I get the voltage up without screwing up the 25khz oscillation? I need a circuit that will accomplish this.
Here's the current wiring:
Resister is 100ohm
Piezo has capacitance of 2500pf
Voltage from Arduino Mega 2560 goes from -3.3v to 0 and 0 to 3.3v on the 2 PWM pins.
These are set to oscillate at 25khz.