I actually use the ToneAC library to drive a speaker on my 3.3V project (arduino pro mini). The main advantage of this library is that two phase PWM pins are used in the push/pull manner. So we get twice the volume with the same current from the battery.
pin9 : 3.3V → 0.0V → 3.3V …
pin10: 0.0V → 3.3V → 0.0V …
But the sound is not enough loud (at 40mA with 3.3V). I would like to drive move current in the speaker. I don’t need sound quality. I just want to generate sounds at different frequencies.
There are many (complex) audio amplifier examples on the Arduino forum. But I don’t really want to amplify a signal. The input and output signals are all 3.3V square wave. I just want to connect the battery directly to the speaker. For example I only want the PWM part of a class D amplifier.
I have found some dual channels H-bridge chips. But they are all intended to drive motors.
Where I can find a classical small DIP chip (<8 pins), that operate at 3.3V, that can drive the current in a speaker, without additional components, in the pull/push fashion ?