Driver circuitry for piezoelectric transducers

Circuitry for driving a piezoelectric transducer, the circuitry comprising:

• charge drive output stage circuitry configured to receive an input signal and to drive the piezoelectric transducer, by charging the piezoelectric transducer based on the received input signal such that a displacement of the piezoelectric transducer is based on a level of charge of the piezoelectric transducer, to produce an output signal based on the input signal;
• variable voltage power supply circuitry configured to output a supply voltage for the charge drive output stage circuitry, wherein the supply voltage output by the variable voltage power supply circuitry varies based on the input signal;
• a supply capacitor for receiving the supply voltage output by the variable voltage power supply circuitry;
• a reservoir capacitor;
• and
• circuitry for transferring charge between the reservoir capacitor and the supply capacitor, wherein the charge drive output stage circuitry comprises charge pump circuitry.