Transducer driver circuitry

A transducer driver circuit for driving a transducer comprising:

• an input node for receiving an input time-varying signal waveform;
• a PWM node for outputting a pulse-width modulation (PWM) signal to drive a transducer via an inductor;
• a feedback node for receiving a feedback signal tapped from one node downstream of the inductor and upstream of the transducer;
• a hysteretic comparator having a first comparator input coupled to the input node;
• a second comparator input coupled to the feedback node and a comparator output coupled to the PWM node, the hysteretic comparator being configured to compare the feedback signal to the input signal to generate the PWM signal;
• and
• a hysteresis controller for controlling hysteresis of the hysteretic comparator.

A transducer driver circuit for driving an acoustic signal waveform into an acoustic transducer to provide an acoustic output therefrom comprising:

• a hysteretic comparator configured to compare, with hysteresis, an input signal received at a first comparator input to a feedback signal received at a second comparator input and to generate a pulse-width modulation (PWM) signal at a comparator output;
• and
• an inductor coupled between the comparator output and an output node;
• wherein the feedback signal is tapped from one point of a signal path between the comparator and the acoustic transducer which is downstream of the inductor.