Methods and apparatus for driving a transducer

A controller for controlling a driving signal to a transducer, wherein the driving signal is output by an amplifier, the controller comprising:

• an estimation block configured to:
• receive an indication of a voltage and a current of the driving signal;
• and
• based on an electrical model of the transducer and the voltage and the current of the driving signal, estimate an estimated electrical response of the transducer representative of movement of a mass in the transducer;
• and
• a comparison block configured to compare the estimated electrical response to a desired electrical response;
• wherein the controller is configured to control the driving signal based on the comparison.

An electronic apparatus comprising:

• a haptic transducer;
• and
• an integrated circuit comprising:
• an amplifier configured to output a driving signal to the haptic transducer;
• and
• a controller comprising:
• an estimation block configured to receive an indication of a voltage and a current of the driving signal;
• and based on an electrical model of the transducer and the voltage and the current of the driving signal, estimate an estimated electrical response of the transducer representative of movement of a mass in the transducer;
• and
• a comparison block configured to compare the estimated electrical response to a desired electrical response;
• wherein the controller is configured to control the driving signal based on the comparison.