Control circuit and method

A method for controlling a voice coil motor actuator, comprising:

• providing a drive circuit, a ringing characteristic determination circuit, and a signal generator, wherein the drive circuit has an input and a first input/output terminal, the first input/output terminal coupled to the voice coil motor actuator, the ringing characteristic determination circuit has an input coupled to the first input/output terminal of the drive circuit and to the voice coil motor actuator and an output coupled to an input of the signal generator, and the signal generator has an output coupled to the input of the drive circuit in response to resonant period data and ringing amplitude data received from the resonant frequency and the ringing amplitude of the movement of the actuator characteristic determination circuit and in response to actuator position data, wherein the actuator position data is derived by summing or subtracting a new position of the actuator generated by a first position indicator to or from a previous position of the actuator generated by a second position indicator;
• determining a resonant frequency and a ringing amplitude of an actuator movement in response to a first drive signal from the signal generator;
• generating a second drive signal from the signal generator in response to the resonant frequency and the ringing amplitude of the actuator movement;
• and
• moving the voice coil motor actuator in response to the second drive signal.

An actuator control circuit, comprising:

• a driver circuit having a plurality of terminals;
• a ringing characteristic determination circuit having an input and an output, the input of the ringing characteristic determination circuit coupled to a first terminal of the plurality of terminals of the driver circuit and configured to provide a resonant frequency and a ringing amplitude in response to a movement of an actuator;
• and
• a signal generator having an input and an output and configured to generate at least a first drive signal and a second drive signal at its output, the input coupled to the output of the ringing characteristic determination circuit and the output coupled to a second terminal of the plurality of terminals of the driver circuit, wherein the second terminal is an input terminal, and wherein the signal generator is configured to generate at least a first drive signal and a second drive signal at the output of the signal generator, wherein the second drive signal is generated in response to resonant period data and ringing amplitude data received from the ringing characteristic determination circuit and in response to actuator position data, wherein the actuator position data is derived by summing or subtracting a new position of the actuator generated by a first position indicator to or from a previous position of the actuator generated by a second position indicator and wherein the second drive signal causes the driver circuit to move the actuator.