System, method, and device for a regenerative constant velocity park for voice coil motor

A method for moving a plurality of heads in a disk drive, the method comprising:

• applying a voltage across a voice coil motor with a voice coil motor driver during read/write operations;
• applying a generally constant voltage across the voice coil motor with a voltage clamp device during head parking;
• moving a voice coil within the voice coil motor as a result of the voltage across the voice coil motor;
• and
• moving the heads as a result of movement of the voice coil;
• wherein the step of applying a generally constant voltage across a voice coil motor with the voltage clamp device during head parking further comprises the steps of:
• applying a time-varying input voltage from the park voltage source to the voltage clamp device,
• closing a switch with the time-varying input voltage,
• flowing current through the closed switch to a clamp terminal of a first transistor,
• dividing down the time-varying input voltage with a voltage divider,
• activating a control terminal of the first transistor with the divided-down time-varying input voltage;
• flowing a time-varying amount of current from the clamp terminal of the first transistor to a reference terminal of the first transistor, the amount dependent on the divided-down time-varying input voltage appearing at the control terminal of the first transistor;
• forcing a generally constant voltage to develop at the clamp terminal of the first transistor by varying the amount of current flowing from the clamp terminal of the first transistor to the reference terminal of the first transistor in response to changes in the time-varying input voltage;
• and
• applying the generally constant voltage at the clamp terminal to the voice coil motor.

A voltage clamp device for providing a constant voltage across a voice coil motor during head parking, the voltage clamp device comprising:

• a device input terminal for receiving a time varying voltage;
• a device output terminal for providing a generally constant voltage signal;
• a voltage divider having an input terminal coupled to the device input terminal and an output terminal for providing a time varying control voltage;
• a first transistor having a clamp terminal coupled to the device output terminal, a control terminal coupled to the voltage divider output terminal, and a reference terminal coupled to a voltage reference;
• and
• a switch coupled between the device input terminal and the device output terminal for enabling the first transistor.