Voice-coil motor control with zero-current sensing
AssigneeMarvell International Ltd.
InventorsSiew Yong Chui, Jye Sheng Hong
Life of this patent
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Abstract
A circuit for controlling a voice-coil motor (VCM) may incorporate a pulse-width modulation driver to drive the VCM, a zero-current detector to determine whether the current across the VCM is zero, and a Back-EMF voltage detector to measure the voltage across the VCM when the current across the VCM is determined to be zero. The circuit may determine the current velocity of the VCM and use this information to control the velocity of the VCM.
Claims20
A circuit for controlling a voice-coil motor, said circuit comprising:
- at least one pulse-width modulation driver to drive said voice-coil motor;
- a zero current detector to detect whether a current across said voice-coil motor is zero, wherein said zero current detector is enabled while said current across said voice-coil motor is substantially zero, and said zero current detector comprises an edge detector that detects whether said current across said voice-coil motor is zero;
- and
- a Back-EMF voltage detector to measure a voltage across said voice-coil motor in response to a detection of zero current by said zero current detector.
A method of controlling a voice-coil motor, said method comprising:
- pulse-width modulation driving a voice-coil motor;
- detecting, via an edge detector, while a current across said voice-coil motor is substantially zero, whether the current across said voice-coil motor is zero;
- and
- responsive to said detecting, measuring a Back-EMF voltage across said voice-coil motor.
A circuit for controlling a voice-coil motor, said circuit comprising:
- means for pulse-width modulation driving a voice-coil motor;
- means for detecting, via an edge detector, whether a current across said voice-coil motor is zero, wherein said detecting means is enabled while said current across said voice-coil motor is substantially zero;
- and
- means for measuring a voltage across said voice-coil motor in response to a detection of zero current by said detecting means.
Dependencies are inferred from the claim text.