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US 8,283,882 B1Granted
Voice coil motor control system and method
AssigneeMarvell International Ltd.
InventorsJye Sheng Hong, Siew Yong Chui
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AssigneeMarvell International Ltd.
InventorsJye Sheng Hong, Siew Yong Chui
Estimating the term…
Analog control of the pulse width used to control the speed of a voice coil motor may be implemented using a “constant-current-charging-capacitor” configuration where the time needed to charge the capacitor is directly related to how far the actual motor speed is from the target speed. The BEMF voltage, indicative of motor speed, is sampled, and then stored in a storage capacitor, which is allowed to charge/discharge to a target voltage level. The time required to charge/discharge the capacitor to the target voltage is directly proportional to the difference between the BEMF voltage and the target voltage, and may be used directly as the pulse width (i.e., the charging time) in the PWM velocity control system. To avoid larger capacitors, a pulse multiplier circuit can be added, allowing charging/discharging the sampled voltage to the target voltage to be repeated by a number, N, of times.
A method for deriving control pulse width for pulse width modulation motor speed control, said method comprising:
Apparatus for deriving control pulse width for pulse width modulation motor speed control, said apparatus comprising:
Apparatus for deriving control pulse width for pulse width modulation motor speed control, said apparatus comprising:
Dependencies are inferred from the claim text.