Digital PLL filter and VCO for use in controlling a spindle motor of a mass data storage device
First Claim
1. A circuit for providing commutation control signals to a commutator for a polyphase brushless dc motor in a mass data storage device, comprising:
- an accumulator to accumulate a digital count that is related to a phase difference between said commutation control signals and a motor bemf; and
a digital variable frequency oscillator to generate an oscillator output signal of frequency related to said digital count to reset said accumulator after a predetermined time determined by said frequency.
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Accused Products
Abstract
A circuit for providing commutation control signals to a commutator for a polyphase brushless dc motor in a mass data storage device includes an accumulator (48) to accumulate a digital count that is proportional or related to a phase difference between the commutation control signals and a motor bemf. A digital variable frequency oscillator (52) generates an oscillator output signal of frequency proportional to the digital count to reset the accumulator (68) after a predetermined time determined by the frequency. The circuit may also include a digital filter (50) between the digital accumulator (48) and the digital variable frequency oscillator (52) to generate a magnitude signal (DRC) of magnitude proportional to the accumulated count for delivery to the variable frequency oscillator (52) to control the frequency thereof.
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Citations
26 Claims
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1. A circuit for providing commutation control signals to a commutator for a polyphase brushless dc motor in a mass data storage device, comprising:
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an accumulator to accumulate a digital count that is related to a phase difference between said commutation control signals and a motor bemf; and
a digital variable frequency oscillator to generate an oscillator output signal of frequency related to said digital count to reset said accumulator after a predetermined time determined by said frequency. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A circuit for providing commutation control signals to a commutator for a polyphase brushless dc motor in a mass data storage device, comprising:
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means for accumulating a digital count that is related to a phase difference between said commutation control signals and a motor bemf; and
means for generating an oscillator output signal of frequency related to said phase difference to reset said means for accumulating after a predetermined time determined by said frequency. - View Dependent Claims (10, 11, 12)
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13. A method for providing commutation control signals to a commutator for a polyphase brushless dc motor in a mass data storage device, comprising:
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accumulating a digital count that is related to a phase difference between said commutation control signals and a motor bemf; and
generating an oscillator output signal of frequency related to said digital count to reset said accumulator after a predetermined time determined by said frequency.
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14. A method for controlling a commutation timing of a polyphase dc motor comprising:
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accumulating a digital count representing a difference between a bemf voltage of said motor and a reference signal;
using said accumulated digital count to generate a digital feedback word for accumulation during a subsequent accumulation window with a previously accumulated value; and
using said accumulated digital count to also control a frequency of a periodically reoccurring reference signal to provide said reference signal, to determine said accumulation window, and to control said commutation timing. - View Dependent Claims (15, 16)
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17. A method for controlling a commutation timing of a polyphase dc motor comprising:
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determining if a phase detection window has begun;
if a phase detection window has begun, loading a register with a first increment value;
determining if the phase detection window has ended;
if the phase detection window has not ended, continuing to add an increment value to an accumulation register;
if the phase detection window has ended, integrating a value in the accumulation register in an integrating accumulator;
and storing the integrated value in a register, said integrated value establishing a reference frequency and establishing when said phase detection window has begun and ended. - View Dependent Claims (18)
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19. A mass data storage device, comprising:
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a circuit for providing commutation control signals to a commutator for a polyphase brushless dc motor in a mass data storage device, said circuit including;
an accumulator to accumulate a digital count that is related to a phase difference between said commutation control signals and a motor bemf; and
a digital variable frequency oscillator to generate an oscillator output signal of frequency related to said digital count to reset said accumulator after a predetermined time determined by said frequency. - View Dependent Claims (20, 21, 22, 23, 24, 25, 26)
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Specification