Phase-locked loop apparatus and method thereof
AssigneeRealtek Semiconductor Corp.
InventorWei-Hung He
Life of this patent
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Abstract
A PLL device includes a first hybrid PLL and a second digital phase/frequency detection module. The second digital phase/frequency detection module and the first hybrid PLL's oscillator, switching unit, and analog control signal generating module are capable of forming a second hybrid PLL. The switching unit selectively activates either the first hybrid PLL or the second hybrid PLL according to a selection signal to generate an analog control signal with the analog control signal generating module for controlling the oscillator, in order to control the frequency of a clock signal generated by the oscillator.
Claims13
A phase-locked loop (PLL) apparatus, comprising:
- a first digital phase frequency detector (PFD) for generating a first phase frequency detection signal according to a first signal;
- a second digital PFD for generating a second phase frequency detection signal according to a second signal;
- a switching unit coupled to the first and second digital PFDs for selectively outputting the first phase frequency detection signal or the second phase frequency detection signal according to a selection signal;
- a digital loop filter (LF) coupled to the switching unit for filtering the signal outputted by the switching unit;
- a DAC, for performing a digital to analog conversion to a filtered result from the digital loop filter to generate an analog signal;
- and
- an oscillator coupled to the digital LF for generating an oscillation signal according to the analog signal.
A phase-locking method of an optical disc drive, comprising:
- digitally detecting the phase and frequency of an RF signal according to an oscillation signal to generate a first phase frequency detection signal;
- digitally detecting the phase and frequency of a wobble signal according to the oscillation signal to generate a second phase frequency detection signal;
- selectively outputting the first phase frequency detection signal or the second phase frequency detection signal;
- digitally loop-filtering the outputted signal to generate a loop-filtered signal;
- performing a digital to analog conversion to a filtered result to generate an analog signal;
- and
- generating the oscillation signal according to the analog signal.
Dependencies are inferred from the claim text.