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US 8,786,334 B2Granted
Lock detection circuit and phase-locked loop circuit including the same
AssigneeSamsung Electronics Co., Ltd.
InventorGuangyuan Lin
Life of this patent
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Abstract
A phase-locked loop circuit including a lock detector is provided comprising a delay circuit including a load capacitor, and a bias circuit configured to generate a constant reference current, wherein the load capacitor is charged or discharged with a current whose level is dependent upon the reference current.
Claims14
A phase-locked loop (PLL) circuit comprising:
- a comparator configured to compare phases of an input clock signal and an output clock signal to generate phase comparison signals;
- a pulse generator configured to generate a first pulse signal based on the phase comparison signals;
- a bias circuit configured to generate a first current and a second current proportional to the first current, wherein the first current is stabilized to a predetermined reference current level;
- a delay circuit configured to draw third and fourth currents proportional to the first and second currents, respectively, and configured to receive the first pulse signal to generate a second pulse signal by delaying the first pulse signal using the third and fourth currents;
- a charge pump configured to receive the phase comparison signals;
- a loop filter configured to receive an output from the charge pump;
- a voltage-controlled oscillator configured to receive an output from the loop filter;
- a frequency divider configured to receive an output from the voltage-controlled oscillator and to provide the output clock signal to the comparator;
- and
- a lock detector comprising the pulse generator and the delay circuit.
7 more elements
A phase-locked loop circuit including a lock detector, the lock detector comprising:
- a delay circuit including a load capacitor;
- and
- a bias circuit configured to generate a constant reference current, wherein the load capacitor is charged or discharged with a current whose level is dependent upon the reference current.
Dependencies are inferred from the claim text.