Circuit and method for controlling mixed mode controlled oscillator and CDR circuit using the same
AssigneeMediatek Inc.
InventorsPing-Ying Wang, Kuan-Hua Chao, Jeng-Horng Tsai
Life of this patent
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Abstract
A circuit for controlling a mixed mode controlled oscillator. The circuit comprises a charge pump, and a digital loop filter. The charge pump is coupled to the mixed mode controlled oscillator. The charge pump receives an up/down signal and sends a current signal to the mixed mode controlled oscillator. The digital loop filter receives the up/down signal and generates a digital code signal to the mixed mode controlled oscillator. An output frequency of the mixed mode controlled oscillator is controlled by the current signal and the digital code signal.
Claims15
A circuit for controlling a mixed mode controlled oscillator, the circuit comprising:
- a phase detector to output an up/down signal;
- a charge pump coupled to the mixed mode controlled oscillator, the charge pump receiving the up/down signal and sending a current signal directly to the mixed mode controlled oscillator;
- and
- a digital loop filter receiving the up/down signal and generating a digital code signal to the mixed mode controlled oscillator;
- wherein an output frequency of the mixed mode controlled oscillator is controlled by both the current signal and the digital code signal simultaneously.
A method for controlling a mixed mode controlled oscillator, the method comprising:
- providing an up/down signal by a phase detector;
- generating a current signal by a charge pump according to the up/down signal;
- sending the current signal directly to the mixed mode controlled oscillator;
- generating a digital code signal by a digital loop filter according to the up/down signal;
- and
- controlling an output frequency of the mixed mode controlled oscillator based on both the current signal and the digital code signal simultaneously.
A clock data recovery (CDR) circuit, comprising:
- a phase detector generating an up/down signal;
- a digital loop filter receiving the up/down signal and generating a digital code signal;
- a mixed mode controlled oscillator receiving the digital control code;
- a charge pump coupled to the mixed mode controlled oscillator, the charge pump sending a current signal directly to the mixed mode controlled oscillator according to the up/down signal;
- and
- a coarse tuning control unit coupled to the mixed mode controlled oscillator and a frequency detector, the coarse tuning control unit coarse tuning an output frequency of the mixed mode controlled oscillator;
- wherein the output frequency of the mixed mode controlled oscillator is controlled by all of the current signal, the coarse tuning control unit, and the digital control code simultaneously.
Dependencies are inferred from the claim text.