Lattice Semiconductor Corporation

Baoli Tong

Fei Song

Xiaozhi Lin

Xiaofeng Wang

Embodiments of the invention are generally directed to charge pump calibration for a dual-path phase-locked loop circuit. An embodiment of an apparatus includes a phase frequency detector; an integral path including a first charge pump; a proportional path including a second charge pump; and a calibration mechanism for the first charge pump and the second charge pump, the calibration mechanism including a phase detector to detect whether a reference clock signal or a feedback clock signal is leading or lagging in phase and to generate a signal indicating which clock signal is leading or lagging, a first memory element and a second memory element to store the signal from the phase detector, a first control logic to adjust current for the first charge pump based on the value stored in the first memory element, and a second control logic to adjust current for the second charge pump based on the value stored in the second memory element.

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Shanghai, China

Baoli Tong