cmos phase interpolation numerically controlled oscillator

Abstract

The invention discloses a CMOS phase interpolation numerical control oscillator, which mainly solves the problems of low frequency modulation resolution and poor linearity of the existing phase interpolation circuit and the ring numerical control oscillator and comprises a coarse-tuning phase interpolation unit (1), a fine-tuning phase interpolation unit (2) and an inverting driver (3), wherein the fine-tuning phase interpolation unit (2) is connected between the coarse-tuning phase interpolation unit (1) and the inverting driver ( 3), the output end of the inverting driver (3) is connected tothe input end of the coarse-tuning phase interpolation unit (1) to form a ring oscillator loop; the control end of the coarse-tuning phase interpolation unit (1) inputs 32-bit coarse control words, and the control end of the fine-tuning phase interpolation unit (2) inputs 64-bit fine-tuning control words to adjust the oscillation frequency of the loop. The invention improves the frequency modulation resolution and linearity of the ring numerical control oscillator, and can be used for the production of an all-digital phase-locked loop integrated circuit as all the circuits are constructed bystandard units.

Description

technical field [0001] The invention belongs to the technical field of microelectronic circuits, in particular to a numerically controlled oscillator, which can be used for a clock generating circuit for frequency synthesis. Background technique [0002] With the reduction of process size, the all-digital phase-locked loop has gradually become a research hotspot. As the most critical module in the all-digital phase-locked loop, the digitally controlled oscillator determines the performance of the entire phase-locked loop. The traditional LC-type numerically controlled oscillator is limited by the existence of analog components, which is not conducive to small-scale design, while the ring oscillator has good portability among different process sizes. [0003] A ring oscillator is usually composed of an odd number of inverter units, and its operating frequency is related to the delay time T of each inverter unit D is inversely proportional, and T D It is determined by the d...

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Problems solved by technology

[0005] It can be seen that the frequency modulation resolution and linearity of the digitally controlled oscillator designed by changing the RC time constant cannot meet the actual needs; while the digitally controlled oscillator based on the traditional phase interpolation structure has a certain improvement in the frequency modulation resolution, but it needs Only by carefully designing the size and load of each stage of the inverter can the linearity of its frequency modulation be guaranteed, and a higher operating frequency cannot be achieved, so it cannot meet the increasingly higher performance requirements of the all-digital phase-locked loop

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