Time-Division PLL Circuit for Low Phase Noise and Power
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Solution Overview
Problem
Conventional PLL circuits reduce noise in the loop band by parallelizing phase frequency detectors and charge pump circuits, but this approach increases power consumption.
Innovation Solution
A PLL circuit configuration that includes a voltage control oscillator, a variable frequency divider, multiple phase frequency detectors, multiple charge pump circuits, a power control circuit to manage power in a time division manner, and a loop filter to combine and smooth the output currents, allowing for phase noise reduction while maintaining low power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If phase frequency detectors and charge pump circuits are parallelized to reduce phase noise in the loop band, then phase noise is reduced by 10 log m (dB), but power consumption increases
Solution Approach 1:
The patent applies periodic action by operating multiple phase frequency detectors and charge pump circuits in time-division manner rather than simultaneously. The power control circuit enables each circuit alternately, achieving phase noise reduction through parallel configuration while maintaining low power consumption by ensuring only one circuit operates at a time. This periodic operation allows the system to benefit from multiple circuits without the continuous power cost of all circuits being active simultaneously.
2Object-affected harmful factors
If multiple phase frequency detectors and charge pump circuits are connected in parallel, then phase noise is reduced, but the complexity of the circuit increases
Solution Approach 1:
The patent merges multiple phase frequency detectors and charge pump circuits into a unified parallel configuration controlled by a single power control circuit. The power control circuit coordinates the operation of all detector and pump circuits, enabling them to function as an integrated system. This merging approach achieves phase noise reduction through parallelization while managing complexity through centralized control rather than independent operation of each circuit.
Solution Approach 2:
The power control circuit serves multiple functions: it manages power distribution to multiple phase frequency detectors, controls the operation of multiple charge pump circuits, and coordinates their time-division operation. This multi-functional control element simplifies the overall system by providing centralized management for what would otherwise require multiple separate control mechanisms, thereby reducing circuit complexity while maintaining the benefits of parallel configuration.
Data Source
AI summary
A first pulse selector outputs an output signal of a variable frequency divider to phase frequency detectors in a time division manner. A second pulse selector outputs a reference signal from a reference signal source to the phase frequency detectors in a time division manner. Outputs of the phase frequency detectors are provided, respectively, for multiple disposed charge pump circuits.