Ring VCO Noise Compensation for Low-Voltage PLL Stability
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Solution Overview
Problem
Designing ICs to reduce power consumption and increase energy efficiency at low power voltages is challenging, especially for Phase-Locked Loops (PLLs), as existing solutions require additional transistor stacking, which is not suitable for low power voltage applications and make PLLs sensitive to power noise.
Innovation Solution
A voltage controlled oscillator and phase locked loop design that includes a noise compensation circuit using a detector and voltage generator to control inverters and feed forward circuits based on detected power noise variations, allowing efficient operation at low power voltages without additional transistor stacking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a power voltage regulator is used to compensate power noise, then power noise is reduced, but additional transistor stacking is required which reduces power head room and is not suitable for low power voltage applications
Solution Approach 1:
The patent extracts the power noise detection and compensation functionality from the traditional power voltage regulator architecture into a separate controller circuit. This allows the oscillator to compensate for power noise without requiring additional transistor stacking in the power delivery path, thus maintaining power head room while achieving noise compensation.
Solution Approach 2:
The patent implements a feedback mechanism where a detector monitors power voltage noise and feeds this information to a controller that adjusts the oscillator's operation accordingly. This closed-loop feedback system enables real-time power noise compensation without the need for complex regulator circuitry, resolving the contradiction between reliability and device complexity.
2Reliability
If traditional power noise compensation methods are used, then power noise is reduced, but power consumption increases which is not suitable for low power voltage applications
Solution Approach 1:
The patent enables the oscillator to self-compensate for power noise through integrated detection and control circuits that operate within the existing oscillator structure. This self-service approach eliminates the need for separate, power-hungry regulator circuits while maintaining power noise reduction, thus resolving the contradiction between reliability and energy efficiency.
3Reliability
If additional transistor stacking is implemented for power noise compensation, then power noise is reduced, but power head room is reduced making it unsuitable for low power voltage applications
Solution Approach 1:
The patent extracts the compensation function from the power delivery path by implementing a separate controller that detects and responds to power noise without adding transistors to the voltage regulator stack. This maintains power head room while achieving noise compensation, resolving the contradiction between reliability and power availability.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution enables efficient operation of voltage controlled oscillators and phase locked loops at low power voltages, reducing power consumption and making them less sensitive to power noise, thereby improving energy efficiency and stability.
Implementation Method 1
the variation may be detected by voltage division from impedance of the first PMOS transistor and the first NMOS transistor
Implementation Method 2
a capacitor connected to the second NMOS transistor in a row, wherein the average may be determined by voltage of a node connected with the second PMOS transistor, the second NMOS transistor, and the capacitor
Data Source
AI summary
The present invention relates to a voltage controlled oscillator and phase locked loop comprising the same for compensating a noise of a power voltage. According to an embodiment of the present invention, a voltage controlled oscillator may comprise: an oscillator comprising a plurality of inverters connected as a ring form for generating a plurality of signals having different phases with each other, and a plurality of feed forward circuits formed between the inverters; and a controller for controlling the inverter and feed forward circuit based on a detected noise by detecting a noise of a power voltage.