Phase-Based ADC Using Voltage-to-Phase Conversion for Low-Voltage CMOS
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Solution Overview
Problem
Existing analog-to-digital converters face limitations in converting low voltage signals effectively, particularly in nanometer-scale CMOS data applications, where voltage signal ranges are constrained, leading to compromised accuracy and increased noise and jitter.
Innovation Solution
A phase-based analog-to-digital converter system that converts input voltage to a phase signal using a voltage-to-phase converter and then to a digital output through a phase-to-digital converter, employing delta-sigma modulation with a feedback path for enhanced resolution and noise shaping, utilizing a voltage-controlled delay line and flip-flops for time quantization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If voltage-based ADC conversion is used in nanometer-scale CMOS applications, then the conversion process can be implemented, but the voltage signal range is constrained leading to compromised accuracy and increased noise and jitter
Solution Approach 1:
The patent introduces phase as an intermediary parameter between voltage and digital output. The voltage signal is first converted to a phase signal through a voltage-controlled delay line, which then undergoes time quantization. This intermediary transformation allows the system to operate effectively in nanometer-scale CMOS where direct voltage quantization would be compromised by noise and limited voltage ranges.
2Object-affected harmful factors
If phase-based conversion with time quantization is employed, then noise and jitter are reduced with improved signal-to-noise ratio, but the device complexity increases due to additional conversion stages
Solution Approach 1:
The patent replaces traditional voltage-based quantization mechanisms with a time-domain approach. Instead of directly quantizing voltage levels, the system uses a voltage-controlled delay line to convert voltage to time delay, which is then quantized in the time domain. This substitution leverages the robustness of time-based measurement against noise and jitter, achieving improved signal-to-noise ratio despite the added conversion stages.
3Measurement precision
If delta-sigma modulation with feedback is implemented, then resolution is enhanced through noise shaping, but the device complexity increases due to feedback path and loop filter
Solution Approach 1:
The patent implements delta-sigma modulation with a feedback path that takes the quantized time signal and feeds it back through a digital-to-time converter to the voltage-controlled delay line. This feedback mechanism enables noise shaping that pushes quantization noise to higher frequencies, thereby enhancing the resolution of the digital output signal. The loop filter processes the feedback signal to maintain stability and optimize performance.
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 phase-based ADC system achieves accurate and resolute digital conversion with reduced power consumption, effectively addressing the limitations of low voltage devices by leveraging phase as an intermediate parameter for quantization and feedback, resulting in improved signal-to-noise ratio and linearity.
Implementation Method 1
The voltage-to-phase converter can include a voltage-controlled delay line that is powered by the control voltage to generate the phase signal having the phase that is proportional to the control voltage
Data Source
AI summary
One embodiment includes a phase-based analog-to-digital converter (ADC) system. The system includes a voltage-to-phase converter configured to convert an input voltage to a phase difference corresponding to a phase-delay with respect to an input clock signal that is based on a magnitude of the input voltage. The system also includes a phase-to-digital converter configured to convert the phase difference into a digital output signal having a digital value corresponding to a magnitude of the phase difference.