Injection-Locked Analog-to-Time Converter for Stable Band-Pass Tuning
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Solution Overview
Problem
Existing analog-duration converters with band-pass filters face challenges such as low quality factor and complexity in adjusting resonance frequency, along with drift due to Process Voltage Temperature (PVT) variations.
Innovation Solution
A voltage-to-duration converter design incorporating a direct path with a first injection-locked oscillator and a feedback loop, where the oscillator is controlled by the difference between the input voltage and the output voltage of the feedback loop, implementing negative feedback and allowing for adjustable resonance frequency without affecting the conversion gain.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If voltage-controlled ring oscillators are used for band-pass filtering, then the filter can be implemented, but the resonant frequency drifts with PVT variations and the quality factor is limited
Solution Approach 1:
The patent implements a feedback mechanism where the output of the injection-locked oscillator is fed back through a band-pass filter to the input, creating a self-tuning system that automatically compensates for frequency drift and maintains stable resonant frequency despite PVT variations
Solution Approach 2:
The patent uses injection locking to fundamentally change the frequency control mechanism from voltage-controlled (prone to drift) to injection-controlled (stable), where the oscillator frequency is determined by the injection signal rather than varying voltage, thus eliminating PVT-related frequency drift
2Adaptability or versatility
If the resonant frequency of the band-pass filter is adjusted, then the filter can be tuned, but the conversion gain changes accordingly
Solution Approach 1:
The patent separates the frequency control function from the gain control function by using injection locking for frequency tuning while maintaining a fixed conversion gain path, allowing independent adjustment of resonant frequency without affecting conversion gain
Solution Approach 2:
The injection signal acts as an intermediary that controls the oscillator frequency independently of the conversion gain path, enabling frequency tuning without disturbing the gain stability
3Reliability
If phase-locked loops are used to limit frequency dispersion, then the oscillator stability improves, but the circuit complexity and power consumption increase
Solution Approach 1:
The patent replaces complex phase-locked loop circuits with a simpler injection-locked oscillator architecture that achieves similar frequency stability with reduced complexity and lower power consumption, effectively using a simpler alternative that suffices for the application
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 a band-pass filter with an adjustable quality factor greater than 0.5 and independent conversion gain, reducing complexity and power consumption compared to traditional designs.
Implementation Method 1
a first injection-locked oscillator and a first circuit, the first circuit being configured to receive an output signal from the first oscillator
Implementation Method 2
provide at least a first pulse signal determined by a phase shift between the output signal from the first oscillator and the reference signal
Implementation Method 3
a feedback loop comprising a second circuit configured to integrate said at least one first pulse signal
Data Source
Figure 1~2
Figure 3~5
Figure 6~8
AI summary
This description relates to a voltage (Vin) to time converter (1). The converter includes a forward path (100) comprising a first injection-locked oscillator (104) and a first circuit (106). The first circuit is configured to receive an output signal (Φsens) from the first oscillator and a reference signal (Φ0), and to provide at least one first impulse signal (out) determined by a phase shift between the output signal (Φsens) of the first oscillator and the reference signal (Φ0). The converter further includes a feedback loop (102) comprising a second circuit (108) configured to integrate said at least one first impulse signal (out).