Phase-Domain Band-Pass Filter for Ultra-Low-Power Sensing
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Solution Overview
Problem
Current ultra-low-power sensor interfaces for applications like medical biological metrology and IoT face challenges in reducing power consumption and maintaining reliability in harsh environments with large variations in manufacturing processes, supply voltage, and temperature, while existing band-pass filters consume too much power and are not robust enough.
Innovation Solution
A band-pass filter design that operates in the phase domain using a phase comparator and injection-locked oscillator, reducing power consumption by processing signals only in the phase domain and incorporating feedback circuits for robustness against PVT variations, implemented using CMOS technology with JK or RS flip-flops.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If conventional band-pass filters are used in sensor interfaces, then signal processing capability is provided, but power consumption is too high (142 nW and above)
Solution Approach 1:
The patent replaces conventional analog band-pass filter circuits with a phase-domain processing system using phase comparators and injection-locked oscillators. This substitution transforms the signal processing approach from traditional filtering to phase comparison, achieving ultra-low power consumption (below 100 nW) while maintaining robustness to PVT variations through the inherent properties of phase-locked loops and injection-locked oscillators
Solution Approach 2:
The patent changes the fundamental operating parameter from analog voltage/current filtering to phase domain processing. By converting the signal representation to phase differences and using phase comparators, the system achieves both low power consumption and high robustness, as phase-domain operations are inherently less sensitive to PVT variations than conventional analog filtering
2Use of energy by moving object
If sensor interfaces are placed in standby mode to reduce power consumption, then power savings are achieved, but event detection capability is lost
Solution Approach 1:
The phase-domain processing system with injection-locked oscillators operates autonomously with extremely low power consumption, enabling the sensor interface to remain active and continuously monitor for events without requiring standby mode. The system's ultra-low power characteristics allow it to serve itself by maintaining operational readiness without significant energy expenditure
3Measurement precision
If conventional filtering channels are used for event detection, then signal parameter extraction is achieved, but overall circuit consumption remains too high
Solution Approach 1:
The patent replaces multiple conventional filtering channels with a single phase-domain processing path. Instead of using several analog filters to extract signal parameters, the system uses phase comparators to directly measure phase differences, which inherently provides event detection capability with ultra-low power consumption below 100 nW
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 achieves ultra-low power consumption of less than 100 nanowatts and robust operation across varying conditions, with a simplified architecture that reduces component count and phase noise, effectively lowering overall power usage and enhancing reliability.
Implementation Method 1
coupled to an injection-locked oscillator arranged to receive the output signal of the phase comparator as injection input, and to generate a signal Vr(t) out of phase with respect to the output signal of the phase comparator
Data Source
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AI summary
The invention relates to a bandpass filter arranged to receive a time-modulated periodic input signal Vin(t), and to deliver an output signal Vout(t), and comprising in combination: - a phase comparator arranged to receive on a first input the time-modulated periodic input signal Vin(t) as the first signal, and to generate an output signal with a variable duty cycle; coupled to - an injection-locked oscillator arranged to receive at the input the output signal of the phase comparator, and to generate a signal Vr(t) out of phase with respect to the output signal of the phase comparator; said out-of-phase signal being applied to a second input of the phase comparator as the second input signal; and said output signal of the phase comparator being the output signal Vout(t) of the bandpass filter and being representative of the phase difference between the two input signals Vin(t) and Vr(t).