Time-Encoded Analog Filter Using DLL-Controlled Delay Elements
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Solution Overview
Problem
Conventional analog filters require large circuit area due to the need for large capacitors, and are susceptible to process, voltage, and temperature fluctuations, leading to filter variation and inefficiency.
Innovation Solution
Analog filters are designed using time encoding machines (TEMs) with digital inverters and delay-locked loops (DLLs) to control filter delay, reducing circuit size and enhancing resilience to environmental variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional analog filters are used, then filter functionality is achieved, but circuit area increases due to large capacitor requirements
Solution Approach 1:
The patent transforms the filter implementation from conventional RC time constants to time-encoded delay elements. By changing the parameter representation from voltage/amplitude domains to time domains, the filter achieves its transfer function without requiring large capacitors, thus reducing circuit area while maintaining filter functionality.
Solution Approach 2:
The patent replaces the mechanical/electrical RC filter structure with a time-encoding machine-based digital delay system. This substitution eliminates the need for physical capacitors and resistors in favor of time-domain processing, significantly reducing the circuit area occupied by filter components.
2Reliability
If conventional analog filters are used, then filter operation is achieved, but filter variation increases due to PVT fluctuations
Solution Approach 1:
The patent employs delay-locked loops (DLLs) that provide feedback control to the time-encoded delay elements. The DLLs continuously monitor and adjust the delay parameters to compensate for PVT variations, thereby stabilizing the filter response and reducing filter variation while maintaining proper filter operation.
Solution Approach 2:
The patent makes the filter parameters dynamic and adjustable through time-encoding and DLL control. Instead of fixed RC values that drift with PVT changes, the filter uses controllable delay elements whose parameters can be dynamically adjusted to maintain stability against environmental variations.
3Area of stationary object
If time encoding machines with digital inverters are used, then circuit area is reduced, but delay control complexity increases
Solution Approach 1:
The patent uses delay-locked loops that serve multiple functions: they control the delay elements, provide calibration, and compensate for PVT variations simultaneously. This multi-functionality reduces the need for separate control circuits, thereby managing complexity while achieving precise delay control with reduced circuit area.
Solution Approach 2:
The time-encoding machines and DLLs are designed to self-calibrate and self-adjust their operation. The DLLs automatically lock onto the desired delay values and maintain them without requiring external intervention, reducing the overall system complexity despite the sophisticated delay control mechanism.
Data Source
AI summary
An analog filter, comprising, a first-time encoding machine (TEM); and a first delay element.