DLL circuit, time difference amplifier circuit, and distance-measuring imaging device
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Solution Overview
Problem
Existing DLL circuits face challenges in adjusting minute phase differences due to a dead zone in phase comparison circuits, making it difficult to synchronize signals with precise timing.
Innovation Solution
The proposed DLL circuit incorporates a time difference amplifier circuit with multiple current sources to amplify the time difference between input signals, a phase comparison circuit to calculate the phase difference, and a variable delay circuit to adjust the signal delay based on the phase difference signal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a conventional phase comparison circuit is used in the DLL circuit, then the circuit structure is simple, but it has a dead zone that prevents adjustment of minute phase differences
Solution Approach 1:
The phase comparison function is segmented into two independent parts: a conventional phase comparison circuit for detecting large phase differences, and a time difference amplifier circuit for detecting minute phase differences. This segmentation allows each circuit to specialize in its optimal detection range, eliminating the dead zone while maintaining overall system functionality.
Solution Approach 2:
The time difference amplifier circuit acts as an intermediary between the input signals and the phase comparison circuit. It amplifies minute time differences before they reach the phase comparison circuit, enabling precise detection of small phase differences that would otherwise fall within the dead zone.
2Measurement precision
If the time difference amplifier circuit is added to amplify minute phase differences, then phase difference adjustment precision is improved, but the circuit structure becomes more complex
Solution Approach 1:
The time difference amplifier circuit combines multiple current sources and capacitors into a unified amplification mechanism that works synergistically. The multiple current sources are controlled by switch elements to collectively amplify the time difference, achieving precise measurement without requiring separate independent circuits for each function.
Solution Approach 2:
The time difference amplifier circuit serves multiple functions: it amplifies time differences, provides adjustable gain through controlled current sources, and interfaces with the phase comparison circuit. This multi-functionality reduces the need for additional separate circuits, balancing precision improvement with controlled complexity.
Data Source
AI summary
A DLL circuit includes: a time difference amplifier circuit that includes current sources for setting a time difference amplification factor and an input time difference range, and amplifies, to a first signal and a second signal which are input, a time difference between edges which are change points of logic levels respectively included in the first and second signals, using the current sources and outputting a first amplified signal and a second amplified signal obtained; a phase comparison circuit that calculates a phase difference between the first and second amplified signals output and outputs a phase difference signal indicating the phase difference calculated; and a variable delay circuit that delays the second signal by an amount of delay depending on the phase difference indicated by the phase difference signal output from the phase comparison circuit and outputs the delayed second signal as a delayed signal.