ΔΣ Time-to-Digital Converter With Time-Domain Phase Integration
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Solution Overview
Problem
Current ΔΣ A/D converters face challenges in processing time axis information effectively due to the need to convert it back to voltage signals for integration, which is difficult in miniaturized LSIs with reduced operating voltages, and there is a lack of promising circuits for integrating time axis signals.
Innovation Solution
A time integrator that integrates time axis information represented by a phase difference between two signals using a pulse generation circuit, load circuit with variable capacitance, and oscillation circuit, allowing phase difference accumulation without converting signals to voltage, and a ΔΣ time-to-digital converter that performs ΔΣ modulation of time axis information without voltage conversion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If time axis information is converted to voltage signals for integration using conventional operational amplifiers, then integration can be performed, but the SN ratio becomes difficult to improve in miniaturized LSIs with reduced operating voltages
Solution Approach 1:
The patent replaces the conventional voltage-based integration mechanism (operational amplifiers with capacitive elements) with a time-based integration mechanism using phase-modulated clock signals and time-axis information processing. This substitution allows integration to occur in the time domain rather than requiring voltage domain operations, thereby avoiding the SN ratio degradation that occurs in miniaturized LSIs with reduced operating voltages.
2Ease of manufacture
If conventional voltage-based integration is used, then integration function is achieved, but circuit complexity increases and no promising circuit has been suggested for integrating time axis signals
Solution Approach 1:
The patent replaces complex voltage-based integration circuits with a time-axis information processing system that uses phase-modulated clock signals. The integration function is achieved by accumulating time-axis information directly in the time domain through phase modulation, eliminating the need for complex operational amplifier circuits and capacitive elements, thereby simplifying the overall circuit structure.
3Measurement precision
If time axis information is processed by converting to voltage signals, then integration can be performed, but the need for voltage conversion increases circuit complexity and reduces processing accuracy
Solution Approach 1:
The patent eliminates the intermediate voltage conversion step by processing time-axis information directly in the time domain. Time-to-digital conversion is performed by accumulating phase-modulated time-axis information and converting the accumulated time value directly to digital form, thereby improving conversion accuracy and reducing circuit complexity associated with voltage conversion stages.
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
Enables highly accurate time-to-digital conversion of time axis information represented by phase differences between signals, improving signal processing accuracy and reducing circuit complexity by eliminating the need for voltage conversion.
Implementation Method 1
an oscillation circuit coupled to the load circuit, and having an oscillation frequency changing in accordance with the load characteristics of the load circuit
Implementation Method 2
The load circuit includes a plurality of variable capacitance circuits, each being configured to receive one or the other of the two pulse signals, and having a capacitance value varying in accordance with a logic level of the received pulse signal
Data Source
AI summary
A time integrator integrates time axis information represented by a phase difference between two signals. The time integrator includes a pulse generation circuit configured to convert a time difference between edges of two input signals to a difference between pulse widths of two pulse signals, and to output the two pulse signals, a load circuit having load characteristics changed by the two pulse signals, and an oscillation circuit coupled to the load circuit, and having an oscillation frequency changing in accordance with the load characteristics of the load circuit. An output of the oscillation circuit is output as a result of time integration.