Delay Line Calibration for Low-Power Precise TDC Timing
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Solution Overview
Problem
Existing high-precision time-to-digital converters (TDCs) using delay lines require continuous power consumption to maintain a stable conversion step and are prone to degradation in extreme environments due to radiation and temperature fluctuations, leading to inaccuracies and a dead-zone in time interval measurements.
Innovation Solution
A calibration method for TDC devices that uses a delay line signal propagation through delay cells, followed by measurement and calibration states to compute time lapses without relying on voltage domain corrections, utilizing a power stabilizer like a low dropout regulator (LDO) to maintain stable conversion steps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If voltage domain corrections are used to maintain stable conversion steps in delay lines, then measurement precision is improved, but power consumption increases and degradation in extreme environments worsens
Solution Approach 1:
The patent extracts and removes the voltage domain correction mechanism from the TDC system. Instead of using active feedback loops and voltage adjustments to maintain delay line stability, the invention relies on passive delay line propagation without continuous power consumption for correction, thereby eliminating the power consumption issue while maintaining measurement precision through the calibration method
Solution Approach 2:
The patent applies preliminary calibration action before measurements are taken. By pre-calibrating the delay line conversion steps and storing calibration data, the system eliminates the need for continuous voltage domain corrections during operation. This preliminary action ensures measurement precision is maintained without requiring ongoing power consumption for active stabilization
2Measurement precision
If voltage domain corrections are used to maintain stable conversion steps, then measurement precision is improved, but reliability in extreme environments worsens due to radiation and temperature fluctuations
Solution Approach 1:
The patent removes the voltage domain correction infrastructure that is vulnerable to radiation and temperature fluctuations. By eliminating active feedback loops, amplifiers, and voltage regulation circuits, the system becomes more reliable in extreme environments while maintaining precision through the passive calibration approach that does not require continuous active stabilization
Solution Approach 2:
The patent employs a calibration approach that accepts temporary drift and recalibrates when needed, rather than maintaining continuous stability through vulnerable active circuits. This disposable-like approach to calibration - where the system can drift and is recalibrated periodically - increases reliability in extreme environments by eliminating the need for continuous operation of sensitive correction circuits
3Measurement precision
If continuous power is supplied to maintain stable conversion steps, then measurement precision is improved, but a dead-zone appears in time interval measurements
Solution Approach 1:
The patent implements periodic calibration rather than continuous operation. The delay line is calibrated at specific intervals using calibration pulses, and measurements can be taken between calibration events. This periodic action eliminates the dead-zone problem because the system does not require continuous correction operations that would block measurement capability, while still maintaining sufficient precision through regular calibration
4Measurement precision
If delay line calibration is performed continuously to maintain precision, then measurement precision is improved, but power consumption increases
Solution Approach 1:
The patent performs calibration periodically rather than continuously. Calibration pulses are injected at specific intervals to update the conversion step values, and between calibration events, the system operates in measurement mode without consuming calibration power. This periodic calibration approach maintains conversion step stability sufficient for precision measurements while dramatically reducing average power consumption compared to continuous calibration
Solution Approach 2:
The patent performs calibration in advance before measurement sequences. By pre-calibrating the delay line and storing the conversion step data, the system eliminates the need for continuous calibration operations during measurement. This preliminary calibration action ensures precision is maintained throughout the measurement sequence without requiring ongoing power consumption
Data Source
AI summary
A method is for measuring a time lapse between a trigger and a pulse of a clock of a time-to-digital converter (TDC) device. The method includes the steps of: a) providing a delay line signal to a delay line of a TDC device; b) subsequently, at a measurement clock pulse: obtaining a measurement delay line state representing states of the delay cells; c) subsequently and within half a clock period of the measurement clock pulse: basing the delay line signal on a clock signal and providing the delay line signal based on the clock signal to the delay line; d) subsequently, at a calibration clock pulse: obtaining a calibration delay line state representing states of the delay cells, and e) computing the time lapse between the trigger and the measurement clock pulse based on the measurement amount of delay cells and the calibration amount of delay cells.