Drive Circuit With TDC Edge Timing for TOF Calibration
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Solution Overview
Problem
Conventional drive circuits lack precise control over rising and falling times of signal waveforms, leading to inaccuracies in detection systems, particularly in TOF ranging processes, and require external equipment for verification and calibration, making adjustments inconvenient and less than ideal.
Innovation Solution
A drive circuit comprising a target waveform conversion module, operation module, and TDC module that converts target waveform information into current or voltage signals, processed by sampling circuits to determine time parameters of rising and falling edges, allowing for self-detection and calibration without external references or comparators.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional drive circuits are used, then the circuit structure is simple, but the rising/falling time control precision is poor leading to detection inaccuracies
Solution Approach 1:
The drive circuit is segmented into multiple functional modules: a waveform generation module that produces target waveforms, a sampling module with first and second sampling circuits that detect rising and falling edges at different thresholds, a time measurement module that calculates time parameters, and a calibration module. This segmentation allows precise control of rising/falling times while maintaining manageable circuit complexity through modular design.
Solution Approach 2:
Sampling circuits are introduced as intermediary components between the drive circuit output and the detection system. These sampling circuits capture voltage signals at specific threshold levels (first threshold for rising edge, second threshold for falling edge) and provide clean timing references for measurement, enabling precise rising/falling time control without directly modifying the main drive circuit.
2Measurement precision
If external oscilloscope and test equipment are used for verification, then the rising/falling time can be measured, but the device complexity and operation convenience deteriorate
Solution Approach 1:
The drive circuit incorporates self-measurement and self-calibration capabilities. The sampling module internally generates and processes timing signals, the time measurement module automatically calculates rising/falling time parameters from sampled signals, and the calibration module performs automatic adjustments. This self-service approach eliminates the need for external oscilloscopes and test equipment, improving both measurement precision and operational convenience.
Solution Approach 2:
The measurement and calibration functions are merged into the drive circuit itself. The sampling circuits, time measurement module, and calibration module are integrated with the drive circuit to form a unified system that can autonomously measure and adjust its own timing characteristics, combining driving, measuring, and calibrating functions in one device.
3Measurement precision
If calibration is performed frequently due to temperature variation and component aging, then the measurement accuracy is maintained, but the productivity and operation convenience deteriorate
Solution Approach 1:
The calibration module implements automatic feedback-based calibration that continuously monitors timing drift caused by temperature variation and component aging. When deviations are detected, the system automatically adjusts calibration parameters to maintain measurement accuracy. This feedback mechanism ensures high detection accuracy while minimizing manual intervention, thereby maintaining productivity.
Solution Approach 2:
The system performs preliminary calibration adjustments automatically based on pre-stored calibration data and real-time environmental sensing. By anticipating and correcting for temperature variation and aging effects before they significantly impact measurement accuracy, the system maintains high precision without requiring frequent manual recalibration, thus preserving productivity.
Data Source
AI summary
A drive circuit, comprising: a target waveform conversion part, configured to convert target waveform information into a current or voltage signal, and output the converted current or voltage signal to a first sampling circuit and a second sampling circuit; a computational module, the computational module outputting an action command on the basis of the output results of the first sampling circuit and the second sampling circuit; and a TDC module for outputting time parameters of a counting interval on the basis of the action command outputted by the computational module. By means of the present circuit, time information of a predetermined interval can be automatically acquired, for example time information of a rising edge or a falling edge, and can then be used to calibrate emission or calibrate the final ranging result of a time-of-flight ranging solution, such that the emitted light waveform of an emission source is more accurate or the ranging result is more accurate.