Square Pulse Optical Transmission Circuit Regulation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing optical emission circuits for square-pulse transmission in time-of-flight cameras face challenges in efficiently regulating current for stable optical pulse emission, particularly at high frequencies, leading to variability in pulse intensity and reliability.
Innovation Solution
An optical emission circuit with a regulation system that controls current based on the product of a peak current set point and the duty cycle of the square pulse signal, using a low-pass filter and digital-to-analog converter, ensuring the average current is independent of the duty cycle, and incorporating a switched-mode DC-DC converter for power supply.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional optical emission circuits are used for square-pulse transmission, then optical pulses can be emitted, but the pulse intensity varies with duty cycle and temperature, reducing reliability
Solution Approach 1:
The regulation circuit uses feedback control to maintain stable optical pulse emission. The circuit regulates current based on the product of peak current set point and duty cycle, creating a closed-loop system that compensates for duty cycle variations and temperature drift, thereby ensuring consistent pulse intensity across varying operating conditions.
Solution Approach 2:
The invention dynamically adjusts current parameters to compensate for duty cycle changes. By regulating current according to the product of peak current set point and duty cycle, the system changes operational parameters in real-time to maintain stable optical output despite variations in pulse width and frequency, effectively decoupling intensity stability from duty cycle variations.
2Measurement precision
If high frequency square pulse signals (>10 MHz) are used for optical transmission, then time-of-flight measurement precision is improved, but conventional regulation circuits cannot respond fast enough, causing intensity variability
Solution Approach 1:
The regulation circuit performs preliminary calculation of the required current based on the known duty cycle and peak current set point. By pre-computing the regulation parameter (product of duty cycle and peak current) before the pulse occurs, the circuit prepares the appropriate current level in advance, enabling fast response to high-frequency pulses without introducing lag that would cause intensity variations.
3Volume of moving object
If all semiconductor elements are integrated on a single chip, then device compactness is improved, but thermal effects and process variations increase, affecting pulse stability
Solution Approach 1:
The integrated regulation circuit implements feedback control that compensates for thermal effects and process variations inherent in monolithic integration. By continuously monitoring and adjusting current based on the duty cycle product, the system counteracts drift caused by temperature gradients and manufacturing tolerances, maintaining stable optical pulse emission despite the challenges of single-chip integration.
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
This solution stabilizes the maximum intensity of optical pulses across varying duty cycles and temperatures, ensuring reliable operation even when all semiconductor elements are integrated within a single chip, independent of external duty cycle variations.
Implementation Method 1
the regulation circuit comprises a low-pass filter having its input receiving the peak current set point via a second switch controlled by the square pulse signal
Implementation Method 2
The camera emits a square-pulse optical radiation, for example, infrared
Data Source
AI summary
An optical emission circuit includes a power supply source and a regulation circuit coupled to control the power supply source. An optical source and a first switch are coupled in series to the power supply source. A square pulse signal source has an output coupled to a control input of the first switch. The square pulse signal source is configured to provide a square pulse signal. The regulation circuit regulates the current supplied by the power supply source according to a product of a peak current set point by a duty cycle of the square pulse signal.