Laser Driver Current Dissipation Path for Fault Firing
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Solution Overview
Problem
Conventional laser drivers often experience fault laser firing, where the laser diode emits light unintentionally, which is undesirable in applications like LIDAR systems, due to the unintentional increase in voltage at the input to the laser diode.
Innovation Solution
The implementation of a current dissipation path in laser drivers that provides resistance to dissipate negative current from the laser diode, controlled by a logic that activates and deactivates the dissipation path to prevent fault firing, using transistors and gate drivers to manage the current flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional laser driver circuit is used, then the laser diode can emit light pulses, but fault laser firing occurs due to unintentional voltage increase at the laser diode input
Solution Approach 1:
The patent extracts the harmful negative current from the laser diode by providing a dedicated dissipation path that separates this harmful current flow from the main laser driving circuit, preventing it from causing unintended voltage increases and fault firing
Solution Approach 2:
The patent introduces an intermediary component (resistor or dissipative element) in the negative current dissipation path that acts as a mediator to safely dissipate the negative current, preventing it from directly affecting the laser diode voltage and causing harmful unintended emission
2Reliability
If a current dissipation path is added to the laser driver, then fault laser firing is reduced or eliminated, but the device complexity increases
Solution Approach 1:
The patent segments the laser driver circuit into distinct functional paths: a main current path for driving the laser diode and a separate negative current dissipation path. This segmentation allows the harmful negative current to be handled independently without interfering with the main laser driving function, thus improving reliability while keeping the added complexity manageable and well-defined
Solution Approach 2:
The patent employs dynamic switching elements (transistors or switches) that control the activation of the negative current dissipation path only when needed, rather than keeping it permanently active. This dynamic approach ensures the dissipation path is engaged during conditions that generate negative current, preventing fault firing while minimizing the impact on overall circuit complexity during normal operation
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 effectively reduces or eliminates fault laser firing by dissipating negative current, thereby preventing unintended light emission and improving the reliability of laser systems.
Implementation Method 1
a current dissipation path configured to start providing a resistance for dissipating at least a portion of a current from the laser diode
Data Source
AI summary
Laser driver designs that aim to reduce or eliminate the problem of fault laser firing are disclosed. Various laser driver designs presented herein are based on providing a current dissipation path that is configured to start providing a resistance for dissipating at least a portion, but preferably substantially all, of the negative current from the laser diode. Dissipating at least a portion of the negative current may decrease the unintentional increase of the voltage at the input to the laser diode and, therefore, reduce the likelihood that fault laser firing will occur. A control logic may be used to control the timing of when the current dissipation path is activated (i.e., provides the resistance to dissipate the negative current from the laser diode) and when it is deactivated.