Laser Diode Power Control via Reference Voltage Segmentation
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Solution Overview
Problem
Existing light output devices face challenges in accurately adjusting laser diode power, particularly in scenarios requiring higher power than usual use, due to errors in the high level of the generated PWM signal, which affects the desired light output.
Innovation Solution
A light output device configuration that includes a controller generating a set signal to adjust the reference voltage, with the set-signal output port being put in a high-impedance state for power accuracy requirements and generating a PWM signal for power adjustments, allowing for precise control of the output power by alternating between high and low levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the LD power is set at a maximum value to achieve higher power output, then the power output increases, but the accuracy in light output power deteriorates due to errors in the generated PWM signal high level
Solution Approach 1:
The patent introduces a reference voltage generating section as an intermediary component that generates a reference voltage independent of the PWM signal. This reference voltage serves as a mediator between the control signal and the laser diode driver, eliminating the dependency on PWM signal high level accuracy while enabling both high power output and high precision control through separate signal paths.
2Adaptability or versatility
If the reference voltage is generated from the PWM signal to enable power adjustment, then the power can be adjusted, but errors in the PWM signal high level cause undesired LD power
Solution Approach 1:
The patent segments the power control function into two independent parts: a PWM signal path for power adjustment (versatility) and a reference voltage generation path for precision control. The reference voltage generating section is separated from the PWM signal processing, allowing each segment to optimize its specific function without interfering with the other's accuracy.
3Adaptability or versatility
If the set-signal output port generates PWM signal for power adjustment, then the output power can be changed, but the accuracy in usually used light output power cannot be maintained
Solution Approach 1:
The patent implements a dynamic switching mechanism where the set-signal output port can alternate between two operational states: high-impedance state for maintaining usual power accuracy and PWM signal generation state for power adjustment. This dynamic state switching allows the system to adapt to different operational requirements while maintaining both accuracy and versatility.
Data Source
AI summary
A light output device comprises a controller configured to generate a set signal that sets a reference voltage for determining a predetermined value of an output power of the light in a case of power adjustment wherein the output power is changed to a power different from in a case of power accuracy requirement, and a reference voltage generating section configured to generate the reference voltage according to the set signal. The controller in the case of power accuracy requirement puts a set-signal output port in a high-impedance state, while in the case of power adjustment generates the set signal using a predetermined voltage, the set signal alternating between a high level and a low level. The reference voltage generating section in the case of power accuracy requirement generates the reference voltage on a basis of a level shift voltage generated by level shifting the predetermined voltage.