Green Laser Diode Drive System with Dynamic Boost Servo
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Solution Overview
Problem
Conventional laser driver circuits for green lasers are inefficient due to limited power supply capacity, leading to significant power wastage as heat, especially when temperature changes, and require additional high voltage power supplies.
Innovation Solution
A boost servo system that dynamically adjusts the boost voltage based on the voltage difference between the laser diode and the drive circuit, optimizing power supply to the green laser diode by measuring and comparing voltages, and adjusting the voltage accordingly to ensure efficient operation across varying temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a fixed boost voltage is supplied to the green laser diode, then the laser can be driven at maximum power, but significant power is wasted as heat especially when temperature changes
Solution Approach 1:
The patent implements a dynamic boost voltage adjustment mechanism that continuously monitors the forward voltage of the green laser diode and adjusts the boost voltage accordingly. Instead of using a fixed boost voltage, the system dynamically adapts the voltage level to match the actual laser requirements, thereby reducing excess power consumption and heat generation while maintaining adequate laser drive power.
Solution Approach 2:
The patent employs a feedback control mechanism where the forward voltage of the green laser diode is measured and fed back to the boost regulator. This feedback loop enables the system to automatically adjust the boost voltage to maintain optimal operating conditions, preventing both under-driving and over-driving of the laser, thus reducing energy waste while ensuring sufficient power delivery.
2Reliability
If additional high voltage power supply is added to drive green lasers, then the laser can be driven properly, but the device complexity increases
Solution Approach 1:
The patent integrates the green laser diode driving capability into the existing boost regulator circuit that is already present in the CMOS laser driver IC. The boost regulator is designed to serve multiple functions: driving both green laser diodes and red laser diodes, eliminating the need for separate high voltage power supply circuits. This multi-functional approach maintains reliable green laser driving capability while avoiding additional complexity in the power supply structure.
Solution Approach 2:
The patent merges the green laser diode drive function with the existing red laser diode drive circuitry by using a single boost regulator for both laser types. The boost regulator is designed to accommodate the higher voltage requirements of green lasers while maintaining compatibility with red laser operation, thereby consolidating power supply functions and reducing overall device complexity.
3Loss of energy
If the boost voltage is reduced to save power, then energy efficiency improves, but the laser may not receive sufficient power to operate
Solution Approach 1:
The patent uses feedback control to continuously monitor the forward voltage of the green laser diode and dynamically adjust the boost voltage. This ensures that the laser receives exactly the power it needs to operate efficiently at any given moment, preventing both power deficiency and excessive power consumption. The feedback mechanism maintains the optimal balance between energy efficiency and adequate laser drive power.
Solution Approach 2:
The system dynamically adjusts the boost voltage based on real-time laser conditions rather than using a fixed voltage level. This dynamic adjustment allows the system to reduce power consumption when the laser requires less power while automatically increasing power delivery when the laser needs more power to operate properly, thus resolving the contradiction between energy efficiency and sufficient drive power.
Data Source
AI summary
Methods and devices for driving a laser diode are disclosed herein. An example method includes a boost regulator outputting a maximum boost voltage to drive a laser diode that is configured to output light within a wavelength range of 495 nanometers (nm) to 570 nm. A boost servo may measure a laser voltage, and calculate a voltage difference between the two voltages. The servo may then compare the voltage difference to a drive voltage to determine an excess voltage, and may cause the boost regulator to output an optimum voltage based on the excess voltage. The boost servo may also calculate a low voltage to drive at least one additional component that is electrically coupled to the boost regulator when the laser diode is inactive; and may cause the boost regulator to output the low voltage to power the at least one additional component.