Resonant Laser Diode Driver for Low-Voltage Nanosecond Pulses
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Solution Overview
Problem
Conventional pulsed laser diode driver circuits face challenges in generating short, high-current pulses due to parasitic inductances and require high voltages, which complicates integration and increases costs, especially when using GaN technology.
Innovation Solution
The design incorporates a tunable resonant circuit with discrete inductors and capacitors to control pulse width and current, allowing for low-input voltage operation using Silicon-based switches and eliminating the need for GaN switches, enabling integration into a single semiconductor die and independent control of multi-channel laser diodes without bootstrap circuitry.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If high source voltage (greater than 40V-100V) is used to overcome parasitic inductances, then the desired short pulse width (5 ns or less) is achieved, but the device complexity and cost increase due to requiring GaN technology
Solution Approach 1:
The patent changes the voltage parameter from high voltage (40V-100V) to low voltage operation by introducing a resonant circuit that generates high current pulses through oscillation rather than direct high voltage application. This allows achieving the same pulse width effect with lower voltage, thereby simplifying the device and enabling standard silicon technology.
Solution Approach 2:
The patent employs a resonant circuit that creates oscillating current through inductive and capacitive elements, analogous to mechanical vibration principles. The resonant frequency of the LC circuit generates the high-current pulse needed to overcome parasitic inductances without requiring high source voltage, thus reducing device complexity.
2Duration of action of moving object
If high source voltage (greater than 40V-100V) is used to overcome parasitic inductances, then the desired short pulse width (5 ns or less) is achieved, but the manufacturing cost increases
Solution Approach 1:
The patent changes the voltage parameter from high voltage (40V-100V) to low voltage operation by introducing a resonant circuit that generates high current pulses through oscillation rather than direct high voltage application. This allows achieving the same pulse width effect with lower voltage, thereby simplifying the device and enabling standard silicon technology.
Solution Approach 2:
The patent replaces expensive GaN switches required for high voltage operation with standard, cheaper silicon-based switches. The resonant circuit architecture enables these lower-cost components to achieve the same functional result, significantly reducing manufacturing cost.
3Duration of action of moving object
If GaN switches are used to withstand high voltages, then the desired pulse width is achieved, but the integration difficulty with Silicon-based architectures increases
Solution Approach 1:
The patent changes the voltage parameter from high voltage (40V-100V) to low voltage operation by introducing a resonant circuit that generates high current pulses through oscillation rather than direct high voltage application. This allows achieving the same pulse width effect with lower voltage, thereby simplifying the device and enabling standard silicon technology.
Solution Approach 2:
The patent substitutes the high-voltage GaN switch architecture with a low-voltage resonant circuit architecture using standard silicon switches. This substitution eliminates the need for specialized GaN components and their associated complex integration requirements, making the system compatible with standard silicon-based architectures.
4Device complexity
If conventional pulsed laser diode driver circuits are used, then high voltage operation is simplified, but the pulse width control precision deteriorates due to parasitic inductances
Solution Approach 1:
The patent employs a resonant circuit that creates oscillating current through inductive and capacitive elements, analogous to mechanical vibration principles. The resonant frequency of the LC circuit generates the high-current pulse needed to overcome parasitic inductances without requiring high source voltage, thus reducing device complexity.
Solution Approach 2:
The resonant circuit provides inherent feedback through the oscillating current waveform, where the LC tank circuit naturally regulates the current pulse shape and duration. This feedback mechanism enables precise pulse width control despite the presence of parasitic inductances, as the resonant frequency and damping characteristics can be designed to compensate for these effects.
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 approach allows for the generation of ultra-short, high-current pulses with tunable parameters, reducing complexity and cost, and enabling efficient integration with Silicon-based architectures while maintaining high power efficiency and independent control of multiple laser diodes.
Implementation Method 1
a resonant circuit formed by reactive components of the pulsed laser diode driver circuit, a voltage level of the resonant waveform being advantageously sufficient to support the high-current pulse
Data Source
AI summary
A pulsed laser diode driver includes an inductor having a first terminal configured to receive a source voltage. A source capacitor has a first terminal connected to the first terminal of the inductor to provide the source voltage. A bypass switch has a drain node connected to a second terminal of the inductor and to a first terminal of a bypass capacitor. A laser diode switch has a drain node connected to the second terminal of the inductor. A laser diode has an anode connected to a source node of the laser diode switch and a cathode connected to a bias voltage node. The laser diode switch and the bypass switch control a current flow through the inductor to produce a high-current pulse through the laser diode, the high-current pulse corresponding to a peak current of a resonant waveform developed at the anode of the laser diode.