Resonant Laser Diode Driver Cells for Low-Voltage Short Pulses
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Solution Overview
Problem
Conventional pulsed laser diode driver circuits face challenges in generating ultra-short, high-current pulses due to parasitic inductances and capacitances, requiring high voltages and complex GaN-based switches, which are costly and difficult to integrate with Silicon-based architectures.
Innovation Solution
The design incorporates multiple resonant laser diode driver cells with intentionally added discrete inductors and capacitors, allowing for tunable pulse width and peak current control using Silicon-based switches, eliminating the need for high-voltage GaN switches and simplifying integration.
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 inductance and achieve desired pulse width, then pulse width can be reduced to 5 ns or less, but device complexity and cost increase due to requiring GaN switches that can withstand high voltages
Solution Approach 1:
The patent changes the voltage parameter from high voltage (40V-100V) to low voltage (5V-20V) by modifying the circuit topology. Instead of using a single high-voltage switch, the invention uses multiple low-voltage switches arranged in series, where each switch only needs to block a fraction of the total voltage, thereby reducing individual switch voltage requirements and simplifying device selection
Solution Approach 2:
The patent segments the high-voltage switching function into multiple low-voltage switches connected in series. Each switch handles only a portion of the total voltage stress, allowing the use of simpler, lower-voltage rated switches (such as Silicon-based devices) instead of complex high-voltage GaN switches, thus reducing device complexity while maintaining the ability to generate ultra-short pulses
2Duration of action of moving object
If high source voltage (greater than 40V-100V) is used to overcome parasitic inductance and achieve desired pulse width, then pulse width can be reduced to 5 ns or less, but cost increases due to expensive GaN switches
Solution Approach 1:
The patent changes the voltage parameter from high voltage (40V-100V) to low voltage (5V-20V) by modifying the circuit topology. Instead of using a single high-voltage switch, the invention uses multiple low-voltage switches arranged in series, where each switch only needs to block a fraction of the total voltage, thereby reducing individual switch voltage requirements and enabling the use of cheaper Silicon-based devices instead of expensive GaN switches
Solution Approach 2:
The patent replaces expensive high-voltage GaN switches with multiple cheaper low-voltage Silicon switches. While more switches are needed, the individual cost of each Silicon switch is significantly lower, and they are more readily available, reducing overall system cost and improving ease of manufacture while achieving the same pulse width performance
3Duration of action of moving object
If GaN switches are used to withstand high voltages in pulsed laser diode driver circuits, then desired pulse width can be achieved, but integration with Silicon-based architectures becomes more difficult
Solution Approach 1:
The patent changes the voltage parameter from high voltage (40V-100V) to low voltage (5V-20V) by modifying the circuit topology. Instead of using a single high-voltage switch, the invention uses multiple low-voltage switches arranged in series, where each switch only needs to block a fraction of the total voltage, thereby enabling the use of Silicon-based switches that are compatible with standard Silicon fabrication processes and easier to integrate with Silicon-based architectures
Solution Approach 2:
The patent segments the high-voltage switching function into multiple low-voltage switches connected in series. Each switch handles only a portion of the total voltage stress, allowing the use of standard Silicon-based devices that are compatible with existing Silicon fabrication infrastructure, thereby simplifying integration with Silicon-based architectures while maintaining the ability to generate ultra-short pulses
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 enables the generation of high-current pulses with lower input voltages (e.g., 6V-15V), improving power efficiency and reducing complexity and cost by using Silicon-based switches, while allowing for independent control of multi-channel laser diodes without bootstrap circuitry.
Implementation Method 1
a resonant waveform is developed at the anode of the laser diode
Implementation Method 2
a bypass capacitor having a first terminal directly electrically connected to the first terminal of the inductor and a second terminal directly electrically connected to the second terminal of the inductor
Data Source
AI summary
A pulsed laser diode driver includes multiple resonant laser diode driver cells, each cell including an inductor having a first inductor terminal to receive a source voltage, a source capacitor coupled between the first inductor terminal and ground, a bypass capacitor having a first terminal connected to the first inductor terminal and a second terminal connected to a second inductor terminal, a laser diode having a cathode that is connected to the first inductor terminal and an anode that is connected to the second inductor terminal, and a bypass switch connected between the second inductor terminal and ground. Each cell's bypass switch is configured to control a current flow through that cell's respective inductor to produce a high-current pulse through that cell's laser diode, the high-current pulse corresponding to a peak current of a resonant waveform developed at the anode of that cell's laser diode.