Pulsed Laser Diode Driver Refresh Circuit for Tunable Resonant 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, requiring high voltages and relying on fixed parasitic capacitances and inductances, which limits pulse width and repetition frequency, and often necessitate complex bootstrap circuitry for multi-channel laser diodes.
Innovation Solution
A configurable high-frequency pulsed laser diode driver with a refresh circuit that generates a refresh current based on input voltage, using a tunable resonant circuit with added inductors and capacitors to control pulse width, peak current, and repetition rate, allowing for independent pulsing 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 pulse width can be reduced to 5 ns or less, but device complexity and cost increase due to requiring high-voltage switching devices like GaN FETs
Solution Approach 1:
The patent changes the voltage parameter from high voltage (40V-100V) to low voltage (5V-15V) by modifying the circuit topology. Instead of using high-voltage switching devices, the invention uses a resonant circuit with an inductor and capacitor to generate the necessary current pulse, thereby eliminating the need for complex high-voltage GaN FETs while achieving the same pulse width performance
Solution Approach 2:
The patent replaces the mechanical/electronic switching mechanism (high-voltage FETs) with a resonant oscillation mechanism. The resonant circuit naturally generates the required current waveform through the interaction of inductance and capacitance, substituting the need for complex active switching devices with a passive resonant system
2Duration of action of moving object
If high source voltage is used to achieve desired pulse width, then pulse width can be reduced, but energy consumption increases
Solution Approach 1:
The patent changes the voltage parameter from high voltage to low voltage operation, which directly reduces energy consumption. The resonant circuit efficiently transfers energy from the capacitor to the laser diode through oscillation, minimizing energy losses that would occur in high-voltage switching operations
3Device complexity
If fixed parasitic capacitances and inductances are relied upon, then circuit complexity is reduced, but pulse repetition frequency is limited and cannot meet high-frequency applications of 5-10 MHz or higher
Solution Approach 1:
The patent introduces a dynamic resonant circuit with adjustable inductance and capacitance values that can be tuned to achieve different pulse repetition frequencies. This dynamic configuration allows the circuit to adapt to high-frequency applications (5-10 MHz or higher) while maintaining manageable circuit complexity through the use of standard electronic components
Solution Approach 2:
The patent utilizes periodic resonant oscillation to generate pulses at high repetition frequencies. The resonant circuit naturally oscillates at a determined frequency based on the L and C values, providing a periodic action that can be tuned to meet high-frequency application requirements without increasing circuit complexity
4Adaptability or versatility
If complex bootstrap circuitry is used for multi-channel laser diodes, then independent pulsing capability is achieved, but device complexity and cost increase
Solution Approach 1:
The patent creates a universal resonant driver circuit that can independently control multiple laser diode channels without requiring separate bootstrap circuitry for each channel. The circuit uses a single resonant tank that can be switched to different configurations, providing multi-functional capability with reduced overall complexity
Solution Approach 2:
The patent merges the control of multiple laser diode channels into a single resonant circuit architecture. Instead of having separate bootstrap circuits for each channel, the invention combines the resonant oscillation mechanism to serve multiple channels, thereby reducing the total device complexity while maintaining independent pulsing capability
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
The solution enables the generation of ultra-short high-current pulses with adjustable parameters, achieving higher pulse repetition frequencies while minimizing voltage overshoot and reducing complexity and cost, improving the efficiency and flexibility of laser diode drivers.
Implementation Method 1
a refresh circuit configured to receive a DC input voltage and to generate a refresh current using the DC input voltage
Implementation Method 2
A first inductor of the pulsed laser diode driver has a first terminal that is directly electrically connected to the first terminal of the first source capacitor
Implementation Method 3
One or more switches of the pulsed laser diode driver are configured to control a current flow through the first inductor to produce a high-current pulse through a first laser diode, the high-current pulse corresponding to a peak current of a resonant waveform developed at an anode of the first laser diode
Data Source
AI summary
A pulsed laser diode driver includes a refresh circuit configured to generate a refresh current using a received input voltage. A current amplitude of the refresh current is controlled by the refresh circuit based on a voltage level of a source voltage received by the refresh circuit. A source capacitor of the pulsed laser diode driver is configured to receive the refresh current and to develop the source voltage therefrom. An inductor of the pulsed laser diode driver has a first terminal that is directly electrically connected to the source capacitor. One or more switches of the pulsed laser diode driver are configured to control a current flow through the inductor to produce a high-current pulse through a laser diode that corresponds to a peak current of a resonant waveform developed at an anode of the laser diode.