Resonant Laser Diode Driver With Auto Flux Timing
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Solution Overview
Problem
Conventional pulsed laser driver circuits rely on parasitic capacitances and inductances, requiring redesign or re-layout to adjust parameters like pulse width, and often use high input voltages necessitating GaN-based switches, limiting flexibility and integration.
Innovation Solution
The pulsed laser diode driver employs a tunable resonant circuit with intentionally added inductors and capacitors, using Silicon-based switches and adaptive switch timing to generate ultra-short high-current pulses, allowing easy tuning of pulse parameters and integration into a single semiconductor die.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional pulsed laser driver circuits use parasitic capacitances and inductances, then the circuit can be simpler, but adjusting pulse parameters requires redesign or re-layout
Solution Approach 1:
The patent extracts the unwanted parasitic reactances from the circuit and replaces them with intentional resonant components. By removing the reliance on parasitic elements and using dedicated inductors and capacitors to form a tunable resonant circuit, the design enables parameter adjustment without redesigning the entire circuit layout.
Solution Approach 2:
The patent introduces a tunable resonant circuit with adjustable inductance and capacitance values, allowing the pulse parameters to be dynamically adjusted. The resonant frequency and pulse characteristics can be modified by changing component values without requiring physical redesign of the circuit structure.
2Power
If high input voltages are used in pulsed laser driver circuits, then the power delivery capability is improved, but GaN-based switches are required increasing cost and complexity
Solution Approach 1:
The patent changes the voltage parameter by using a resonant circuit that can deliver high current pulses at lower input voltages. By utilizing the resonant oscillation to build up current in the inductor and then discharge it through the laser diode, the circuit achieves high power delivery without requiring high-voltage GaN switches, thereby reducing cost and complexity.
3Ease of operation
If delay circuits are used to time flux current development, then the timing can be controlled, but the delay duration must be adjusted when inductive or capacitive components change
Solution Approach 1:
The patent employs feedback by using a voltage detector that monitors the source capacitor voltage and automatically determines when the resonant current reaches its peak. This feedback mechanism eliminates the need for manual delay adjustment, as the timing is automatically adapted to the actual resonant conditions of the circuit components.
Solution Approach 2:
The resonant circuit itself provides the timing information through its natural oscillation characteristics. The voltage detector monitors the capacitor voltage which naturally reaches zero when the inductor current peaks, allowing the circuit to self-determine the optimal switching time without external delay circuit adjustments.
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 flexible adjustment of pulse parameters without redesign, uses lower input voltages, and integrates seamlessly into semiconductor devices, improving efficiency and reducing costs by avoiding parasitic reactances.
Implementation Method 1
a source capacitor having i) a first terminal configured to receive a refresh current and to develop a source voltage therefrom
Implementation Method 2
a timing of the one or more gate driver signals being based on a voltage level of the source voltage... to produce a high-current pulse through the laser diode, the high-current pulse corresponding to a peak current of a resonant waveform
Data Source
AI summary
A pulsed laser diode driver includes a source capacitor that receives a refresh current at a first terminal and develops a source voltage therefrom. A first terminal of an inductor is connected to the first terminal of the source capacitor. A second terminal of the inductor is connected to an anode of a laser diode and a bypass capacitor. One or more switches are configured to control a current flow through the inductor. A timing and control circuit is configured to receive the source voltage and to generate one or more gate driver signals to control the switches to produce a high-current pulse through the laser diode. The high-current pulse corresponds to a peak current of a resonant waveform developed at the anode of the laser diode. A timing of the one or more gate driver signals is based on a voltage level of the source voltage.