LiDAR Light Module Layout for Low-Parasitic Pulse Discharge
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Solution Overview
Problem
Existing light modules and LiDAR devices suffer from parasitic inductances and capacitances that hinder the generation of high-energy, short-duration light pulses, and they often require complex and inefficient mechanical components for beam deflection.
Innovation Solution
A light module design with a carrier containing a circuit die, a power transistor, a light-emitting diode die, and a charge storage component, optimized for minimal parasitic impedances, using bond wires and integrated circuits to minimize inductances and capacitances, and a driver circuit for rapid charging and switching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the charge storage component is electrically connected to the transistor via die-to-die bonds with short bond wires, then the parasitic inductances and ohmic resistances are reduced, but the device complexity and manufacturing difficulty increase
Solution Approach 1:
The light-emitting diode die and charge storage component are integrated in close proximity on the same carrier, connected by short bond wires. This merging of components minimizes the length of electrical connections, thereby reducing parasitic inductances and ohmic resistances while maintaining a compact structure that balances complexity reduction.
Solution Approach 2:
The system is divided into functionally separate dies (light-emitting diode die and charge storage component) that are bonded together. This segmentation allows each component to be optimized independently while maintaining short interconnections, resolving the contradiction between performance and complexity by enabling modular design with minimal parasitic effects.
2Ease of manufacture
If the second bond wire is made longer to connect the charging circuit to the charge storage component, then the ease of manufacture is improved, but the parasitic inductances increase
Solution Approach 1:
Different bond wire lengths are used for different functional requirements: short bond wires connect the light-emitting diode die to the charge storage component for low parasitic inductance, while a longer second bond wire connects the charging circuit to the charge storage component where parasitic effects are less critical. This local differentiation optimizes both performance and manufacturability.
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
Enables high-energy, short-duration light pulses with reduced electrical losses and interference, and eliminates the need for mechanical components by using a compact, efficient driver circuit.
Implementation Method 1
a light-emitting diode die (D1D)
Data Source
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AI summary
The light module comprises a carrier (TR) with a circuit die. On the top side (TRO) of the carrier (TR), a light-emitting diode die (D1D) and an associated charge storage component (LSBT) are electrically connected to the conduction path terminals (TAF1, TAF2) of a transistor (Tdis) via die-to-die bonds. The electrical connection between the two dies and the conduction path (LPF) of the transistor (Tdis) is as short as possible. On the top side of each of the two dies are terminals (DAF2, LAF2) connected to each other by a short bond wire (BD1). This discharge circuit is optimized to reduce parasitic inductances and ohmic resistances. The charge storage component (LSBT) is charged by a charging circuit (B1), which is electrically connected to the charge storage component (LSBT) via a second bond wire (BD2). The second bond wire (BD2) is longer than the first bond wire (BD1).The light module can be part of a LiDAR device, which may include a special optical system. The driver circuit for the transistor (Tdis) may also be designed in a special way.