Monolithic Optocoupler Voltage Source Using Tunnel Diodes
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Solution Overview
Problem
Existing optocouplers with scalable voltage sources face limitations in achieving high voltage levels and efficient space utilization, particularly in their design and functionality when using III-V materials.
Innovation Solution
A monolithically integrated optocoupler design featuring a series-connected stack of semiconductor diodes with p-n junctions, each with passivated absorption layers and tunnel diodes, forming a compact voltage source that can achieve voltages above 3 volts when irradiated, allowing for scalable and efficient power generation with reduced space requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a conventional optocoupler design with simple voltage sources is used, then the device structure is simple, but the achievable voltage level is limited and cannot exceed 3 volts
Solution Approach 1:
The voltage source is divided into multiple semiconductor diodes connected in series, where each diode contributes a portion of the total voltage. This segmentation allows the system to achieve higher voltage levels (above 3V) by combining individual diode voltages, while each diode remains a simple, manufacturable component.
Solution Approach 2:
The patent transitions from planar device layouts to a three-dimensional stacked configuration of semiconductor diodes. This vertical stacking in the thickness dimension enables higher voltage output within a compact footprint, effectively using the third dimension to overcome voltage limitations without proportionally increasing device area.
2Power
If the number of series-connected diodes is increased to achieve higher voltage, then the voltage level increases, but the device thickness and manufacturing complexity increase
Solution Approach 1:
The patent employs thin-film semiconductor layers with optimized thicknesses (e.g., absorption layers with specific thickness ranges) that maintain electrical functionality while minimizing physical thickness. This allows multiple diodes to be stacked in series without proportionally increasing the overall device thickness, enabling high voltage in a compact form factor.
3Reliability
If tunnel diodes are added between successive partial voltage sources, then the voltage stability and scalability improve, but the manufacturing precision requirements increase
Solution Approach 1:
The tunnel diodes are monolithically integrated with the series-connected semiconductor diodes in a unified stack structure. This merging of components into a single integrated device reduces the number of separate fabrication steps and alignment operations required, thereby lowering manufacturing precision requirements while maintaining voltage stability and scalability.
4Area of stationary object
If the illuminated area is reduced to match the stack top surface, then the space utilization improves, but the light absorption efficiency may decrease
Solution Approach 1:
The patent optimizes the optical parameters of the semiconductor materials, including absorption coefficients and bandgap energies, to maximize light absorption within the available illuminated area. By carefully selecting material parameters and layer thicknesses, the design achieves high absorption efficiency in a compact stack with minimized surface area.
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 design enables the production of a reliable, inexpensive, and scalable power source with voltages above 4 volts, offering significant space savings and improved usability as a reference voltage source, while maintaining high efficiency and reliability.
Implementation Method 1
a tunnel diode is formed in each case between two successive partial voltage sources
Implementation Method 2
each semiconductor diode having a p-doped absorption layer... the light on the top surface is incident on the first stack
Data Source
AI summary
An optocoupler having a transmitter module and a receiver module that are galvanically isolated from each other and optically coupled with one another and are integrated in a common housing. The receiver module has a voltage source that has a number N of partial voltage sources mutually connected in series and constructed as semiconductor diodes. Each of the partial voltage sources has a semiconductor diode having a p-n junction, and the partial source voltages of the individual partial voltage sources each deviate by less than 20% from one another. Between each two successive partial voltage sources, a tunnel diode is formed and the partial voltage sources and the tunnel diodes are monolithically integrated together and jointly form a first stack having a top surface and a bottom surface, and the number N of the partial voltage sources is greater than or equal to three.