High Voltage Junction Isolation in Integrated Circuits
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Solution Overview
Problem
Existing high-side transistor drive circuits in bridge circuits require complex charge pump circuits and floating drivers to control high-side transistors, increasing complexity and cost, particularly in integrating low-voltage control circuits with high-voltage floating drive circuits.
Innovation Solution
A monolithic IC process is used to integrate low-voltage control circuits with a high-voltage floating drive circuit, employing a P substrate with N and P diffusion regions to form isolation structures, restricting device space and creating a high-voltage junction barrier to isolate control and floating circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If complex charge pump circuits and floating drivers are used to control high-side transistors, then high-voltage operation is achieved, but device complexity increases
Solution Approach 1:
The patent divides the integrated circuit into distinct isolation regions separated by deep trench isolation structures. Low-voltage control circuits and high-voltage power circuits are physically segmented into separate regions, allowing each to operate independently at their respective voltage levels without interfering with the other, thus enabling high-voltage operation while maintaining circuit simplicity
Solution Approach 2:
The patent introduces deep trench isolation structures filled with dielectric material as intermediary elements between low-voltage and high-voltage circuits. These isolation trenches act as mediators that block electric field coupling and prevent voltage interference, enabling high-voltage operation without requiring complex charge pump circuits
2Reliability
If complex charge pump circuits and floating drivers are used to control high-side transistors, then high-voltage operation is achieved, but manufacturing cost increases
Solution Approach 1:
By segmenting the circuit into isolated low-voltage and high-voltage regions using deep trench isolation, the patent eliminates the need for complex charge pump circuits and floating drivers. This segmentation allows standard CMOS fabrication processes to be used throughout, significantly reducing manufacturing cost while maintaining high-voltage operation capability
Solution Approach 2:
The patent replaces expensive, complex charge pump circuits with simple deep trench isolation structures that can be fabricated using standard CMOS processes. The isolation trenches are relatively simple structures to manufacture compared to charge pump circuits, reducing overall manufacturing cost
3Adaptability or versatility
If low-voltage control circuits and high-voltage floating drive circuits are integrated, then integration is achieved, but isolation between voltage levels becomes difficult
Solution Approach 1:
The patent successfully integrates low-voltage control circuits and high-voltage power circuits on the same chip by using deep trench isolation to create physically separated regions. This segmentation approach allows both circuit types to coexist on a single substrate without requiring complex isolation schemes, achieving integration while maintaining simple isolation structures
Solution Approach 2:
Deep trench isolation structures filled with dielectric material serve as intermediary elements between low-voltage and high-voltage circuits. These trenches provide effective electrical isolation and prevent voltage interference, enabling successful integration of circuits operating at different voltage levels without increasing isolation complexity
4Reliability
If maximum space of devices is restricted to develop high voltage junction barrier, then voltage isolation is improved, but area utilization decreases
Solution Approach 1:
The patent uses deep trench isolation to create physically separated low-voltage and high-voltage regions, providing effective voltage isolation through spatial segmentation. This approach achieves reliable voltage isolation without requiring excessive spacing between devices within each region, optimizing area utilization while maintaining isolation integrity
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 simplifies the integration of low-voltage control circuits with high-voltage floating drive circuits, reducing production costs and improving yield while effectively isolating voltage levels, enabling efficient high-voltage operation.
Implementation Method 1
An N diffusion region containing N conductivity type forms an N well barrier disposed in the substrate
Implementation Method 2
A high voltage junction barrier is formed to isolate the control circuit and the floating circuit
Data Source
AI summary
The high voltage integrated circuit comprises a P substrate. An N well barrier is disposed in the substrate. Separated P diffusion regions forming P wells are disposed in the substrate for serving as the isolation structures. The low voltage control circuit is located outside the N well barrier. A floating circuit is located inside the N well barrier. In order to develop a high voltage junction barrier in between the floating circuit and the substrate, the maximum space of devices of the floating circuit is restricted.