High Voltage Floating Well Isolation in Silicon Die
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In DC-to-DC power converters, high voltage drops across switches can lead to device breakdown, as most circuit components, except for the inductor and capacitor, are integrated on a single silicon die, and components within the controller may not be designed to handle such high voltage drops, necessitating electrical isolation to prevent device failure.
Innovation Solution
A silicon die structure with a floating well region, featuring a p-doped substrate, n-doped buried layer, and graded doping regions, along with a spiral resistor, provides electrical isolation and mitigates high electric fields, allowing devices within the floating well to operate at high voltages while preventing breakdown by setting voltage potentials and profiling the depletion region.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If circuit components are integrated on a single silicon die, then device complexity is reduced and productivity is improved, but high voltage drops cause device breakdown and reliability deteriorates
Solution Approach 1:
The patent divides the silicon die into distinct regions: a first doped region for high-voltage switches and a second doped region for low-voltage controller components. This segmentation allows each region to be optimized for its specific voltage requirements, enabling integration while preventing breakdown through spatial separation of voltage domains.
Solution Approach 2:
The patent introduces a drift region as an intermediary between the first doped region and the second doped region. This drift region with graded doping profile acts as a buffer that manages the transition between high-voltage and low-voltage domains, reducing electric field concentration and preventing breakdown at the interface between different voltage regions.
2Power
If high voltage switches are used, then power conversion capability is improved, but voltage drops across switches increase and device breakdown risk increases
Solution Approach 1:
The patent applies different doping characteristics to different spatial locations: the first doped region has doping optimized for high-voltage switch operation, while the second doped region has doping optimized for low-voltage controller operation. This local quality differentiation allows each region to handle its specific voltage level efficiently, enabling high power capability while protecting sensitive components from high voltage effects.
Solution Approach 2:
The drift region serves as an intermediary structure between high-voltage and low-voltage regions. Its graded doping profile gradually transitions the electric field, reducing the concentration of high voltage drops and their harmful effects on nearby components while maintaining the high voltage capability needed for power conversion.
3Ease of operation
If controller components are designed for low voltage operation, then ease of operation is improved, but electrical isolation from high voltage is required to prevent breakdown
Solution Approach 1:
The patent segments the silicon die into electrically isolated doped regions, creating a first doped region for high-voltage switches and a second doped region for low-voltage controller components. This segmentation provides inherent electrical isolation through the doped region boundaries, allowing controller components to operate at low voltage without requiring additional complex isolation structures.
Solution Approach 2:
The drift region acts as an intermediary that provides electrical isolation between high-voltage and low-voltage domains. Its graded doping profile creates a natural barrier that prevents high voltage from directly affecting low-voltage controller components, simplifying the isolation requirement while maintaining ease of operation for the controller.
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 effectively isolates components from high voltage drops, reducing the risk of device breakdown and maintaining efficient operation by managing voltage potentials and reducing current to minimize power loss and heat, thereby ensuring reliable performance in high voltage applications.
Implementation Method 1
profiling the depletion region
Implementation Method 2
provides electrical isolation and mitigates high electric fields
Implementation Method 3
reducing current to minimize power loss and heat
Data Source
Figure 1
Figure 2
Figure 3
AI summary
Disclosed is an electronic device, comprising a substrate (208), an n-doped buried layer (210), an n-doped region (212,220,222) adjacent to the n-doped buried layer and the substrate, the n-doped region comprising a first n-doped region (212) adjacent to the n-doped buried layer and having a first doping concentration, and a second n-doped region (222) not adjacent to the n-doped buried layer and having a second doping concentration less than the first doping concentration, and a p-doped region (224) adjacent to the second n-doped region and to the substrate, and a spiral resistor (228) coupled to the first n-doped region and to the p-doped region. Thus, regions 212,214,216 and 218 are electrically isolated from the rest of the circuit, which is important for devices integrated in these regions that may be at or near the high voltage (VIN), for example in DC-to-DC converters.