Guard Ring and Guard Wall Layout for Converter Noise Isolation
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Solution Overview
Problem
Switch-mode voltage converters generate significant noise due to high-voltage and high-current switching, which interferes with noise-sensitive control circuits, leading to undesired leakage and circuit degradation.
Innovation Solution
Implementing a guard ring and guard wall structure in the substrate to collect and recombine minority carriers, with the guard wall connected to a positive potential to further reduce noise impact on control circuits, while minimizing footprint and cost.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a guard ring and guard wall structure is implemented to collect minority carriers and reduce noise, then noise interference is minimized and control circuit reliability is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
A guard ring structure is introduced as an intermediary element between the power circuit and control circuit. The guard ring includes a first doped region, second doped region, third doped region, and buried doped region that collectively form a noise collection mechanism. This intermediary structure captures minority carriers generated by the power circuit before they can reach the control circuit, thereby protecting the control circuit from noise while maintaining a relatively simple overall device architecture
Solution Approach 2:
The harmful minority carriers are extracted and collected by the guard ring structure before they can interfere with the control circuit. The guard ring's doped regions are strategically positioned to capture and remove these carriers from the substrate, effectively separating the noise source from the sensitive control circuitry
2Object-affected harmful factors
If the second doped region extends further into the substrate to improve noise collection, then noise interference is reduced, but manufacturing precision requirements increase
Solution Approach 1:
The guard ring employs different doped regions with varying properties at different locations. The second doped region extends deeper into the substrate specifically at positions where noise collection is most critical, while other regions maintain standard depths. This localized variation in doped region depth optimizes noise collection efficiency without requiring uniform increases in manufacturing precision across the entire device
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 guard ring and guard wall effectively minimize noise interference, protecting noise-sensitive circuits by collecting and recombining minority carriers, thus enhancing the reliability and efficiency of switch-mode voltage converters.
Implementation Method 1
The guard ring includes a first doped region, a second doped region, a third doped region, and a buried doped region. The second doped region extends further into the substrate than the first doped region or the third doped region. The second doped region contacts the buried doped region.
Implementation Method 2
The guard wall includes a first doped region laterally surrounding an insulating region, and a polysilicon region laterally surrounded by the insulating region. The polysilicon region of the guard wall is connected to the second ground supply terminal.
Data Source
AI summary
Some aspects relate to a device comprising a power circuit, a control circuit, a guard ring, a guard wall, and a voltage generator. The power circuit is disposed within a substrate and includes a transistor of a first type. The control circuit is disposed within the substrate and includes a transistor of a second type different from the first type, and is coupled to the power circuit. The guard ring includes a plurality of doped regions within the substrate, and the guard ring laterally surrounds the power circuit. The guard wall is disposed within the substrate and between the guard ring and the control circuit. The guard wall includes a first doped region laterally surrounding an insulating region, and a polysilicon region laterally surrounded by the insulating region. The voltage generator has a first terminal coupled to the first doped region of the guard wall.