Semiconductor Device High-Side Gate Driver Negative Voltage Surge Protection
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Solution Overview
Problem
Conventional high-voltage integrated circuits (HVICs) using self-isolation or junction isolation processes are prone to malfunctions due to negative voltage surges, which require costly negative voltage power supplies to prevent forward biasing of parasitic diodes and subsequent surge currents.
Innovation Solution
A semiconductor device with a first conductivity type semiconductor layer, first and second semiconductor regions, a control circuit, a gate driver circuit, a diode with reverse characteristics to block surge currents, and a level shift circuit to convert gate control signals, allowing operation without external diodes and reducing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional self-isolation or junction isolation processes are used in HVICs, then manufacturing cost is reduced, but the device becomes vulnerable to negative voltage surges causing malfunctions
Solution Approach 1:
The patent applies preliminary action by forming a protective p-type semiconductor region and diode structure during the initial self-isolation process, before negative voltage surge protection is needed. This pre-configured structure passively blocks surge currents when negative voltage occurs, eliminating the need for active negative voltage power supplies while maintaining reliability.
Solution Approach 2:
The patent introduces a p-type semiconductor region as an intermediary element between the n-type drift region and the substrate. This intermediate structure acts as a passive barrier that blocks negative voltage surge currents without requiring external power sources, resolving the contradiction between cost reduction and reliability.
2Reliability
If negative voltage power supplies are used to prevent forward biasing of parasitic diodes, then reliability against surge currents is improved, but device complexity and cost increase
Solution Approach 1:
The patent implements self-service by designing a protective structure that uses the device's own semiconductor regions and built-in diode characteristics to block surge currents. The p-type region and associated diode passively prevent forward biasing of parasitic diodes during negative voltage events, eliminating the need for external negative voltage power supplies and reducing overall system complexity.
Solution Approach 2:
The patent converts the potentially harmful effect of negative voltage surges into a beneficial protective mechanism. By utilizing the diode's reverse blocking characteristics in the self-isolation structure, the design transforms the vulnerability of parasitic diodes into an active protection mechanism that automatically blocks surge currents without requiring additional power supplies.
3Reliability
If external diodes are used to block surge currents, then reliability is improved, but device area and complexity increase
Solution Approach 1:
The patent merges the surge protection function with the existing self-isolation structure by integrating a p-type semiconductor region and diode formation into the conventional HVIC fabrication process. This consolidation eliminates the need for separate external diodes, reducing device area while maintaining reliable surge current blocking capability.
Solution Approach 2:
The patent achieves multi-functionality by designing a p-type semiconductor region that simultaneously serves as part of the self-isolation structure and as a surge protection element. This universal structure performs both isolation and surge blocking functions within the same device area, eliminating the need for additional dedicated protection components.
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 semiconductor device effectively prevents malfunctions of the high-side gate driver circuit from negative voltage surges without requiring negative voltage power supplies, achieving cost reduction and reliable operation up to a negative voltage surge of approximately 1200 V.
Implementation Method 1
a diode with reverse characteristics to block surge currents
Data Source
AI summary
Provided is a semiconductor device capable of preventing a malfunction of a high-side gate driver circuit that is caused by a negative voltage surge. A diode is connected between a p-type bulk substrate configuring a semiconductor layer, and a first potential (GND potential), and a signal is transmitted from a control circuit that is formed in an n diffusion region configuring a first semiconductor region through a first level down circuit and a first level up circuit to a high-side gate driver circuit that is formed in an n diffusion region configuring a second semiconductor region. As a result, a malfunction of the high-side gate driver circuit that is caused by a negative voltage surge can be prevented.