Dummy MOSFET Network for Core Transistor SOA Protection
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Solution Overview
Problem
Semiconductor devices face limitations in operating at the same voltage as input/output devices due to differences in safe operating area (SOA), leading to restricted applications and performance issues.
Innovation Solution
Incorporating dummy devices with specific transistor configurations and voltage connections that allow core devices to operate within the safe operating area of input/output voltage ranges by using n-channel and p-channel MOSFETs, ensuring all transistors remain within predetermined voltage limits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If core devices are operated at higher voltage (IO device voltage level), then operating speed and driving capability are improved, but the devices may exceed their safe operating area (SOA) and suffer from electrical overstress
Solution Approach 1:
The patent introduces dummy devices as intermediary elements that are electrically connected in parallel with the core device. These dummy devices act as mediators that share the voltage and current stress, allowing the core device to operate at higher IO voltage levels without exceeding its SOA limits. The dummy devices absorb excess stress and protect the core device from electrical overstress while enabling high-speed operation.
Solution Approach 2:
The patent changes the electrical parameters (voltage and current distribution) by introducing dummy devices that modify the operating conditions. By adjusting the configuration and parameters of the dummy devices, the system can operate the core device at higher voltage levels while maintaining all devices within their respective SOA boundaries through parameter optimization.
2Reliability
If IO devices with thicker oxide structure are used to achieve better SOA for higher voltage operation, then reliability is improved, but operating speed and driving capability deteriorate
Solution Approach 1:
The patent segments the high-voltage handling function from the high-speed core device by introducing separate dummy devices. The core device maintains its thin oxide structure for high-speed operation, while the dummy devices handle the voltage stress and SOA compliance, effectively dividing the conflicting requirements into separate functional components.
Solution Approach 2:
The dummy devices serve as intermediaries that enable the core device to operate at higher voltages without requiring the core device itself to have a thicker oxide structure. The dummy devices absorb the voltage stress and protect the high-performance core device, allowing it to maintain both speed and reliability.
3Speed
If core devices are designed with thinner oxide structure for better performance, then operating speed and driving capability are improved, but the devices cannot operate at the same voltage as IO devices due to limited SOA
Solution Approach 1:
The patent makes the core device system universal by enabling it to operate at both core voltage and IO voltage levels. The dummy devices provide the adaptability needed for the thin-oxide core device to function at higher IO voltage levels, giving the system multi-voltage compatibility and broader application versatility while maintaining high-speed performance.
Data Source
AI summary
A semiconductor device is provided. The semiconductor device comprises a core transistor having a drain configured to receive a first voltage, and a first dummy device connected to the drain of the core transistor, the first dummy device having a first dummy transistor, a second dummy transistor, and a third transistor. A gate and a source of the first dummy transistor are connected to each other; a drain of the second dummy transistor is connected to the source of the first dummy transistor; a gate of the second dummy transistor is connected to the drain of the core transistor; a source of the third dummy transistor is connected to a drain of the first dummy transistor, and a gate of the third dummy transistor is connected to the source of the third dummy transistor.