Tub-Isolated Level Shifter Circuit for Fast Voltage-Domain Switching
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
There is a need for an electronic circuit with a level shifter that can transmit signals quickly and reliably between different voltage domains.
Innovation Solution
The electronic circuit includes a level shifter transistor with a load path coupled between a low-side reference node and a high-side supply node, integrated in a semiconductor body with a base region, a tub, and a device region. The tub is connected to the high-side supply node, and the base region is connected to the low-side reference node, enabling efficient signal transmission across voltage domains.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the level shifter transistor is integrated in a semiconductor body with a tub structure, then the switching speed is improved, but the device complexity increases
Solution Approach 1:
The level shifter transistor is integrated within a semiconductor body that contains a tub structure. The tub is formed within the semiconductor body, creating a nested configuration where the transistor is embedded in the tub region. This nesting approach enables fast switching by utilizing the tub structure to isolate the transistor from the substrate, reducing parasitic capacitance and improving switching speed, while the integration maintains a compact form factor.
Solution Approach 2:
The tub structure extends vertically into the semiconductor body, creating a three-dimensional configuration that separates the level shifter transistor from the substrate in the vertical dimension. This vertical separation reduces parasitic effects and improves switching performance without significantly increasing the horizontal footprint of the device.
2Reliability
If the level shifter transistor is integrated in a device region separated from the base region by the tub, then the signal transmission reliability is improved, but the manufacturing precision requirements increase
Solution Approach 1:
The level shifter transistor is nested within a tub structure that is formed in the semiconductor body. The tub acts as an isolation structure that separates the transistor's device region from the base region, providing electrical isolation and improving signal transmission reliability. The nested configuration ensures consistent electrical characteristics while maintaining manufacturability through standard semiconductor fabrication processes.
3Speed
If the tub is connected to the high-side supply node and the base region to the low-side reference node, then the signal transmission speed is improved, but the energy consumption increases
Solution Approach 1:
The tub structure is connected to the high-side supply node, allowing the transistor to utilize the supply voltage directly for its operation. The base region is connected to the low-side reference node, creating a self-contained electrical configuration where the transistor can switch signals efficiently between voltage domains. This self-service configuration reduces the need for additional energy-consuming isolation circuits.
Data Source
Figure 1~2B
Figure 3
Figure 4~5
AI summary
An electronic circuit and an integrated circuit are disclosed. The electronic circuit includes: a level shifter (2) comprising a level shifter transistor (TL1) having a load path coupled between a low-side reference node (N11) and a high-side supply node (N13) of the electronic circuit (1). The electronic circuit further includes a semiconductor body (100) having a base region (110) of a first doping type, a tub (120) of a second doping type complementary to the first doping type, and a device region (130) of the first doping separated from the base region (110) by the tub (120). The level shifter transistor (TL1) is at least partially integrated in the device region (130), and the tub (120) is connected to the high-side supply node (N13) and the base region (110) is connected to the low-side reference node (N11).