Voltage Switching Circuit With Transistors On Different Wells
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Solution Overview
Problem
Existing voltage switching circuits in semiconductor memory devices face challenges in stabilizing the supply of negative and positive voltages to multiple planes, leading to increased power consumption and instability due to leakage currents when voltages of different polarities are applied.
Innovation Solution
A voltage switching circuit is designed with transistors formed on different wells, allowing for selective transfer of voltages between input and output terminals, preventing leakage currents by ensuring that transistors directly coupled to input and output terminals are on different p-wells, regardless of voltage polarity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If transistors are formed on the same well to simplify circuit structure, then device complexity is reduced, but leakage currents increase when voltages of different polarities are applied
Solution Approach 1:
The circuit is divided into separate well regions (first well and second well) to isolate transistors handling different voltage polarities. This segmentation prevents leakage currents by ensuring that n-type and p-type transistors are formed in different wells, eliminating the harmful interaction between opposite polarity voltages while maintaining clear functional separation.
Solution Approach 2:
Different well regions are assigned specific characteristics: the first well is optimized for transistors handling first polarity voltages, while the second well is optimized for transistors handling second polarity voltages. This local quality differentiation ensures that each transistor operates in an electrically optimal environment, preventing leakage currents while maintaining overall circuit functionality.
2Adaptability or versatility
If transistors handle voltages of different polarities simultaneously, then power consumption increases due to leakage currents, but voltage switching capability is improved
Solution Approach 1:
The voltage switching circuit is segmented into distinct well regions, with the first transistor handling first polarity voltages in the first well and the second transistor handling second polarity voltages in the second well. This segmentation eliminates leakage currents between opposite polarity voltages, reducing power consumption while preserving the ability to switch between different voltage polarities at different output terminals.
3Ease of manufacture
If transistors are coupled directly to input terminals without well separation, then ease of manufacture is improved, but voltage supply stability deteriorates due to leakage currents
Solution Approach 1:
The manufacturing process is extended to include well separation, where the first transistor is formed in a first well directly coupled to the first input terminal, and the second transistor is formed in a second well directly coupled to the second input terminal. This segmentation maintains ease of manufacture through systematic fabrication steps while ensuring voltage supply stability by preventing leakage currents between opposite polarity voltage paths.
Data Source
AI summary
A voltage switching circuit selectively transfers voltages applied to a first input terminal and a second input terminal to a first output terminal and a second output terminal. The voltage switching circuit includes a first transistor and a second transistor. The first transistor is formed on a first well on a substrate, and is coupled between the first input terminal and the first output terminal. The second transistor is formed on a second well different from the first well, and is coupled to the second input terminal. In a first mode in which a first voltage applied to the first input terminal is transferred to the first output terminal and the second output terminal, the first transistor is turned on and the second transistor is turned off.