Drain-Extended High-Voltage Switch Circuit for 45 nm Reliability
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Solution Overview
Problem
Semiconductor devices with small process technologies, such as 45 nm, face reliability issues due to the inability to handle high voltage inputs and outputs without damaging or rendering unreliable the switch or other components, as existing switches are often unreliable when subjected to high voltages beyond their supported voltage levels.
Innovation Solution
A switch design utilizing pairs of n-type and p-type drain-extended transistors that can withstand high voltages across the drain, with control mechanisms to manage voltage levels across all transistor terminals within the process technology limits, preventing damage and ensuring reliability by isolating high voltages from inappropriate nodes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If high voltage inputs and outputs are applied to existing switches, then voltage handling capability is improved, but reliability deteriorates due to damage or unreliability of the switch and other components
Solution Approach 1:
The switch is segmented into multiple transistor stages: drain-extended transistors (first and second) that handle high voltage inputs and outputs, and regular transistors (third and fourth) that operate at lower voltages. This segmentation allows different parts of the circuit to operate at appropriate voltage levels, enabling high voltage handling while protecting sensitive components from damage.
Solution Approach 2:
The drain-extended transistors act as intermediary components between the high voltage input/output nodes and the low voltage internal circuitry. These transistors with extended drain regions can withstand high voltages and gradually transition the voltage levels, protecting the regular transistors from exposure to damaging high voltages while maintaining signal integrity.
2Volume of moving object
If small process technology (e.g., 45 nm) is used, then device size is reduced, but voltage handling capability deteriorates due to inability to support high voltages
Solution Approach 1:
The drain-extended transistors incorporate locally modified regions with extended drain structures that can withstand high voltages. This local quality enhancement is applied only where high voltage exposure occurs (at the input and output nodes), while the rest of the circuit maintains the benefits of small process technology for miniaturization. This allows the device to be compact overall while having specific high-voltage-resistant zones.
Data Source
AI summary
In some examples, a switch comprises first and second drain-extended transistors of a first type, third and fourth drain-extended transistors of a second type, a switch input coupled between drains of the first and third drain-extended transistors, a switch output coupled between drains of the second and fourth drain-extended transistors, and a control input. The control input is coupled to gates of the first and second drain-extended transistors, a first switch coupled to sources of the first and second drain-extended transistors, a second switch coupled between a voltage supply and gates of the third and fourth drain-extended transistors, and a third switch coupled between the voltage supply and sources of the third and fourth drain-extended transistors. The control input comprises a fifth drain-extended transistor coupled between the sources of the third and fourth drain-extended transistors and the gates of the third and fourth drain-extended transistors.