Protection Transistor Structure for Power-Down Voltage Clamping
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Solution Overview
Problem
Integrated circuits face challenges in protecting transistors from voltages exceeding their withstand voltage, both in normal and power down modes, which can lead to non-functional operation or damage.
Innovation Solution
A device incorporating protection transistors that are turned off in normal mode and turned on in power down mode to provide protection voltages to critical nodes, ensuring transistors are not exposed to excessive voltages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If protection transistors are added to protect elements from excessive voltages in power down mode, then reliability is improved, but device complexity increases
Solution Approach 1:
The protection transistor is designed to serve dual purposes: it protects circuit elements from excessive voltages during power down mode while also functioning as a regular transistor during normal operation. This multi-functionality reduces the need for separate dedicated protection components, thereby limiting the increase in device complexity while maintaining improved reliability.
Solution Approach 2:
The protection transistor dynamically changes its state based on the operational mode of the device. During normal operation, it remains in a non-conductive state and functions as a regular transistor. During power down mode, it transitions to a conductive state to provide voltage protection. This dynamic behavior allows the same component to adapt to different operational requirements without adding permanent complexity to the circuit structure.
2Reliability
If protection transistors are added to protect elements from excessive voltages, then reliability is improved, but area of the device increases
Solution Approach 1:
By designing the protection transistor to also function as a regular transistor during normal operation, the patent eliminates the need for separate dedicated protection components. This multi-functional approach ensures that the same transistor serves both protection and operational purposes, thereby minimizing the additional area required while maintaining reliable voltage protection during power down mode.
Data Source
Figure 1~2A
Figure 2B~2C
Figure 2D
AI summary
A device includes: a plurality of first transistors included in a first current path, in a normal mode, between a first power node to which a positive supply voltage is configured to be applied and a second power node to which a negative supply voltage is configured to be applied; and a first protection transistor connected to a first node which two of the plurality of first transistors are connected to, wherein the first protection transistor is configured to be turned off in the normal mode and to be turned on to provide a protection voltage to the first node in a power down mode.