IC ESD Protection with Shutoff Switching for Low-Voltage Cores
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Solution Overview
Problem
Integrated circuits with high-voltage power supply terminals and internal circuits operating at low voltage face challenges in electrostatic discharge (ESD) protection due to limited terminal availability, requiring separate high-voltage and low-voltage protection circuits, which increases the total circuit area.
Innovation Solution
The integrated circuit design includes a first power supply line connected to a protection circuit and an internal circuit with a shutoff control circuit, featuring transistors and a combination of resistive and capacitive elements with inverters to switch between conduction and non-conduction states, allowing the protection circuit to disconnect from the internal circuit during ESD events, reducing the need for dual protection circuits and minimizing circuit area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a separate low-voltage power supply terminal is provided, then the internal circuit can operate at low voltage, but the number of available terminals is limited and a low-voltage power supply terminal may not be provided easily
Solution Approach 1:
The patent combines the high-voltage and low-voltage power supply functions into a single terminal. The protection circuit includes a first protection circuit connected to the high-voltage terminal and a second protection circuit that provides low-voltage operation capability through the same terminal, eliminating the need for separate terminals while maintaining both voltage operation capabilities
Solution Approach 2:
The single power supply terminal serves multiple functions: it provides high-voltage power supply when needed and low-voltage power supply when needed, acting as a universal terminal that adapts to different voltage requirements through the integrated protection circuit architecture
2Reliability
If two separate ESD protection circuits are provided (high-voltage and low-voltage), then both the high-voltage terminal and internal circuit are protected from ESD, but the total required circuit area increases
Solution Approach 1:
The patent merges the high-voltage protection circuit and low-voltage protection circuit into a single integrated protection circuit. The first protection circuit handles high-voltage ESD events while the second protection circuit handles low-voltage ESD events, both operating through the same terminal and sharing common circuit elements, thereby reducing the total circuit area compared to having two completely separate protection circuits
Solution Approach 2:
The protection circuit employs dynamic switching mechanisms where protection paths are activated based on the voltage level and ESD event characteristics. This allows the circuit to adaptively select the appropriate protection path (high-voltage or low-voltage) without requiring both protection circuits to be fully active simultaneously, optimizing area usage
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration effectively protects both the high-voltage power supply terminal and the internal circuit from ESD without the need for two separate protection circuits, reducing the overall circuit area and allowing for the use of smaller transistors, thereby minimizing the device die size.
Implementation Method 1
a capacitive element and a resistive element that form an RC circuit
Implementation Method 2
a second transistor that switches between conduction and non-conduction states to disconnect and connect the protection circuit and the internal circuit from each other
Data Source
AI summary
According to one embodiment, an integrated circuit includes a first power supply line, a protection circuit, an internal circuit, a second transistor, and a shutoff control circuit. A first power supply voltage is supplied to the first power supply line. The protection circuit is connected to the first power supply line. The internal circuit includes a first transistor whose breakdown voltage is lower than the first power supply voltage. A drain or a source of the first transistor is connected to the first power supply line. The second transistor is on the first power supply line between the protection circuit and the internal circuit and is configured to switch between conduction and non-conduction states to connect and disconnect the protection circuit and the internal circuit from one another along the first power supply line. The shutoff control circuit is configured to turn off the second transistor during an ESD operation.