I/O Cell Overvoltage Protection Using Switchable Diode Chains
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Integrated circuits face challenges in protecting input/output cells from overvoltages, particularly at high-speed communication domains, without disrupting signal transmission.
Innovation Solution
An integrated circuit design incorporating a network of diodes and control means with MOS transistors and resistors to autonomously short-circuit diodes in response to overvoltages, using an RC filter to manage high-frequency signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a network of diodes is used to protect against overvoltages, then protection effectiveness is improved, but leakage current increases
Solution Approach 1:
The protection circuit dynamically adjusts the number of active diodes based on voltage conditions. During overvoltage events, fewer diodes are active providing strong protection. During normal operation, more diodes are active reducing leakage current. This dynamic reconfiguration resolves the contradiction between protection effectiveness and leakage current.
Solution Approach 2:
The circuit changes the electrical parameters (number of active diodes in series) based on operating conditions. By controlling which diodes are active through control means, the overall threshold voltage and leakage characteristics are adjusted to match current operational needs, balancing protection and power consumption.
2Reliability
If control means are added to autonomously short-circuit diodes, then protection responsiveness is improved, but device complexity increases
Solution Approach 1:
The control means are designed to automatically detect overvoltage conditions and trigger diode short-circuiting without external intervention. The circuit monitors its own state and self-corrects by activating appropriate transistors to short-circuit diodes when needed, eliminating the need for complex external control systems.
Solution Approach 2:
Transistors are introduced as intermediary elements that mediate between the voltage detection function and the diode short-circuiting action. These transistors act as controlled switches that can rapidly change the circuit state in response to voltage conditions, providing responsive protection with minimal additional complexity.
3Loss of energy
If the number of diodes is increased to reduce leakage current, then power consumption is improved, but protection threshold increases
Solution Approach 1:
The circuit dynamically adjusts the number of active diodes based on voltage conditions. During overvoltage events, fewer diodes are active providing strong protection. During normal operation, more diodes are active reducing leakage current. This dynamic reconfiguration resolves the contradiction between protection effectiveness and leakage current.
Solution Approach 2:
The diode network is segmented into multiple controllable groups. Control means can selectively activate or deactivate specific diodes within the network based on operational requirements. This segmentation allows optimization of both protection threshold and leakage current by adjusting which segments are active under different conditions.
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
Effectively protects against overvoltages while maintaining high-frequency signal transmission by autonomously limiting voltages to safe levels, even in the absence of power supply.
Implementation Method 1
The input/output cell comprises a network of N diodes, for example 4 diodes, connected in series between the second signal terminal and a cold supply point, typically ground, said network having an overall threshold voltage greater than V1.
Implementation Method 2
control means connected between the first signal terminal and the diode network, and configured to, in the presence of a voltage V2, for example 5 volts or more, on the first signal terminal higher than the voltage V1, automatically and autonomously short-circuit at least one of the diodes so as to limit the voltage on the second signal terminal to a value V3 lower than V1.
Implementation Method 3
An integrated circuit design incorporating a network of diodes and control means with MOS transistors and resistors to autonomously short-circuit diodes in response to overvoltages, using an RC filter to manage high-frequency signals.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
Integrated circuit (IC) comprising an input/output cell (IOC) having a first signal terminal (E1) for receiving/transmitting a signal and having a second signal terminal (ND3) connected to a domain (DV) configured to operate under a supply voltage V0 and capable of withstanding a maximum voltage V1 greater than V0, wherein the input/output cell (IOC) has an array of N diodes connected in series between the second signal terminal (ND3) and a supply cold point (GND), said array having an overall threshold voltage greater than V1, and control means (M0, M2) connected between the first signal terminal (E1) and the diode array and configured to, in the presence of a voltage V2 on the first signal terminal (E1) greater than the voltage V1, automatically and autonomously short-circuit at least one of the diodes (D3, D4) so as to limit the voltage on the second signal terminal (ND3) to a value V3 less than V1.