ESD Protection Circuit with Discharge Acceleration for Low-Power ICs
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Solution Overview
Problem
Integrated circuits in low-power processes are vulnerable to electrostatic discharge (ESD) due to lower supply voltages, which existing ESD protection circuits are unable to effectively manage, leading to potential damage from ESD events.
Innovation Solution
An ESD protection circuit incorporating a first n-type transistor, a discharge acceleration circuit, and a discharge time circuit, utilizing a resistance-capacitance (RC) time-constant circuit and inverters to control the discharge of ESD current, with additional transistors to enhance performance and speed up the discharge process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If conventional ESD protection circuits are used in low-power processes, then the circuit operates at lower supply voltages for power-saving, but the circuit becomes more vulnerable to ESD stress and cannot effectively conduct larger ESD discharge currents
Solution Approach 1:
The ESD protection circuit dynamically adjusts its operation mode based on the ESD event detection. The circuit transitions from a high-impedance state during normal low-power operation to a low-impedance discharge path when ESD is detected, allowing the same circuit to achieve both power-saving during normal operation and effective ESD protection when needed
Solution Approach 2:
The circuit changes its electrical parameters (impedance, current conduction capability) in response to ESD detection. By detecting voltage changes associated with ESD events, the circuit modifies its conduction characteristics to handle large discharge currents while maintaining low supply voltage operation during normal conditions
2Reliability
If the ESD protection circuit is designed to conduct larger ESD discharge currents, then ESD protection capability is improved, but the circuit complexity and chip area increase
Solution Approach 1:
The ESD protection circuit is designed to perform multiple functions: normal signal transmission, ESD detection, and ESD current discharge. By integrating these functions into a unified circuit structure rather than separate components, the design achieves effective ESD protection without proportionally increasing circuit complexity
Solution Approach 2:
The circuit employs detection circuits that act as intermediaries to sense ESD events and trigger the discharge mechanism. This intermediary detection layer allows the circuit to activate protection only when needed, avoiding the need for always-on complex protection structures that would increase static power consumption and circuit complexity
3Reliability
If the ESD discharge time is extended to ensure complete discharge, then ESD current is fully dissipated, but the voltage stress on the circuit persists longer and chip area increases
Solution Approach 1:
The circuit employs a fast discharge mechanism that rapidly dissipates ESD current through a low-impedance path. By creating a direct discharge path that bypasses normal circuit operations, the circuit achieves rapid ESD current dissipation in a short time window, minimizing voltage stress duration without requiring extended discharge periods
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
The proposed ESD protection circuit effectively manages ESD events by providing a discharge path for ESD current, reducing voltage stress on integrated circuits, and allowing for a smaller chip design through faster discharge times and enhanced protection mechanisms.
Implementation Method 1
a resistance-capacitance (RC) time-constant circuit
Implementation Method 2
a resistance-capacitance (RC) time-constant circuit
Implementation Method 3
Electrostatic discharge (ESD) is the sudden and momentary electric current that flows between two electric elements of different electrical potentials
Data Source
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AI summary
An electrostatic discharge (ESD) protection circuit includes a first n-type transistor, a discharge acceleration circuit and a discharge time circuit. The first n-type transistor has a first terminal coupled to a supply voltage, a second terminal coupled to a reference voltage, and a gate, wherein the first n-type transistor couples the supply voltage to the reference voltage during an ESD event at an I/O pad. The discharge acceleration circuit is coupled to the gate of the first n-type transistor to the I/O pad during the ESD event and coupled to the gate of the first n-type transistor to the reference voltage when there is no ESD event. The discharge time circuit, coupled to the discharge acceleration circuit and the supply voltage, controls a discharge time of the first n-type transistor of coupling the supply voltage to the reference voltage during the ESD event at the I/O pad.