ESD Clamp Circuit With Assist Gating for Lower Turn-On Resistance
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Solution Overview
Problem
The miniaturization of integrated circuits (ICs) has increased their susceptibility to electrostatic discharge (ESD) events due to thinner dielectric thicknesses and lower dielectric breakdown voltages, leading to potential electronic circuit damage.
Innovation Solution
The integration of an ESD circuit that includes an ESD detection circuit, a clamp circuit with a first transistor, and an ESD assist circuit. The ESD assist circuit is configured to clamp a third voltage at the first voltage during an ESD event, controlling the gate potential of the first transistor and causing it to turn on, thereby discharging the ESD current in a forward ESD direction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If miniaturization is implemented to reduce device size and power consumption, then device functionality and integration density are improved, but susceptibility to electrostatic discharge damage increases due to thinner dielectric layers
Solution Approach 1:
The ESD protection circuit is pre-configured with detection circuits and clamp circuits that are activated before ESD damage can occur. The detection circuit continuously monitors voltage levels, and when an ESD event is detected, the clamp circuit is immediately activated to discharge the ESD current, preventing damage to the miniaturized circuit components.
Solution Approach 2:
The patent introduces an intermediary ESD protection circuit between the external environment and the miniaturized IC components. This protection circuit includes detection circuits that sense ESD events and clamp circuits that provide a controlled discharge path, acting as a mediator that protects the sensitive miniaturized components from direct ESD exposure.
2Volume of moving object
If dielectric thickness is reduced to enable miniaturization, then device size and power consumption are improved, but dielectric breakdown voltage decreases leading to lower ESD tolerance
Solution Approach 1:
The ESD protection mechanism is prepared in advance with detection circuits monitoring voltage levels across the thin dielectric layers. When voltage approaches breakdown levels, the system preemptively activates clamp circuits to discharge the energy before dielectric breakdown occurs, protecting the miniaturized structure.
Solution Approach 2:
The patent dynamically changes electrical parameters by activating different clamp circuits based on detected voltage levels and ESD event characteristics. The system adjusts gate potentials and discharge paths in real-time to match the specific ESD conditions, optimizing protection for the thin dielectric structure.
3Reliability
If conventional ESD protection circuits are used in miniaturized devices, then ESD protection is provided, but the protection circuits occupy valuable chip area and increase device complexity
Solution Approach 1:
The ESD protection functionality is merged with the existing circuit structures. Detection circuits are integrated into signal paths, and clamp circuits share nodes and connections with functional circuits wherever possible. This merging approach provides ESD protection while minimizing the additional area required for dedicated protection structures.
Solution Approach 2:
The ESD protection circuits are designed to serve multiple functions: voltage detection, ESD clamping, and normal operation biasing. The same circuits and components are used for both ESD protection and standard circuit operation, eliminating the need for separate dedicated protection structures and reducing overall chip area.
4Speed
If faster ESD response is achieved by reducing transistor turn-on resistance, then ESD discharge speed is improved, but capacitive coupling effects increase affecting circuit operation
Solution Approach 1:
The patent applies different quality characteristics to different parts of the ESD protection system. The clamp circuit transistors are optimized with low turn-on resistance for fast ESD discharge, while detection circuits and associated nodes are designed with controlled capacitance to minimize coupling effects. This local differentiation allows fast protection response without excessive capacitive interference.
Solution Approach 2:
The system dynamically changes transistor parameters during ESD events. Gate potentials are adjusted in real-time to optimize the balance between turn-on resistance (for fast discharge) and capacitive coupling (for circuit stability). The detection circuit monitors voltage levels and adjusts clamp circuit parameters to achieve optimal ESD protection with minimal impact on normal circuit operation.
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 solution effectively reduces capacitive coupling effects and lowers the turn-on resistance of the first transistor, resulting in improved ESD performance and robustness compared to other approaches.
Implementation Method 1
discharge an ESD current of the ESD event in a forward ESD direction from the second node to the first node
Data Source
AI summary
An electrostatic discharge (ESD) circuit includes a first ESD detection circuit, a first discharging circuit and a first ESD assist circuit. The first ESD detection circuit is coupled between a first node having a first voltage and a second node having a second voltage. The first discharging circuit includes a first transistor. The first transistor has a first gate, a first drain, a first source and a first body terminal. The first gate is coupled to the first ESD detection circuit by a third node. The first drain is coupled to the first node. The first source and the first body terminal are coupled together at the second node. The first ESD assist circuit is coupled between the second and third node, and configured to clamp a third voltage of the third node at the second voltage during an ESD event at the first or second node.