ESD Protection Circuit with Switched Supply Decoupling
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Solution Overview
Problem
Conventional ESD protection circuits suffer from voltage instability and mutual coupling between I/O nodes during ESD events, which can damage sensitive components by transferring disturbances from the I/O node to the supply node.
Innovation Solution
An ESD protection circuit comprising a clamp circuit coupled between an ESD bus and a ground node, a switch element between a supply node and the ESD bus, and a detection circuit that controls the switch element to decouple the ESD bus from the supply node during an ESD event, ensuring voltage stability by isolating disturbances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a coupling path is formed from I/O node to supply node in conventional ESD protection circuit, then the ESD bus can be stabilized, but disturbances from I/O node transfer to supply node causing voltage instability and damaging sensitive components
Solution Approach 1:
The patent introduces a switch element as an intermediary between the ESD bus and supply node. This switch acts as a controllable mediator that can be opened during ESD events to block disturbance propagation, while remaining closed during normal operation to maintain voltage stability. The detection circuit detects ESD events and controls the switch element accordingly, implementing the intermediary principle to resolve the contradiction between ESD protection and voltage stability.
Solution Approach 2:
The patent implements a dynamic coupling path by using a controllable switch element that changes its state based on detected ESD events. During normal operation, the switch is closed to maintain the coupling path for voltage stability. When an ESD event is detected, the switch opens to disconnect the coupling path and prevent disturbance propagation. This dynamic adjustment resolves the contradiction by adapting the system configuration to operational conditions.
2Stability of the object's composition
If the switch element is opened to isolate ESD disturbances from the supply node, then voltage stability is maintained, but the ESD bus becomes decoupled from supply node requiring additional control circuitry
Solution Approach 1:
The patent implements a feedback mechanism where the detection circuit monitors the ESD bus for ESD events and provides control signals to the switch element based on the detected conditions. This feedback loop enables automatic response to ESD events, opening the switch to isolate disturbances while maintaining voltage stability during normal operation. The feedback principle resolves the contradiction by automating the control process and reducing the need for complex external control circuitry.
Data Source
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AI summary
The invention provides an ESD (Electrostatic Discharge) protection circuit (110, 120, 130) including a clamp circuit (110), a switch element (120), and a detection circuit (130). The clamp circuit is coupled between an ESD bus (EB) and a ground node. The switch element is coupled between a supply node (NVDD) and the ESD bus. The detection circuit is configured to detect whether an ESD event occurs. When no ESD event occurs, the detection circuit closes the switch element, such that the ESD bus is coupled to the supply node. When the ESD event occurs, the detection circuit opens the switch element, such that the ESD bus is decoupled from the supply node. Fig. 1