MOS Switch ESD Protection with Clamp Circuits
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Summary
Problems
Existing bi-directional MOS-based switches face challenges in protecting against electrostatic discharge (ESD) and hot-plug events, which can cause damage and require effective protection mechanisms.
Innovation solutions
A bi-directional MOS-based switch arrangement incorporating first and second clamp circuits with transistors and diodes to provide ESD protection, clamping terminal-to-terminal voltages, and ensuring the MOS switch is self-protected by shorting its body to the source terminal during transient events.
TRIZ Analysis
Specific contradictions:
General conflict description:
Principle concept:
If a bi-directional MOS-based switch is used, then the switch can operate bidirectionally with low on-resistance, but the switch becomes vulnerable to electrostatic discharge and hot-plug events
Why choose this principle:
The patent introduces intermediary protection circuits between the MOS switch and the external environment. These circuits include clamp circuits with Zener diodes and transient voltage suppression networks that act as mediators to capture and dissipate voltage transients before they reach the MOS switch, thereby protecting the switch from ESD and hot-plug events while maintaining its bidirectional operation
Principle concept:
If a bi-directional MOS-based switch is used, then the switch can operate bidirectionally with low on-resistance, but the switch becomes vulnerable to electrostatic discharge and hot-plug events
Why choose this principle:
The protection circuits are designed to activate before voltage transients can damage the MOS switch. Zener diodes are selected with breakdown voltages slightly above the normal operating voltage, creating a cushioning effect that absorbs excess voltage energy through controlled breakdown, preventing direct exposure of the MOS switch to harmful voltage spikes
Application Domain
Data Source
AI summary:
A bi-directional MOS-based switch arrangement incorporating first and second clamp circuits with transistors and diodes to provide ESD protection, clamping terminal-to-terminal voltages, and ensuring the MOS switch is self-protected by shorting its body to the source terminal during transient events.
Abstract
A switch arrangement comprising: a bi-directional metal-oxide-semiconductor, MOS, switch having a drain, source and gate and a body; a first circuit coupled between the drain, the gate and the source for providing electrostatic discharge protection; a first transistor having a source coupled to the body of the MOS switch, a drain coupled to the source of the MOS switch and a gate coupled to the gate of the MOS switch; and a second circuit for providing electrostatic discharge protection comprising a first diode of Zener diode type having an anode coupled to the body of the MOS switch and a cathode coupled to the source, and a second transistor having a source coupled to the body of the MOS switch, a drain coupled to the source of the MOS switch and a gate coupled to the anode of the first diode.