ESD Clamp RC Trigger Circuit Intermediate Voltage
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Solution Overview
Problem
Conventional ESD protection devices using low-voltage devices are unable to reliably withstand high-voltage signals, posing a risk to integrated circuits with different voltage requirements, such as 1.8-V and 3.3-V FETs, which can lead to damage from electrostatic discharge events.
Innovation Solution
An area-efficient ESD clamp incorporating an RC trigger circuit with low-voltage, thin-oxide devices connected to an intermediate supply voltage, allowing them to operate reliably at higher voltages by connecting the source and drain to an intermediate supply voltage node, thereby streamlining manufacturing and ensuring fast response times to ESD events.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If low-voltage devices are used in ESD protection circuits, then manufacturing is simplified and area is reduced, but the devices cannot reliably withstand high-voltage signals
Solution Approach 1:
An intermediate voltage node is introduced between the high-voltage ESD event and the low-voltage thin-oxide devices. The RC trigger circuit detects high-voltage ESD events and generates trigger signals at the intermediate voltage level, which then control the shunt switch. This intermediary voltage level allows low-voltage devices to operate safely while still providing high-voltage protection.
Solution Approach 2:
The operating voltage parameter of the protection circuit is dynamically changed based on the detected ESD event. During normal operation, the circuit operates at low voltage to preserve thin-oxide devices. Upon detecting an ESD event through the RC trigger circuit, the voltage parameter changes to high voltage to activate the shunt path and divert the ESD current.
2Area of moving object
If thin-oxide devices are used, then device area is reduced and manufacturing is streamlined, but the devices are more susceptible to damage from high-voltage ESD events
Solution Approach 1:
The RC trigger circuit is configured to detect ESD events before they can damage the thin-oxide devices. The circuit performs preliminary detection and triggers the shunt switch in advance to divert the harmful ESD current, preventing damage to the area-critical thin-oxide devices.
Solution Approach 2:
The intermediate voltage node acts as a mediator that isolates the thin-oxide devices from direct exposure to high-voltage ESD events. The RC trigger circuit and shunt switch controlled by intermediate-voltage signals create a protective barrier, allowing thin-oxide devices to maintain their small area while being protected from high-voltage damage.
3Reliability
If conventional high-voltage devices are used for ESD protection, then reliability against ESD events is improved, but device area increases and manufacturing complexity increases
Solution Approach 1:
The ESD protection circuit is segmented into distinct functional blocks: the RC trigger circuit for detection, the intermediate voltage node for signal conditioning, and the shunt switch for current diversion. This segmentation allows each block to be optimized independently, enabling the use of compact thin-oxide devices while maintaining high-voltage protection capability.
Solution Approach 2:
The RC trigger circuit serves multiple functions: it detects ESD events, generates trigger signals at the appropriate voltage level, and controls the timing of the shunt switch activation. This multi-functionality reduces the need for separate dedicated components, thereby reducing overall device area while maintaining reliable ESD protection.
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 RC trigger circuit enables low-voltage devices to effectively protect integrated circuits from high-voltage signals by generating trigger signals at an intermediate supply voltage, facilitating the use of low-power devices and preventing damage from ESD events, while maintaining uniform performance across different oxide thicknesses.
Implementation Method 1
The RC trigger circuit comprises a resistive element and a thin-oxide MOS capacitor connected in series between the first and second circuit nodes
Implementation Method 2
The MOS capacitor has a source and drain connected to an intermediate supply voltage between the first and second voltage
Data Source
AI summary
Some embodiments relate to an area efficient electrostatic discharge (ESD) clamp comprising an RC trigger circuit, having one or more low-voltage, thin-oxide devices, which is configured to operate with a high-voltage power supply. In some embodiments, the ESD clamp comprises an RC trigger circuit connected between a first circuit node having a first voltage and a second circuit node having a second voltage. The RC trigger circuit comprises a resistive element connected in series with a thin-oxide MOS capacitor. The MOS capacitor has a source and drain connected to an intermediate supply voltage between the first and second voltage, and a body connected to the second voltage. By connecting the source and drain to the intermediate supply voltage, the thin-oxide MOS capacitor is able to reliably operate with a high-voltage power supply.