Voltage Clamp Circuit for EOS Protection Against PVT Variations
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Semiconductor devices face reliability issues due to electrical overstress (EOS) caused by thermal, electromigration, and electric field-related factors, particularly in high voltage and multiple power domain circuits, where process-voltage-temperature (PVT) variations and load changes make it difficult to maintain safe voltage levels, leading to potential failures.
Innovation Solution
An on-chip voltage clamp circuit is designed using a reference voltage module and a voltage clamp module with active elements and programmable current sources to provide a clamped voltage that is resistant to PVT and load variations, ensuring the voltage across sensitive semiconductor device terminals remains within safe limits without excessive design cost.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional voltage clamping methods are used, then voltage protection is provided, but the clamping voltage varies due to PVT and load variations
Solution Approach 1:
The voltage clamp module uses feedback mechanisms where the reference voltage module continuously monitors and adjusts the clamping voltage to compensate for PVT variations and load changes, maintaining accurate voltage levels despite environmental and operational fluctuations
Solution Approach 2:
The circuit dynamically adjusts electrical parameters such as reference voltage levels and current source values to compensate for process, voltage, and temperature variations, ensuring the clamping voltage remains within safe limits across different operating conditions
2Device complexity
If fixed clamping voltage is used, then circuit protection is simplified, but the circuit cannot adapt to different circuit requirements
Solution Approach 1:
The voltage clamp module incorporates programmable current sources that can be configured through control signals to adjust the clamping voltage level dynamically, allowing the same circuit to serve multiple applications with different voltage requirements without hardware changes
Solution Approach 2:
The reference voltage module and voltage clamp module are designed as universal building blocks that can be programmed to provide appropriate clamping voltages for different circuit types and protection requirements, making the design applicable across multiple scenarios
3Measurement precision
If complex voltage clamp circuits are used, then accurate clamping voltage is achieved, but design cost increases
Solution Approach 1:
The voltage clamp circuit is divided into two independent but coordinated modules: a reference voltage module that generates stable reference voltages and a voltage clamp module that applies clamping action. This segmentation allows each module to be optimized independently while working together to achieve accurate protection
Solution Approach 2:
The reference voltage module acts as an intermediary between the power supply and the voltage clamp module, providing stable reference voltages that enable the clamp module to achieve accurate clamping without requiring complex circuitry, thus simplifying the overall design while maintaining precision
Data Source
AI summary
A voltage supply for providing a clamped voltage to a circuit element to be protected against electrical overstress (EOS) has a reference voltage module and a voltage clamp module. The reference voltage module has a first field-effect transistor (FET) whose source and drain are connected in series between a programmable reference current source and a first resistor across a power supply. The gate of the first FET is connected to its drain to provide a reference voltage defined by the reference current flowing in the first resistor. The voltage clamp module has a second FET whose gate receives the reference voltage and whose source is connected to provide to the protected circuit element the clamped voltage whose variation is limited by the reference voltage.