Adjustable Over-Voltage Protection Circuit for ICs
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Solution Overview
Problem
Conventional over-limit protection circuits for integrated circuits often require redesign to adjust trigger conditions, compromising between ESD and latch-up protection, and are 'hard-wired' and non-modifiable after fabrication, lacking flexibility in handling different over-limit electrical conditions.
Innovation Solution
A protection circuit with a shunt circuit and trigger circuit, where the trigger circuit can adjust trigger conditions using a control circuit to provide a current path for over-voltage protection, featuring adjustable snapback characteristics to handle various over-limit conditions, including ESD and latch-up, by modulating resistance and voltage levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional over-limit protection circuits are designed with fixed trigger conditions, then the circuit structure is simple, but the adaptability to different over-limit conditions (ESD and latch-up) is poor
Solution Approach 1:
The patent implements a control circuit that dynamically adjusts the trigger condition of the protection circuit based on operational parameters. The trigger condition is no longer fixed but can be modulated in real-time to adapt to different over-limit conditions such as ESD and latch-up, resolving the contradiction between fixed simplicity and adaptive versatility.
Solution Approach 2:
The patent changes the electrical parameters (trigger voltage, trigger current) of the protection circuit through a control circuit. By modulating these parameters dynamically, the circuit can adapt to different over-limit conditions without requiring multiple fixed circuits, thus improving versatility while managing complexity.
2Reliability
If the trigger condition is set to be sensitive for ESD protection, then ESD protection is improved, but false triggering during normal high-voltage operation occurs
Solution Approach 1:
The control circuit dynamically adjusts the trigger condition parameters based on the operational state. During normal high-voltage operation, the trigger condition is raised to prevent false triggering, while during ESD events, it is lowered to ensure effective protection. This dynamic parameter adjustment resolves the contradiction between sensitivity and stability.
Solution Approach 2:
The control circuit monitors operational parameters and provides feedback to adjust the trigger condition accordingly. This feedback mechanism ensures that the protection circuit responds appropriately to actual conditions, preventing false triggering during normal operation while maintaining high sensitivity for genuine ESD events.
3Reliability
If the protection circuit is designed to trigger at low voltage for maximum protection, then protection coverage is improved, but the circuit triggers during normal high-voltage operation
Solution Approach 1:
The patent employs a dynamic trigger condition that adapts to the operational voltage context. The control circuit adjusts the trigger voltage threshold based on the current operational state, allowing the circuit to provide maximum protection coverage when needed while maintaining versatility to operate under different voltage conditions without inappropriate triggering.
4Ease of manufacture
If conventional protection circuits are fabricated with fixed characteristics, then manufacturing is simple, but post-fabrication adjustment is impossible
Solution Approach 1:
The patent introduces a control circuit that enables dynamic adjustment of protection characteristics after fabrication. This allows the circuit to be reconfigured for different applications and conditions without requiring complex custom fabrication, thus maintaining manufacturing simplicity while adding post-fabrication adaptability.
Solution Approach 2:
The control circuit provides a universal interface for adjusting protection characteristics, allowing a single fabricated circuit to serve multiple functions and adapt to different applications. This multi-functionality approach maintains simple fabrication while enabling post-fabrication customization.
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 solution provides flexible and adaptive over-voltage protection that can effectively prevent damage from both ESD and latch-up conditions, ensuring the integrated circuit operates within safe voltage and current limits while maintaining high voltage requirements and low trigger currents, thus enhancing protection without redesign.
Implementation Method 1
the over-limit protection circuit provides a low-impedance conductive path from the node to a reference voltage, such as ground, to dissipate the over-limit electrical condition
Implementation Method 2
a snap-back characteristic provides a trigger condition which when exceeded, causes the circuit to enter a low-impedance state. The low-impedance state is maintained while the electrical condition on a node exceeds a hold condition
Data Source
AI summary
Apparatuses and methods for protecting a circuit from an over-limit electrical condition are disclosed. One example apparatus includes a protection circuit coupled to a circuit to be protected. The circuit to be protected is coupled to a pad node. The protection circuit is configured to conduct current from the pad node to a reference voltage node to protect the circuit from an over-limit electrical condition. The protection circuit has a trigger circuit coupled to the pad node and configured to trigger a shunt circuit to conduct current from the pad node to the reference voltage node responsive to a voltage provided to the pad node having a voltage exceeding a trigger voltage. In some embodiments, the trigger circuit is matched to the circuit being protected.