Load Switch Short-Circuit Protection With Staged Current and VOUT Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Load switches face challenges in designing effective short circuit protection while maintaining a low power and low surface area design, especially when dealing with widely varying load conditions.
Innovation Solution
The implementation of a short circuit protection circuit that includes a current limiting circuit, an over-current protection (OCP) circuit, and an output voltage (VOUT) clamp, which work together to regulate the output current and voltage, providing comprehensive protection against short circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a power switch operates as a load switch with widely varying load conditions, then the switch can handle different load types (inductive loads, capacitive loads, etc.), but the switch becomes vulnerable to short circuits that can damage the device
Solution Approach 1:
The protection mechanism is segmented into three distinct circuits: a current limiting circuit with first threshold, an over-current protection circuit with second threshold, and a VOUT clamp circuit with third threshold. Each circuit operates independently at different threshold levels to provide comprehensive protection while maintaining adaptability to various load conditions.
Solution Approach 2:
The patent employs multiple threshold parameters (first threshold for current limiting, second threshold for OCP, third threshold for VOUT clamp) that can be independently configured. These parameter changes allow the single power switch to adapt to widely varying load conditions while maintaining reliable short circuit protection through staged response levels.
2Reliability
If comprehensive short circuit protection circuits are added to protect the power switch, then the reliability improves, but the device complexity and surface area increase
Solution Approach 1:
The patent merges three protection functions (current limiting, over-current protection, and output voltage clamping) into a unified protection system that operates through coordinated threshold comparisons. This combining approach provides comprehensive protection while reducing overall circuit complexity compared to implementing three separate protection mechanisms.
Solution Approach 2:
The protection circuit is designed with multi-functionality, where a single integrated protection mechanism handles current limiting, over-current protection, and voltage clamping through different threshold levels. This universal approach reduces device complexity and surface area while maintaining comprehensive short circuit protection.
3Reliability
If protection circuits are designed to handle short circuits effectively, then the reliability improves, but the transient response speed may be reduced
Solution Approach 1:
The current limiting circuit operates proactively at a first threshold level to prevent current from reaching dangerous levels during transient conditions. By taking preliminary action before full short circuit conditions develop, the system maintains fast transient response while ensuring reliability through staged protection.
Solution Approach 2:
The VOUT clamp circuit provides preliminary anti-action by clamping the output voltage at a third threshold to prevent voltage spikes during transient events. This preemptive voltage clamping counteracts potential harmful effects before they can damage the power switch, maintaining both fast response and high reliability.
Data Source
AI summary
In some examples, this description provides for an apparatus. The apparatus includes a power switch having a power switch source configured to receive an input voltage, a power switch drain, and a power switch gate. The apparatus also includes a current sense component coupled to the power switch. The apparatus also includes a current limiting circuit coupled to the power switch gate, the power switch drain, and the current sense component. The apparatus also includes an over-current protection (OCP) circuit coupled to the power switch source, the power switch drain, and the power switch gate. The apparatus also includes an output voltage (VOUT) clamp coupled to the power switch drain and the power switch gate.