Power Transistor Overload Recognition for Input Transients
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Solution Overview
Problem
Existing protection mechanisms for power transistors fail to accurately distinguish between input and output stimulated stressing conditions, leading to unnecessary shutdowns or inadequate protection.
Innovation Solution
A power supply system with a state machine and detectors to differentiate between input transients and output short circuits, using a combination of voltage and current monitoring to control the power transistor's operation accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the electronic fuse responds solely based on current magnitude regardless of origin, then protection against excessive output currents is provided, but unnecessary shutdowns occur when current excess originates at the input side
Solution Approach 1:
The protection mechanism is segmented into two independent detection paths: one monitoring input voltage transients and another monitoring output current conditions. This segmentation allows the system to identify the origin of current excess and apply differentiated responses, preventing unnecessary shutdowns while maintaining reliable protection.
Solution Approach 2:
A transient detector acts as an intermediary component that monitors input voltage conditions and provides information to the control logic. This intermediary enables the system to distinguish between input-side and output-side current causes, allowing appropriate response selection without unnecessary shutdowns.
2Reliability
If multiple detection mechanisms are implemented to distinguish between input and output stimulated conditions, then protection accuracy is improved, but device complexity increases
Solution Approach 1:
The control logic unit serves multiple functions: it receives inputs from both the transient detector and overcurrent detector, processes this information, and generates appropriate control signals for the power transistor. This multi-functionality consolidates what could be separate complex circuits into a single integrated control unit.
Solution Approach 2:
The transient detection circuit and overcurrent detection circuit are merged into a unified protection system with a common control logic unit. This combination allows the system to achieve high protection accuracy through multiple detection mechanisms while avoiding the complexity of completely separate protection systems.
Data Source
AI summary
Disclosed herein is circuitry for protecting a power supply system from overcurrent conditions by monitoring an input voltage and an output voltage of the power supply system, detecting an overcurrent condition based on the monitored input and output voltages, and determining whether the overcurrent condition is caused by an input transient or an output short circuit. When the detected overcurrent condition is caused by an input transient, a gate of a power transistor is controlled to maintain current flow to a load. When the detected overcurrent condition is caused by an output short circuit, the power transistor is turned off to protect the power supply system.