Feedback Terminal Inspection in Power Supplies to Prevent Overvoltage
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Solution Overview
Problem
Conventional power supply devices fail to prevent overvoltage conditions when the feedback terminal is abnormal, such as due to open or short circuits in the resistors, leading to potential damage to the load.
Innovation Solution
Incorporating a terminal inspection circuit that detects abnormalities in the feedback terminal during startup and forcibly stops the switching drive of the output stage to prevent overvoltage conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a feedback terminal is used to control output voltage, then the output voltage can be regulated to a target value, but the system becomes vulnerable to overvoltage conditions when the feedback terminal is abnormal
Solution Approach 1:
The patent implements a startup inspection period during which the feedback terminal voltage is monitored before normal operation begins. This preliminary detection mechanism identifies abnormalities in the feedback terminal (such as open or short circuit conditions) before they can cause overvoltage damage, allowing the system to prevent operation or alert users before reliability issues arise
Solution Approach 2:
The patent introduces an intermediate detection mechanism that monitors the feedback terminal voltage during startup to distinguish between normal operating conditions and abnormal conditions. This intermediary inspection layer acts as a mediator between the feedback control system and the output stage, preventing direct transmission of abnormal feedback signals that could cause overvoltage
2Productivity
If the power supply device operates continuously without inspection, then productivity is maintained, but abnormalities in the feedback terminal can cause overvoltage and potential damage
Solution Approach 1:
The patent implements periodic inspection at specific intervals (particularly during startup phases) without disrupting continuous operation during normal phases. The inspection occurs periodically at critical transition points while allowing uninterrupted operation during stable phases, thus maintaining productivity while periodically eliminating harmful overvoltage risks
3Device complexity
If no inspection mechanism is added to detect feedback terminal abnormalities, then device complexity remains low, but the system cannot prevent overvoltage conditions
Solution Approach 1:
The patent adds a relatively simple preliminary inspection mechanism that operates only during startup before normal continuous operation begins. This preliminary action detects feedback terminal abnormalities using basic voltage comparison circuitry during a brief inspection period, providing overvoltage prevention capability without significantly increasing overall device complexity or affecting normal operation
Solution Approach 2:
The patent implements inspection during specific critical periods (startup phase) rather than continuous monitoring throughout all operation. This partial inspection approach provides sufficient protection against overvoltage conditions at critical moments without the complexity and resource requirements of continuous monitoring, achieving adequate reliability with minimal added complexity
Data Source
AI summary
A power supply control device includes a feedback terminal, a feedback control circuit, and a terminal inspection circuit. The feedback control circuit is configured to control an output stage of a power supply device according to a feedback voltage applied to the feedback terminal. The terminal inspection circuit is configured to forcibly stop driving the output stage when it is detected that the feedback voltage is lower than a first threshold and an output current flowing through the output stage is higher than a second threshold during a first period at start-up, or when it is detected that the feedback voltage is lower than the first threshold at completion of the first period.