Power Supply Control Circuit with Peak-Detection and Over-Voltage Protection
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Solution Overview
Problem
Conventional power supply control circuits fail to accurately protect the power supply due to voltage ripple in the input voltage, which affects precise comparison and control of the switching signal, thereby reducing the safety and efficiency of the power supply.
Innovation Solution
A control circuit with a peak-detection circuit and protection circuit that generates a peak-detection signal to accurately detect AC input voltage peaks, utilizing a sample-hold circuit to eliminate voltage ripple and an over-voltage protection circuit to generate a reset signal for reducing the output of the power supply when necessary.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a filter capacitor is used to filter the input voltage, then the voltage ripple is reduced, but the response time to detect AC input voltage peaks is delayed
Solution Approach 1:
The patent divides the voltage filtering function into two separate paths: one path uses a filter capacitor to provide a ripple-free voltage for accurate comparison, while the other path directly detects the AC input voltage peaks without filtering. This segmentation allows each path to optimize for its specific function without compromising the other.
Solution Approach 2:
The patent introduces an intermediary peak detection circuit that captures the peak voltage information from the AC input voltage before it reaches the filter capacitor. This intermediary circuit transfers the peak detection function to a separate pathway, allowing the main filtering path to focus on providing stable comparison voltage.
2Reliability
If the input voltage is filtered to remove voltage ripple, then the safety and reliability of the power supply is improved, but the efficiency and responsiveness of the control circuit is reduced
Solution Approach 1:
The control circuit is segmented into two independent functional paths: a filtering path that ensures safety by removing voltage ripple for reliable comparison, and a direct detection path that maintains efficiency by quickly responding to AC input voltage peaks. This segmentation resolves the contradiction between safety and efficiency.
Solution Approach 2:
The peak detection circuit performs preliminary action by detecting and capturing the peak voltage information before the voltage signal undergoes filtering. This preliminary detection ensures that the control circuit can respond efficiently to voltage changes while the filtered voltage provides reliable comparison data.
3Device complexity
If a conventional filter capacitor is used for input voltage filtering, then the circuit complexity is minimized, but the measurement precision of voltage comparison is insufficient due to remaining voltage ripple
Solution Approach 1:
Instead of using a complex multi-stage filter to achieve precise voltage comparison, the patent segments the function into a simple filter capacitor for basic ripple reduction and a separate peak detection circuit for precise peak voltage measurement. This segmentation achieves high measurement precision while keeping the filtering circuit simple.
Data Source
AI summary
A control circuit with protection circuit for power supply according to the present invention comprises a peak-detection circuit and a protection circuit. The peak-detection circuit detects an AC input voltage and generates a peak-detection signal. The protection circuit comprises an over-voltage protection circuit. The over-voltage protection circuit generates an over-voltage protection signal in response to the peak-detection signal. The protection circuit generates a reset signal to reduce the output of the power supply in response to the over-voltage protection signal. The present invention can protect the power supply in response to the AC input voltage effectively through the peak-detection circuit.