Voltage Fluctuation Detection Circuit Using Rising Edge Trigger
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Solution Overview
Problem
Existing switching power supply controllers face challenges in accurately detecting AC line voltage fluctuations, which is crucial for determining when to start or stop operation to prevent damage from excessive voltages, and adding digital circuits to analog ICs increases costs.
Innovation Solution
A voltage fluctuation detection circuit that includes a rising edge trigger circuit and a detection and output circuit, using a voltage divider, comparator, and latch circuit to detect voltage changes and generate control signals based on consecutive clock periods, allowing the IC to operate only at the rising edge of the AC line.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If digital circuits are added to analog ICs to detect AC line voltage fluctuations, then detection accuracy is improved, but IC cost and complexity increase
Solution Approach 1:
The patent replaces complex digital voltage detection circuits with a simplified analog circuit implementation. The rising edge trigger circuit uses basic analog components (comparators, resistors, capacitors) to detect voltage fluctuations, eliminating the need for complex digital processing circuits while maintaining detection accuracy.
Solution Approach 2:
The patent extracts only the essential detection function needed for voltage fluctuation detection, removing unnecessary complex digital processing components. The detection focuses specifically on rising edge voltage changes above a threshold, extracting only the critical information needed for accurate detection without requiring full-spectrum digital analysis.
2Measurement precision
If complex detection circuits are used to accurately detect voltage fluctuations, then detection accuracy is improved, but manufacturing cost increases
Solution Approach 1:
The patent employs inexpensive analog components (standard comparators, resistors, capacitors) that can be easily manufactured and integrated into the IC process, replacing expensive digital processing units. These simple analog components are mass-producible and significantly reduce manufacturing costs while maintaining sufficient detection accuracy for the application.
Solution Approach 2:
The patent changes the detection approach from digital parameter analysis to analog voltage threshold comparison. By detecting voltage fluctuations through simple threshold-based analog comparison rather than complex digital parameter analysis, the circuit achieves accurate detection with minimal components, thereby reducing manufacturing complexity and cost.
3Speed
If the detection circuit responds to every voltage change, then detection speed is improved, but false detection increases
Solution Approach 1:
The patent implements a preliminary threshold check before triggering detection output. The rising edge trigger circuit first compares the voltage change against a preset threshold voltage, and only when the change exceeds this threshold does it generate a detection output. This preliminary filtering action prevents false detections from minor voltage fluctuations while maintaining rapid response to significant changes.
Solution Approach 2:
The detection and output circuit incorporates feedback mechanisms to monitor and validate detection signals. By continuously monitoring the output signal patterns and comparing them against expected characteristics, the circuit can distinguish between genuine voltage fluctuations and noise, thereby reducing false detections while maintaining fast response times.
Data Source
AI summary
The present disclosure provides a voltage fluctuation detection circuit, which includes a rising edge trigger circuit and a detection and output circuit connected to an output terminal of the rising edge trigger circuit. When a change of the operating voltage within a preset clock period is greater than a preset bias voltage, an output signal of the output terminal undergoes at least one target flip between a high level and a low level. When the output signal of the rising edge trigger circuit always undergoes the target flips in N consecutive preset clock periods, and the operating voltage is always not less than a starting threshold value in each target flip of all the target flips in the N consecutive clock periods, the detection and output circuit generates an first signal, where N is a natural number not less than 2.