Voltage Converter Resistor Aging Detection
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Solution Overview
Problem
Traditional flyback power converters rely on opto-couplers for electrical isolation, which are temperature-sensitive, and face issues with dynamic voltage stability due to voltage-dividing resistor aging, leading to abnormal output voltages.
Innovation Solution
A voltage converting apparatus with a transformer circuit, feedback circuit, and control circuit that includes a disturbance element to detect abnormality in the voltage-dividing resistor by generating a detection voltage during the off period of the switch, allowing for over and low output voltage protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a voltage-dividing resistor network is used in the feedback circuit to maintain dynamic stability of output voltage, then the output voltage stability is improved, but the reliability deteriorates due to resistor aging causing abnormal output voltage
Solution Approach 1:
The control circuit performs resistance detection during the off-period of the power switch to proactively identify aging resistors before they cause output voltage abnormalities. By detecting resistance values in advance and comparing them against threshold ranges, the system can take preventive actions such as adjusting feedback coefficients or triggering protection mechanisms, thus resolving the contradiction between maintaining voltage stability and ensuring long-term reliability.
2Reliability
If primary-side sensing methods are used to replace opto-couplers, then the temperature sensitivity issue is resolved, but the ability to detect voltage-dividing resistor aging deteriorates
Solution Approach 1:
The control circuit introduces an intermediary detection mechanism that indirectly measures the resistance values of voltage-dividing resistors by injecting test signals during the off-period and measuring the resulting voltage divisions. This intermediary approach allows the primary-side sensing method to not only replace temperature-sensitive opto-couplers but also simultaneously detect resistor aging through the same control circuitry, resolving both the temperature stability and detection capability requirements.
3Measurement precision
If the control circuit continuously monitors the feedback voltage to detect resistor aging, then the detection accuracy is improved, but the energy consumption and device complexity increase
Solution Approach 1:
The control circuit implements periodic resistance detection during the off-period of the power switch rather than continuous monitoring. By utilizing the natural off-period when the switch is already non-conducting, the system can inject test signals and measure resistance values without requiring additional continuous power consumption or complex dedicated monitoring circuitry. This periodic approach maintains high detection accuracy while minimizing added complexity and energy usage.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Effectively determines voltage-dividing resistor aging and provides protection against abnormal output voltages, ensuring dynamic stability and preventing damage to connected devices.
Implementation Method 1
The transformer circuit includes a primary-side coil and a secondary-side coil
Data Source
AI summary
A voltage converting apparatus is provided. A control circuit connects a disturbance element to a voltage-dividing resistor network to disturb a feedback voltage and generate a detection voltage during a resistance detection period, and determines whether the voltage-dividing resistor network is aging according to the detection voltage.