Power Converter Feedback Timing for Accurate Output Voltage Sensing
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Solution Overview
Problem
Existing power converters using auxiliary windings for output voltage feedback experience inaccuracies due to fast variations in secondary side current, leading to potential circuit faults.
Innovation Solution
A power converter system with a transformer, main power switch, and feedback control circuit that includes a voltage detect circuit, timing circuit, and delay circuits to accurately sense the output voltage by delaying the feedback signal based on calculated or fixed time lengths, depending on the converter's state.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the feedback voltage is sensed immediately after being pulled high, then the feedback control responds quickly, but the feedback voltage becomes inaccurate due to fast variations in secondary side current
Solution Approach 1:
The patent applies preliminary action by performing a delay operation on the feedback voltage signal before it is used for control. The delay circuit delays the feedback voltage for a calculated time length since the time point that the feedback voltage is pulled high, which allows the secondary side current to stabilize before sampling, thereby improving measurement precision while maintaining acceptable response speed
Solution Approach 2:
The patent implements dynamics by making the delay time length adaptive rather than fixed. The delay time is calculated based on the actual operating conditions of the power converter, allowing the system to dynamically adjust the sampling timing to optimize between response speed and measurement precision under different operating conditions
2Device complexity
If a fixed delay time is used for feedback voltage sampling, then the circuit operation is simple, but the feedback accuracy deteriorates under varying operating conditions
Solution Approach 1:
The patent applies parameter changes by making the delay time length a variable parameter that changes according to operating conditions. The timing circuit calculates the delay time length based on the duration that the feedback voltage is higher than a reference voltage, allowing the system to adapt to different operating conditions and maintain high measurement precision without excessive complexity
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
Ensures accurate feedback control of the output voltage, reducing the risk of circuit faults by providing precise regulation and protection mechanisms.
Implementation Method 1
a transformer having a primary winding, configured to receive an input voltage; a second winding, configured to provide an output voltage to a load
Implementation Method 2
a third winding, configured to generate a feedback voltage indicative of the output voltage
Data Source
AI summary
A power converter with accurate output voltage feedback is discussed. The power converter has a feedback control circuit to sense a feedback voltage indicative of the output voltage at a time point after a calculated time length since the feedback voltage is pulled high. The calculated time length is generated by timing a duration that the feedback voltage is above a reference voltage.