Auxiliary Winding Voltage Sampling for Converter Control
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Solution Overview
Problem
There is a need for an efficient method to communicate the voltage level of an output voltage from the secondary side to the primary side in switched-mode voltage converters that utilize a transformer, as existing solutions fail to effectively control the output voltage without accurate voltage sensing across the transformer.
Innovation Solution
A method and circuit that involve sampling the voltage across an auxiliary winding inductively coupled with the transformer, evaluating samples before the auxiliary voltage reaches a predefined threshold, and generating an output signal to control the duty cycle of the switching element, allowing for precise control of the output voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If the auxiliary winding voltage is sampled continuously, then voltage level communication is improved, but loss of time increases due to extended sampling duration
Solution Approach 1:
The patent implements periodic action by sampling the auxiliary winding voltage at specific periodic intervals synchronized with the switching element's operation. The control circuit samples the voltage during defined time windows in each switching cycle, ensuring adequate voltage level communication while minimizing the total sampling duration and avoiding continuous sampling overhead.
2Productivity
If sampling is performed after the switching element assumes its first operation state, then productivity is improved, but measurement precision deteriorates due to voltage threshold effects
Solution Approach 1:
The patent applies preliminary action by performing the voltage sampling at a precisely timed moment within the switching cycle - specifically, during the period after the switching element assumes its first operation state but before the auxiliary winding voltage reaches the predefined threshold. This timing ensures both productivity (sampling occurs during the active switching phase) and measurement precision (voltage threshold effects are avoided).
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
This approach enables accurate communication and control of the output voltage, ensuring efficient operation of the voltage converter by effectively sensing and adjusting the voltage level across the transformer.
Implementation Method 1
the auxiliary winding is inductively coupled with the transformer
Data Source
AI summary
A method for sensing an output voltage in a voltage converter includes at least one switching element and a transformer. A voltage is sampled across an auxiliary winding or a signal obtained from the voltage across an auxiliary winding in order to obtain a plurality of samples after the at least one switching element has assumed a first operation state and until the auxiliary voltage reaches a predefined threshold. The auxiliary winding is inductively coupled with the transformer. At least one sample obtained is evaluated before the auxiliary voltage reaches the predefined threshold.