Flyback Power Supply Regulation via Auxiliary Winding Feedback
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Solution Overview
Problem
Existing flyback power supplies face challenges in maintaining constant voltage and current regulation across varying load ranges without ancillary secondary feedback components, particularly in addressing line input voltage-dependent primary current overshoot.
Innovation Solution
The implementation of a primary side regulated (PSR) flyback power converter that utilizes error signals derived from the characteristics of the voltage waveform in the auxiliary primary winding to modulate the frequency and amplitude of the primary current waveform, ensuring constant voltage and current regulation through on/off control of a switch in series with the primary winding, independent of line input voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional secondary feedback components (optocoupler or auxiliary winding) are used for voltage regulation, then output voltage regulation is achieved, but device complexity and power consumption increase
Solution Approach 1:
The patent extracts the feedback function from the secondary side and implements it on the primary side by sensing the auxiliary winding voltage directly at the primary controller. This eliminates the need for optocouplers and secondary reference voltages, reducing component complexity while maintaining regulation accuracy
Solution Approach 2:
The auxiliary winding serves multiple functions: it provides the feedback signal for voltage regulation, supplies power to the primary controller, and enables current sensing. This multi-functionality eliminates the need for separate feedback and power supply components
2Speed
If peak current mode control is used for fast response, then dynamic regulation improves, but line voltage-dependent current overshoot occurs
Solution Approach 1:
The patent implements feedback by sensing the auxiliary winding voltage waveform characteristics (peak voltage, timing) and using this information to regulate the primary current. This feedback mechanism allows the controller to adjust the current waveform dynamically, preventing overshoot while maintaining fast response
Solution Approach 2:
The patent changes the control parameters from fixed peak current thresholds to dynamically adjusted parameters based on the sensed auxiliary winding voltage characteristics. This allows the current waveform to adapt to line voltage variations, eliminating overshoot while preserving fast response capability
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 efficient regulation of output voltage and current, reducing power consumption and eliminating line voltage-dependent primary current overshoot, while providing robust regulation capabilities without the need for secondary feedback components.
Implementation Method 1
Characteristics of a voltage waveform generated in an auxiliary primary winding of a flyback transformer
Implementation Method 2
The PSR apparatus modulates the frequency of subsequent conduction cycles and/or the amplitude of the primary current waveform via on/off control of a switch in series with the primary winding
Data Source
AI summary
Apparatus and methods disclosed herein are associated with a primary side voltage and/or current regulator (PSR) in a flyback power converter. Apparatus and methods sense characteristics of a waveform generated in an auxiliary primary winding of a flyback transformer at a single terminal of the PSR. The waveform is analyzed, and error signals derived therefrom are used to maintain constant voltage and/or constant current regulation and to generate a peak current stabilization signal that is independent of line input voltage.