Primary-Side Feedback Voltage Control for High-Power Converters

The patent implements primary-side feedback control by sensing the primary side current, integrating it to obtain average voltage, comparing it with a reference voltage, and adjusting the duty cycle accordingly. This feedback mechanism enables the controller to maintain stable output voltage under varying load conditions without requiring complex secondary-side circuitry, thus resolving the contradiction between circuit simplicity and voltage regulation stability.

The system uses the primary side winding itself to generate the feedback signal through current sensing and integration, eliminating the need for separate sensing components on the secondary side. The primary side current waveform contains the necessary information for voltage regulation, allowing the system to self-regulate without external assistance, thereby maintaining both simplicity and stability.

The patent employs dynamic conduction mode selection that adapts to load conditions. The controller automatically transitions between discontinuous conduction mode (DCM) for light loads and continuous conduction mode (CCM) for heavy loads based on the primary side current characteristics. This dynamic adaptation allows the simple primary-side feedback control to efficiently handle both low-power and high-power applications, expanding the power range while maintaining circuit simplicity.

The system changes its operational parameters (conduction mode) based on load requirements. By monitoring the primary side current waveform and switching between DCM and CCM operations, the controller optimizes performance across different power levels. This parameter change strategy enables the same simple control circuit to achieve both low-power efficiency and high-power capability without increasing complexity.