Dual-mode operation controller for flyback converter with primary-side regulation

Abstract

Disclosed is a dual-mode operation controller in collocation with an input capacitor, a flyback transformer, a first primary-side switch, a second primary-side switch, a current-sensing resistor, a primary-side voltage-sensing unit, a secondary-side rectifier, and an output capacitor as a Primary-Side Regulation (PSR) flyback converter, which is dynamically controlled to operate in two operating modes, including Quasi-Resonant-Discontinuous Conduction Mode (QR-DCM) and Continuous Conduction Mode (CCM), in accordance with a loading condition so as to convert a unregulated DC input voltage source into a regulated DC output voltage source. The dual-mode operation controller has at least 5 pins, and the flyback transformer includes a primary-side winding, a secondary-side winding, and an auxiliary winding. The first primary-side and second primary-side switches are connected in series with the current-sensing resistor and placed at the low side of the primary-side winding, and the second primary-side switch is driven by the dual-mode operation controller.

Description

technical field [0001] The present invention relates to a dual-mode operation controller for a flyback converter, in particular, the dual-mode operation controller is used in conjunction with a flyback converter with Primary-Side Regulation (PSR) to dynamically control the flyback converter. Flyback converter, so that in the relatively light load range, the flyback converter is operated in discontinuous conduction mode (DCM) and optimizes light load conversion efficiency by minimizing the main switching loss; or, flyback When the converter is in a relatively heavy load range, it operates in continuous conduction mode (CCM) and optimizes the heavy load conversion efficiency by minimizing the main conduction loss, thereby optimizing the power conversion efficiency over the entire load range . Background technique [0002] Different electrical / electronic devices operate at specific operating voltages. For example, integrated circuits (ICs) are typically powered with 5V, 3V, o...

AI Technical Summary

Problems solved by technology

The first type of problem is that the switching elements on the primary side are hard-switched and have high switching losses

The second type of problem is that soft-switched flyback converters always operate in DCM to maintain valley switching, and thus suffer from higher conduction losses

Accordingly, neither Type 1 nor Type 2 can achieve the best of both worlds while simultaneously reducing switching loss and conduction loss

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