A novel constant current and constant voltage adaptive blanking regulation scheme for primary-side controlled flyback converter

Abstract

Primary-side regulation (PSR) scheme is widely used in low cost and low power applications such as the cell phone charger or LED lighting. However, a major disadvantage of PSR is that the feedback signal in the control loop is not accurate enough. So it is hard to obtain better regulation either for the output voltage or for the output current. In this paper, a novel constant current and constant voltage regulation scheme with adaptive blanking method is proposed. It can acquire accurate detection cycle by cycle with low standby power loss. Moreover, in order to eliminate the influence of transformer leakage inductance on the control loop, related factors of primary-side control are analyzed in detail. To verify the efficiency of the proposed constant current and constant voltage (CCCV) adaptive blanking method, a dedicated primary-side controller integrated in a power integrated chip (IC) is fabricated. The experimental results demonstrated the prototype based on the proposed IC has excellent regulation performance.